Since guidelines regarding low-dose-rate radiation have yet to be established, there are no systematic protocols followed in studies examining these types of radiation. However, studies on mice suggest that low-dose-rate radiation does not damage stem spermatogonia and probably stimulates repair in damaged spermatogonial stem cells. Spermatogonia are especially sensitive to irradiation doses as low as 0.1 Gy may damage these cells. Abnormalities include low sperm counts, increased abnormal spermatozoa, and defective sperm function. Such adverse events in the testis result in several abnormalities in spermatogenesis, potentially resulting in temporary or permanent infertility. Ionizing radiation disturbs normal metabolism, proliferation and differentiation, which may lead to mutagenesis, apoptosis, and necrosis of radiosensitive cells. The latter are particularly susceptible to radiation-induced injury, and infertility is a common post-irradiation problem. Irradiation has long been established as an iatrogenic male reproductive toxin, as it can affect normal cells, especially rapidly proliferating ones such as spermatogenic cells. Side-effects from radiation exposure can reduce the quality of life and can be dose limiting, leading to potential treatment reduction for patients with testicular cancer. In particular, the association between accumulated radiation dose and adverse effects has not been clearly elucidated.Īs one of the most radiosensitive organs, the testis can be significantly functionally impaired by very low doses of radiation. However, these studies do not adequately account for the systemic responses of low-dose-rate radiation. In contrast, low-dose (≤0.2 Gy) radiation has been reported to exert various beneficial effects in living organisms. High doses and high-dose-rate radiation have been shown to be detrimental, causing cell death. The systemic effect of radiation increases in proportion to the dose amount and rate. In conclusion, the damage exerted on the testes and epididymis largely depended on the total dose of low-dose-rate radiation. The expressions of DNA methlytransferases-1 and histone deacetylases 1 in testes irradiated with 2 Gy were significantly decreased compared with the sham group. The sperm count and motility in the epididymis also decreased in mice irradiated with 2 Gy at 1 and 9 days after exposure, whereas there was no significant effect on the proportion of abnormal sperm. Moreover, the low-dose-rate radiation exposure induced an increase in malondialdehyde levels, and a decrease in superoxide dismutase activity in the testis of mice irradiated with 2 Gy at 1 and 9 days after exposure. Testicular weight, seminiferous tubular diameter, and seminiferous epithelial depth were significantly decreased in the mice irradiated with 2 Gy at 1 and 9 days after exposure. C57BL/6 mice were divided into sham and radiation groups ( n = 8 each), and were exposed to either sham irradiation or 2 Gy for 21 days, 0.2 Gy for 2 days, or 0.02 Gy for 6 h of low-dose-rate irradiation. Low-dose protocols are needed to reduce radiation exposure from these methods and minimise associated health risks.This study examined the effects of continuous low-dose-rate radiation exposure (3.49 mGy/h) of gamma rays on mice testicles. New 3D volumetric hip and spine quantitative computed tomography (QCT) techniques and high-resolution MDCT for evaluation of bone structure deliver doses to patients from 1 to 3 mSv. Methods based on multi-detector CT (MDCT) are associated with higher radiation doses. Dose optimisation is more important for paediatric examinations because children are more vulnerable to radiation than adults. When an examination is justified, the emphasis must be on dose optimisation of imaging protocols. However, as with any X-ray imaging technique, each particular examination must always be clinically justified. Radiation doses associated with dual-energy X-ray absorptiometry are very low. This article provides (a) a brief review of the current X-ray methods used for quantitative assessment of the skeleton, (b) data on the levels of radiation exposure associated with these methods and (c) information about radiation safety issues. Recent advances in medical X-ray imaging have enabled the development of new techniques capable of assessing not only bone quantity but also structure. Radiation exposure in X-ray-based imaging techniques used in osteoporosis Radiation exposure in X-ray-based imaging techniques used in osteoporosisĭamilakis, John Adams, Judith Guglielmi, Giuseppe Link, Thomas