The effect of lead free cap on the doses of ionizing radiation to the head of interventional cardiologists working in haemodynamic room.

OBJECTIVES: The study aim was to analyse the influence of the lead free cap on doses received by interventional cardiologists. The impact of lead free cap on doses to the head were evaluated in number of studies. As different methods used to assess the attenuation properties of protective cap can lead to ambiguous results, a detailed study was performed. MATERIAL AND METHODS: The effectiveness of a lead free cap in reducing the doses to the skin was assessed in clinic by performing measurements with thermoluminescent dosimeters attached inside and outside the cap first during individual coronary angiography (CA) or CA/percutaneous transluminal coronary angioplasty (CA/PTCA) procedures and then cumulated during few procedures of the same type. In order to investigate the effect of the cap on reducing the doses to the brain additional measurements were performed with a male Alderson Rando and polymethyl methacrylate (PMMA) phantoms representing the physician and the patient, respectively for different projections. The brain dose per procedure, annual and cumulated during entire working practice were estimated for both cases working with and without the cap. RESULTS: The dose reduction factor (RF) for the skin (the quotient of doses outside and inside the cap) vary from 1.1 up to 4.0 in clinical conditions; on average 2.3-fold reduction is observed in the most exposed left temple. The RFs determined for the part of the head covered by the cap range from 1.4 to 1.8 while for the brain from 1.0 to 1.1 depending on the projection. The estimated annual brain dose for interventional cardiologist performing yearly 550 CA/PTCA procedures without any protective shields is 7.2 mGy and it is reduced with the lead free cap by an average factor of 1.1. CONCLUSIONS: The study results proved the considerable effectiveness of lead free cap to protect the skin but very limited to protect the brain. Int J Occup Med Environ Health. 2022;35(5):549-60.

Occupational exposure to physicians working with a Zero-Gravity™ protection system in haemodynamic and electrophysiology labs and the assessment of its performance against a standard ceiling suspended shield.

A two centre clinical study was performed to analyse exposure levels of cardiac physicians performing electrophysiology and haemodynamic procedures with the use of state of the art Zero-Gravity™ radiation protective system (ZG). The effectiveness of ZG was compared against the commonly used ceiling suspended lead shield (CSS) in a haemodynamic lab. The operator's exposure was assessed using thermoluminescent dosimeters (TLDs) during both ablation (radiofrequency ablation (RFA) and cryoablation (CRYA)) and angiography and angioplasty procedures (CA/PCI). The dosimeters were placed in multiple body regions: near the left eye, on the left side of the neck, waist and chest, on both hands and ankles during each measurement performed with the use of ZG. In total 29 measurements were performed during 105 procedures. To compare the effectiveness of ZG against CSS an extra 80 measurements were performed with the standard lead apron, thyroid collar and ceiling suspended lead shield during CA/PCI procedures. For ZG, the upper values for the average eye lens and whole body doses per procedure were 4 µSv and 16 µSv for the left eye lens in electrophysiology lab (with additionally used CSS) and haemodynamic lab (without CSS), respectively, and about 10 µSv for the remaining body parts (neck, chest and waist) in both labs. The skin doses to hands and ankles non-protected by the ZG were 5 µSv for the most exposed left finger and left ankle in electrophysiology lab, while in haemodynamic lab 150 µSv and 17 µSv, respectively. The ZG performance was 3 times (p < 0.05) and at least 15 times (p < 0.05) higher for the eye lenses and thoracic region, respectively, compared to CSS (with dosimeters on the apron/collar). However, when only ZG was used slightly higher normalised doses were observed for the left finger compared to CSS (5.88e - 2 Sv/Gym2 vs. 4.31 e - 2 Sv/Gym2, p = 0.016). The study results indicate that ZG performance is superior to CSS. It can be simultaneously used with the ceiling suspended lead shield to ensure the protection to the hands as long as this is not obstructive for the work.