Electromagnetic Radiation and Human Health

How To Beat Electrical Sensitivity

This ebook is the complete guide to learning about electrical sensitivity and how to prevent getting it in your life. You will learn what electrical sensitivity is, and what causes it. Once you have started learning about it you will learn how to get rid of it and protect yourself from the dangers of electrical sensitivity. You will also learn how to heal yourself. This book is the product of careful research by the scientific and medical communities into the dangers and preventative measures of electrical sensitivity. ES is one of the most under-diagnosed conditions in the world right now, and this ebook is designed to education people as to how it works and how to prevent it. Do not let it take hold of your family; take control and prevent it now! Do not let yourself get any more hurt; learn about this condition and fight it! More here...

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Electromagnetic Radiation

Electromagnetic radiation may irritate the skin. The effects of short-wave ultraviolet irradiation present a good example of this type of irritation. Details on UV protection are presented in the chapter by Kutting and Drexler (pp. 87-97). Changes in small cutaneous vessels, particularly capillaries, represent the earliest damage induced in the skin by ionizing radiation in those individuals administering X-rays. Later the caliber of the vessels increases, accompanied by a reduced blood flow. In severer forms of skin damage, atrophy, teleangiectasia, keratoses and epitheliomas may develop. Of 819 subjects professionally exposed to ionizing radiation, 27 revealed light, 16 moderate, 18 severe and 12 very severe damage of the capillaries 44 . The adherence and migration of leukocytes through the endothelium of blood vessels is an important early event following ionizing irradiation. Intercellular adhesion molecule (ICAM) 1, vascular cell adhesion molecule 1 and CD31 are membrane...

Electrical and Electromagnetic Fields

The clinical effect of electrical and electromagnetic fields on enhancing stress fracture healing is not clearly defined by the literature. Most studies deal with their effect on delayed unions or nonunions and are not specifically designed to evaluate the efficacy on stress fractures. Two studies 41,42 often sited in support of electromagnetic field treatment were unblinded without controls. Compounding the confusion is the various options in which a current may be directed to the fracture site. The modalities of bone-growth stimulation available include direct-current stimulation with percutaneous or implanted electrodes, electromagnetic stimulation by inductive coupling using time-varying magnetic fields, and capacitive-coupling stimulation using electrodes placed on the skin. Sharrard 44 , in 1990, published a study on pulsed electromagnetic fields on delayed tibial unions. The trial took place over a 12-week period and had a successful union rate of 45 in the treated group...

Ionizing Radiation

Ionizing radiation induces a variety of different types of DNA alterations, including nucleotide-base alterations and breaks in the sugar-phosphate backbone (Schwartz, 1995). Normally, cells handle these base alterations and singlestrand breaks very well using base excision repair processes. Base excision repair is an error-free process that removes damaged bases and then takes advantage of an intact complementary strand to fill in missing information. Defects in excision repair can lead to mutagen sensitivity and cancer susceptibility (see also the section The Molecular Basis of Cell and Tissue Organisation). For X-rays, about one in 10-20 breaks span both strands of the DNA molecule. This ratio of double-to single-strand breaks increases with increasing LET. DNA double-strand breaks can form directly as a result of radiation exposure, or can develop during excision repair due to the formation of overlapping gaps. DNA double-strand breaks are repaired by homologous and nonhomologous...

Clinical Presentations

Radiation exposure greater than 50 Gy to the posterior fossa was associated with a higher likelihood of developing hearing impairment, probably due to irradiation of the cochlea and shunting procedures (refer to the chapter 8 by Landier et al.). Con-formal radiation therapy may reduce such risks in future survivors. Packer et al. reported seizure disorders in 25 of patients, including 6.5 who had a late first occurrence. Exposure of any cortical segment of CNS to 30 Gy or more was associated with a two-fold elevated risk for a late seizure 16 .

PET and fMRI Procedures

However, PET has no time resolution. 15O-water, the radiotracer used for activation studies, has a half-life of 2 min. Due to the long integration time of each scan, only block designs are possible. Scans of active tasks and control tasks are separated by periods of no acquisition, lasting 10 min, to allow a complete return to baseline of the activations and a complete decay of the radiotracer. Typically 8 to 12 scans are acquired, with 2 to 4 repetitions of each task. The main limitation of PET is the radiation exposure, particularly for women of fertile age and children, which limits repeated testing, and the need of a cyclotron nearby, with a high cost.

Performance and Quality Control of the MomTc Generator

99Mo 99mTc generators produced for worldwide application have a sophisticated system for safe elution of the daughter radionuclide. The generator column is well shielded with lead, and the whole system must be adequately shielded to reduce radiation exposure of the operator to a permissible level (Fig. 5.1).

Specific Chemotherapeutic Agents

Agents, including ionizing radiation, and expression of the receptor in a cancer is often associated with an aggressive neoplasm that is resistant to chemotherapy (Mendelsohn and Fan 1997 SchmidtUllrich et al. 2000). The formation of blood vessels necessary for tumor growth is dependent on angiogenic factors such as VEGF, and inhibitors have been shown to improve the efficacy of irradiation (Teicher et al. 1995 Mauceri et al. 1998).

Electroencephalogram And Magnetoencephalogram

From an electrofunctional point of view, the activity of the brain essentially translates into (1) wave-formed electromagnetic fields or potentials, which constitute the electroencephalogram and the magnetoen-cephalogram and (2) transient changes in the electromagnetic fields caused by nerve impulses induced by external stimuli or independent mental events, which constitute the event-related potentials (ERPs) and event-related fields (ERFs), respectively. It is not the aim of this review to discuss the electroencephalogram (EEG). The reader interested in the EEG and the rhythmical waves that distinguish it, as well as its origins in the cerebral cortex or in processes regulating these waves (pacemaker) in the thalamic nuclei, is referred to the excellent works by Buzsaki (1991) and Silberstein (1995a,b), as well as the impressive review by Nunez et al. (2001).

Spectroscopic Techniques 331 Background and Survey

Spectroscopy has been defined 1 as the study of the interaction of electromagnetic radiation with matter, excluding chemical effects (i.e., photochemistry). The origin of the field has its roots in the detection of black body radiation by Planck in 1900, which was later recognized by Einstein (in 1905) and others as due to the release of photons (E hv) by matter. This led ultimately to the first atomic and then molecular spectra and an understanding of how matter absorbs and releases energy in quantized packets of energy.

Heterogeneity in Senescence

Modification of chromatin by inhibitors of histone deacetylases also induces a senescent phenotype (Ogryzko et al. 1996). Oxidative stress, ionizing radiation, and other DNA-damaging agents can also induce the senescent phenotype without any detectable telomere shortening (Dumont et al. 2000, Herskind and Rodemann 2000, Jeyapalan et al. 2004, Robles and Adami 1998). Therefore, it is sometimes assumed that all early-occurring senescence might be both stress-induced and telomere-independent and thus premature. In other words, in any given cell culture experiment, most cells would senesce by a process that is altogether different from telomere-driven senescence, which would happen only in the last surviving clone. However, telomere shortening is by itself distinctly stress-dependent (von Zglinicki 2002), suggesting an alternative explanation for cell-to-cell heterogeneity in replicative senescence.

But everyones brain functions similarly

A simple example may demonstrate how an aspect of the physical world can help us understand an aspect of the mental, even though it does not explain the mental phenomenon entirely. We know that light is a form of electromagnetic radiation, with different colors corresponding to different frequencies of this radiation. The radiation is the physical aspect of light, while the mental aspect involves the different colors we see. Nothing in our knowledge of electromagnetic radiation can explain the blueness of blue or the redness of red. These are essentially mental properties and will remain so no matter how much we know about the physical structure of light. But knowing the structure of the radiation can help us understand the structure of our color vision. The fact that blue and green look more similar to each other than red and green is explained quite simply by the fact that the frequencies corresponding to blue and green are closer to each other than the frequencies corresponding to...

