Radiation Exposure and Radiation Protection in Interventional Cardiology

In an era of an increasing number of invasive procedures particular attention to radiation exposure and protection measures for patients and staff is warranted. Ionising radiation accounts for risk-dose-dependent stochastic effects (no threshold dose) and dose-dependent deterministic effects (threshold dose). The effective dose (ED) is a weighted sum of equivalent doses delivered to various organs to assess the stochastic risk, whereas deterministic effects are related to the entrance dose. Dosearea- product (DAP) is an indicator of the ED to the patient, which is approximately 5–20 mSv per coronary angiography (CA). The most important factors influencing DAP are fluoroscopy level, the use of cinegraphy, complexity of the procedure, and skill of the operator, which most of can be optimised to reduce radiation to the patient. The operator is not directly exposed to the X-beam, but to a considerable amount of scatter radiation. The annual ED of an interventional cardiologist consequently using a lead apron will hardly exceed the annual dose limit of 20 mSv. However, ED measurement with one or two dosimeters does not reflect the doses to susceptible unprotected parts of the body, namely the hands and the eyes, which may be affected by deterministic effects such as the development of cataract. The use of a lead glass screen placed between patient and operator markedly reduces the dose to the operator’s eyes but has almost no effect on the dose to the hands. As shown by several recently published studies, there is a high potential to reduce DAP levels and thus to reduce radiation to the patient and to improve lead shielding with subsequently enhanced safety for staff. Unfortunately, these trials do not reflect the current practice in many catheterisation laboratories. Therefore, awareness of the problem and efforts to improve the current standard are required.