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PubMed1995

Mammary tumor occurrence in beagles given 239Pu.

Comparison of 120 young adult female beagles given 0.026 to 106 kBq 239Pu kg-1 by intravenous injection and 63 comparable female control beagles showed that there were no significant differences in the risk of mammary tumor appearance between the two groups. This was the case for benign tumors only, for malignant tumors only, and for both malignant and benign tumors considered together. For malignant tumors the observed number was 73 as compared with 69 expected; for benign tumors, there were 131 observed and 126 expected; for all tumors (separate analysis, not just the addition of malignant plus benign), there were 199 observed and 199 expected. Chi-square analysis indicated that the p values for all these comparisons were > 0.05. There were 45 controls (71.4%) with any tumor vs. 67 dogs (55.8%) given Pu (95% C. I. = 46.9% to 86.2%). No significant differences could be established (Kaplan-Meier analysis) between these two groups for survival age at diagnosis of the first mammary tumor, 11.75 +/- 0.30 y for dogs given Pu vs. 11.90 +/- 0.36 y for controls. We reported previously that differences in mammary cancer occurrence had been identified between this same group of control dogs and 57 female beagles given 226Ra as young adults. The present study appears to support the earlier conclusion that something other than alpha irradiation of the skeleton (both 226Ra and 239Pu deposit in bone) seems to affect the appearance of mammary cancers, since internally deposited 226Ra does appear to induce these malignancies, possibly from initial deposition in mammary tissue of the parent radionuclide or the subsequent concentration in sensitive tissue of its radioactive progeny, 22Rn or isotopes of polonium, lead, and bismuth, which are absent in the case of 239Pu.

Animals↗
PubMed2005

Radionuclides and trace metals in Canadian moose near uranium mines: comparison of radiation doses and food chain transfer with cattle and caribou.

Tissues from 45 moose and 4 cattle were collected to assess the health of country foods near uranium mines in northern Saskatchewan. Bone, liver, kidney, muscle and rumen contents were analyzed for uranium, radium-226 (226Ra), lead-210 (210Pb), and polonium-210 (210Po). Cesium-137 (137Cs), potassium-40 (40K), and 27 trace metals were also measured in some tissues. Within the most active mining area, Po in liver and muscle declined significantly with distance from tailings, possibly influenced by nearby natural uranium outcrops. Moose from this area had significantly higher 226Ra, 210Pb, 210Po, and 137Cs in some edible soft tissues vs. one control area. However, soil type and diet may influence concentrations as much as uranium mining activities, given that a) liver levels of uranium, 226Ra, and 210Po were similar to a second positive control area with mineral-rich shale hills and b) 210Po was higher in cattle kidneys than in all moose. Enhanced food chain transfer from rumen contents to liver was found for selenium in the main mining area and for copper, molybdenum and cadmium in moose vs. cattle. Although radiological doses to moose in the main mining area were 2.6 times higher than doses to control moose or cattle, low moose intakes yielded low human doses (0.0068 mSv y(-1)), a mere 0.3% of the dose from intake of caribou (2.4 mSv y(-1)), the dietary staple in the area.

Animals↗
PubMed2006

A comprehensive dose reconstruction methodology for former rocketdyne/atomics international radiation workers.

