A Study of Usefulness on Respiratory Control Methods During Radiotherapy of Hepato-biliary System

Objectives: In the radiation therapy of cancer that occurs in hepatobiliary system, we want to compare and study the usefulness of the method to minimize movement of tumor by using artificially respiratory control device (Abdominal Compressor: AC) and the inducing respiratory control equipment (Abches System: AS). Methods/Statistical Analysis: For the purpose of the present study, analysis is conducted by acquiring images of free breathing(FB), artificially AC and inducing AS respectively of 30 patients. Findings:Results of the analysis to the subjects in 3 specific groups Analysis results of 3 patients groups according to the movement of tumor controlled by three methods is the following. Average ITV and PTV are reduced in AC and AS group by 42.0% and 32.6% respectively. In reproducibility, the variation values are lateral (RL) direction (X) -0.28 ± 0.65mm, vertical (SI) direction (Y) 0.02 ± 1.22mm, and (AP) direction (Z) 0.29 ± 1.55mm. Among the three-target-groups of patients, the maximum error occurs in FS which are side (RL) direction (X) -0.77 ± 1.65mm, vertical (SI) direction (Y) 0.05 ± 3.4mm, and (AP) direction (Z) 5.7 ± 2.86mm so that AC and AS group have less error and better reproducibility. Statistical analysis on tumor volume (ITV,PTV) of 3 specific group shows reduction of volume in respiratory control group. The most reduction is in AC apply from 1468.3±446.8 cc in FB to 757.7±210.3 cc in AC((p<0.00). Application/Improvements: In conclusion, radiation therapy is to protect normal tissues, with the aim of suppressing tumors so the motion associated with respiration during radiation therapy is minimized. Fractionated radiation therapy and high dose 1 fraction radiation therapy demands great reproducibility and appropriate respiratory control for site- specific tumor needs to be considered.