What Are the Plans to Perform Epidemiology and Monitoring

Plans exist to monitor indicators for a number of physiological changes in International Space Station (ISS) astronauts. These include measurements of bone density change, radiation exposure, orthostatic intolerance, and cardiac atrophy after missions longer than 30 days. Muscle atrophy will be monitored as part of a program of countermeasure testing, and the capability for in-flight monitoring of psychological status is planned. There are, however, a number of factors that may limit the usefulness of the collected data. Much of the data is collected for medical operations purposes and will not be accessible to the scientific community, nor in many cases do there appear to be plans even within the clinical program to systematically analyze and interpret the data. In addition, it is not clear that in every discipline the techniques best suited to the measurement, such as the use of magnetic resonance imaging (MRI) to measure cardiac mass, will be used on a routine basis.

Transcriptioncoupled NER

Cells of a rare genetic disease, Cockayne syndrome (CS), are defective in TCR, but proficient in GGR of UV-induced DNA damage. Affected individuals suffer from postnatal growth failure resulting in cachectic dwarfism, photosensitivity, skeletal abnormalities, mental retardation, progressive neurological degeneration, retinopathy, cataracts and sensorineural hearing loss. Two complementation groups, CS-A and CS-B, have been identified and the corresponding genes have been cloned. The cellular phenotype of CS includes increased sensitivity to a number of DNA-damaging agents including UV radiation, ionizing radiation and hydrogen peroxide (Friedberg, 1996).

Cell cycle transitions in early Xenopus development

Xenopus oocytes and embryos undergo two major maternally controlled cell-cycle transitions oocyte maturation and the mid-blastula transition (MBT). During maturation, the essential order of events in the cell cycle is perturbed in that the M phases of Meiosis I and II occur consecutively without an intervening S phase. Use of U0126, a new potent inhibitor of MAPK kinase (MEK), shows that MaPk activation is essential to inhibit the anaphase-promoting complex and cyclin B degradation at the MI MII transition. If MAPK is inactivated, cyclin B is degraded, S phase commences and meiotic spindles do not form. These events are restored in U0126-treated oocytes by a constitutively active form of the protein kinase p90Rsk. Thus all actions of MAPK during maturation are mediated solely by activation of p90Rsk. At the MBT, commencing with the 13th cleavage division, there are profound changes in the cell cycle. MBT events such as maternal cyclin E degradation and sensitivity to...

Prediction of ovarian damage

The ability to measure the likely toxic impact of chemotherapy and radiation exposure regimes on the ovaries of pre- and post-pubertal girls would enable us to predict how such treatments will affect the future reproductive lifespan and fertility of these individuals (Singh, Davies and Chatterjee 2005). Tests of ovarian damage must assess the number of primordial follicles present in the ovary (the ovarian reserve) rather than the number of more advanced growing follicles and mature oocytes, as the later stages of follicle and oocyte development are less likely to survive the treatment. Hundreds of thousands of primordial follicles are present in the ovaries of young patients (Gougeon, Echochard and Thalabard 1994) of these follicles only 400-500 would ovulate during the reproductive lifespan of a woman. The usual fate of the vast majority of the follicles present in the ovary is therefore degeneration through a process termed apoptosis (Gosden and Spears 1997). There is, therefore, a...

The DNA damage checkpoint

Genetic and biochemical evidence in yeast and mammalian cells has indicated that the DNA damage checkpoint has overlapping components with the DNA replication checkpoint, and recent evidence implicates polo-like kinases in the DNA damage checkpoint (Sanchez et al 1999). Moreover, the response to DNA damage (double-stranded DNA breaks) is different in G1 and G2 phase, with the latter response targeted at Cdc25 as described above. To assess the ontogeny of the DNA damage checkpoint, this laboratory embarked several years ago on a study of the effect of ionizing radiation on Xenopus development, comparing effects before and after the MBT. In mammalian cells, ionizing radiation in G1 phase activates transcription and or stabilization of p53, which leads to either cell cycle arrest (allowing time for repair of damage) or apoptosis if damage is extensive or Initial studies showed that ionizing radiation given any time before the MBT had no effect on cleavage or cell cycle timing, but...

Protecting the ovaries

Evidence suggests that it is possible to shield vulnerable organs such as the ovaries from the damaging effects of cancer treatments. The ovaries can be surgically moved out of the direct path of radiation exposure. Ovarian transposition can be to an alternative location in the abdomen or to a heterotopic site such as the forearm (Oktay and Karlikaya 2000). While this ovarian transposition has been used in adults with limited success, it is not a long-term solution for the preservation of fertility in younger patients.

Indications for CardiovascularMDCT

Echocardiography remains the imaging technique of choice for the initial assessment of young subjects with suspected congenital heart disease, as it provides anatomical and functional information in real time. Echocardiography is non-invasive, portable, relatively inexpensive, and does not use ionizing radiation. Extra-cardiac structures, however, may not be easily visualized, due to the limited ultrasound window, especially in older subjects. Cardiac catheterization with projectional angiography has been used to define anatomy not well shown by echocardiography and to assess haemodynamic status. However, imaging the great vessels of the thorax is often limited by the presence of overlapping adjacent vascular structures and the difficulty of demonstrating systemic and pulmonary vascular systems simultaneously. Furthermore, the procedure is invasive and relatively high doses of ionizing radiation and iodated contrast material may be required.

What Causes Thyroid Cancer

As discussed in the previous chapter, it is well known that radiation exposure to the thyroid gland, particularly a young child's thyroid gland, predisposes the child to develop thyroid cancer in later years. Papillary thyroid cancer is the most common type. (Types of thyroid cancer will be explored later in this chapter.) Research is revealing that the chromosomes of thyroid cells are organized in a particular structural pattern in the nucleus (or center) of thyroid follicular cells. When radiation inside the cell strikes the nucleus, it causes particular breaks and rearrangements in the chromosomes that result in a greater chance that the cells will eventually become cancers. Unfortunately, known exposures to radiation seem to account for only a small portion of the thyroid cancers seen every year.

Near infrared spectroscopy

The region of the electromagnetic spectrum associated with NIR is broadly that covering 800-2500 nm (Fig. 7.1). The region from 800-1100 nm is often referred to as the near visible and represents energy having wavelengths just slightly longer than those generally seen as red by the human eye. The use of this region is primarily in those instruments used to determine the proportion of light transmitted through food materials. There is some debate

Conclusions and future trends

The use of spectroscopic approaches for texture measurement may at first seem counter-intuitive to many readers as many of these techniques have traditionally been seen as tools to probe the chemistry of materials rather than their physical structures. Nevertheless, certain regions of the electromagnetic spectrum allow the interaction of light with the physical structure of the material to be quantified relatively easily. Both the visible and near infrared regions contain relevant information for this purpose as has been demonstrated by many of the papers cited in this chapter.

Pathophysiologic Changes Induced by Cytotoxic Therapy

Dence suggests that damage to the type II pneumo-cyte and to the endothelial cell is closely linked to the pneumonitic process 99,137,138,147 . The type II pneumocyte, which produces surfactant and maintains patent alveoli, has been well studied. After radiation exposure a rapid decrease in the content of cytoplasmic surfactant-containing lamellar bodies occurs, followed by the ultimate sloughing of some of the cells into the alveolar lumen 97, 98 . Changes in the surfactant system that lead to alterations in alveolar surface tension and low compliance are most likely a direct result of the radiation 99, 118, 119 , although it has been postulated that the changes indirectly result from exudation of plasma proteins 47 . Endothelial cell damage results in changes in perfusion and permeability of the vessel wall. Endothelial leakage and increased permeability allow immune cells to undergo transendothelial migration and extravasation from the vascular compartment into the alveolar space.

