Vulva Kanserinde Elektron-YART Hibrit Tedavi Modalitesinin Tedavi Planlama Sistemi ve Dozimetrik Yöntemlerle İncelenmesi

Abstract

In recent years, in the treatment of vulvar cancer, intensity modulated radiation therapy (IMRT) have been used instead of 3 dimensional conformal radiotherapy (3DCRT). In this thesis study, 7 patients who were diagnosed and treated for cancer of the vulva, have been analyzed with using 3DCRT, IMRT and a combination of electron-IMRT hybrid plans in the terms of the comparison of the target volume, critical organs and normal tissue integral dose (NTID) were reviewed. The study examined for wide-field radiation therapy region, which the vulvar cancer patients in the region of the diseased vulva, as well as the surrounding lymphatic region also enters in the treatment area. In electron-IMRT hybrid treatment modalities, the tissues of critical organs are better protected with electrons for treatment advantage of the rapid dose fall off while maintaining alone, intensity modulated radiation therapy (IMRT) is caused increase in normal tissue integral dose in the treatments decreased with the hybrid treatment modality. For CTV D98%, D2%, Dmax and Dmean values; for PTV D95%, D5%, Dmax and Dmean values are examined and a comparison was made in three different planning techniques. Also for critical organs; volumes and doses of V40Gy and Dmax for bladder and rectum, V35Gy and Dmax for the small bowel, Dmax and V50Gy for femoral heads were analyzed. In the dosimetric part of the thesis Alderson Rando woman phantom (25 - 35 section interval) CT scans were taken and contoured the target volumes and critical organs. TPS was observed in the axial cross section for determined the TLD points and then taking measurements in those points. The measurement process was also defined on EBT3 gafchromic films. By using gafchromic films is provided to measure the dose on the skin of the vulva. TLD measurement results compared with TPS doses in the range of 0.9% to 13% differences were taken, while gafchromic film measurements were in 0.2% to 4.2% range. According to TLD, gafchromic EBT3 films were given better results in hybrid planning applications. According to the data obtained from the treatment planning system, critical organ doses in both the 3DCRT and IMRT techniques were found higher than electron-IMRT hybrid technique. Rather than two others, in the technique of Electron-IMRT hybrid treatment, significant decline was observed in the values of NTID (p = 0.018). In conclusion, electron-IMRT technique in vulvar cancer, both it present acceptable better coverage in targets and desirable dose coverage in vulva skin and also better agreements with dose limits in critical structures and NTID.