Incomplete radiation exposure histories, inadequate treatment of internally deposited radionuclides, and failure to account for neutron exposures can be important uncertainties in epidemiologic studies of radiation workers. Organ-specific doses from lifetime occupational exposures and radionuclide intakes were estimated for an epidemiologic study of 5,801 Rocketdyne/Atomics International (AI) radiation workers engaged in nuclear technologies between 1948 and 1999. The entire workforce of 46,970 Rocketdyne/AI employees was identified from 35,042 Kardex work histories cards, 26,136 electronic personnel listings, and 14,189 radiation folders containing individual exposure histories. To obtain prior and subsequent occupational exposure information, the roster of all workers was matched against nationwide dosimetry files from the Department of Energy, the Nuclear Regulatory Commission, the Landauer dosimetry company, the U.S. Army, and the U.S. Air Force. Dosimetry files of other worker studies were also accessed. Computation of organ doses from radionuclide intakes was complicated by the diversity of bioassay data collected over a 40-y period (urine and fecal samples, lung counts, whole-body counts, nasal smears, and wound and incident reports) and the variety of radionuclides with documented intake including isotopes of uranium, plutonium, americium, calcium, cesium, cerium, zirconium, thorium, polonium, promethium, iodine, zinc, strontium, and hydrogen (tritium). Over 30,000 individual bioassay measurements, recorded on 11 different bioassay forms, were abstracted. The bioassay data were evaluated using ICRP biokinetic models recommended in current or upcoming ICRP documents (modified for one inhaled material to reflect site-specific information) to estimate annual doses for 16 organs or tissues taking into account time of exposure, type of radionuclide, and excretion patterns. Detailed internal exposure scenarios were developed and annual internal doses were derived on a case-by-case basis for workers with committed equivalent doses indicated by screening criteria to be greater than 10 mSv to the organ with the highest internal dose. Overall, 5,801 workers were monitored for radiation at Rocketdyne/AI: 5,743 for external exposure and 2,232 for internal intakes of radionuclides; 41,169 workers were not monitored for radiation. The mean cumulative external dose based on Rocketdyne/AI records alone was 10.0 mSv, and the dose distribution was highly skewed with most workers experiencing low cumulative doses and only a few with high doses (maximum 500 mSv). Only 45 workers received greater than 200 mSv while employed at Rocketdyne/AI. However, nearly 32% (or 1,833) of the Rocketdyne/AI workers had been monitored for radiation at other nuclear facilities and incorporation of these doses increased the mean dose to 13.5 mSv (maximum 1,005 mSv) and the number of workers with >200 mSv to 69. For a small number of workers (n=292), lung doses from internal radionuclide intakes were relatively high (mean 106 mSv; maximum 3,560 mSv) and increased the overall population mean dose to 19.0 mSv and the number of workers with lung dose>200 mSv to 109. Nearly 10% of the radiation workers (584) were monitored for neutron exposures (mean 1.2 mSv) at Rocketdyne/AI, and another 2% were monitored for neutron exposures elsewhere. Interestingly, 1,477 workers not monitored for radiation at Rocketdyne/AI (3.6%) were found to have worn dosimeters at other nuclear facilities (mean external dose of 2.6 mSv, maximum 188 mSv). Without considering all sources of occupational exposure, an incorrect characterization of worker exposure would have occurred with the potential to bias epidemiologic results. For these pioneering workers in the nuclear industry, 26.5% of their total occupational dose (collective dose) was received at other facilities both prior to and after employment at Rocketdyne/AI. In addition, a small number of workers monitored for internal radionuclides contributed disproportionately to the number of workers with high lung doses. Although nearly 12% of radiation workers had been monitored for neutron exposures during their career, the cumulative dose levels were small in comparison with other external and internal exposure. Risk estimates based on nuclear worker data must be interpreted cautiously if internally deposited radionuclides and occupational doses received elsewhere are not considered.

Adult↗
PubMed1968

Atmospheric bismuth-212: measurement and some geophysical applications.

The concentrations of lead-212 and its short-lived daughter bismuth-212 in air near the ground were determined simultaneously by adaptation of the immersed-filter, delayed-coincidence technique of Assaf and Gat to measurement of the 3 x 10-(7)-second bismuth-212 and polonium-212 pair. The radioactive disequilibrium between lead-212 and bismuth-212 depends strongly on the efficiency of the ground in acting as a sink for these nuclides. This efficiency is low under dry conditions.

Air Pollution, Radioactive↗
PubMed1988

Mortality of employees of the Atomic Weapons Establishment, 1951-82.

