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Öğe Boost volume assessment in breast cancer: Preop tumor volume vs clips used in oncoplastic surgery(Elsevier Ireland Ltd, 2016) Altınok, Ayşe Yıldrım; Doyuran, Mine; Çağlar, Mustafa; Canoğlu, Doğu; Küçükmorkoç, Esra; Acar, Hilal; Küçük, Nadir; Çağlar, Hale BaşakThe aim of this study was to compare the volumes obtained with surgical clips during breast conserving surgery of breast cancer patients with volume determined using FDG positive tumor volumes outlined in pre -operative PET-CT imaging and find out the deviations that arise.Öğe Deformable MRI fusion for intracranial SRS: Can we trust?(Elsevier İreland Ltd., 2015) Çağlar, Hale; Küçükmorkoç, Esra; Küçük, Nadir; Altınok, Ayşe; Acar, Hilal; Doyuran, MinePurpose/Objective: The aim of this study is to evaluate the reliability of MRI fusion for the determination of target volume when performing CT based intracranial stereotactic radiosurgery. Materials and Methods: Patients treated with CT based intracranial stereotactic radiosurgery with various diagnoses are included in the study. All patients were immobilized using stereotactic thermoplastic masks prior to simulation. The planning CT was obtained both with and without iv contrast with 1mm slice thickness.Öğe Does preoperative positron emission tomography help delineate the boost volume after oncoplastic surgery for breast cancer?(Kare Publishing, 2017) Yıldırım Altınok, Ayşe; Doyuran, Mine; Çağlar, Mustafa; Çakır, Tansel; Acar, Hilal; Küçükmorkoç, Esra; Küçük, Nadir; Çağlar, Hale; Atasever, TamerOBJECTIVE The tumor bed within the breast shifts during oncoplastic surgery (OPS) for breast cancer (BC). Preoperative imagery is used to determine the boost volume (BV) for patients not implanted with surgical clips. This prospective study was conducted to geometrically compare BVs determined using preoperative imagery and BVs determined utilizing surgical clips. METHODS Patients diagnosed with BC were scanned using PET-CT during 2013-2015. Twenty patients who had undergone OPS but who did not have metastasis underwent CT prior to radiotherapy. Their preoperative images were fused with planning CT images. The tumor volume (CTVboost-pet), as determined from the preoperative PET-CT images, was contoured. Next, CTVboost-clips was determined using surgical clips. Geometric relationships between these two volumes were statistically compared. RESULTS Planar projections of CTVboost-pet and CTVboost-clips were evaluated. Displacements between CTVboost-pet and CTVboost-clips in the axial (XZ) and coronal (XY) planes were 1.17 cm (min-max: 0.03-3.64 cm) and 1.67 cm (min-max: 0.38-4.14 cm), respectively, and were statistically significant (p<0.001), whereas the displacement in the sagittal (YZ) plane was 1.07 cm (min-max: 0.04-4.45 cm) and was not significant (p>0.7). CONCLUSION Preoperative imaging alone was not reliable when determining the BV in patients who had undergone OPS and had no clips. Large PTV margins can be an option to overcome this issue. Surgical clips need to be inserted during OPS.Öğe Dosimetric comparison of linac-based modulated techniques for hippocampal sparing whole brain radiotherapy(Springer Heidelberg, 2020) Acar, Hilal; Altınok Yıldırım, Ayşe; Doyuran, MineObjective Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques were compared in terms of their dosimetric quality, treatment efficiency, and delivery accuracy for hippocampal sparing prophylactic whole brain radiotherapy. Methods Ten previously treated patients were selected for this study. All plans were prescribed to deliver 30 Gy in 10 fractions to 90% of the target volume. RTOG 0933 recommendations were applied for treatment planning. Plans were compared based on the organ at risk (OAR) sparing, homogeneity and conformity indexes, monitor unit (MU), and beam on time (BOT). Delivery accuracy of the plans was also compared. Results VMAT plans had better homogeneity index and conformity index than IMRT plans. In terms of hippocampus sparing, VMAT plans were superior to other plans. Since brainstem, optic nerves, and chiasm were in the PTV, their doses were nearly equal to each other for both techniques. So, there were no statistical differences between techniques. Although both eyes were not in the PTV, there was no significant dose difference between techniques. However, due to the posterior gantry angles of IMRT plans, lens doses were lower in IMRT plans than those in VMAT plans. The VMAT technique had lower MU and BOT values than the IMRT technique. In terms of delivery accuracy, VMAT plans were superior than IMRT plans. Conclusion VMAT plans provide better target volume coverage, homogeneity, conformity, and hippocampus sparing when compared with IMRT plans. VMAT plans are also the best in terms of treatment efficiency since they require a much smaller number of MUs and thus a shorter treatment time than IMRT plans.