Scopus İndeksli Yayınlar Koleksiyonu

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Subject: search.filters.subject.Brachytherapy

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    Definitive Brachytherapy in Inoperable Endometrial Cancer
    (2019) Onal, Cem
    In elderly patients with medical comorbidities that increase perioperative risks, surgery cannot be performed, and definitive radiotherapy (RT) is a therapeutic option. Although staging for endometrial cancer is based on surgical findings, clinical and radiological imaging has not been standardized yet. For a radiological evaluation of inoperable endometrial cancer, magnetic resonance imaging (MRI) is preferred for local tumor infiltration, and positron emission tomography is accepted as the most accurate modality for assessing lymph node and distant metastases. External RT alone is inadequate, and intracavitary brachytherapy with or without external RT is recommended depending on the disease stage in patients with inoperable endometrial cancer. However, there is currently no standard treatment approach for patients with inoperable endometrial cancer. For patients with inoperable endometrial cancer treated with definitive RT, there are some problems including the RT technique, treatment volumes, and systemic treatment. Based on clinical practice, image-based brachytherapy using computed tomography and magnetic resonance imaging is highly recommended.
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    Dosimetric comparison of vaginal vault brachytherapy vs applicator-guided stereotactic body radiotherapy with volumetric modulated arc therapy and helical tomotherapy for endometrium cancer patients
    (2019) Yildirim, Berna Akkus; Dolek, Yemliha; Guler, Ozan Cem; Arslan, Gungor; Onal, Cem; 0000-0001-6908-3412; 0000-0001-6661-4185; 0000-0002-2742-9021; 30551844; AAC-5654-2020; D-5195-2014
    We performed this dosimetric study to compare a nonstandard volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) techniques with high-dose rate (HDR) brachytherapy (BRT) plan of vaginal vault in patients with postoperative endometrial cancer (EC). Twelve postoperative patients with early stage EC were included in this study. Three plans were performed for each patient; dosimetric and radiobiological comparisons were made using dose-volume histograms and equivalent dose for determining the planning target volume (PTV) coverages in brachytherapy and external beam radiotherapy, and organs-at-risk (OARs) doses between three different delivery techniques. All the plans achieved adequate dose coverage for PTV; however, the VMAT plan yielded better dose conformity, and the HT plan showed better homogeneity for target volume. With respect to the OARs, the bladder D-2cc was significantly lower in the BRT plan than in the VMAT and HT plans, with the highest bladder D-2cc value being observed in the HT plan. However, no difference was observed in the rectum D-2cc of the three plans. Other major advantages of the BRT plan over the VMAT and HT plans were the relatively lower body integral doses and femoral head doses as well as the fact that the integral doses were significantly lower in the BRT plan than in the VMAT and HT plans. This is the first dosimetric comparison of vaginal vault treatment for EC with BRT, VMAT, and HT plans. Our analyses showed the feasibility of stereotactic body radiotherapy technique as an alternative to HDR-BRT for postoperative management of EC patients. (C) 2018 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.
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    Effects of vaginal cylinder position on dose distribution in patients with endometrial carcinoma in treatment of vaginal cuff brachytherapy
    (2017) Ozdemir, Yurday; Dolek, Yemliha; Onal, Cem; 0000-0002-2218-2074; 0000-0002-2742-9021; 28725246; AAG-5629-2021; D-5195-2014
    Purpose: To investigate the impact of different cylinder positions on dosimetry of critical structures in patients with endometrial carcinoma undergoing three-dimensional image-based vaginal cuff brachytherapy (VCB). Material and methods: We delivered VCB at a dose of 4 Gy to a depth of 5 mm in the vaginal cuff of 15 patients using three different cylinder positions (neutral [N], parallel [P], and angled [A]) according to the longitudinal axis of the patient. We analyzed the dose-volume distribution and volumetric variability of the rectum and bladder. We converted the total doses to equivalent doses in 2 Gy (EQD(2)) using a linear-quadratic model (a/b = 3 Gy). Results: The mean rectum volume for the N, P, and A positions was 68.2 +/- 22.7 cc, 79.3 +/- 33.7 cc, and 74.2 +/- 29.6 cc, respectively. The mean rectum volume for the P position was significantly larger than that for the N position (p = 0.03). Relative to the N position, the A position resulted in a lower total EQD(2) in the highest irradiated 2 cc (D-2cc; p = 0.001), 1 cc (D-1cc; p = 0.004), and 0.1 cc (D-0.1cc; p = 0.047) of the rectum. Similarly, the P position resulted in a lower EQD(2) in the D-2cc (p = 0.018) and D-1cc (p = 0.024) of the rectum relative to the N position. In the bladder, the P position resulted in a higher EQD(2) in the D-2cc, relative to the N position (p = 0.02). There was no dosimetric difference between the P and A positions in either the rectum or the bladder. Conclusions: Vaginal cuff brachytherapy in the P and A positions is significantly superior to that in the N position in terms of rectum dosimetry. The bladder dose in the N position is considerably lower than that in the other positions.