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    Antiapoptotic effect of l-carnitine on testicular irradiation in rats
    (Springer, 2010) Kanter, Mehmet; Topcu-Tarladacalisir, Yeter; Parlar, Sule
    We evaluated the effects of l-carnitine on apoptosis of germ cells in the rat testis following irradiation. Male Wistar rats were divided into three groups. Control group received sham irradiation plus physiological saline. Radiotherapy group received scrotal gamma-irradiation of 10 Gy as a single dose plus physiological saline. Radiotherapy + l-carnitine group received scrotal irradiation plus 200 mg/kg intraperitoneally l-carnitine. Twenty-four hours post-irradiation, the rats were sacrificed and testes were harvested. Testicular damage was examined by light and electron microscopy, and germ cell apoptosis was determined by terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) technique. Morphologically, examination of irradiated testis revealed presence of disorganization and desquamation of germinal cells and the reduction in sperm count in seminiferous tubule lumen. Under electron microscopy, the morphological signs of apoptosis were frequently detected in spermatogonia. Apoptotic spermatogonia showed the marginal condensation of chromatin onto the nuclear lamina, nucleus and cytoplasm shrinkage and still functioning cell organelles. TUNEL-positive cells were significantly more numerous in irradiated rats than in control rats. l-carnitine treatment significantly attenuated the radiation-induced morphological changes and germ cell apoptosis in the irradiated rat testis. In conclusion, these results suggested that l-carnitine supplementation during the radiotherapy may be beneficial for spermatogenesis following testicular irradiation by decreasing germ cell apoptosis.
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    Breast Cancer Radiotherapy-induced Cardiotoxicity
    (Kare Publ, 2022) Nurlu, Dilek; Cosar, Rusen; Parlar, Sule; Uzal, Cem
    In the multimodality treatment of breast cancer, adjuvant radiotherapy (RT) has an important role in achieving local control and increasing survival. Cardiac toxicity due to breast RT, especially left-sided breast RT, is rare but clearly recognizable. As overall survival rates are steadily increasing, long-term toxicities also become increasingly important in terms of late cardiac events, possibly caused by RT. Even small doses for the heart are thought to increase the risk of cardiac toxicity. Advanced radiation techniques such as intensity-modulated radiation therapy, volumetric-modulated arc RT, deep inspiration breath-hold techniques, and prone positioning for pendular breast can eliminate the heart from the primary beams. In addition to mean heart dose, breast cancer RT planning should also include constraints for cardiac subvolumes. Especially for patients who have pre-existing such as cardiovascular disease, diabetes mellitus, dyslipidemia, arterial hypertension, lifestyle factor (tobacco smoking, alcohol, physical inactivity, and poor nutrition), and physicians have to be careful about cardiotoxicity. Radiation oncologists and cardiology specialists should provide closely cooperating regular and long-term followup. This will provide the improvement of patient outcomes.
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    Does Gender Difference Effect Radiation-Induced Lung Toxicity? An Experimental Study by Genetic and Histopathological Predictors
    (Radiation Research Soc, 2022) Cosar, Rusen; Ozen, Alaattin; Tastekin, Ebru; Sut, Necdet; Cakina, Suat; Demir, Selma; Parlar, Sule
    Several studies have reported differences in radiation toxicity between the sexes, but these differences have not been tested with respect to histopathology and genes. This animal study aimed to show an association between histopathological findings of radiation-induced lung toxicity and the genes ATM, SOD2, TGF-beta 1, XRCC1, XRCC3 and HHR2. In all, 120 animals were randomly divided into 2 control groups (male and female) and experimental groups comprising fifteen rats stratified by sex, radiotherapy (0 Gy vs. 10 Gy), and time to sacrifice (6, 12, and 24 weeks postirradiation). Histopathological evaluations for lung injury, namely, intra-alveolar edema, alveolar neutrophils, intra-alveolar erythrocytes, activated macrophages, intra-alveolar fibrosis, hyaline arteriosclerosis, and collapse were performed under a light microscope using a grid system; the evaluations were semi quantitatively scored. Then, the alveolar wall thickness was measured. Real-time quantitative reverse transcription PCR (RT-qPCR) was used to determine gene expression differences in ATM, TGF-beta 1, XRCC1, XRCC3, SOD2 and HHR2L among the groups. Histopathological data showed that radiation-induced acute, subacute, and chronic lung toxicity were worse in male rats. The expression levels of the evaluated genes were significantly higher in females than males in the control group, but this difference was lost over time after radiotherapy. Less toxicity in females may be attributable to the fact that the expression of the evaluated genes was higher in normal lung tissue in females than in males and the changes in gene expression patterns in the postradiotherapy period played a protective role in females. Additional data related to pulmonary function, lung weights, imaging, or outcomes are needed to support this data that is based on histopathology alone. (C) 2022 by Radiation Research Society