A total of 22,552 workers employed by the Atomic Weapons Establishment between 1951 and 1982 were followed up for an average of 18.6 years. Of the 3115 who died, 865 (28%) died of cancer. Mortality was 23% lower than the national average for all causes of death and 18% lower for cancer. These low rates were consistent with the findings in other workforces in the nuclear industry and reflect, at least in part, the selection of healthy people to work in the industry and the disproportionate recruitment of people from the higher social classes. At some time during their employment 9389 (42%) of the workers were monitored for exposure to radiation, the average cumulative whole body exposure to external radiation being 7.8 mSv. Their mortality was generally similar to that of other employees, even when exposures were lagged by 10 years. The rate ratio after a 10 year lag in workers with a radiation record compared with other workers was 1.01 (95% confidence interval 0.92 to 1.10) for all causes of death and 1.06 (0.89 to 1.27) for all malignant neoplasms. The only significant differences were for prostatic cancer (rate ratio 2.23; 95% confidence interval 1.13 to 4.40) and for cancers of ill defined and secondary sites (rate ratio 2.37; 1.23 to 4.56). Cancers of lymphatic and haemopoietic tissues were notable for their low occurrence in the study population, with only four deaths from leukaemia and two from multiple myeloma in workers with a radiation record, 9.16 and 3.55 deaths respectively being expected on the basis of national rates. Among workers who had a radiation record 3742 (40%) were also monitored for possible internal exposure to plutonium, 3044 (32%) to uranium, 1562 (17%) to tritium, 638 (7%) to polonium, and 281 (3%) to actinium. In these workers mortality from malignant neoplasms as a whole was not increased, but after a 10 year lag death rates from prostatic and renal cancers were generally more than twice the national average, these excesses arising in a small group of workers monitored for exposure to multiple radionuclides. Though mortality from lung cancer in workers monitored for exposure to plutonium was below the national average, it was some two thirds higher than in other radiation workers, the excess being of borderline statistical significance. Mortality from malignant neoplasms as a whole showed a weak and non-significant increasing trend with increasing level of cumulative whole body exposure to external radiation. When the exposures were lagged by 10 years the trend became stronger and significant, the estimated increase in relative risk per 10 mSv being 7.6% (95% confidence interval 0.4% to 15.3%). This trend was confined almost entirely to workers who were also monitored for exposure to radionuclides (p<0.001), the main contributions coming from lung cancer and prostatic cancer. Exposures of the lung and prostate from internal sources of radiation were not quantified, except for the contribution from tritium. It was therefore not possible to assess the extent to which the associations were due to internally deposited radionuclides rather than external exposure. The finding for prostatic cancer taken in conjunction with the results of other studies suggest a specific occupational hazard in a small group of workers in the nuclear industry who had comparatively high exposures to external radiation and who were also monitored for internal exposure to multiple radionuclides. Research is needed to discover whether any of the radionuclides and other substances concerned are concentrated in the prostate. The occurrence of lung cancer in this workforce requires further investigation taking into account smoking habits and tissue doses from inhaled radionuclides.

Cardiovascular Diseases↗
PubMed2004

Smokeless tobacco and oral cancer: a review of the risks and determinants.

Smokeless tobacco has been associated with oral cancer for many decades. The purpose of this article is to review research relevant to this association, including epidemiologic studies, studies of putative carcinogens such as tobacco-specific nitrosamines (TSNAs) and other contaminants, and possible cancer inhibitors. Epidemiologic studies addressing this issue primarily consist of case-control studies. They show that the use of chewing tobacco and moist snuff is associated with very low risks for cancers of the oral cavity and related structures (relative risks [RR] from 0.6 to 1.7). The use of dry snuff is associated with higher RRs, ranging from 4 to 13, while the RRs from smokeless tobacco, unspecified as to type, are intermediate (RR = 1.5 to 2.8). With regard to TSNAs, historical levels in American moist snuff products were higher than those in their Swedish counterparts, but levels in contemporary products are uniformly low. TSNA levels in chewing tobacco have always been low, but levels in dry snuff have been higher, including some very high levels in current products. In general, smokeless tobacco users are not exposed to significant levels of cadmium, lead, benzo(a)pyrene, polonium-210, and formaldehyde, when compared with concentrations of these compounds in foods. Finally, low oral cancer risk from smokeless tobacco use may be influenced by the presence of cancer inhibitors, mainly anti-oxidants, in smokeless tobacco products.

Anticarcinogenic Agents↗
PubMed1999

Radionuclides in the lichen-caribou-human food chain near uranium mining operations in northern Saskatchewan, Canada.

The richest uranium ore bodies ever discovered (Cigar Lake and McArthur River) are presently under development in northeastern Saskatchewan. This subarctic region is also home to several operating uranium mines and aboriginal communities, partly dependent upon caribou for subsistence. Because of concerns over mining impacts and the efficient transfer of airborne radionuclides through the lichen-caribou-human food chain, radionuclides were analyzed in tissues from 18 barren-ground caribou (Rangifer tarandus groenlandicus). Radionuclides included uranium (U), radium (226Ra), lead (210Pb), and polonium (210Po) from the uranium decay series; the fission product (137Cs) from fallout; and naturally occurring potassium (40K). Natural background radiation doses average 2-4 mSv/year from cosmic rays, external gamma rays, radon inhalation, and ingestion of food items. The ingestion of 210Po and 137Cs when caribou are consumed adds to these background doses. The dose increment was 0.85 mSv/year for adults who consumed 100 g of caribou meat per day and up to 1.7 mSv/year if one liver and 10 kidneys per year were also consumed. We discuss the cancer risk from these doses. Concentration ratios (CRs), relating caribou tissues to lichens or rumen (stomach) contents, were calculated to estimate food chain transfer. The CRs for caribou muscle ranged from 1 to 16% for U, 6 to 25% for 226Ra, 1 to 2% for 210Pb, 6 to 26% for 210Po, 260 to 370% for 137Cs, and 76 to 130% for 40K, with 137Cs biomagnifying by a factor of 3-4. These CRs are useful in predicting caribou meat concentrations from the lichens, measured in monitoring programs, for the future evaluation of uranium mining impacts on this critical food chain.

