:: Volume 24, Issue 4 (11-2016) ::
Journal of Ilam University of Medical Sciences 2016, 24(4): 61-70 Back to browse issues page
Influence of Compensator Thickness and Field Size on the Effective Attenuation Coefficient of a Brass Compensator for Intensity-Modulated Radiation Therapy
Elnaz Balvasi1 , Abas Haghparast2 , Payman Hejazi * 3
1- Dept of Medical Physics, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
2- Dept of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
3- Dept of Medical Physics, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran , hejazip@semums.ac.ir
Abstract:   (5444 Views)

One of the intensity modulated radiation therapy (IMRT) methods is based on using compensators. The most important factor in designing a compensator is the accurate calculation of its thickness to achieve the intensity modulation of interest. To achieve that, the exact attenuation coefficient of compensator materials must be calculated.Using MapCHECK 2 model 1177 and phantom (SP34). We studied the effect of compensator thickness and field size on the calculation of the effective attenuation coefficient (EAC) of the brass compensator for 6-MV photon beams.

Experimental measurements were carried out at 100 cm source-to-surface distance and 5 cm depth for the 6-MV photon beams of an Elekta  linac using various field size and compensator thickness. The field sizes investigated ranged from 1×1 cm2 to 20×20 cm2 and the brass compensator thickness from 0.5-6 cm. Our results indicated that the compensator thickness and field size have the most significant effect on the calculation of the compensator EAC for the 6-MV photon beam and also these parameters can reduce the error due to delivered dose to target volume and organs at risk.

Keywords: Intensity modulated radiation therapy, Compensators, Brass, Effective attenuation coefficient
Full-Text [PDF 666 kb]   (2045 Downloads)    
Type of Study: Research | Subject: Medical physics
Received: 2015/06/20 | Accepted: 2015/09/19 | Published: 2016/11/5



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Volume 24, Issue 4 (11-2016) Back to browse issues page