Personal Characteristics

Because the incidence of most cancers increases rapidly with age, exceptions to this pattern may have aetiological significance. Acute leukaemia, for example, shows both an early and a late peak, which led investigators to consider intrauterine carcinogenesis. The subsequent discovery that intrauterine exposure to ionizing radiation may increase the risk of childhood leukaemia provided empirical support to this hypothesis. Similarly, the bimodal incidence pattern of Hodgkin disease in many countries (Figure 5) led to the prevailing hypothesis that the early peak is due to an infectious agent. Finally, the slowing of the rate of increase of the incidence of breast cancer after menopause has underlined the importance of ovarian oestrogens in the aetiology of this disease.

High Dose Treatments for Aggressive Cancers

Some physicians tell their patients that there is a lifetime limit to the cumulative amount of I-131 that they can safely tolerate (sometimes as low as 600 millicuries). This is an example of a doctor's old wives' tale. Unfortunately, I've (Ken) seen too many references to this fictitious lifetime limit of I-131. There is absolutely no basis in reality for such a limit. Although you may find references to such a limit in some medical articles, careful research of this claim reveals that there is no data anywhere to support such a concept. In fact, I have treated patients to total cumulative doses of 2,000 to 3,000 millicuries without any significant ill effect from the treatment, aside from dysfunctional salivary glands. If the thyroid cancer is distantly spread and still is able to respond to radioiodine, then there is no reason to withhold therapy if it can be helpful. As long as dosimetry shows that each single I-131 dose is within the safety margins of 200 REM (a measure of...

Basic Principles and Techniques

Ultrasonography depends on the presence of sonographic windows, which allow sound wave propagation and detection of echo signals. These signals form the basic sonographic units for image generation. Therefore, as a general rule, US is indicated when visualization of the target object is not blocked by intervening bone or air, such as calvarium or bowel gas. This limitation does not completely negate the use of US in the evaluation of adult brain disorders, as discussed later. The usefulness of US as an imaging tool in pediatrics is particularly appealing owing to its inherent lack of ionizing radiation.

Risk Models And Protection Standards

There are a number of ways to model risk. Absolute risk refers to the number of cancers induced over spontaneous levels. Relative risk is a multiplicative increase over spontaneous. As cancer latency periods are generally long, time-dependent relative risk models are also used. With ionizing radiation, there are a number of other dependent variables that are considered in developing risk models. These include dose and (dose)2, age at exposure, time since exposure and gender. Risk estimate development for ionizing radiation is handled by the BEIR (Biological Effects of Ionizing Radiation) Committee in the USA and by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) for the United Nations. The NCRP (National Council for Radiation Protection) in the USA and the ICRP (International Commission of Radiation Protection) for the United Nations use BEIR UNSCEAR information to develop appropriate radiation protection standards. Total cancer mortality risks for a...

Summary And Conclusions

It has clearly been established that ionizing and UV radiation are both carcinogens. They represent the primary physical carcinogens in our environment and most efforts at reducing cancer risks are appropriately focused on these agents. There remain questions as to mechanisms of car-cinogenesis for ionizing radiation, and in particular the effects of low-level exposures. Most ongoing studies in this area are attempting to address these questions. The answers may have a profound effect on radiation protection standards. In contrast to ionizing and UV radiation, the evidence for an association between cancer and microwave and RF radiation, ultrasound or EMF exposure is weak and inconsistent. The levels of exposure to these types of radiation are increasing, as are the numbers of individuals exposed. There is also some uncertainty as to potential interactions between different types of radiation. Hence there are likely to be continuing investigations into the effects of these different...

Analytical Methodologies

NMR spectroscopy is based on the principle that hydrogen and carbon-13 atoms contain nuclei that can absorb energy when subjected to electromagnetic radiation in a strong magnetic field (through a process called magnetic resonance). Sweeping the magnetic field strength or electromagnetic radiation will produce a series of frequencies that can then be amplified and displayed as a series of signals. Although NMR can provide valuable structural information on a wide spectrum of metabolites, the sensitivity is significantly lower than MS, restricting it primarily to the analysis of the most abundant metabolites within samples. Furthermore, data acquisition time can be significantly longer than MS, limiting throughput to fewer than 10 samples per day. Analysis of intact tissues or whole surrogate tissues with NMR is possible however, interpretation of the resulting spectra can be very complicated, even with the best computational tools available. Ideally, NMR is best used as a complement...

Positron Emission Tomography PET and Single Photon Emission Computed Tomography SPECT orSPET

Because its short half-life (2 minutes) allows research subjects to be scanned several times in different cognitive states or doing various tasks. With all techniques involving ionizing radiation, however, there are limits on the total acceptable amount of radiation exposure for the subject.

Hematopoietic Stem Cell Ageing

It should be noted, however, that the case may be different in other experimental settings. For example, several forms of marrow toxins (chemotherapy, ionizing radiation) severely limit long-term HSC function and hasten stem cell exhaustion (Boccadoro et al. 2002, Gardner et al. 1997, Ito et al. 2004, Ito et al. 2006, Knudsen et al. 1999, Meng et al. 2003, Wang et al. 2006). Furthermore, as mentioned, certain strains of mice do not show expansion of the HSC compartment

Autosomal Recessive Inheritance

Ataxia and telangiectasias of the bulbar conjunctivae, malar eminences, ear lobes, and upper neck increased increased of respiratory infections, Iymphomas, Hodgkins disease, acute leukemia, and a variety of cancers thymus gland is hypoplastic or absent there is decreased IgA and IgG increased chromosomal breakage and increased sensitivity to ionizing radiation of fibroblasts and Iymphocytes

Balance of Ground and Flight Investigations

The overwhelming majority of radiobiological experiments are, and will be, carried out on the ground and, of necessity, will use animals. The flux rate of HZE particles in space is low, and although the particles, if not appropriately shielded, could over a long period of time produce deleterious effects in humans, the use of such radiation for radiobiological experiments on small vertebrates in space is impractical because it is not possible to transport an HZE accelerator into space. Some radiation experiments in space, using sparsely ionizing radiation, have been carried out on human lymphocytes, microorganisms, and the small roundworm Caenorhabditis elegans. The radiation sources used were radioisotopes emitting -particles. None of these experiments have shown any significant synergistic or antisynergistic effect of radiation and microgravity. Similar experiments on mice on the ISS would require an x-ray or y-ray source to irradiate animals at 1 g and at microgravity. Since there...

What Induces p16INK4a with Ageing

Given these results, the regulation of the INK4a ARF locus becomes a crucial question. In particular, a knowledge of what induces p16INK4a with ageing would in turn suggest the true molecular causes of why stem cells fail with age. The stimuli that activate these senescence-promoting pathways with ageing are not clearly elucidated and likely differ among species and tissue type (Fig. 9.4). Clearly, a wide variety of noxious stimuli induce p16INK4a in humans and mice, including ionizing radiation, reactive oxygen species, telomere dysfunction, and replicative stress (reviewed in Kim and Sharpless 2006, von Zglinicki et al. 2005). While Arf expression with ageing closely mirrors that of p16INK4a in rodents, in humans, ARF expression does not appear to increase as markedly. The molecular pathways that activate the INK4a ARF locus in response to such stresses are less well understood, although roles for E2F (Aslanian et al. 2004, DeGregori et al. 1997, Kotake et al. 2007) and MAP kinase...

Utilization and Validation of Animal Models

Other possible countermeasures, which are currently impractical, are (a) identification of individuals with high radiation resistance (b) the use of chemical radioprotectors (c) genetic methods to enhance the repair of radiation damage and (d) interventions following unexpected radiation exposures that might enhance repair or induce apoptosis of damaged cells. These countermeasures are among the low-priority research questions of the Strategy report. NASA in collaboration with the National Cancer Institute should stimulate research in these areas. Autologous bone marrow transplants have been used on Earth to counteract acute radiation exposure. The proposal, in the NASA Strategic Program Plan, to use this as a countermeasure (NASA, 1998, p. 24) is of questionable feasibility. Presumably, exposed individuals will have to return to Earth for the procedure.

