Determination of field output correction factors of radiophotoluminescence glass dosimeter and CC01 ionization chamber and validation against IAEA-AAPM TRS-483 code of practice. (August 2021)

• Record Type: Journal Article
• Authors: Yabsantia, Sumalee; Suriyapee, Sivalee; Phaisangittisakul, Nakorn; Oonsiri, Sornjarod; Sanghangthum, Taweap; Mirzakhanian, Lalageh; Heng, Veng Jean; Seuntjens, Jan
• Is Part Of: Physica medica. Volume 88(2021)
• Page Start: 167
• Page End: 174
• Publication Date: 2021-08
• Subjects: egs_chamber -- Field output correction factors -- Radiophotoluminescence glass dosimeter -- Small field dosimetry; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2021.07.004
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: The egs_chamber determined the field output correction factors of RPLGD and CC01. The field output correction factors were validated against IAEA-AAPM TRS-483. The parallel orientation improved the small field output factors of RPLGD. The volume averaging effect was small for RPLGD in parallel orientation. RPLGD in parallel orientation is practical for field sizes down to 0.6 × 0.6 cm 2 . Abstract: Purpose: To determine the field output correction factors of the radiophotoluminescence glass dosimeter (RPLGD) in parallel and perpendicular orientations with reference to CC01, the ionization chamber. Methods: The dose to a small water volume and the sensitive volume of the RPLGD and the IBA-CC01 were determined for 6-MV, 100-cm SAD, 10-cm depth using egs_chamber user-code. The RPLGD in perpendicular and parallel orientations to the beam axis were studied. The field output correction factors of each detector for 0.5 × 0.5 to 10 × 10 cm 2 field sizes were determined. These field output correction factors were validated by comparing field output factors against data determined from IAEA-AAPM TRS-483 code of practice. Results: The field output correction factors of all detectors were within 5% for field sizes down to 0.8 × 0.8 cm 2 . For 0.5 × 0.5 cm 2, the field output correction factors of CC01, RPLGD in perpendicular and parallel orientations differed from unity by 14%, 19%, and 5%, respectively. The percentage difference between field output factors determined using RPLGD and CC01 data, corrected using the field output correction factors determined in this work and measurements with CC01 data corrected using TRS-483, was less than 3% for all field sizes, except for the smallest field size of RPLGD in perpendicular orientation and the CC01. Conclusions: The field output correction factors of RPLGD and CC01 are reported. The validation proves that RPLGD in parallel orientation combined with the field output correction factors is the most suitable for determining the field output factors for the smallest field used in this study.