A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

Radiation Oncology

Pushkar Desai¹  Blas Caroprese¹  Christopher F Njeh² 

[1] East Texas Medical Center, Radiation Oncology Department, ETMC_Cancer Institute, 721 Clinic Drive, Tyler 75701, TX, USA;Physics Department, Queensland University of Technology, Brisbane, Australia

关键词: Computed radiography;    Electronic portal images device;    Linear accelerator;    Light field;    Radiation field;    Quality assurance;   

Others  :  1160867
DOI  :  10.1186/1748-717X-7-49

 received in 2011-12-30, accepted in 2012-03-27,  发布年份 2012

【 摘 要 】

Background

The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field.

Method

A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID) or computed radiography (CR). We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system.

Results

Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance.

Conclusion

The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence.

【 授权许可】

   
2012 Njeh et al; licensee BioMed Central Ltd.

【 图 表 】

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