Retrospective investigation of the dosimetric comparison of low and high energy fotons in VMAT treatment planning of cervical cancer patients


Thesis Type: Postgraduate

Institution Of The Thesis: Bursa Uludağ University, Tıp Fakültesi, Dahili Tıp Bilimleri, Turkey

Approval Date: 2019

Thesis Language: Turkish

Student: ABDULHAMİT TURAN

Supervisor: Candan Demiröz Abakay

Abstract:

In this study, 20 patients who had RT with the diagnosis of cervical cancer were planned by using the VMAT technique. Conformity index (CI) and homogeneity index (HI) were also compared for target volumes. Using CT images of the patients treated in our clinic, 4 different treatment techniques were planned for each patient, including 6 MV single arc, 6 MV double arc, 15 MV single arc, 15 MV double arc. VMAT plans are prepared in Monaco TPS, which uses the Elekta linear accelerator. Using the Monte Carlo algorithm, the target volume was prepared to receive a dose of 50.4 Gy from 25 fractions. The dose distribution of the virtual plans for PTV and risky organs (bladder, rectum, right-left femur and small intestine) was examined with the help of DVH and the appropriate tests were performed in SPSS program for statistical analysis. As a result; No significant differences were found between low photon energy and high photon energy in terms of critical organ doses. In this study in which cervical cancer cases were evaluated, although the use of single and double arteries in the VMAT technique did not show a significant difference in terms of critical organ doses, the lowest values were obtained from 6 MV double arc technique. Therefore, photon energy of 6 MV may be the prudent choice for pelvic radiotherapy.