Open AccessMonte Carlo‐based beam quality and phantom scatter corrections for solid‐state detectors in 60 Co and 192 Ir brachytherapy dosimetry
Author(s) -
Subhalaxmi Mishra,
Selvam T. Palani
Publication year - 2014
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1120/jacmp.v15i6.4907
Subject(s) - scintillator , imaging phantom , detector , physics , monte carlo method , diamond , dosimetry , optics , beam (structure) , brachytherapy , solid angle , materials science , nuclear medicine , composite material , medicine , statistics , mathematics , radiation therapy
Beam quality correction, k QQ 0( r ) , for solid‐state detectors diamond, LiF, Li 2 B 4 O 7 , Al 2 O 3 , and plastic scintillator are calculated as a function of distance, r, along the transverse axis of the60Co and192Ir brachytherapy sources using the Monte Carlo‐based EGSnrc code system. This study also includes calculation of detector‐specific phantom scatter correction, k phan ( r ) , for solid phantoms such as PMMA, polystyrene, solid water, virtual water, plastic water, RW1, RW3, A150, and WE210. For60Co source, k QQ 0( r ) is about unity and distance‐independent for diamond, plastic scintillator, Li 2 B 4 O 7 and LiF detectors. For this source, k QQ 0( r ) decreases gradually with r for Al 2 O 3 detector (about 6% smaller than unity at 15 cm). For192Ir source, k QQ 0( r ) is about unity and distance‐independent for Li 2 B 4 O 7 detector (overall variation is about 1% in the distance range of 1–15 cm). For this source, k QQ 0( r ) increases with r for diamond and plastic scintillator (about 6% and 8% larger than unity at 15 cm, respectively). Whereas k QQ 0( r ) decreases with r gradually for LiF (about 4% smaller than unity at 15 cm) and steeply for Al 2 O 3 (about 25% smaller than unity at 15 cm). For60Co source, solid water, virtual water, RW1, RW3, and WE210 phantoms are water‐equivalent for all the investigated solid‐state detectors. Whereas polystyrene and plastic water phantoms are water‐equivalent for diamond, plastic scintillator, Li 2 B 4 O 7 and LiF detectors, but show distance‐dependent k phan ( r ) values for Al 2 O 3 detector. PMMA phantom is water‐equivalent at all distances for Al 2 O 3 detector, but shows distance‐dependent k phan ( r ) values for remaining detectors. A150 phantom shows distance‐dependent k phan ( r ) values for all the investigated detector materials. For192Ir source, solid water, virtual water, RW3, and WE210 phantoms are water‐equivalent for diamond, plastic scintillator, Li 2 B 4 O 7 and LiF detectors, but show distance‐dependent k phan ( r ) values for Al 2 O 3 detector. All other phantoms show distance‐dependent k phan ( r ) values for all the detector materials. PACS numbers: 87.10.Rt, 87.53.Bn, 87.53.Jw