Prog Med Phys.  2021 Dec;32(4):179-184. 10.14316/pmp.2021.32.4.179.

Dosimetric Characteristics of Flexible Radiochromic Film Based on LiPCDA

• Jung S
• Cho JD
• Kim Ji
• Park JM
• Choi CH

• KMID: 2524166
• DOI: http://doi.org/10.14316/pmp.2021.32.4.179

Abstract

This study aimed to determine the optimal thickness of the active layer and scan mode for a flexible radiochromic film (F-RCF) based on the active lithium salt of pentacosa-10,12-diynoic acid (LiPCDA). F-RCFs of 90, 120, 140, and 170-μm thickness were fabricated using LiPCDA. Several pieces of the F-RCFs were exposed to doses ranging from 0 to 3 Gy. Transmission and reflection modes were used to scan the irradiated F-RCFs. Their dose-response curves were obtained using a second-order polynomial equation. Their sensitivity was evaluated for both scanning modes, and the uniformity of the batch was also examined. For both the transmission and reflection modes, the sensitivity increased as the film thickness increased. For the reflection mode, the dose response increased dramatically under 1 Gy. The value of the net optical density varied rapidly as the thickness of the film increased. However, the dose-response curves showed a supralinear-curve relationship at doses greater than 2 Gy. The sensitivity of the reflection scan at doses greater than 2 Gy was higher than that of the reflection scan within 0–2 Gy. The sensitivity steadily decreased with increasing doses, and the sensitivity of the two modes was within 0.1 to 0.2 at 2 Gy and was saturated beyond that. For the transmission scan, the sensitivity was approximately 0.2 at 3 Gy. For the intra-batch test result, the maximum net optical density difference of the intra-batch was 5.5% at 2 Gy and 7.4% at 0.2 Gy in the transmission and reflection scans, respectively. In the low-dose range, film thickness of more than 120-μm was proper in the transmission mode. In contrast, the transmission mode showed a better result compared to the reflection mode. Therefore, the proper scan mode should be selected according to the dose range.

Keyword

Radiochromic film; LiPCDA; Reflection; Transmission; Dosimetry

Figure

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  Fig. 1 Calibration curve for various thicknesses of the flexible radiochromic film within the range of 0–3 Gy in the transmission mode (a) and reflection mode (b). netOD, net optical density.

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  Fig. 2 Sensitivity as a function of the dose in the transmission mode (a) and reflection mode (b).

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  Fig. 3 Intra-batch test in a manufactured single batch. netOD, net optical density.

Reference

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