Gastrointestinal Sistem Kanserli Hastalarda Mide Doluluğunun Radyoterapiye Etkisi

Abstract

In the treatment of gastrointestinal system (GIS) cancers, radiotherapy (RT) is frequently applied as three dimensional conformal RT (3BKRT) or intensity adjusted RT (YART). GIS tumors are very sensitive to environmental organ movements due to their location. Changes in the volume of organs, such as the patient's hungry or fullness, the intestines being full or empty, can change the intended target volumes to be irradiated and cause more irradiation of the RAO. For this reason, it is very important to ensure the same conditions of the patient in all treatments during and after the simulation process in terms of the correctness of the treatment. Otherwise, target abduction may result in reduced local-regional control rates and increased toxicity. In this thesis study, the effect of the change in stomach fullness (empty versus full) target coverage and RAO doses in patients with upper GI cancer was examined. Ten patients who underwent surgery with adjuvant RT and diagnosed with stomach cancer (n = 5) and pancreatic cancer (n = 5) were included. Two computerized tomography (CT) images were taken of the patients for planning purposes. After the target volumes and RAOs are contoured on the CT sections, 3DCRT (3field, 3field1 and 4field) and YART (5field and 7field) plans have been made. As a result 10 treatments were planned, 5 in the stomach empty and 5 in the full and the same radiation oncologist tried to determine the best planning technique by comparing dose distribution and RAO doses. We also examined changes in target volume and RAO doses in the case of patients entering with full stomach instead of empty stomach. In the dosimetric part of our study, measurements were taken with thermoluminescence dosimeter (TLD) and Gafochromic EBT3 films using Aldersonrando phantom. According to the results obtained from the treatment planning system (TPS) in patients with stomach and pancreatic cancer, there was no significant difference in the target volume doses from empty to full stomach in 3DCRT or YART plans. When compared treatment plans with empty stomach, the best planning technique for patients with pancreatic cancer is the 7field YART and in patients with stomach cancer, it was found to be a 4field 3DCRT technique. When assessed together with doses of RAO, the 7field YART technique is considered the best planning technique. When the TLD measurement results are compared with the data obtained from the TPS in the 7th YART plans, the difference values are between 1,15% and 8,08% in the plans containing the empty stomach and 1,49% and 5,49% in the plans involving the full stomach. When the TPS and Gafochromic EBT3 film measurement results are compared, the % difference values are between 1.20% and 3.99% on planes containing empty stomach and between 0.65% and 3.34% on planes containing full stomach. When the patients entered with full stomach instead of empty stomach, there was a significant decrease in target volume doses in both pancreas and stomach cancer cases. In conclusion, the most important point in terms of the correctness and reproducibility of treatment in patients with upper gastrointestinal cancer is that the gastric filling is the same throughout the treatment period. For this purpose, each clinic should prepare its own treatment protocol and this protocol should be explained to patient and patient relatives before treatment.