Function And Proliferation

In the rat liver, use of DNA-damaging agents has been helpful for inducing liver repopulation with transplanted cells. Obviously, such liver injury should be insidious without precipitating acute liver failure. Use of the pyrollizidine alkaloid retrorsine, which alkylates DNA and inhibits proliferation in native hepato-cytes, has been extraordinarily effective for liver repopulation in the DPPIV- rat (Laconi et al., 1998). It is noteworthy that retrorsine induces extensive polyploidy in the rat liver, which is also induced by two-thirds partial hepatectomy and the thyroid hormone triiodothyronine (T3) (Sigal et al., 1999 Torres et al., 1999). Polyploid hepatocytes exhibit DNA damage with evidence for the activation of cell-aging events, increased apoptosis, and decreased proliferation capacity in vitro, as well as in vivo after transplantation into DPPIV- rats (Sigal et al., 1999 Gorla et al., 2001). Therefore, it should not be surprising that the combination of either partial...

Additional Information

The patient should be adequately hydrated before injecting 99mTc-MAG3. Insufficient hydration of the patient will affect the renal excretion rate. In order to reduce the radiation exposure to the bladder wall, the patient should be asked to drink water during the following hours.

Clinical Features

Primary squamous cell carcinomas of the salivary glands (PSSC) are rare, extremely aggressive neoplasms, the majority of patients presenting with advanced disease 384, 513 . In Spiro's review of 2,807 salivary gland tumors, PSSC accounted for only 1.9 23, 513 . Nine percent of patients have a history of prior radiation exposure 23, 131, 237, 355, 389, 513 .

Preservation of oocytes

Unlike secondary oocyte freezing, the technology of ovarian tissue banking involves freezing immature primordial follicles in situ in slices of ovarian cortex (Picton etal. 2000 Gosden etal. 1994 Newton etal. 1996). The harvesting and freeze-storage of ovarian tissue for oncology patients has proved surprisingly easy to do as the outer region of the ovarian cortex contains tens to hundreds or even thousands of primordial and primary follicles, depending on the mass of tissue and age of the patient (Faddy etal. 1992). Paradoxically, while primordial follicles are a more effective subject for tissue banking than secondary oocytes, animal studies have demonstrated that it is precisely this stage of follicle development that is most susceptible to the effects of ionizing radiation and alkylating agents (Meirow et al. 1999b). Furthermore, a number of studies, including a recent case report of human autografting (see Figure 5.1) after cryopreservation (Radford etal. 2001), suggest that the...

Radioactive Thyroid Tests

The low-iodine diet (see Chapter 20) is critical in all methods of scan preparation and can enhance the sensitivity of the scan around tenfold. This is because the cancer cells, stimulated by TSH, suck up iodine regardless of whether it is radioactive or non-radioactive. The amount of iodine in the average American diet exceeds the amount of iodine in the radioactive tracer dose by several hundredfold and can dilute the uptake of the radioactive iodine, making the scan much less effective for detecting tumor. Of course, it is important to avoid radiation exposure to a fetus in a pregnant woman and appropriate contraception is necessary to guard against this.

Predisposing factors to developing cancer

As society becomes more affluent, so the incidence of cancer can be demonstrated to rise. There could be a number of explanations for this, including increased wealth and improved health care enabling individuals to achieve a greater life expectancy than their grandparents (Gabriel, 2001). People are also surviving previously life-threatening illnesses, such as infectious diseases, major accidents, etc., only to live longer and possibly to develop cancer later in life. We also know that more affluent societies consume higher amounts of convenience foods, alcohol and tobacco, as well as being exposed to higher levels of chemicals and pollutants compared with people living in some less developed parts of the world. All these factors can contribute to an individual developing a malignancy (Venitt, 1978 Cartmel and Reid, 2000 Corner, 2001). Other factors can include past exposure to ionizing radiation, viruses and a genetic disposition (Cartmel and Reid, 2000 Yarbro, 2000a).

Formulation Of Aetiological Hypotheses

The rule of agreement focuses on common factors identifiable in different settings characterized by a high incidence of particular cancers. Thus, exposure to ionizing radiation was the common factor characterizing patients with ankylosing spondylitis therapeutically irradiated and children diagnostically X-rayed in utero, when both groups were found to have increased incidence of leukaemia. Also, multiplicity of sexual partners is the likely common factor characterizing women with squamous carcinoma of the uterine cervix and male homosexuals with anal cancer.

Protein Profiling With Antibody Arrays

Several laboratories have successfully proven the power of antibody microarrays by employing the two-color method to study protein profiling and post-translational modifications 40-48 . Sreekumar and colleagues discovered novel radiationregulated proteins by profiling proteins in LoVo colon carcinoma cells after treatment with ionizing radiation with arrays made up of 146 antibodies 40 . In order to decrease the effect of the bioconjugation bias towards particular proteins, oppositely labeled sample and reference protein extracts can be mixed and the normalized ratio values from two parallel experiments can provide more reliable information on profiling (see fig. 10.2A). In this way, differential expression was monitored by comparing deregulated pathways in hepatocellular carcinomas and normal liver protein samples with an array composed of 83 antibodies. Of the 33 proteins detected, 21 were up-regulated and 12 down-regulated in carcinoma biopsies from different patients 46 .

Introduction To Radiotherapy

RT involves the use of ionizing radiation in the treatment of malignant disease. Conventional external-beam treatments are administered with high-energy photon beams, typically with energy of 1.25 megaelectron volts (MV) to 15 MV or higher. These energies significantly exceed those of x-rays used in diagnostic radiology. The high energy of therapeutic radiation beams enables the treatment to penetrate the body and to be used to treat deep tissues. Depending on the actual energy, only several percent of the energy of the photon beam is absorbed per centimeter of tissue. Routine availability of high-energy radiation sources in the years after World War II dramatically increased the clinical usefulness of RT. Previously, only low-energy radiation sources, which emitted radiation that was absorbed to a significant extent by superficial tissues, were widely available. These low-energy beams required that an excessive (and often toxic) dose of radiation be delivered to the surface of the...

Sacral Stress Fractures

MRI may offer a way to evaluate bony anatomy and bony edema 13 . This method of diagnostic imaging has been used in several studies to detect sacral stress fractures 24 . MRI offers the absence of ionizing radiation. It is also advantageous in that it can define the anatomic location 24 . CT scans also can be used to stage the fracture line, which is why they are believed currently to be the gold standard for demonstrating details of bony morphology and osseous pathoanatomy 13 .

Units of Dose and Activity

Radiation exposure is usually expressed either as energy incident on a surface or energy absorbed per gram of tissue. For ionizing radiation (Table 2), the gray (Gy) is the Syst me Internationale (SI) unit of dose that is most Table 2 Ionizing radiation units often used. It is equal to 1 J kg An older term still in use is the rad, which is equal to 0.01 Gy. For ionizing radiation, the unit of absorbed dose does not take into account the differences in efficiency with which one type of radiation might act. Therefore, to describe exposures to different types of radiation, a dose equivalent is used. The dose equivalent is calculated by multiplying the absorbed dose by a quality factor that takes into account the biological effectiveness of the radiation. The quality factor for 60Co 7-rays is 1. For some energies of a-particles, the quality factor can be as high as 100. The original term used to compare radiation of different qualities was the rem (roentgen equivalent in man), which was...

