Dose assessment with radiochromic film in interventional cardiology in Latin America

Interventional Cardiology (IC) is considered a practice with important benefits but also with the potential of high radiation doses (and radiation injuries) for patients and staff. Dosimetric data for this practice are still scarce in Latin America (LA). Radiation protection (RP) training for interventionalists and support of Medical Physicists are also scarce in the Region. The IAEA has promoted a large scale programme on RP of Patients in Medical Exposures (RLA/9/057) including as one of the objectives the avoidance of radio-injuries in interventional radiology. This paper presents the methodology of the project including the use of radiochromic films during IC procedures in a sample of LA centres. Skin dose distributions and peak skin dose have been measured with radiochromic films. These films have a dynamic range of 0.1 to 15 Gy. Films were positioned over the table and below the patient and the mattress. Manufacturer includes a calibration strip with each set of films. This standard strip allows to estimate the doses through comparing the optical densities of the strip and the film used during the clinical procedures. Results from 8 Centres in LA have been obtained for Coronary Angiography (CA), Percutaneous Transluminal Coronary Angioplasty (PTCA), and combined PTCA+CA. In 54.6% of the procedures, one or more factors that could enhance the risk of skin lesions were identified. For PTCA the measured peak skin doses are higher than during CA. When procedures are combined (CA+PTCA), in almost all the cases, the maximum doses are higher than 1 Gy (but the sample of the procedures was not selected at random). We conclude that procedures with CA+PTCA with large fluoroscopy time or large number of cine frames, carried out on patients with large body mass index, are the target group to investigate the risk of skin injuries. It is difficult to propose trigger levels for these parameters considering the lack of direct relation with the real peak skin dose, but 60 minutes of fluoroscopy and 3000 cine frames could be indicative values. This project is the first step in the process of optimization of RP in IC in LA. A first set of data on the maximum skin dose values during clinical procedures has been obtained. The impact of training courses on RP and licensing programmes to interventional cardiologists has been positive and the effort should continue. (author)