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Öğe The Effect of Positional Movement of a Semiflexible Applicator on Dose Distrubutions in Low Dose Rate Brachytherapy for Cervical Carcinoma(Ortadogu Ad Pres & Publ Co, 2010) Kucucuk, Seden; Kemikler, Gonul; Okutan, Murat; Aslay, Isik; Disci, Rian; Alas, Rusen Cosar; Tore, GokhanObjective: Current study aims to detect the movements of a semiflexible applicator (TORE's applicator) in the first 24 hours and to analyze its effect on the calculated point A, bladder and rectum doses in low dose rate brachytherapy (LDR-BT) applications. Material and Methods: Eighty films were evaluated on 18 cervical carcinoma patients (20 applications) who were treated with curative radiotherapy. The comparison of the reference points and doses at critical organs were performed by using a reference axis which was fixed to bony landmarks in the pelvis. To evaluate the movement of the applicator, distance of the upper point and lower point of the tandem to the reference axis were measured. Additionally, the angular deviation of the applicator was tested. Results: The movements of the upper point and lower point of the tandem in x, y, z axes were 5.30 +/- 6.33 mm, 2.80 +/- 2.24 mm, 6.65 +/- 8.33 mm and 3.45 +/- 4.32 mm, 3.75 +/- 3.59 mm, 3.05 +/- 3.08 mm, respectively. The mean differences were 3.30 +/- 2.99 degrees in alpha-angle and 5.65 +/- 4.76 degrees in beta-angle. The mean percent dose changes in point A, bladder and rectum were 1.5 +/- 1.2%, 3.7 +/- 3.1%, 4.4 +/- 4.0%, respectively. Conclusion: Our study demonstrates that there are some movements of the applicator during LDR-BT, however these movements do not result in significant dose changes in target volumes and critical organs. Therefore, positional correction is not required. In conclusion, CT-compatible TORE's applicator that allows an advantage for CT-based 3D planning is useful and safe for brachytherapy.Öğe Treatment Planning Comparison of Intensity Modulated Arc Therapy and CyberKnife Techniques in Early Stage Glottic Larynx Radiotherapy(2022) Alay, Serdar; Göksel, Evren Ozan; Toraman, Kübra Özkaya; Okutan, Murat; Demir, BayramWe aimed to compare two radiotherapy techniques (the robotic-based linear accelerator Stereotactic Body Radiotherapy (SBRT) and linear accelerator-based Intensity Modulated Arc Therapy (IMAT)) dosimetrically on Early Glottic Larynx Cancerx (EGL) treatment plans in the terms oftarget volume and critical organ doses. The computerized tomography (CT) images of 15 patients treated with EGLdiagnosis were used retrospectively. The Planning Target Volumes (PTV) was generated with a margin of 0.5 cm from the laryngeal volume. The PTV dose was defined as 45Gy delivered in 10 fractions within each of treatment plans. At least 95% of PTV treatment volumes (D95%) were to receive the treatment dose. The average PTV volume was 95.56 cm3 (range: 68.8 cm3 - 142.6 cm3). The average D98%, D2% and Dmean values of PTV were lower in IMAT plan than in CK plan. In CK plans, the mean ofthe spinal cord maximum dose (Dmax) for all patients was statistically significantly lower than in IMAT plans. Dmax and Dmean values for the right and left carotid arteries was significantly lower in IMAT plans. Also, the Dmean value of thyroid gland was significantly lower in IMAT plans. Our dosimetric comparison study made using images of 15 EGL cancer patients shows that the desired critria for the critical organ doses can not reached with CK plans, especially when the treatment volume is large.