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. 2025 Jul;26(7):e70117.
doi: 10.1002/acm2.70117. Epub 2025 May 9.

Energy dependence of the GAFCHROMIC LD-V1 in the diagnostic radiographic modalities

Tatsuhiro Gotanda  1 , Tomoyuki Hasuo  1 , Shinnosuke Nishihara  1 , Kohsei Matsuura  1 , Yasuyuki Kawaji  2 , Hidetoshi Yatake  3 , Shinya Imai  4 , Takuya Akagawa  5 , Nobuyoshi Tanki  6 , Toshizo Katsuda  7
Affiliations

Energy dependence of the GAFCHROMIC LD-V1 in the diagnostic radiographic modalities

Tatsuhiro Gotanda et al. J Appl Clin Med Phys. 2025 Jul.

Abstract

The GAFCHROMIC LD-V1 radiochromic film is widely used in dosimetry because it can provide high-resolution two-dimensional dose distributions without processing. This study aimed to evaluate the response characteristics at different effective energies, from the low-energy range of mammography to the high-energy range of computed tomography. Net pixel value (NPV)-absorbed dose calibration curves for the GAFCHROMIC LD-V1 were generated using x-rays with effective energies of 18, 30, 50, and 80 keV to reflect those used in different diagnostic radiographic modalities. The film response was analyzed using calibration curves at each energy level. The coefficients of determination for the calibration curves at 18, 30, 50, and 80 keV were 0.9992, 0.9997, 0.9999, and 0.9976, respectively. The pixel value change at 30 keV was the largest and most sensitive, while the smallest change in pixel value and lowest sensitivity were noted at 18 keV. Because the energy dependence of the GAFCHROMIC LD-V1 is significant below 18 keV and above 80 keV, it is necessary to establish an appropriate NPV-absorbed dose calibration curve for energies below 18 keV and consider the possibility of underestimating the dose at energies above 80 keV.

Keywords: GAFCHROMIC LD‐V1; diagnostic radiographic modalities; energy dependence.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
Scanned image of the LD‐V1 after exposure for calibration curve construction for mammography. Regions of interest (ROIs) on the LD‐V1 are shown as white circles with 30‐pixel diameters. LD‐V1, GAFCHROMIC LD‐V1.
FIGURE 2
FIGURE 2
Graphical representation of the LD‐V1 irradiation apparatus. The distance from the x‐ray focus to the LD‐V1 was 600 and 500 mm for (a) mammography and (b) the other diagnostic radiographic modalities, respectively. LD‐V1, GAFCHROMIC LD‐V1.
FIGURE 3
FIGURE 3
Calibration curve of NPV versus the absorbed dose for the LD‐V1. NPV, net pixel value; LD‐V1, GAFCHROMIC LD‐V1; R 2, coefficient of determination.
FIGURE 4
FIGURE 4
Deviation from the fitted calibration curves at different dose levels for each effective energy.
FIGURE 5
FIGURE 5
Relative response of the LD‐V1 for each effective energy when irradiated with 20 mGy based on 30 keV. LD‐V1, GAFCHROMIC LD‐V1.
See this image and copyright information in PMC

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