Fakülteler / Faculties
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Item Incidental testicular doses during volumetric-modulated arc radiotherapy in prostate cancer patients(2020) Onal, Cem; Bozca, Recep; Dolek, Yemliha; Guler, Ozan Cem; Arslan, Gungor; 0000-0001-6908-3412; 0000-0002-2742-9021; 32125635; AAC-5654-2020; D-5195-2014Purpose To compare the incidental testicular doses during volumetric-modulated arc therapy (VMAT) in patients receiving prostate-only and pelvic lymphatic irradiation. Materials and methods Testicular doses in 40 intermediate- and high-risk prostate cancer patients were determined on treatment planning system (TPS) using the VMAT technique at 6 MV. Scattered testicular doses were also measured by MOSFET detectors placed on testis surface. The testicular doses of patients treated with prostate-only and pelvic field irradiation were compared. Results The median testicular doses measured per 200 cGy fraction by TPS and MOSFET detectors were 1.7 cGy (0.7-4.1 cGy) and 4.8 cGy (3.6-8.8 cGy), respectively. The TPS doses and MOSFET readings showed a significant strong correlation (Pearson r = 0.848, p < 0.001). The testicular doses measured by TPS (1.34 +/- 0.36 cGy vs. 2.60 +/- 0.95 cGy; p < 0.001) and MOSFET (4.52 +/- 0.64 cGy vs. 6.56 +/- 1.23 cGy; p < 0.001) were significantly lower in patients with prostate-only irradiation than in those with pelvic field irradiation. The mean cumulative scattered dose for prostate-only field delivering 78 Gy was 1.8 Gy and that for pelvic field irradiation was 2.6 Gy, consistent with the reported findings. Conclusions The patients with prostate-only irradiation received lower testicular doses than those with additional pelvic field irradiation possibly due to the increased scattered doses in large field irradiation using the VMAT technique. The clinical response to increased incidental testicular doses due to pelvic field irradiation remains unknown, and it warrants further investigation.Item The Comparison of Helical-IMRT, Direct-IMRT and 3D Radiotherapy Modalities in Breast Radiotherapy Planning(2020) Erdis, Eda; Yucel, Birsen; Ozyurek, Betul; Bozca, RecepOBJECTIVE This study aims to compare dosimetric 3D-CRT, Tomo-helical mu and Direct IMRT methods in intact breast irradiation. METHODS Radiotherapy was planned with three different techniques simulated images of 30 breast cancer patients with negative lymph nodes who underwent breast-conserving surgery. RESULTS The maximum and minimum doses, homogeneity and conformity index and cold-zone volumes were found to be different in all three techniques (p<0.001). The PTV boost maximum doses and homogeneity index were found to be different (p<0.001). The maximum non-PTV dose (110% volume) and the hot zone volumes grasped by these doses, the V5 volume of the body and V5 volumes, outer of PTV were found to be statistically significant for all three techniques (p<0.001). A statistically significant difference was found between the three techniques concerning the ipsilateral lung V5 and V20 volumes, the contralateral lung V5 and V10 volumes and the counter breast maximum and mean doses (p<0.001). The mean and V10 volume of the heart was statistically significant (p<0.001), while the left breast irradiation and mean values were not statistically significant between the three techniques (p=0.529). However, there was a statistically significant difference in the V10 volume of the left breast irradiation between the three techniques (p=0.033). CONCLUSION According to 3D-CRT, it is possible to achieve better dose distribution and dose homogeneity with Tomo-helical and direct IMRT. Low dose volumes arc high with tomo-helical IMRT. Torno-helical IMRT planning provides better ipsilateral lung and heart doses but causes an increase in heart dose/contralatcral breast and for right breast irradiation causes an increase in heart dose