D-Fructose Chemically Cross-Linked PVA Fricke Gel Sheets as in Vivo Dosimeters and Boluses for Radiotherapy
J Cabahug1,2*, M Bacaling3, R Cruzpero3, M Ceballos3, B Barba2, J Madrid2, (1)University of Santo Tomas Graduate School, Manila, 1015, Philippines, (2)Department of Science and Technology - Philippine Nuclear Research Institute, Quezon City, 1101, Philippines, (3)University of the Philippines-Philippine General Hospital, Manila, 1000, Philippines
Presentations
WE-A-202-2 (Wednesday, 7/13/2022) 7:30 AM - 8:30 AM [Eastern Time (GMT-4)]
Room 202
Purpose: The study demonstrated two-fold work systems which can be simultaneously used as boluses to increase the surface dose and as in vivo dosimeters for verification of surface dose distribution in radiation therapy.
Methods: The dosimetric properties of the fabricated dosimeters such as dose linearity, sensitivity, and stability were characterized using Gammacell-220 and UV–Vis spectrophotometer read-out. The mechanical and chemical properties of the 2D-FR gel dosimeters were characterized in terms of compression test analysis, and FTIR-Analysis and gel fraction, respectively. The Fricke gel sheet dosimeters and EBT3 films surface doses were evaluated through point dose verification at different dose points. The point dose deposition was carried out using a calibrated ROOS® type ionization chamber at the depth of 1.5 cm. The calculated tissue equivalency properties include physical density and relative electron density generated from the physical equation using Archimedes’ Principle, CT and TPS.
Results: The fabricated Fricke-radiochromic gel dosimeters with 0.3 mM D-fructose exhibited best stability response, lowest oxidation rate, linear dose-response (R2 = 0.9868), higher sensitivity (0.080±0.004 Gy-1), and minimum detectable dose (0.110±0.003 Gy) comparable to control. The fabricated Fricke gel sheet is a tissue equivalent material with density value relative to breast, brain, lung, and skeletal muscles. The change in absorbed doses were observed at the point of measurement (d1.5 cm) when 5 mm and 10 mm thick Fricke gel sheets were placed on the top of the slab phantom. The data suggests that the surface dose measurements generated from Fricke gel sheets were relative to the EBT3 films, with percent differences in the absorbed dose of 0.40%, 2.62% and 2.55% in the upper, mid, and lower dose point locations in the mediastinum superficial electron plan.
Conclusion: This preliminary investigation provides significant results on the potential utility of Fricke gel sheets in clinical dosimetry.
Keywords
Not Applicable / None Entered.
Taxonomy
TH- Radiation Dose Measurement Devices: Development (new technology and techniques)
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