Clinical evaluation of a dose management system-integrated 3D skin dose map by comparison with radiochromic films

Abstract

Objectives: To validate the performance of an automatic tool to estimate a patient's peak skin dose (PSD) and a skin dose map from data collected by a radiation dose management system (RDMS) during interventional procedures.

Methods: In total, 288 eligible consecutive patients undergoing abdominopelvic embolisation or planned coronary angioplasty using radiochromic films were screened between June 2018 and March 2019. For 98 included patients, PSD was measured using radiochromic films (PSD_Film) and computed by RDMS (PSD_RDMS) using one flat and two anthropomorphic phantoms. Statistical concordance between PSD_Film and PSD_RDMS was computed with Lin's concordance correlation coefficient and clinical concordance with the Bland and Altman graphic; values were compared using the paired Mann-Whitney-Wilcoxon test.

Results: In total, 190/288 patients were excluded and 98 patients were analysed (69 men, mean age 66 ± 14 years). The PSD_Film median (1st; 3rd quartile) was 0.59 Gy (0.40; 1.08). PSD_RDMS was 0.62 Gy (0.43; 1.22) for the flat phantom and 0.62 Gy (0.42; 1.19) for anthropomorphic phantoms. The concordance between PSD_Film and PSD_RDMS was good for both phantoms (flat: 0.94 [0.91; 0.95]; anthropomorphic 0.94 [0.91; 0.96]). Compared with the values of PSD_Film, the values of PSD_RDMS were significantly increased by 5% (- 4%; 16%) for flat phantom (p = 0.001) and 7% (- 6%; 22%) for anthropomorphic phantoms (p = 0.002) for vascular procedures and 9% (- 4%; 26%, p = 0.01) and 6% (- 4%; 23%, p = 0.02) for cardiac procedures, respectively. Dose map representations matched for most patients. The gaps identified were due to table displacement during fluoroscopy events and the use of a wedge filter.

Conclusions: The RDMS skin dose map tool allowed the computation of the PSD and skin dose distribution for all patients with fewer constraints than radiochromic films. However, the computed PSD was overestimated, increasing the number of patients requiring follow-up.

Key points: • A good concordance correlation was identified between the peak skin dose (PSD) values measured with radiochromic films and estimated with the radiation dose management system (RDMS) skin dose map tool. • Differences were related to table displacement during fluoroscopy events and the use of a wedge filter, which are not accounted in the Digital Imaging and Communications in Medicine Radiation Dose Structured Reports. • For all procedures, the estimated PSDs were significantly higher than the measured PSDs by 5% (- 4%; 18%) for flat phantom (p < 0.001) and 6% (- 5%; 22%) for anthropomorphic phantoms (p < 0.001).

Keywords: Film dosimetry; Fluoroscopy; Physics; Radiology, interventional.