Feasibility study of the Fricke chemical dosimeter as an independent dosimetric system for the small animal radiation research platform (SARRP). (March 2020)

• Record Type: Journal Article
• Authors: Muñoz Arango, Erika; Pickler, Arissa; Mantuano, Andrea; Salata, Camila; de Almeida, Carlos Eduardo
• Is Part Of: Physica medica. Volume 71(2020)
• Page Start: 168
• Page End: 175
• Publication Date: 2020-03
• Subjects: Fricke dosimetry -- SARRP -- X-ray beam dosimetry -- Preclinical radiation research; 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.2020.03.006
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: Code of Practice for dosimetry of non-standard X-ray beams of medium energy is not available. Methodologies for dosimetry of non 10 × 10 cm 2 field size are necessary. The Fricke is feasible for dose to water determination in X-ray beams of medium energy. The Fricke is feasible for dosimetry at high doses and high dose rates in X-ray beams. Fricke is suitable for dose verifications in a variety of preclinical irradiation configurations. Abstract: For the small animal radiation research platform (SARRP) with X-ray beams in the medium energy range (tube operating voltage at 220 kVp), reference dosimetry is based on the AAPM TG-61 recommendations following the in-phantom method. The objective of this study was to evaluate the feasibility of the Fricke solution as a dosimeter to determine the absorbed dose to water. Feasibility studies at this X-ray energy range are not widely available. We evaluated the accuracy, dose linearity and dose rate dependence in a comparison with an NE 2571 Farmer ionization chamber (IC) and measurements in water. The G(Fe 3+ ) factor was calculated from the curve fitting of the chemical yields for two radioactive sources ( 192 Ir and 60 Co) and one X-ray system with a tube operating at 150 and 250 kVp. The same methodology was followed for the dependence of the G(Fe 3+ ) value on the energy and the dose agreement assessment for 180 and 200 kVp in the SARRP. The Fricke system exhibits a good linear response over the range of 5–70 Gy and an accuracy better than 2% for a 2 Gy/min dose rate. The dose rate dependence is smaller than 1% for dose rates greater than 1 Gy/min. The dependence of the G(Fe 3+ ) value on the energy is smaller than 0.41%, with dose agreements better than 2%. The feasibility of the dosimeter for measurements at high doses and high dose rates makes it a suitable tool for dosimetric verifications in several preclinical irradiation configurations.