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Concept: Radiobiology

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The use of novel radiotherapy techniques is widely increasing, allowing clinicians to treat diseases that were previously difficult to treat with radiation therapy. Malignant pleural mesothelioma is a clear example of this clinical challenge. We describe our first experience with intensity-modulated radiotherapy technique which was used to treat a 73-year-old patient with multiple relapsing malignant pleural mesothelioma. Intensity-modulated radiation therapy has allowed to respect the QUANTEC (quantitative analyses of normal tissue effects in the clinic) dose constraints, patient has experienced a 14 months progression-free time, without relevant subacute or late lung toxicity.

Concepts: Medicine, Cancer, Ionizing radiation, Medical terms, Radiation therapy, Radiobiology, Mesothelioma

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An assessment of the external and internal radiation exposure levels, which includes calculation of effective doses from chronic radiation exposure and assessment of long-term radiation-related health risks, has become mandatory for residents living near the nuclear power plant in Fukushima, Japan. Data for all primary and secondary children in Minamisoma who participated in both external and internal screening programs were employed to assess the annual additional effective dose acquired due to the Fukushima Daiichi nuclear power plant disaster. In total, 881 children took part in both internal and external radiation exposure screening programs between 1st April 2012 to 31st March 2013. The level of additional effective doses ranged from 0.025 to 3.49 mSv/year with the median of 0.70 mSv/year. While 99.7% of the children (n = 878) were not detected with internal contamination, 90.3% of the additional effective doses was the result of external radiation exposure. This finding is relatively consistent with the doses estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The present study showed that the level of annual additional effective doses among children in Minamisoma has been low, even after the inter-individual differences were taken into account. The dose from internal radiation exposure was negligible presumably due to the success of contaminated food control.

Concepts: Ionizing radiation, Chernobyl disaster, Radiobiology, United Nations, Nuclear weapon, Radiation poisoning, Nuclear safety, Linear no-threshold model

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Purpose To compare mortality rates from all causes, specific causes, total cancers, and specific cancers to assess whether differences between radiologists and psychiatrists are consistent with known risks of radiation exposure and the changes in radiation exposure to radiologists over time. Materials and Methods The authors used the American Medical Association Physician Masterfile to construct a cohort of 43 763 radiologists (20% women) and 64 990 psychiatrists (27% women) (comparison group) who graduated from medical school in 1916-2006. Vital status was obtained from record linkages with the Social Security Administration and commercial databases, and cause of death was obtained from the National Death Index. Poisson regression was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for all causes and specific causes of death. Results During the follow-up period (1979-2008), 4260 male radiologists and 7815 male psychiatrists died. The male radiologists had lower death rates (all causes) compared with the psychiatrists (RR = 0.94; 95% CI: 0.90, 0.97), similar cancer death rates overall (RR = 1.00; 95% CI: 0.93, 1.07), but increased acute myeloid leukemia and/or myelodysplastic syndrome death rates (RR = 1.62; 95% CI: 1.05, 2.50); these rates were driven by those who graduated before 1940 (RR = 4.68; 95% CI: 0.91, 24.18). In these earliest workers (before 1940) there were also increased death rates from melanoma (RR = 8.75; 95% CI: 1.89, 40.53), non-Hodgkin lymphoma (NHL) (RR = 2.69; 95% CI: 1.33, 5.45), and cerebrovascular disease (RR = 1.49; 95% CI: 1.11, 2.01). The 208 deaths in female radiologists precluded detailed investigation, and the number of female radiologists who graduated before 1940 was very small (n = 47). Conclusion The excess risk of acute myeloid leukemia and/or myelodysplastic syndrome mortality in radiologists who graduated before 1940 is likely due to occupational radiation exposure. The melanoma, NHL, and cerebrovascular disease mortality risks are possibly due to radiation. The authors found no evidence of excess mortality in radiologists who graduated more recently, possibly because of increased radiation protection and/or lifestyle changes. (©) RSNA, 2016 Online supplemental material is available for this article.