Treatment Oesophagus Squamous Cell Carcinoma

The treatment of the late-stage oesophageal cancer that typically confronts the physician in most Western countries is more likely to be palliative than curable. Surgery may resect or bypass the tumour, ionizing radiation may be used to shrink or destroy it and chemotherapy may be used

Telomere Shortening and Organismal Aging

Of this hypothesis, increasing evidence links human premature aging syndromes and mouse models of premature aging with DNA damage-induced genome dysfunction. Mutant mice unable to repair accumulated DNA damages exhibit symptoms of premature aging and die early (Rudolph et al. 1999, Tyner et al. 2002, Cao et al. 2003, de Boer et al. 2002, Wong et al. 2003), suggesting that proper maintenance of genomic integrity is essential for longevity. Late-generation telomerase null animals display a subset of aging phenotypes, including alopecia, hair greying, a reduced stress response, and decreased longevity (Rudolph et al. 1999). These animals also exhibit elevated genomic instability, manifested as chromosomal fusions and increased cancer incidence. Enhanced sensitivity to genotoxic agents such as ionizing radiation and alkylating agents is also noted in late generation mTerc ' mice and derivative cell lines (Wong et al. 2000, Goytisolo et al. 2000, Lee et al. 2001), suggesting that...

The Simplest Modeling

The object of the present modeling is to find similar biological effects to the radiotherapy treatments with which we are familiar, from different scheduling of time and dose. That is the isoeffect modeling that has much history, passing through the cube root law of the 1930s, the Strandqvist slope of the 1940s, and the Nominal Standard Dose (NSD) or Time-dose Factor (TDF) of Dr Frank Ellis in the 1960s and 1970s - and then to evaluate methods of doing better. We shall start by writing down some ideas for explaining the non-linear action of ionizing radiation in damaging biological cells.

Quasiexperiments casecontrol studies and cohort studies

To test the hypothesis that 'childhood leukaemia and non-Hodgkin's lymphoma can be caused by fathers' exposure to ionising radiation before the conception of the child, and more generally, to investigate whether such radiation exposure of either patient is a cause of childhood cancer'. These included (a) parental employment as radiation worker before conception of child, (b) cumulative dose of external ionizing radiation for various of periods of employment before conception of child, and (c) dose during pregnancy.

MMR Apoptosis and Chemotherapy Resistance

The role of MMR in apoptosis signalling may have relevance for chemotherapy with DNA-damaging agents, because drug resistance may develop by loss of MMR function in a single selection step (Aebi et al., 1996). Loss of MMR may also confer resistance to low doses of ionizing radiation (Fritzell et al., 1997 DeWeese et al., 1998) (see review by Li (1999)).

Skin and Mucous Membranes

Skin and mucosa exhibit early epithelial damage and delayed permanent vascular injury that are dependent on the total radiation dose, the fraction size and the volume of irradiated tissue. Early radiation injury to the skin is directly attributable to the effect of ionizing radiation on the stratum germinativum cells 20 . Release of vasoactive substances results in increased capillary permeability and dilatation that

The Dna Replication Checkpoint

DNA damage during S phase normally causes temporary arrest of DNA replication. Proteins required for this checkpoint include ATM, Mre11, Rad50 and NBS1. Genetic defects occur in ATM (ataxia telangiectasia), NBS1 (Nijmegen breakage syndrome) and Mre11 (ataxia telangiectasia-like disorder) (see the chapter Inherited Predispositions to Cancer). In all three syndromes, DNA damage (e.g. by ionizing radiation) fails to arrest replication and leads to extensive chromosome damage (Petrini, 2000). Although the mechanistic details are not yet in, we know a few steps in the process. DNA damage causes phosphorylation of NBS1. This is required for replication arrest. ATM senses the DNA damage and carries out the phosphorylation of NBS1. The activity of JNK (c-Jun N-terminal kinase), which is normally stimulated in response to DNA damage, fails to respond in cells derived from patients having any of the three syndromes (see review by Petrini (2000)). Figure 6 includes the molecular interactions for...

Squamous Cell Carcinoma

Squamous cell carcinoma is the most common tumour arising on chronically sun-exposed sites. As such, it is typically detected on facial, extremity and trunk skin of older people. Except for lesions that develop on the lower legs, these tumours have a higher incidence in men than in women. Industrial carcinogens (tars and oils), chronic ulcers and draining osteomyelitis, old burn scars, ingestion of arsenicals, ionizing radiation and in the oral cavity tobacco and betel nut chewing, immunosuppression and genetic factors (xeroderma pigmentosum) are all implicated in the pathogenesis of squamous cell carcinoma, in addition to exposure to sunlight. In the case of tumours induced by sunlight exposure, endogenous melanin pigment is believed to provide an important photoprotective effect. UV radiation is believed to damage DNA by directly forming photoadducts, which contribute to cell mutation and altered proliferation. Normally, many such altered cells may be eliminated by...

Quantitative Research

To test the hypothesis that 'childhood leukaemia and non-Hodgkin's lymphoma can be caused by fathers' exposure to ionizing radiation before the conception of the child, and more generally, to investigate whether such radiation exposure of either patient is a cause of childhood cancer'. These included (i) parental employment as radiation worker before conception of child, (ii) cumulative dose of external ionizing radiation for various periods of employment before conception of child and (iii) dose during pregnancy.

Observational Studies

* Subjects would find it difficult to avoid cell phone use in a society where these tools are so popular and convenient. Also, those who would be able to avoid their use would still be exposed to the electromagnetic radiation of people nearby who used these phones. Additionally, it is unethical deliberately to expose subjects to interventions when there is prima facie evidence suggesting that they will suffer harm that exceeds any benefit of the intervention. It is useful to think of epidemiologists as good detectives who get only the toughest cases to solve. Many important studies and landmark research efforts (e.g. the Framingham analyses) are observational. These studies have been, and will continue to be, critical. What is the relationship between the heavy metal content of tooth fillings and the occurrence of disease in later life What is the relationship between silicone breast implants and autoimmune disorders The relationship between magnetic field exposure and cancer in...

Obstructing Tracheobronchial Tumors

The majority of patients presenting with lesions that obstruct the central airways all have tumors that are inoperable, because of mediastinal or lymph node involvement, or lesions that are too central for surgical resection. The most common primary lung tumor treated with the Nd YAG laser is squamous cell carcinoma, followed by adenocarcinoma (Figure 37-4 Color Plate 9 ).43 Many of these patients have failed radiation therapy and or chemotherapy (Table 37-4). Unlike ionizing radiation therapy, the laser may be used repeatedly for the palliation of malignant tracheobronchial obstruction.

Diagnostic And Staging Investigations

Magnetic resonance imaging does not involve the patient or staff being exposed to ionizing radiation. The patient lies on a couch within a powerful magnetic field and the field aligns the patient's hydrogen nuclei in one direction. Pulses of radio waves are used to disturb the magnetized nuclei and change their alignment. This results in images being generated, which are captured and analysed by a computer. This procedure is excellent for generating detailed images, especially of soft tissue structures. The procedure from the patient's perspective is not dissimilar to undergoing a CT scan (Yarbro, Frogge and Goodman, 2005).

Magnetic Resonance Imaging

Aconstant magnetic field, known as the static field, aligns all magnetically sensitive particles uniformly, so that perturbations can be detected. In clinical machines, this magnetic field is generally between 0.5 and 1.5 tesla (T) and in high-field research machines, it is either 3 or 4 T (as reference, the magnetic field of the earth is 0.0001 T). The perturbation is supplied by a second magnetic field, known as the pulse sequence, which is an oscillating electromagnetic field tuned to a set frequency (resonant frequency) of a particular substance, typically hydrogen atoms. The relaxation time, the time it takes for the protons to revert to their original state, is recorded through a radio frequency coil, also known as a receiver coil. Because hydrogen atoms in different substances have different relaxation times, distinct tissues, such as white matter and gray matter, can be differentiated. Information on where in the brain those substances are...