Animals↗
PubMedDate not supplied

Mineral particles in the human bronchial mucosa and lung parenchyma. II. Cigarette smokers without emphysema.

The effects of cigarette smoke on the microanatomic deposition and retention pattern of exogenous mineral particles is unknown. To determine how cigarette smoke affects long-term particle retention in those with minimal smoke-related disease, we selected autopsy lungs from ten smokers without evidence of emphysema at autopsy, and used analytical electron microscopy to examine exogenous mineral particle concentration in the mucosa of seven different bronchi of varying sizes and four parenchymal sites fed by those bronchi. These data were compared with values from twelve lifetime nonsmokers. Overall, total mean particle burden in the parenchyma in the smokers and nonsmokers was similar, but there was a markedly decreased particle load retained in the smokers' airways. The consistent increase in particle burden seen in nonsmokers as airways became narrower and more distant from the carina was lost in many, but not all, of the smokers, especially for particles larger than 1 micron, and this effect did not appear to depend on amount of smoking. Rare polonium particles were found but were too sparse to use as a smoke distribution marker. However, calcium-containing particles, previously suggested by us to represent calcium carbonate actually derived from the smoke, were present in greatest concentration in the larger airways and distal parenchyma. These observations indicate the following in smokers without parenchymal smoke-induced structural damage: (1) Overall, cigarette smoking disrupts the normal retention (? deposition) pattern of particles in the airways. (2) Cigarette smoking leads to markedly decreased long-term retention of exogenous mineral particles in the airways without significantly affecting overall tissue particle retention. (3) The distribution of calcium particles in the airways and parenchyma in smokers is similar to that predicted in a recently published model of smoke particle deposition, and further supports the idea that calcium-containing particles can be used as a direct tracer of smoke particle deposition. In the present study this distribution indicates that the large airways and parenchyma receive the greatest smoke deposition. (4) Within the group of smokers, some people appear resistant to the disruptive effects of smoke on particle retention patterns, whereas other people smoking comparable amounts show markedly abnormal retention patterns. The latter may have unusual sensitivity to cigarette smoke and perhaps susceptibility to smoke-induced diseases.

Aged↗
PubMed1996

[Chronological table of Mr. and Mrs. Curie and Mr. and Mrs. Joliot-Curie--in connection with the 100-year anniversary since Dr. H. Becquerel discovered radial ray in 1896].

This year (1996) is the 100th year since Dr. Henri Becquerel discovered radial rays in 1896 in France. In 1897, Dr. Pierre Curie and Marie Curie preliminarily reported the existence of polonium and radium which have radioactivity. H. Becquerel, Pierre and Marie Curie were awarded the Nobel Chemical Prize for discovering artificial radioactivity in 1935. I report herein the chronological table of Mr. and Mrs. Curie and Mr. and Mrs. Joliot-Curie spanning about one century.

Chemistry↗
PubMed1999

Dr. Nobuo Yamada's whole life, dead due to his radioactive studies at the Radium Institute (Part 2): in celebration of the 100-year anniversary of the discovering radium, 1898-1998.

On the occasion of the 100th anniversary of the discovery of radium by M. & Mme. Curie, commemorative lecture meetings were held in Japan in 1998 as follows. 1) The 42nd Symposium on Radiochemistry was held in Sendai on September 18. Dr. M. Sakanoue, Professor Emeritus Kanazawa University, presented a commemorative lecture entitled "Collaborative Research done by Irene Curie and Nobuo Yamada." He explained an outline of the studies on the measurement of long-range particles emitted by various radioactive substances such as polonium, radium and thorium. In addition to his lecture, I made a comment on the curriculum vitae of Dr. N. Yamada. 2) On October 24, another commemorative lecture meeting was held in Tokyo. At this meeting, Helene Langevin-Joliot, daughter of Irene Joliot-Curie presented a lecture on whole life of M. & Mme. Curie as a guest speaker. After meeting ended, I had the opportunity to talk with her personally. I have been investigating references describing the cause of death of Dr. Nobuo Yamada and found the following. The inadequacy of an apparatus for protection from radioactivity in the 1920s and reference to the death of Dr. Nobuo Yamada specifically were described in an article written by Dr. S. Iimori and in a nonograph written by Dr. M. Furukawa. The tragedy of scientists who suffered severe radiation syndrome during experiments at the Radium Institute was described in a biography of Marie Curie written by Susan Quinn.