Concepts: Cancer, Death, Mortality rate, Demography, Actuarial science, Leukemia, Radiobiology, Acute myeloid leukemia

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Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific.

Concepts: Chernobyl disaster, Radiobiology, Nuclear weapon, Radioactive contamination, Nuclear fallout, Nuclear safety, Three Mile Island accident, Nuclear accidents

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High-grade glioma is one of the most aggressive cancers in adult humans and long-term survival rates are very low as standard treatments for glioma remain largely unsuccessful. Cannabinoids have been shown to specifically inhibit glioma growth as well as neutralize oncogenic processes such as angiogenesis. In an attempt to improve treatment outcome, we have investigated the effect of Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) both alone and in combination with radiotherapy in a number of glioma cell lines (T98G, U87MG, and GL261). Cannabinoids were used in two forms, pure (P) and as a botanical drug substance (BDS). Results demonstrated a duration- and dose-dependent reduction in cell viability with each cannabinoid and suggested that THC-BDS was more efficacious than THC-P, whereas, conversely, CBD-P was more efficacious than CBD-BDS. Median effect analysis revealed all combinations to be hyperadditive [T98G 48-hour combination index (CI) at FU50, 0.77-1.09]. Similarly, pretreating cells with THC-P and CBD-P together for 4 hours before irradiation increased their radiosensitivity when compared with pretreating with either of the cannabinoids individually. The increase in radiosensitivity was associated with an increase in markers of autophagy and apoptosis. These in vitro results were recapitulated in an orthotopic murine model for glioma, which showed dramatic reductions in tumor volumes when both cannabinoids were used with irradiation (day 21: 5.5 ± 2.2 mm(3) vs. 48.7 ± 24.9 mm(3) in the control group; P < 0.01). Taken together, our data highlight the possibility that these cannabinoids can prime glioma cells to respond better to ionizing radiation, and suggest a potential clinical benefit for glioma patients by using these two treatment modalities. Mol Cancer Ther; 1-13. ©2014 AACR.

Concepts: Cancer, Ionizing radiation, Oncology, Radiation therapy, Radiobiology, Cannabis, Cannabinoid, Cannabidiol

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Abstract Purpose: Our study was designed to assess the effects of low intensity radiation of a GSM (Global System for Mobile communication) 900 MHz cellular phone on early embryogenesis in dependence on the duration of exposure. Materials and methods: Embryos of Japanese Quails were exposed in ovo to GSM 900 MHz cellular phone radiation during initial 38 h of brooding or alternatively during 158 h (120 h before brooding plus initial 38 h of brooding) discontinuously with 48 sec ON (average power density 0.25 µW/cm(2), specific absorption rate 3 µW/kg) followed by 12 sec OFF intervals. A number of differentiated somites was assessed microscopically. Possible DNA damage evoked by irradiation was assessed by an alkaline comet assay. Results: Exposure to radiation from a GSM 900 MHz cellular phone led to a significantly altered number of differentiated somites. In embryos irradiated during 38 h the number of differentiated somites increased (p<0.001), while in embryos irradiated during 158 h this number decreased (p<0.05). The lower duration of exposure led to a significant (p<0.001) decrease in a level of DNA strand breaks in cells of 38-hour embryos, while the higher duration of exposure resulted in a significant (p<0.001) increase in DNA damage as compared to the control. Conclusion: Effects of GSM 900 MHz cellular phone radiation on early embryogenesis can be either stimulating or deleterious depending on the duration of exposure.

