Fakülteler / Faculties

Permanent URI for this communityhttps://hdl.handle.net/11727/1395

Browse

Filters

2020 - 20233

Settings

Author: search.filters.author.Bozca, Recep

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Comparison of Helical and TomoDirect Techniques with Simultaneous Integrated Boost in Early Breast Cancer Patients
    (REPORTS OF PRACTICAL ONCOLOGY AND RADIOTHERAPY, 2023) Onal, Cem; Bozca, Recep; Oymak, Ezgi; Guler, Ozan Cem
    Background: The aim of the study was to perform dosimetric comparisons of helical (H) and TomoDirect (TD) plans for whole-breast irradiation (WBI) with simultaneous integrated boost (SIB) in early-stage breast cancer patients undergoing breast conserving surgery.Materials and methods: Fifty patients, 25 with left-side and 25 with right-side tumors, were determined for a treatment planning system for a total dose of 50.4Gy in 1.8Gy per fraction to WBI, with a SIB of 2.3Gy per fraction delivered to the tumor bed. The planning target volume (PTV) doses and the conformity (CI) and homogeneity indices (HI) for PTV(breast )and PTVboost, as well as organ-at-risk (OAR) doses and treatment times, were compared between the H and TD plans.Results: All plans met the PTV coverage criteria for the H plan, except for mean V107 of PTVbreast for TD plan. The H plan yielded better homogeneity and conformity of dose distribution compared to the TD plan. The ipsilateral mean lung doses were not significantly different between the two plans. The TD plans is advantageous for mean doses to the heart, contralateral breast and lung, spinal cord, and esophagus than the H plans. In both the H and TD plans, the right-sided breast patients had lower heart dose parameters than the left-sided breast patients. The TD plan is superior to the H plan in sparing the contralateral breast and lung by decreasing low-dose volumes.Conclusions: While the OAR dose advantages of TD are appealing, shorter treatment times or improved dose homogeneity and conformity for target volume may be advantageous for H plan.
  • No Thumbnail Available
    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-5195-2014
    Purpose 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.
  • No Thumbnail Available
    Item
    The Comparison of Helical-IMRT, Direct-IMRT and 3D Radiotherapy Modalities in Breast Radiotherapy Planning
    (2020) Erdis, Eda; Yucel, Birsen; Ozyurek, Betul; Bozca, Recep
    OBJECTIVE 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