Academies and Institutes↗
PubMed1975

Lung response to localized irradiation from plutonium microspheres.

Uniform spherical 10-micrometer diameter particles of ZrO2 ceramic, containing various concentrations of PuO2, have been injected into the jugular vein of Syrian hamsters with subsequent permanent lodgement in the lung capillaries. The number of particles injected has varied from 2000 to 2 000 000 and the specific activity has been from 0.16 to 59 pCi/sphere so that lung burdens range from 0.2 to 700 nCi. To date, approximately 3000 hamsters have been committed to the experiment and two-thirds have died--the expected rate for normal animals. Little biological damage has been observed, and only five primary lung tumours have been found that may be due to radiation delivered to the lung. To provide a comparison to more uniform radiation, soluble polonium has also been instilled intratracheally. Results from the microspheres suggest that localized lung irradiation alone is not sufficient cause for tumour induction and is much less hazardous than diffuse exposure.

Animals↗
PubMed2004

[Determination of cadmium in urine of tobacco smoking pregnant women].

Tobacco smoke contain few thousands of chemical compounds, among them heavy metals. From toxicological point of view most important are lead, cadmium and radioactive polonium 210. The aim of the study was determination of cadmium in urine of tobacco smoking pregnant woman and checking if there is a correlation between the concentration of cadmium and cotinine, the most frequently used tobacco smoke biomarker. The study showed that concentration of cotinine in urine of smoking women was 702.5 +/- 1131.4 ng/mg creatinine and ranged from 50 to more than 6000 ng/mg creatinine. Cadmium concentration in smokers was 1.6 +/- 2.6 ng/ml and ranged from 0 to 11.5 ng/ml. In urine of woman who do not smoke and are not exposure to ETS was 1.1 +/- 2.2 ng/ml in the range 0-2.5 ng/ml and was not statistically different from concentration of cadmium in urine of smoking pregnant woman. In any one non-smoking woman, concentration of cadmium was not higher than 5 ng/ml, but in 11.8% of smoking women this level was exceeded. Calculations showed a weak correlation between concentration of cadmium and cotinine in urine of smoking pregnant women.

Biomarkers↗
PubMedDate not supplied

[Determination of americium-241 in urine].

A technique has been developed for the determination of americium 241 in urine by a radiochemical purification of the nuclide from uranium (upon co-precipitation of americium 241 with calcium and lanthanum), plutonium, thorium, and polonium 210 (upon co-precipitation of these radionuclides with zirconium iodate). alpha-Radioactivity was measured either in a thick layer of the americium 241 precipitate with a nonisotope carrier or in thin-layer preparations after electrolytic precipitation of americium 241 on a cathode.

Americium↗
PubMed1983

A solvent extraction technique for the measurement of 222Rn at ambient air concentrations.

The high solubility of radon in cold organic solvents is exploited to extract radon directly from a sample air stream into a hexane-based liquid scintillation solution. Up to 10 l. of air is passed through 20 ml of solvent held at -78 degrees C in a bath of dry ice and acetone. The solvent is then transferred to an ordinary glass liquid scintillation vial that has been preloaded with 2 ml of concentrated fluors. A large number of samples can be prepared in a short time with minimal equipment, making it possible for field workers to conveniently collect numerous samples prior to returning to the laboratory. After allowing an interval of at least 3 hr after processing for radon daughter ingrowth, the vials are counted on an unmodified liquid scintillation system with a narrow window set around the radon and polonium alpha peaks. The large sample volume more than compensates for the relatively high alpha background of liquid scintillators. Relevant theoretical considerations and alternate sampling strategies are discussed.

Air↗
PubMed1994

[Optimization of the indoor air conditioning in the places of excessive radon release].

The experimental modelling covered ventilation and air purification as well as air pollution with radon and such derivatives as polonium-218b, lead-214 and bismuth-214. The modelling was designed for industrial conditions with higher radon release in technologic conversion at enterprises processing uranium. The investigators obtained some information to optimize air processing and to lower the workers exposure to radon and its derivatives.