Dysrhythmia Conduction Abnormalities

Life-threatening arrhythmia and conduction disturbances are rare and occur years after radiation exposure. They are different from the frequent, asymptomatic, nonspecific and transient repolarization abnormalities seen shortly after irradiation 50 . Serious abnormalities reported after radiotherapy include atrioventricular nodal bradycardia, all levels of heart block - including complete heart block 103, 104 - and sick sinus syndrome 66,104 .In their case series report and review of the literature, Orzan et al. 103 reported that infranodal blocks were more common than nodal blocks, and that right bundle branch block was one of the most common abnormalities. Many, but not all, of the reports reviewed by Orzan, however, involved survivors who had received RT with techniques and doses no longer in use. Unfortunately, only a few prospective studies have reported the incidence of conduction abnormalities. In a study of 134 survivors of childhood cancer treated

Chemical Shift

Electromagnetic radiation causes the reorientation of spin-L 2 nuclei that have become aligned in external magnetic fields most efficiently when the product of Planck's constant and the frequency of the reorienting radiation equals the difference in energy between their two possible orientations, i.e. hv A E. That frequency, the resonant frequency, is the one at which the intensity of a resonance in a spectrum is maximum. The energy difference that determines a resonant frequency is the product of the strength of the orienting magnetic field a nucleus experiences and its intrinsic magnetic moment.

Rotating Frame

What is the B1 field and why must it be an oscillating electromagnetic field The Larmor frequency of a nuclear isotope is the resonance frequency of the isotope in the magnetic field. For example,1H Larmor frequency will be 500 MHz for all protons of a sample in a magnetic field of 11.75 T. If the Larmor frequency were the only observed NMR signal, NMR spectroscopy would not be useful because there would be only one resonance signal for all 1H. In fact, chemical shifts are the NMR signals of interest (details in section 1.7), which have a frequency range of kilohertz, whereas the Larmor frequency of all nuclei is in the range of megahertz. For instance, the observed signals of protons are normally in the range of several kilohertz with a Larmor frequency of 600 MHz in a magnetic field of 14.1 T. How the Larmor frequency is removed before NMR data are acquired, what the rotating frame is, why we need it, and how the bulk magnetization changes upon applying an additional electromagnetic...

Radiation

Ionizing radiation therapy produces biologically charged materials within the target tissue, which leads to DNA damage. While radiation therapy may lead to immediate cell death in some instances (as a result of the direct ionization of DNA), cell death is more commonly delayed until the cells attempt to move through mitosis. This loss of proliferative capacity eventually leads to tissue death within the irradiated field, ideally leading to death of the tumor target but sparing the normal tissue nearby. To achieve this effect it is helpful to think of the delivery of radiation therapy within a therapeutic window that is, a range in which the therapy will cause death of the tumor cell, but not produce unacceptable damage to the normal tissue of adjacent structures. This therapeutic window varies from site to site within the body, and, while the CNS is able to withstand significant doses of ionizing radiation, the window of acceptable normal tissue damage may be quite small....

Osteopenia

Osteopenia in cancer survivors may be unrecognized in the absence of fractures unless evaluation is performed. Serum osteocalcin and urine pyridinoline crosslinks or N-telopeptide do not identify whether there is low bone mineral density. Identification requires performance of either a dual-energy x-ray absorptiometry (DEXA), which offers precise estimates of bone mineral area density (mg cm2) at multiple sites for the least amount of radiation exposure, or a quantitative computerized tomography (QCT), which measures true volumetric density (mg cm3) of trabecular or cortical bone at any skeletal site. T-score may be calculated in reference to normal young adults (age of peak bone mass is between 20-35 years) and Z-score in reference to age-matched normal individuals of the same gender. Results of DEXA must be adjusted for patient height and age.

Assessments

Figure 3.2 shows a quantitative gait analysis in a normal subject for the timing and amplitude of elec-tromyographic (EMG) activation of muscle groups (3.2a), the ground reaction forces elicited (3.2b), and the joint angles at the hip, knee, and ankle (3.2c) during the step cycle (Dobkin, 2003a). Surface and wire electrodes are used for EMG data. Electrogoniometers, computerized video analysis with joint markers, and electromagnetic field motion analysis will reveal the kinematics in two or three dimensions. Kinetics are measured by a force plate in the ground or embedded in a treadmill, as well as by a load cell embedded in a shoe. Energy cost is also measurable by oxygen consumption studies. These procedures take considerable expertise, time, and equipment to perform and analyze. The numerous variables collected and their interactions demand special statistical and

Cancer

X-rays and related radiation are estimated to cause no more than 3 percent of cancers. Radon gas exposure is clearly a cause of lung cancer in uranium miners. If the concentration of radon in some homes were found to be sufficiently carcinogenic, presumably the proportion of known cases of radiation-caused cancer would increase substantially. Thyroid cancer results from small-to-moderate radiation exposure to the neck, with a latency period of about a decade. Bone marrow is another radiosensitive organ. Increased risk of leukemia begins as early as 2 years after radiation exposure, reaches peak probability after 6-8 years, and then diminishes.

System Overview

The basic components of an NMR spectrometer are shown in Figure 2.1(a), and include three major elements a magnet, console, and host computer. The working function of an NMR spectrometer is basically similar to a radio system. Some of the components are called by the terms used in a radio system, such as transmitter, synthesizer, and receiver. The magnet of an NMR spectrometer produces a stable static magnetic field which is used to generate bulk magnetization in an NMR sample. The linear oscillating electromagnetic field, Bi, (see Chapter 1), is induced by a transmitter with a desirable Bi field strength to interact with nuclei under study. The NMR signal, known as free induction decay (FID), generated in the probe coil after irradiation by radio frequency (RF) pulses is first amplified by a preamplifier, then detected by a receiver. This detected signal is digitized by an analog-to-digital converter (ADC) for data processing and display, which is done on a host computer.

Lymphedema

Chronic lymphedema due to surgery, radiation, or parasitic infection can lead to lymphangiosarcoma of the extremity. The most common clinical setting is the postmastectomy patient with lymphangiosarcoma of the ipsilateral upper extremity (Steward-Treves syndrome). While postoperative lymphedema alone can lead to lym-phangiosarcoma, it is much less common than in patients with lymphedema and a history of prior radiation exposure. Modern surgical and radiotherapeutic techniques have led to a decreased incidence of severe lymphedema of the extremity and subsequently, a decreased incidence of the disease.

Toxicant Exposure

There have already been multiple in vivo rodent studies, referred to earlier, demonstrating how gene expression profiles can be used to classify toxicant exposures in specific tissues such as liver. However, few studies have been conducted to determine whether accessible biospecimens such as peripheral blood lymphocytes (PBLs) can also be used in this way. Of those that have, the two most commonly reported models have been exposure of cell lines and ex vivo PBLs to ionizing radiation (IR). For example, Amundson et al. (2000) found that the induction of DDB2, CDKN1A, and XPC in human ex vivo PBLs showed a linear dose-response relationship between 0.2 and 2 Gy of IR at 24 and 48 h after exposure, but with less linearity at earlier or later times. Although the magnitude of mRNA induction generally decreased over time, the expression of many of these genes was still significantly elevated up to 72 h after irradiation. Gene expression changes also occur at low doses of IR (0.002 to 0.05...

Atrial Septal Defect

Haemodynamic assessment is also an important part of the evaluation of ASDs. Invasive catheterization has previously been used to accurately quantify left-to-right (L-R) shunts (Beerbaum etal., 2001). Quantification of L-R shunts using velocity-encoded phase-contrast MR compares well to invasive catheterization results. It has the benefits of being non-invasive, not requiring exposure to ionizing radiation and in certain situations being more accurate than invasive catheterization (Muthurangu et al, 2004). Ventricular overload can also be accurately assessed using multi-slice SSFP short-axis imaging (Fogel and Rychik, 1998) and can give important information regarding the timing of invasive intervention.