Concepts: DNA, Radiobiology, Specific absorption rate, Mobile phone, Cellular network, Base station, Mobile phone radiation and health, GSM

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Object The focus of the present study was the evaluation of outcomes after unstaged and staged-volume Gamma Knife surgery (GKS) in children harboring intracranial arteriovenous malformations (AVMs). Methods Twenty-two children (median age 9.5 years) underwent GKS for AVMs and were followed up for at least 2 years thereafter. The disease manifested with intracranial hemorrhage in 77% of cases. In 68% of patients the lesion affected eloquent brain structures. The volume of the nidus ranged from 0.1 to 6.7 cm(3). Gamma Knife surgery was guided mainly by data from dynamic contrast-enhanced CT scans, with preferential targeting of the junction between the nidus and draining vein. The total prescribed isodose volume was kept below 4.0 cm(3), and the median margin dose was 22 Gy (range 20-25 Gy). If the volume of the nidus was larger than 4.0 cm(3), a second radiosurgical session was planned for 3-4 years after the first one. Nine patients in the present series underwent unstaged radiosurgery, whereas staged-volume treatment was scheduled in 13 patients. Results Complete obliteration of the AVM was noted in 17 (77%) of 22 patients within a median period of 47 months after the last radiosurgical session. Complete obliteration of the lesion occurred in 89% of patients after unstaged treatment and in 62.5% after staged GKS. Four (67%) of 6 high-grade AVMs were completely obliterated. Complications included 3 bleeding episodes, the appearance of a region of hyperintensity on T(2)-weighted MR images in 2 patients who had no symptoms, and reappearance of the nidus in the vicinity of the completely obliterated AVM in 1 patient. Conclusions Radiosurgery is a highly effective management option for intracranial AVMs in children. For larger lesions, staged GKS may be applied successfully. Initial targeting of the nidus adjacent to the draining vein and application of a sufficient radiation dose to a relatively small volume (≤ 4 cm(3)) provides a good balance between a high probability of obliteration and a low risk of treatment-related complications.

Concepts: Brain tumor, Anatomical pathology, Radiobiology, Gamma knife, Neurosurgery, Congenital disorders, Arteriovenous malformation, Cerebral arteriovenous malformation

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Since the development of the CT scanner in the early 1970s, CT scanner technology has continuously developed through technical advancement, faster computer processing, superior detectors and helical and multi-detector scanning modes. As a result, the scope of clinical examinations has broadened considerably, and in parallel, this has been achieved with improvement in image quality and radiation dose efficiency. Despite this, and perhaps because image quality can always be improved at the expense of increased radiation dose, CT examinations are among the highest-dose procedures encountered routinely in medical imaging. The qualitative criteria for acceptability in RP 162 address some functional and operational issues, and the quantitative criteria, in the form of suspension levels, focus primarily around hardware aspects of the CT scanner, though consideration is also given to software, operator aspects and selection of scan protocols. Some of the specific aspects and challenges in modern CT systems, in particular multi-slice and wide beams are also addressed.

Concepts: Medicine, Improve, X-ray, Radiobiology, Radiology, Qualitative research, Scan, Scanner

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Inhibition of the monocarboxylate transporter MCT1 by AZD3965 results in an increase in glycolysis in human tumour cell lines and xenografts. This is indicated by changes in the levels of specific glycolytic metabolites and in changes in glycolytic enzyme kinetics. These drug-induced metabolic changes translate into an inhibition of tumour growth in vivo. Thus, we combined AZD3965 with fractionated radiation to treat SCLC xenografts and showed that the combination provided a significantly greater therapeutic effect than the use of either modality alone. These results strongly support the notion of combining MCT1 inhibition with radiotherapy in the treatment of SCLC and other solid tumours.

Concepts: Cancer, Ionizing radiation, Oncology, Metabolism, Adenosine triphosphate, Tumor, Radiobiology, Glycolysis

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The National Quality Forum (NQF) is a nonprofit consensus organization that recently endorsed a measure focused on CT radiation doses. To comply, facilities must summarize the doses from consecutive scans within age and anatomic area strata and report the data in the medical record. Our purpose was to assess the time needed to assemble the data and to demonstrate how review of such data permits a facility to understand doses.

Concepts: Ionizing radiation, Radiobiology, Sievert, Safety, Patient safety, Gray, Absorbed dose, Equivalent dose