ESTRO 2023 - Abstract Book

S1516

Digital Posters

ESTRO 2023

Conclusion We developed three simple AP/PA techniques to treat frail TSEBT patients in the recumbent position. While 300 cm SSD supports better uniformity laterally, there may be advantages to the supine/prone positioning with the SSD=170 cm technique. These techniques are only intended for urgent treatments of a few fractions, as dosimetry is not ideal. The conventional standing technique should be used as soon as possible.

PO-1793 Commissioning of radio-photoluminescent dosimeters for postal dosimetry audits

A. Dimitriadis 1 , G. Ule-Duque 1 , P. Kazantsev 1 , R. Abdulrahim 1 , G. Azangwe 1 , J. Swamidas 1

1 International Atomic Energy Agency, Nuclear Sciences and Applications, Division of Human Health, Vienna, Austria

Purpose or Objective To report the commissioning of radio photoluminescent dosimeters (RPLDs) for dosimetry audits and to investigate the sensitivity differences within the batch. Materials and Methods RPLDs type FD-7 (Chiyoda Technol Corporation, Japan) (n=1000), made of silver activated phosphate glass, 12 mm long and 1.5 mm in diameter, with an atomic composition of 0.17% of Ag, 6.12% of Al, 11.0% of Na, 31.55% of P and 51.16% of O, were commissioned. The RPLDs were annealed at 400 °C and irradiated with a dose of 2 Gy in a 10 × 10 cm2 field using a gamma beam from Co-60 unit (Nordion X200), in a water equivalent plastic phantom set up at an SSD of 95 cm with the dosimeters at a depth of 5 cm. A custom-made insert was used during the irradiations, accommodating 10 RPLDs into two vertical lines of 5 RPLDs in each, 1.4 cm to the left and right of the vertical beam axis. Position correction factors for each RPLD were applied to account for the small dose variations due to the beam profile. After irradiation, the RPLDs were preheated at a temperature of 70°C to enhance the stability of the signal and cleaned in an ethanol bath to remove any dirt or dust that would influence the signal. The reading process was carried out by four different operators on three different readers (Dose Ace FGD-1000), which resulted in six readings for each dosimeter. The signal fading was considered negligible as the gap between the irradiation date and the reading dates ranged from 10 to 43 days, corresponding to insignificant fading correction differences of <0.1%. The six reading sessions were processed, and the signals acquired were corrected so that any factors that are not related to RPLD sensitivity are removed. The corrections applied were to account for the reading magazine dependence, the room temperature dependence, and the position during irradiation.

Results