Browsing by Author "Efe, Esma"

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    Dosimetric Analysis of Testicular Doses in Prostate Intensity-Modulated and Volumetric-Modulated Arc Radiation Therapy at Different Energy Levels
    (2016) Onal, Cem; ArsIan, Gungor; Dolek, Yemliha; Efe, Esma; 0000-0002-2742-9021; 27623736; D-5195-2014
    The aim of this study is to evaluate the incidental testicular doses during prostate radiation therapy with intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc radiotherapy (VMAT) at different energies. Dosimetric data of 15 patients with intermediate-risk prostate cancer who were treated with radiotherapy were analyzed. The prescribed dose was 78 Gy in 39 fractions. Dosimetric analysis compared testicular doses generated by 7-field intensity-modulated radiotherapy and volumetric modulated arc radiotherapy with a single arc at 6, 10, and 15 MV energy levels. Testicular doses calculated from the treatment planning system and doses measured from the detectors were analyzed. Mean testicular doses from the intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy per fraction calculated in the treatment planning system were 16.3 +/- 10.3 cGy vs 21.5 +/- 11.2 cGy (p = 0.03) at 6 MV, 13.4 +/- 10.4 cGy vs 17.8 +/- 10.7 cGy (p = 0.04) at 10 MV, and 10.6 +/- 8.5 cGy vs 14.5 +/- 8.6 cGy (p = 0.03) at 15 MV, respectively. Mean scattered testicular doses in the phantom measurements were 99.5 +/- 17.2 cGy, 118.7 +/- 16.4 cGy, and 193.9 +/- 14.5 cGy at 6, 10, and 15 MV, respectively, in the intensity-modulated radiotherapy plans. In the volumetric-modulated arc radiotherapy plans, corresponding testicular doses per course were 90.4 +/- 16.3 cGy, 103.6 +/- 16.4 cGy, and 139.3 +/- 14.6 cGy at 6, 10, and 15 MV, respectively. In conclusions, this study was the first to measure the incidental testicular doses by intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy plans at different energy levels during prostate-only irradiation. Higher photon energy and volumetric-modulated arc radiotherapy plans resulted in higher incidental testicular doses compared with lower photon energy and intensity-modulated radiotherapy plans. (C) 2016 American Association of Medical Dosimetrists.
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    Dosimetric Comparison of Sequential Versus Simultaneous-integrated Boost in Early-stage Breast Cancer Patients Treated With Breast-conserving Surgery
    (2019) Onal, Cem; Efe, Esma; Guler, Ozan C.; Yildirim, Berna A.; 0000-0001-6908-3412; 31662554; AAC-5654-2020
    Background/Aim: To compare simultaneous-integrated boost (SIB) versus sequential-boost (SB) delivered in the context of whole-breast irradiation (WBI) via volumetric-modulated arc therapy (VMAT) and helical-tomotherapy (HT). Materials and Methods: Planning target-volume (PTV) dosimetric parameters and organs at risk (OAR) were analyzed for SB plan (50 Gy plus 16 Gy boost) and SIB plan (50.4 Gy WBI and 64.4 Gy tumor bed boost) in VMAT and HT techniques. Results: Conformity and homogeneity for target-volume doses were better in HT plans compared to VMAT plans. There were no significant differences in ipsilateral lung doses between VMAT and HT plans for SB/SIB techniques, except for a significantly higher lung V5 value with VMAT-SB, and lung V13 value with HT-SIB technique. HT provided a statistically significant decrease in contralateral lung mean V5. Conclusion: The SIB technique showed better target-volume dose distribution in both HT and VMAT plans, and better sparing heart in HT compared to the SB technique.