Introduction

Chronic exposure to scatter radiation (SCR) causes a significant degree of work-related damages in interventional cardiologists (IC), including cataracts, vascular alterations, and left-sided brain tumors. Conventional lead aprons provide no protection for the head. The openings for the arms leave a large entry for lateral radiation into the mediastinum.

A ceiling suspended operator radiation protection system (Zero Gravity, TIDI Products, WI, USA), addresses these shortcomings with additional SCR protection for the head with a lead glass visor and for the mediastinum with additional lateral protectors, while being weightless for the operator. The Zero Gravity system (ZG) has shown high efficacy in reducing scatter radiation for the operator in a limited number of trials.

Methods

We have created a prospective registry (OSCAR Registry; clinicaltrials.org identifier NCT04945538) in order to study the impact of the ZG system on IC and sterile assistant (SA) SCR exposure. IC and SA were equipped with 5 Unfors RaySafe i3 live-dosimeters (DLD) at prespecified locations. 1125 consecutive cardiac procedures were recorded, in which either both IC and SA were using standard X-ray protection (SXP; lead apron, thyroid shield, lead glasses) or the IC was using the ZG system and the SA was wearing SXP. Statistic averages are shown as Mean±SEM. Groups were compared with the two-sample t-test or Mann-Whitney-U test. p<0.05 was considered statistically significant.

Resultate / Results

From a total of 1125 procedures recorded with DLD, 164 were acute PCIs for NSTEMI or STEMI. 86 PCIs were performed with SXP, 77 with ZG. Compared to SXP, the use of the ZG system reduced the average SCR doses per procedure of the IC recorded at the left lateral head from  22.54±2.15 µSv to 1.33±0.19 µSv (-94%; p<0.0001). The IC’s average frontal dose at eye level was reduced from 7.18±0.76 µSv to 0.44±0.07 µSv (-94%; p<0.0001). Consistently, the dose recorded immediately under the IC’s left shoulder was reduced from 70.22±7.17 µSv to 1.13±0.24 (-98%; p<0.0001). Furthermore, when the IC used the ZG system, the average SCR dose recorded at the SA’s upper neck was reduced from 12.98±2.02 µSv to 3.47±0.52 µSv (-73%, p<0.05). All SCR dose effects remained significant after correction for total dose-area product (µSv/Gy*cm2). Procedure duration, contrast use, procedural success rate, time to lesion crossing and patient radiation dose were not affected by ZG use.

Conclusions

Consistent with preliminary data we had presented in 2021 and 2022, the current analysis of 164 procedures from the OSCAR Registry confirms an impressive potential for SCR reduction when using the ZG system in an emergency setting of NSTEMI and STEMI. ZG provided a drastic improvement of SCR protection for ICs and SAs in critical anatomical areas - even in a state-of-the-art cathlab inventory with multiple SCR reduction measures already in place. The current data also confirms a protective effect for the sterile assistant at the table wearing SXP.

These findings, together with a growing number of clinical trial results, call for greater awareness of SCR protection in interventional cardiology. Advanced radiation protection systems like ZG should be used whenever possible including acute PCI procedures and should be implemented in current guidelines for interventional cardiology.