Öğe Dosimetric evaluation of right coronary artery in radiotherapy for breast cancer(Elsevier Inc., 2019) Yıldırım Altınok, Ayşe; Askeroğlu, Orbay; Doyuran, Mine; Çağlar, Mustafa; Cantürk, Emir; Erol, Cengiz; Şenel Beşe, NuranComparison with control groups of untreated patients suggests that right-breast-cancer patients who receive radiotherapy have a higher rate of heart disease. Dose constraint for heart has been established to minimize radiotherapy-induced cardiotoxicity during left breast cancer treatment. Additionally, it is suggested to minimize the dosage on left anterior descending (LAD) artery. Right coronary artery (RCA), is the second largest artery, after left main coronary artery, supplying the heart. A dose evaluation study is not present for RCA; the proximal part of which is included in the irradiation field during breast cancer treatment of right breast. To investigate the presence of a correlation, doses resulting from right and left breast radiotherapy on proximal RCA (pRCA), LAD, and heart are evaluated in this study. Forty breast cancer patients who went under breast-conserving surgery are the subject of this study. Four groups were established; right breast, right breast and internal mammary (IM), left breast and left breast, and IM. pRCA, LAD, and heart volumes were contoured for each group on the planning tomographies. Resultant doses of tangential fields planning on these volumes were compared using dose-volume histograms. Mean and maximum doses of pRCA were statistically compared between groups. The highest mean and maximum point doses (192 to 284 cGy) were found in the right breast + IM group (p <0.05). The mean and maximum doses only in the right breast and left breast + IM group did not differ statistically. However, the mean and maximum pRCA doses in these 2 groups were higher than only the left breast group (p<0.05). pRCA receives high doses during radiotherapy of right and left breast especially if IM is included. This may predispose to coronary artery disease.Öğe Evaluation of interfractional bladder doses for two different patient positioning methods in prostate cancer(Elsevier Ireland Ltd., 2015) Altınok, Ayşe; Acar, Hilal; Rzazade, Rashad; Küçük, Nadir; Küçükmorkoç, Esra; Doyuran, Mine; Mabhouti, H.; Çağlar, Hale BaşakPurpose/Objective: MR imaging following needle implantation in high dose rate brachytherapy (HDR BT) provide more anatomical details for improved definition of the prostate gland, organs at risk, and needles. The purpose of this study was to evaluate the introduction of MRI guided HDR BT, including time consumption, dose volume parameters, and changes over time. Materials and Methods: A team of radiation oncologists, physicists, radiologists, and nurses was trained to perform MRI guided HDR BT. Between September 2012 and November 2014, 42 consecutive high risk prostate cancer patients received two times HDR BT of each 8.5 Gy after EBRT. Time was recorded for initiation of anaesthesia, end of ultrasound guided needle implantation, MR scan, and HDR BT delivery.Öğe Feasibility investigation of prone position robotic radiosurgery treatment for dorsal metastasis(Elsevier Ireland Ltd, 2017) Küçükmorkoç, Esra; Küçük, Nadir; Doyuran, Mine; Acar, Hürtan; Canoğlu, Doğu; Rashad, Radwaa; Çağlar, Hale BaşakThe combination of Adaptive Radiotherapy (ART) and VMAT allows to create more conformal plans for patients with bladder cancer without risk of missing target during changes of bladder volume and shape. Relative position of small bowel is influenced by the volume of treated bladder. Recent reviews demonstrated the advantages of using ART in bowel sparing during bladder irradiation. The aim of this study was to assess feasibility of simultaneous sparing of bone marrow, small bowel and rectum using combination of ART and VMAT.