Quality Control of Acuity-Varian Radiotherapy Simulator System

Mansour Zabihzadeh,Sholeh Arvandi,Mohammad Birgani

doi:10.13005/bpj/941

Abstract

One of the main and primarily phase to success of radiotherapy is accurately localization of the target volume and health peripheral tissues by radiotherapy simulator. The aim of this study is to investigate the some specific quality control tests necessary to provide adequate confidence of radiotherapy simulator performance Various essential parameters for quality control of Acuity- Varian radiotherapy simulator such as matching of mechanical measurements and electrical readouts, isocenter check, Congruence between optical field and radiation field, laser positioning system, kVp accuracy of X-ray beam, flat panel performance (resolution and low contrast sensitivity), etc were checked by quality control test tools. All investigated tests for matching of mechanical measurements and electrical readouts of field size, rotation and movement of table, gantry and flat panel detector were within the tolerance limits. The accuracy and reproducibility of KV passed the acceptable values. All the lasers were aligned with isocenter. However resolution of flat panel was within tolerance limit but low contrast sensitivity was not passed. The various quality control tests carried out on Acuity-Varian radiotherapy simulator were within recommended limits except the low contrast sensitivity that is in borderline of tolerance.

Highlights

Reaching to the maximum probabilities of tumor control without severe normal tissue damage, still remains as the major challenge in radiotherapy 1
A conventional radiotherapy simulator is a Kv x-ray machine and detector, that is attached to a machine that emulates the movements of a radiotherapy treatment machine as linear accelerator (Linac)
In developed countries the ssimulator fluoroscopy have been replaced by the modern CT simulator, due to its inability to accurately distinguish the different densities of areas, such as bone and air, but it is useful for checking radiotherapy plans and planning palliative treatments very quickly and efficiently 3

Summary

Introduction

Reaching to the maximum probabilities of tumor control without severe normal tissue damage, still remains as the major challenge in radiotherapy 1. Among the many important proccess to obtain this end point of radiotherapy, one of the main and primarily phase is the localization of the tumor volume which is to receive the prescribed dose and the peripheral critical normal tissues which is to receive minimum possible dose 2. This process is so called as simulation. It makes possible to produce x-ray images from the patient body under positioning conditions simulating a Linac and make it possible to control of all parameters on the treatment plan such as the field size, beam directions, collimator setting, etc.

Objectives

Methods

Results