Estimation of Patient Lens Dose Associated With C-Arm Cone-Beam Computed Tomography Usage During Interventional Neuroradiology

Abstract

The purpose of this study was to investigate the dose distribution and lens doses associated with C-arm cone-beam computed tomography (CBCT), using a head phantom, and to estimate the contribution ratio of C-arm CBCT to each patient’s lens dose during interventional neuroradiology (‘lens dose ratio’) in 109 clinical cases. In the phantom study, the peak skin doses and respective right and left lens doses of C-arm CBCT were as follows: 63.0 ± 1.9 mGy, 19.7 ± 1.4 mGy and 21.9 ± 0.8 mGy in whole brain C-arm CBCT and 39.2 ± 1.4 mGy, 4.7 ± 0.9 mGy and 3.6 ± 0.3 mGy in high-resolution C-arm CBCT. In the clinical study, the lens dose ratios were 25.4 ± 8.7% in the right lens and 19.1 ± 9.8% in the left lens. This study shows that, on average, ~25% of patients’ total lens dose was contributed by C-arm CBCT.

Optimization of the Maximum Skin Dose Measurement Technique Using Digital Imaging and Communication in Medicine—Radiation Dose Structured Report Data for Patients Undergoing Cerebral Angiography

“…The skin dose (D skin,RPLGD ) from the patient's head to their neck was measured using the RADIREC ® system [3,[21][22][23][24][25]. This system consists of 64 RPLGDs (GD-302M, Chiyoda Technol, Corporation, Tokyo, Japan), which are passive dosimeters, placed on a special cap that covers the entire circumference of the head.…”

“…This system consists of 64 RPLGDs (GD-302M, Chiyoda Technol, Corporation, Tokyo, Japan), which are passive dosimeters, placed on a special cap that covers the entire circumference of the head. The maximum skin dose (D skin,max,RPLGD ) can thus be obtained from the dose distribution and measurements at these 64 points [24,25].…”

“…Diagnostics 2021, 11, 14 6 of 17 (Dskin,max,RPLGD) can thus be obtained from the dose distribution and measurements at these 64 points [24,25].…”

“…It was shown that the correlation between K a,r and the directly measured D skin,max is high, and if the K a,r values are measured accurately, D skin,max can be sufficiently predicted by indirect measurement through K a,r . We previously estimated the D skin,max for patients undergoing NIR using a RADIREC ® system (Chiyoda Technol Corporation, Tokyo, Japan) (Scheme 1a) [3,[21][22][23][24][25]. However, the greatest disadvantages of using the RADIREC system, a passive dosimeter system with 64 radio-photoluminescence glass dosimeters (RPLGDs) (GD-302M, Chiyoda Technol Corporation, Tokyo, Japan), for measuring the dose in a single patient are the time and effort required to obtain readouts from the RPLGDs, which make it impracticable to ascertain the D skin,max in real time during NIR and to take measures at the right time to avoid damaging patient skin.…”

“…As an alternative method, we analyzed the D skin,max measured by the RADIREC system (D skin,max,RPLGD ) and the total air kerma at the patient entrance reference point (Total K a,r ) in the same patient among an appropriate number of patients (approximately 50). We used the ratio of the D skin,max,RPLGD and the Total K a,r (D skin,max,RPLGD /Total K a,r ) as the Total K a,r to the D skin,max,Ka conversion factor (CF Ka,constant ) (Scheme 1b) [21][22][23][24][25]. Using this CF Ka,constant enabled the D skin,max (D skin,max,Ka ) to be estimated from the Total K a,r in real time during procedures, thereby enabling the operator to be warned when the dose approaches the thresholds for skin reddening and hair loss at 2 and 3 Gy, respectively.…”