Öğe Investigation of the accuracy of different lung SBRT plans created in multiplan treatment planning system(Wiley, 2017) Cebe, Mehmet Ata; Mabhouti, H.; Pacaci, P.; Serin, L.; Şanlı,Elif; Yıldırım, Sami; Eşitmez, Dursun; Küçük, Nadir; Doyuran, Mine; Küçükmorkoç, Esra; Çağlar, Mete; Canoğlu, Doğu; Rzazade, Rashad; Acar, Hilal; Özkök, H. Çağlar[Abstract Not Available]Öğe Right coroner artery assessment in radiotherapy of breast cancer(Elsevier Ireland Ltd, 2017) Altınok Yıldırım, Ayşe; Askeroğlu, Orbay; Çağlar, Mustafa; Doyuran, Mine; Cantürk, Emir; Erol, Cengiz; Beşe, NuranThe risk of developing coronary ischemic heart disease and the radiation doses to heart and left anterior descending coronary artery (LAD) have been very well documented in breast cancer patients who underwent radiotherapy (RT). On the other hand, there is limited information regarding the right coronary artery (RCA) doses which feeds the heart in 48% of the human population. In this study proximal RCA (pRCA) doses are evaluated in the treatment plans of breast cancer patients who underwent RT.Öğe The analysis of different diagonal profiles Used for commissioning in eclipse(American Association of Physicists in Medicine, 2015) Mabhouti, H.; Acar, Hilal; Küçük, Nadir; Küçükmorkoç, Esra; Doyuran, Mine; Çağlar, Mustafa; Altınok, Ayşe; Cebe, Mehmet; Yıldır, G.; Çağlar, Hale BaşakPurpose: The effect of diagonal profiles measured with different types of detectors to the improvement of the quality of the algorithm configuration is analysed. Methods: For commissioning of Truebeam STx machine, Eclipse requires a diagonal profiles of the largest field size. The left side of the beam profile with 5cm overscan at depths of 30cm for a 40×40cm2 field at 100cm SSD was scanned. The scan was made using PTW 0.125cc semiflex ionization chamber and PTW microDiamond with 0.004mm3 sensitive volume. Two different machnines were created in Eclipse with the same beam data except for diagonal profiles. A single 6 FFF beam with zero gantry and collimator angle for 10×10cm2 field size was planned on the CT scan of RW3 solid water. The dose calculation was done with 1mm grid size using AcurosXB v13 algorithm. Dose profile measurements were made in a RW3 solid water phantom at depths of 5, 10, 15cm using EBT3 Gafchromic film extending from field edge up to 15cm. The gamma index analysis of measured and calculated dose profiles were compared. Result: For the plan using semiflex configured machine, the measured and the calculated dose distributions gamma analysis passing rate was 98.1% within ±2% dose difference and ±2mm distance?to?agreement for in field doses. However they decreases to 96.8% for out of field doses. For the plan using microDiamond configured machine had 98.9% passing rate for ±2% in field but it decreases to 97.6% for out of field doses. Although passing rates were increasing with the depth for in field doses they were decreasing with depth for out of field doses. Conclusion: Diagonal profiles are used for source configuration in Eclipse. Because of that it can be advisable to use fine resolution detector.Öğe The analysis of different percentage depth dose curves used for commissioning in eclipse(Wiley, 2015) Cebe, Mehmet; Acar, Hilal; Küçük, Nadir; Küçükmorkoç, Esra; Doyuran, Mine; Çağlar, Mustafa; Altınok, Ayşe; Yilidir, G.; Mabhouti, H.; Çağlar, HalePurpose: Percentage Depth Doses (PDDs) used for balance fitting of the calculation model in Eclipse. The effect of PDD curves measured with two different detectors for the commissioning of Truebeam STx machine to the improvement of the quality of the algorithm configuration is analysed. Methods: The measurement of open field PDD for 2×2cm2 to 40×40cm2 field sizes were done with two different detector types. The scan was made using 0.125cc semiflex thimble ionization chamber (PTW TM31010) and PTW 60019 microDiamond with 0.004mm3 sensitive volume. Two different machines were created in Eclipse with the same beam data except for PDD measured with two different detector types. A single 6 FFF beam with zero gantry and collimator angles for 2×2, 3×3, 5×5cm2field sizes were planned on the CT scan of RW3 solid water. The dose calculation was done with 1mm grid size using AcurosXB v13 algorithm using two different machine created. PDD measurements were made in a RW3 solid water phantom using EBT3 Gafchromic film extending from surface to 30cm. The gamma