Dysplasia

The causes for morphological changes leading to dysplasias are only partially understood. Migrational abnormalities may be the consequence of altered cell-cell interactions but can also result secondarily from radiation exposure. Altered cell-cell interactions can be caused either by mutations in the genes coding for cell surface proteins or by environmental factors that change the expression of cell surface proteins. Neuronal differentiation is controlled by a plethora of factors including cell surface interactions, neurotrophins, cytokines, neurotransmitters and neuromodulators, and, last but not least, synaptic activity. Disruptions of any one, or any combination, of these factors may induce altered neuronal maturation. In addition to genetic mutations, aberrant neuronal migration and maturation may be caused by environmental factors, such as heavy metals (for example, lead) ethanol and other psychoactive drugs of abuse or gestational and perinatal insults, such as hypoxia and...

Cardiac Anatomy

There are two main disadvantages of MDCT compared with MR imaging. The first is the use of ionizing radiation. As explained above, this can be kept to a minimum, by using low kV, low mAs acquisitions, with current modulation, and image acquisition over the minimal area of interest. Using such protocols, our mean dose for non-cardiac gated cardiovascular MDCT in children is 1.2 0.57 mSv. This equates to approximately 60 chest radiographs (standard PA chest radiograph 0.02 mSv) or 6 months of background radiation exposure (UK average background radiation 2.2mSv year Royal College of Radiologists, 2003 Owens et al, 2005). Furthermore, in critically ill patients the ability to perform a rapid examination without the need for general anaesthesia or even sedation may be more crucial, as the risk of prolonged sedation may be greater than that of radiation (Siegel, 2003). The second disadvantage of current MDCT techniques is that easy quantification of cardiac function (at high heart rates)...

Preventative Therapy

The difficult issue in screening is that there is no definitive therapy. Before therapy, the prophylactic administration of steroids has no proven benefit and may present potential risks. A study of inhaled fluti-casone propionate, however, demonstrated some potential benefit with reduction of acute pneumoni-tis in patients treated for breast cancer 83 . Confirmation of this benefit and whether like interventions can reduce long-term pulmonary sequelae requires further study. The role of amifostine as a radiopro-tector in preventing lung toxicity has been investigated. Amifostine is a sulfhydryl compound that was originally developed as an agent to protect against ionizing radiation in the event of nuclear war 27, 121 . It was also found to protect normal tissues from toxicities of radiotherapy for head and neck tumors 15 ,alkylating agents and cisplatin 148,154 .Recent clinical studies have shown a reduction in pneumoni-tis using amifostine in chemoradiation treatments for lung...

Definitions

The amount of energy deposited in biological tissue, and therefore the types of changes seen in cells, depend on the nature of the radiation (Table 1). Ionizing radiation refers to those types of radiation that produce the ejection of an orbital electron from an atom or molecule and result in the formation of an ion pair. The ionization potential of most molecules in biological materials is 10-15 electronvolts (eV), so in order to be ionizing, the radiation must be able to impart at least that much energy. Ionizing radiation can be either electromagnetic (X-rays and 7-rays) or particulate (neutrons and a-particles). Energy loss varies with the Table 1 Examples of ionizing and non-ionizing radiation Table 1 Examples of ionizing and non-ionizing radiation Ionizing radiation ( > 10-15 eV) Nonionizing radiation (< 10 eV) The major mode of energy loss for radiation having energy of 1-10 eV (nonionizing radiation) is excitation. Excitation refers to elevation of an electron to a higher...

Sources of Exposure

Ionizing radiation exposure varies widely for different populations. In part, exposure levels depend on altitude and latitude. The atmosphere attenuates dose from extraterrestrial sources of radiation thus higher elevations receive greater doses of 7-rays from cosmic radiation. In the USA, the highest background exposures in a heavily populated area occur in Denver, which experiences about 0.25 mSv per year more than the US average. Higher exposure levels also accompany high-altitude flight. For flights at around 40 000 feet, the average exposure is between 0.005 and 0.01 mSvh1. The Earth's magnetic field acts to deflect the protons from cosmic radiation towards the poles. Thus the polar regions tend to receive greater doses of ionizing radiation. There are also areas in the world where the natural background is higher than the average. These areas include the monozite regions of India and Brazil. Background radiation levels in these areas may exceed 10 times the world average. The...

Dose Gy

Delayed appearance of elevated frequencies of gene and chromosome mutations has been reported for cells exposed both in vitro and in vivo. The target for the effect is unknown. Instability is a frequent byproduct of radiation exposure. Rates as high 3 Gy-1 have been reported. (See also the chapter Genomic Instability and DNA Repair.) Exposure to ionizing radiation can also induce alterations in gene expression as part of a generalized stress response. This stress response can affect DNA repair, cell toxicity and cell growth. As such, they may lead to more permanent genetic effects. While DNA damage can initiate these stress responses, other targets of radiation have also been identified. Alterations in redox levels or energy levels or specific molecular alterations in key protein molecules may trigger these responses. For example, direct activation of TGF- 3 by ionizing radiation can influence cell growth and apoptosis.

Carcinogenesis

It has clearly been established that ionizing and UV radiation are both carcinogens. In contrast, the epidemio-logical evidence for an association between cancer and microwave and RF radiation, ultrasound or EMF exposure is weak and inconsistent. cancer and leukaemias, reflecting the nature of their exposure. Many worked with radium, a bone-seeking isotope. Others studied relatively low-energy X-rays where skin would be the primary tissue exposed. Radium dial painters were a group (mostly women) who painted watch dials with a radioactive solution. In the course of their work, they ingested radium. The radium deposited in bone, resulting primarily in higher incidences of bone cancers. Uranium mineworkers inhaled radon gas. The a-radiation exposure resulting from that inhaled radon led to a higher incidence of lung cancer. Thorotrast was a contrast agent used in the late 1920s and early 1930s. It is a colloidal preparation of thorium-232 dioxide that tends to concentrate in the liver....

Lifestyle

The most thoroughly studied and most widely used technique to measure BMD is the dual-energy x-ray absortiometry (DEXA) scan. This is considered to be the gold standard screening test to measure the BMD of the hip and spine. It is less expensive and involves less radiation exposure than the quantitative computed tomography (CT). Since some patients don't respond to therapy for osteoporosis, the BMD results can also be used to follow them and evaluate their response to treatment. Bone mass should be measured in postmenopausal women 1 to 2 years following the initiation of therapy.

Survivin

Considering that apoptosis is the primary mode of cell death induced by several classes of anticancer agents and ionizing radiation, a possible general role of sur-vivin in determining the chemo- and radio-sensitivity profiles of tumor cells has been hypothesised. Moreover, because survivin is associated with microtubules and with the mitotic spindle it is likely that this protein can specifically contribute to the response of cells to microtubule-interacting agents. Li et al. (55) first demonstrated that transfection of wild-type survivin efficiently protected murine NIH3T3 fibroblasts from apoptosis induced by the microtubule-stabilizing agent taxol. In agreement with this observation, Giodini et al. (41) reported that infection of HeLa cells with an adenoviral vector expressing survivin suppressed apoptosis induced by taxol. Based on this finding, our laboratory performed a parallel investigation on cell lines and clinical specimens from ovarian carcinomas to determine whether...

