Study On Application Of Multi-wire Ionization Chamber For Real-time Monitoring Of Dose And MLC

Intensity Modulated Radiation Therapy (IMRT) often form multi-segmentedirregular fields using multi-leaf (MLC) of linear accelerator (LINAC), and its shapingsizes and doses will lead to conform the tumor target and modulate the field beams fordelivering the radiation treatment on patient. How to ensure the precision of MLC leafand accuracy of dose delivered from LINAC is more critical during the course oftreatment. It is also important to ensure the effectiveness of accurate radiotherapy.This study analyzed the performance and characteristics of DAVID real-timemonitoring device, and was done for the feasibility and practicality of monitoringfunctions during treatment. Multi-wire ionization chamber (DAVID) is a kind of newequipment for quality assurance, which is used to monitoring the position and dose fromMLC field in a real-time way during the course of treatment. Based on the influence ofblocking the field beam during the measurement of DAVID, evaluation for DAVIDdetection accuracy of the radiation field and repetitive doses in different field sizes, andassessment of DAVID detection capabilities for the error of the field and dose, thetheoretical and experimental basis were found in the clinical application of DAVIDsystem for real-time monitoring. Comparing with the data of real-time measurement inIMRT treatment, the effectiveness and clinical value of DAVID system weresummarized and developed.The results in the study showed that verification and monitoring of MLC leafposition and dose accuracy were able to be achieved using DAVID system duringradiotherapy. However, there were also some limitations on DAVID application, soattentions should be taken and overcome in practice.