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    The effect of ion chamber volume on intensity-modulated radiotherapy small field dosimetry
    (Elsevier, 2022) Parlar, Sule; Uzal, Cem
    The use of appropriate equipment during the measurements required for a treatment planning system (TPS) directly affects the quality of treatment. The present study investigates the effect of small field output factors (OF) obtained with ion chambers of different volumes on intensity-modulated radiotherapy (IMRT) treatment plans. Three different beam models (BM65, BM13, BM04) were created at TPS using small fields OFs measured by ion chambers with three different volumes, i.e. 0.65, 0.13 and 0.04 cc respectively. IMRT plans with the same features were designed for these models. The difference between the calculated and measured doses at dose distributions for each IMRT plan was investigated using point-dose measurement and gamma index method. The OF values obtained with a 0.65 cc ion chamber were significantly different, especially in small fields. The greatest difference in point-dose measurements made in IMRT plans was observed in the plans produced in the BM65 beam model. There was no significant difference in gamma passing rate (GPR) values in 2D array measurements. Inaccurate OF values obtained during small-field measurements is one of the important parameters that affect dosimetric accuracy. Therefore, using different dosimetric methods in quality assurance during TPS commissioning may allow to detect measurement errors, especially in small-field measurements.
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    The Effects of Micronuclei with Whole Chromosome on Biological Dose Estimation
    (Tubitak Scientific & Technological Research Council Turkey, 2008) Pala, Funda S.; Alkaya, Fadime; Tabakcioglu, Kiymet; Tokatli, Fuesun; Uzal, Cem; Parlar, Sule; Alguenes, Cetin
    The total micronucleus (MN) assay has been used for purposes of biological dosimetry for many years. The variable spontaneous incidence of micronuclei in peripheral blood lymphocytes affects the sensitivity of biological dose estimations at low doses. It has been suggested that this problem could be solved by using the micronuclei-centromere assay. In this study. Co-60 gamma ray dose response curves for micronuclei (MN) and micronuclei without centromeres (MNC-) in the range of 0-5.0 Gy were established using a pancentromeric FISH probe on cultured binucleate lymphocytes from 2 donors. There were no significant inter-donor differences in the dose responses for either MN or MNC-. The relative proportions of MN that contained centromeres (MNC+) decreased with radiation dose, which is in line with the proposition that radiation predominately causes chromosomal breakage rather than whole chromosome loss. The a coefficients of MNC- curves decreased to 62% of the values for total MN whilst the beta coefficients were unchanged. MN and MNC+ frequencies of 60 control smoker and 40 non-smoker donors were also compared. No effect of smoking was observed. However the MNC+ spontaneous frequencies showed an age and gender effect with the highest frequencies in older women.
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    Investigation of awareness level concerning radiation safety among healthcare professionals who work in a radiation environment
    (Taylor & Francis Ltd, 2021) Zekioglu, Aysu; Parlar, Sule
    Radiation safety has become more important issue due to increased use of ionizing radiation in diagnosis and treatment. The aim of this study is to investigate the awareness and knowledge level concerning radiation safety among healthcare professionals who work in a radiation environment. The study population consisted of healthcare professionals who work in a radiation environment at a state hospital, a university hospital and a private hospital in Edirne province. The survey used in this study was prepared by the investigators after reviewing previous studies on similar subjects, and opinions were sought from experts in relevant fields. The survey consists of two parts and a total of 28 questions. Results of this study revealed that the rate of correct answers was 68.6% for questions on radiation safety among all healthcare professionals. The present study demonstrated an insufficient level of knowledge and awareness on radiation safety, even in the occupational groups that continuously work in a radiation environment. Periodic trainings should be conducted in hospitals. Pre-test and post-test exercises should be performed in order to increase the effectiveness of the trainings, and interactive case studies specific to the clinic should be included in the program. Finally, with electronic learning programs which may be implemented at national level, all relevant persons would have access to these programs.