Breast Cancer

Radiation to the breast tissue may induce secondary breast cancers. Although the risk is not isolated to those with HD, SMNs are recognized as a leading cause of death in long-term survivors of HD, with breast cancer representing the most frequent solid tumor among such women 4, 57,60 . Radiation exposure to the breast between the ages of 10-30 years imparts the greatest risk of developing secondary breast cancer. During puberty, the breast undergoes rapid growth and differentiation secondary to a surge in pituitary hormones and the resultant increase in estrogen. Hormonal stimulation of proliferating tissue may potentiate the risk of developing subsequent breast cancer. The role of genetic predisposition is less clear. It has been speculated that genetic predisposition could accelerate the tumorigenic process by providing the initiating event, as is known to occur for renal cancer in rats that carry the tuberous sclerosis 2 gene 22 . Many reports have documented that the risk of...

Skin Cancer

Both non-melanoma (NM) and malignant melanoma skin cancer (MMSC) are known to increase following ionizing radiation, with the former being more prevalent than the latter 19,41,47 . Of the two histologic types of NMSC, the risk of basal cell carcinoma is increased following ionizing radiation, while that of squamous cell carcinoma is not increased 26 . To facilitate early detection and the removal of suspicious lesions, patients who have been exposed to ionizing radiation may benefit from an annual skin examination performed by a trained dermatologist.

Thyroid Cancer

The thyroid gland is one of the most sensitive organs to the carcinogenic effects of ionizing radiation. Although radiation-induced thyroid cancer is a frequently reported SMN, it is rarely fatal. Thyroid SMNs range from well-differentiated, highly curable papillary and follicular carcinomas to poorly differentiated, rapidly fatal anaplastic carcinoma, with the former being the most common 24 . Papillary carcinoma accounts for 75-90 of all radiation-induced thyroid SMNs in survivors of childhood cancer. There is a striking increased risk for young children exposed to ionizing radiation, as shown by both the atomic bomb experience and in studies of children who were less than five years of age at the time of exposure. In general, children younger than 10 years are at the greatest risk 53,59 . This has been attributed to the known age-related changes in cell proliferation with the thyroid gland. The younger the child at the time of exposure, the more actively dividing are the thyroid...

Sarcomas of Bone

Bone sarcomas were the most common SMN reported in a childhood cancer survivor cohort treated between 1940 and 1983 in Great Britain. The overall cumulative risk was approximately 1 within the 20-year period following the original diagnosis 21 . Patients who have survived Ewing's sarcoma appear to have a cumulative risk between 7-22 of developing a second bone tumor by 20 years, depending on the cohort studied 14 . Radiation has been implicated as the major predisposing factor, with the risk increasing substantially with increased doses, especially at doses > 60Gy 11,32 . Because this dose has not commonly been used during the past two decades for Ewing's sarcoma, the risk should be lower in patients treated during this period. There is also evidence that exposure to the highest doses of radiation (i.e. doses greater than 80Gy - which is not used in any current pediatric regimen) does not carry an excess risk. Presumably, this is secondary to the cell kill phenomenon, in which cells...

Aetiology

There are numerous environmental factors responsible for the genesis of skin cancer. Predisposing factors for squamous cell carcinoma include exposure to ultraviolet (UV) radiation, industrial carcinogens (tars and oils), chronic, draining ulcers potentially giving rise to free radical formation, old burn scars, arsenical ingestion, ionizing radiation, and tobacco and betel nut chewing in the case of perioral and intraoral cancers. Sun exposure, particularly UVB, is a primary cause of most basal cell cancers, and both UVB and UVA have been implicated in the cause of melanomas. Products that may activate the carcinogenic process may be generated as a consequence of UV radiation absorbed by epidermal melanin pigment. Because the relevant cellular targets of such carcinogens may reside in the basal cell layer, which is less accessible to their diffusion, the upper layers of the skin may actually be protective (Moan et al., 1999). Prolonged exposure to UV radiation in the UVB part of the...

Info

Irradiation, both external beam and intracavitary, has been used in the curative and palliative treatment of patients with esophageal cancer, either alone or combined with surgery. LDR intracavitary insertions have been performed using 226Ra, 60Co, 137Cs, or 192Ir sources. FLorEs et al. (1989) outlined the advantages of intracavitary brachytherapy radiation sources can be easily placed and removed at the desired tumor site normal anatomy is preserved radiation dose to the tumor is higher than to the adjacent tissues and, with remote afterloading, radiation exposure to the staff can be eliminated. The insertion technique can be performed as an outpatient procedure under local anesthesia, usually xylocaine spray (1-2 ), or mild sedation. A soft rubber bougie or French catheter (No. 24-26) is inserted, preferably through the nose. The rubber tube is removed, and a 260-cm Teflon-coated guidewire in a 60-cm FA-f10 cut-end feeding tube is inserted to the stomach. The cut-end feeding tube is...

Concluding Comments

Several presentations stressed the nutritional value of taurine to the human, under conditions that included pregnancy, early development, exercise and diabetes as well as for protection against ionizing radiation and the ageing process. Because of this it is important that recommended dietary intake levels are established for taurine.

Radiation Dose

The radiation exposure after the intravenous administration of 99mTc-pertechnetate depends on the thyroid status, and whether a blocking agent has been administered. The thyroid gland, stomach wall, small intestine, upper and lower intestinal wall, and urinary bladder wall are the most exposed organs.

Basal Cell Carcinoma

Subject to chronic sun exposure and in lightly pigmented people. Other predisposing factors include ionizing radiation, chronic scarring and arsenical exposure. As with squamous cell carcinoma, the incidence of basal cell carcinoma increases sharply with immunosuppression and in patients with inherited defects in DNA replication or repair (xeroderm pigmentosum). The rare, dominantly inherited basal cell naevus syndrome (Bale, 1997) is associated with the development of numerous basal cell carcinomas in early life, with abnormalities of bone, nervous system, eyes and reproductive organs, and with a specific gene mutation which now has been characterized.

Figure 143

Flowmeter of the electromagnetic type, showing generation of an electrical voltage in a wire as it passes through an electromagnetic field (A) generation of an electrical voltage in electrodes on a blood vessel when the vessel is placed in a strong magnetic field and blood flows through the vessel (B) and a modern electromagnetic flowmeter probe for chronic implantation around blood vessels (C).

UV Radiation

The excitations induced by UV exposure will also produce DNA base changes and breaks in the sugar--phosphate backbone. The most important alterations appear to be cyclobutanepyrimidine dimers and pyrimidine-(6,4)-pyrimidone photoproducts. Replication of DNA containing these lesions leads to C to T transitions at dipyrimidine sites. Nucleotide excision repair processes normally repair these base alterations efficiently and without error. Like ionizing radiation, UV radiation can also induce alterations in gene expression as part of a generalized stress response. (See also the chapter Genomic Instability and DNA Repair.)

Melanocytic Nevi

Also known as liver spots, occur in elderly persons on the dorsa of the hands, the forearms, and the face. Solar ink-spot lentigo is commonly seen on sun-exposed areas and has a characteristic black, splotchy, reticulated pattern. Lentigo maligna melanoma (see Fig.SS-B) is a dark brown or black macular, malignant lesion, usually on the face or arms of elderly persons, that has a slow peripheral growth (see under Malignant Melanoma earlier). Lentigines can be caused by ionizing radiation, a tanning bed, a sunlamp, PUVA therapy, and, most commonly, from sun exposure.

Alpha Rhythms

Ensembles of synchronously active cortical neurons generate electromagnetic field potentials that can be measured by electroencephalography (EEG) or magnetoencephalog-raphy (MEG). The alpha frequency band is defined to be between 8 and 13 Hz (Berger, 1929 Adrian & Mathews, 1934). The classical alpha rhythm is prominent at electrodes overlying the occipital (visual) cortex and to a lesser extent over the posterior temporal and parietal areas. Alpha rhythm occurs in a condition of relaxed wakefulness with eyes closed, and it is depressed upon eye opening. The alpha rhythm disappears gradually during drowsiness, and different types of alpha activity appear in rapid eye movement (REM) sleep (Cantero, Atienza, & Salas, 2002).

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