index analysis of measured and calculated PDD curves were compared. Result: For the plan made using machine configured with semiflex measured PDD curves, the measured and the calculated dose distributions for 2×2cm2 field size gamma analysis passing rate was 97.6% within 2% dose difference and 2mm distance-to-agreement. For the plan made using machine configured with microDiamond measured PDD curves had 98.1% passing rate for ±2% in field but the passing rates. Passing rates were increasing with the field sizes. For 5×5cm2 field size they are 98.3% and 99.1% respectively. Conclusion: The agrement with treatment planning system and measurement was better when fine resolution detector was used especially for small field sizes.Öğe The effect of adaptive planning on target and critical structures during radiation treatment for locally advanced lung cancer(Elsevier Science, 2015) Çağlar, Hale; Küçükmorkoç, Esra; Altınok, Ayşe; Küçük, Nadir; Doyuran, Mine; Acar, Hilal[Abstract Not Available]Öğe The effect of depth and control point number for MLC transmission and dosimetric leaf gap(Elsevier Ireland Ltd., 2015) Küçükmorkoç, Esra; Doyuran, Mine; Çağlar, Mustafa; Küçük, Nadir; Acar, Hilal; Altınok, Ayşe; Çağlar, HalePurpose/Objective: MLC transmision (MLCT) and dosimetric leaf gap (DLG) in Treatment Planning System (TPS) are important parameters for dose calculation and they provide accuracy of delivering IMRT plans. MLCT and DLG account the leakage of MLC and the effect of rounded leaf ends, respectively. The aim of this study is to examine control point (CP) and depth dependance for MLCT and DLG. Materials and Methods: MLCT and DLG parameters were measured with PTW 0.125 cc semi-flex ionization chember in a solid water phantom for Varian Trilogy machine with Millenium MLC. MLCT measurements were obtained 15x15cm2 field size at different depths (Dmax,5,10 and 15cm) for 6 MV photon beam. To derive the DLG measurement , a series of Sliding Window (SW) fields of 2,4,7,10,15 and 20 mm gap widths were used. These SW fields were prepared with different number of CP (2,3,5,7,9,11,13,16 and 21) and DLG measuremets were performed at same depths and field size. DLG values were calculated for each depth using MLCT parameters which were measured at same depth.Öğe The effect of thermoplatic mask to the surface dose in sterotactic brain treatments with flattening filter free beams with ebt3 gafchromic film and osl dosimeter(American Association of Physicists in Medicine, 2015) Yılıdır, G.; Acar, Hilal; Küçük, Nadir; Küçükmorkoç, Esra; Doyuran, Mine; Çağlar, Mete; Yıldırım Altınok, Ayşe; Cebe, Mehmet Ata; Mabhouti, H.; Çağlar, Hale BaşakAbstractPurpose:The surface dose of flattening filter free beams is higher than conventional flattening filter beams. In this study, The effect of thermoplatic mask to the surface dose in sterotactic brain treatments was compared using EBT3 Gafchromic film and OSL dosimeter.Methods:Treatment planning were done using 2 full arc VMAT technique with 6 FFF beam on the CT scan of Randophantom simulating the treatment of sterotactic treatments for one brain metastasis.1×1 cm2 Gafchromic EBT 3 film pieces were placed under the thermoplastic mask on the lens of the phantom. Then OSL dosimeter was also placed at the same way in the same place. Then phantom was irradiated without mask with film and OSL again. The surface doses with or without mask was compared for film and OSL dosimeter seperately.Results:The calibration of film and OSL dosimetry were done at first. Surface dosemeasurements made using the EBT3 film showed good agreement with results of the OSL dosimetry for standard fields of FFF beams within the measurement uncertainty of 3.1%. The surface dose determined using EBT3 film was found to change from 57 % to 93 % to with the mask. The surface dose determined using OSL dosimeter was found to change from 56 % to 93 % to with the mask. This study also demonstrates the suitability of Gafchromic EBT3 film and OSL dosimeter for surface dose measurements in FFF beams.Conclusion:The skin sparing effect FFF beams are lower than conventional beams. Significant bolus effect on skin dose in the presence of thermoplastic mask was seen. The skin reactions resulting from thermoplastic masks should be monitored especially for FFF beams and corrective measures should be taken during treatment to avoid skin toxicity.
