In response to the International Commission on Radiological Protection, which lowered the lens equivalent dose limit, Japan lowered the lens dose limit from 150 mSv y⁻¹ to 100 mSv/5 years and 50 mSv y⁻¹, with this new rule taking effect on 1 April 2021. DOSIRIS^® is a dosimeter that can accurately measure lens dose. Herein, we investigated lens dose in interventional cardiology physicians 1 year before and after the reduction of the lens dose limit using a neck dosimeter and lens dosimeter measurements. With an increase in the number of cases, both personal dose equivalent at 0.07 mm depth [Hp(0.07), neck dosimeter] and personal dose equivalent at 3 mm depth [Hp(3), lens dosimeter] increased for most of the physicians. The Hp(3) of the lens considering the shielding effect of the Pb glasses using lens dosimeter exceeded 20 mSv y⁻¹ for two of the 14 physicians. Protection from radiation dose will become even more important in the future, as these two physicians may experience radiation dose exceeding 100 mSv/5 years. The average dose per procedure increased, but not significantly. There was a strong correlation between the neck dosimeter and lens dosimeter scores, although there was no significant change before and after the lens dose limit was lowered. This correlation was particularly strong for physicians who primarily treated patients. As such, it is possible to infer accurate lens doses from neck doses in physicians who primarily perform diagnostics. However, it is desirable to use a dosimeter that can directly measure Hp(3) because of the high lens dose.

In 2011, the International Commission on Radiological Protection (ICRP) recommended reducing the annual equivalent dose limit to the eye lens. This study investigated the effects of physician height and years of experience on lens radiation exposure in a clinical setting. The lens dose was measured using the DOSIRIS dosimeter, which quantified Hp(3) while accounting for the shielding effect of lead glasses, and a neck dosimeter for Hp(0.07). A significant negative correlation was found between physician height and both Hp(0.07) (R = −0.642) and Hp(3) (R = −0.728), suggesting that taller physicians received lower lens doses because of their greater distance from the scatter source. A positive correlation was observed between years of experience and Hp(0.07) (R = 0.650). Two-group comparisons showed that physicians shorter than 170 cm had a 2.77-fold higher median Hp(3) than those ≥170 cm (p < 0.05). As experienced physicians may be exposed to higher radiation levels, regular review of protective practices and continued radiation safety education are essential, regardless of clinical experience. This is the first clinical study to simultaneously evaluate the effects of physician height and experience on lens dose in interventional cardiology. Regular review of protective practices remains essential regardless of operator height or experience.

This retrospective study evaluated patient radiation dose during fluoroscopy-guided peripherally inserted central catheter (PICC) placement. A total of 1240 consecutive adult patients who underwent PICC placement between January 2023 and December 2024 were analyzed. Patient radiation dose indices, including air kerma (AK) and dose–area product (DAP), as well as fluoroscopy time and number of radiographic acquisitions, were obtained from the radiology information system. The mean and median AK were 2.47 mGy and 1.54 mGy, respectively, and the median DAP was 901.9 mGy·cm². The median fluoroscopy time was 1.9 min, and the median number of radiographic acquisitions was 1. Patient radiation dose during PICC placement was lower than the Japanese Diagnostic Reference Levels (Japan DRLs 2025). AK showed a strong positive correlation with fluoroscopy time (Spearman’s rank correlation, $\rho$ = 0.77), whereas correlations between AK and BMI or the number of radiographic acquisitions were weak. In some patients with high BMI, AK values exceeding 40 mGy were observed. These findings indicate that patient radiation dose during PICC placement is generally low but remains closely associated with fluoroscopy time. Optimization of the patient radiation dose should be considered, particularly for patients with high BMIs or those undergoing repeated PICC placements.