Air Conditioning↗
PubMed1994

Occurrence of mammary tumors in beagles given radium-226.

A total of 128 primary mammary tumors (66 of them malignant) occurred in 35 female beagles injected with 226Ra at eight dose levels ranging from 0.2 to 440 kBq/kg body mass as young adults, while a total of 156 mammary tumors (57 of them malignant) were seen in 46 female control beagles not given any radioactivity. Sixty-three of 65 control dogs and 59 of 61 dogs given 226Ra survived the minimum age for diagnosis of mammary tumors of 3.75 years. Based on the observed age-dependent tumor incidence rates in the controls and on the corresponding number of dog-years at risk, the total number of observed malignant tumors in the radium group was statistically greater than the number of expected malignant tumors (66 observed vs 34 expected, P < 0.005). There was no such difference for the benign tumors. Cox regression analysis indicated no increased risk for the first tumor occurrence in irradiated dogs. Cox regression analysis of the multivariate risk sets showed no significantly increased risk for the occurrence of benign tumors but a statistically higher risk of 1.66 with a confidence interval of 1.15-2.40 for the occurrence of malignant tumors. The increased risk was dependent on dose, but a dependence on the frequency of previous occurrence of mammary tumors could not be confirmed. Censoring ovariectomized dogs at time of surgery decreased the relative risks slightly but did not alter the significance. Exposure to diagnostic X rays with cumulative exposures below 0.2 Gy had no effect on tumor formation. It is unknown whether the increased risk for malignant mammary tumors was due to some initial deposition of radium in sensitive tissue, a possible irradiation of fatty mammary tissue from transient radon-->polonium deposition, or a general effect of the overall radium deposition on the immune system of the dogs that lowered their resistance to formation of mammary tumors. Results of this study are potentially useful in understanding risks of radium-induced breast cancers in humans.

Age Factors↗
PubMed1996

[Henri Beckquerel's discovery of radioactivity, and history of nuclear medicine. 100 years in the shadow or on the shoulder of Röntgen].

In 1896 Henri Becquerel discovered that uranium emitted penetrating rays similar to X-rays. His finding started a series of discoveries that were rewarded with numerous Nobel prizes. Marie and Pierre Curie found that thorium was radioactive too, and discovered and described two new elements, polonium and radium. They also found that radioactive radiation could be separated into alpha, beta and gamma rays. In 1993 their daughter Irene Joliot-Curie and her husband Frederic Joliot managed to produce radioactivity artificially by bombarding atomic nuclei with alpha particles. Enrico Fermi did likewise, but bombarded the nuclei with neutrons. In the cyclotron invented by Ernest Lawrence, radioactive isotopes were produced by proton bombardment. The ability to produce radioisotopes of different elements initiated a variety of tracer studies in biology and medicine. The number of studies increased exponentially when the nuclear reactor in Oak Ridge, US, was opened for radionuclide production in 1946. This article summarises the history of the application of radionuclides in science and medicine internationally and in Norway until now.

History, 19th Century↗
PubMed1998

Heavy-ion radiobiology: new approaches to delineate mechanisms underlying enhanced biological effectiveness.

Shortly after the discovery of polonium and radium by Marie Curie and her husband and colleague, Pierre Curie, it was learned that exposure to these alpha-particle emitters produced deleterious biological effects. The mechanisms underlying the increased biological effectiveness of densely ionizing radiations, including alpha particles, neutrons and highly energetic heavy charged particles, remain an active area of investigation. In this paper, we review recent advances in several areas of the radiobiology of these densely ionizing radiations, also known as heavy ions. Advances are described in the areas of DNA damage and repair, chromosome aberrations, mutagenesis, neoplastic transformation in vitro, genomic instability, normal tissue radiobiology and carcinogenesis in vivo. We focus on technical innovations, including novel applications of pulsed-field gel electrophoresis, fluorescence in situ hybridization (FISH), linkage analysis, and studies of gene expression and protein expression. We also highlight the use of new cellular and animal systems, including those with defined DNA repair deficiencies, as well as epithelial cell model systems to assess neoplastic transformation both in vitro and in vivo. The studies reviewed herein have had a substantial impact on our understanding of the genotoxic effects of heavy ions as well as their distinct effects on tissue homeostasis. The use of these radiations in cancer therapy is also discussed. The use of both heavy-ion and proton therapy is on the upswing in several centers around the world, due to their unique energy deposition characteristics that enhance the therapeutic effect and help reduce damage to normal tissue.

Animals↗