Patient dosimetry during biventricular I.C.D. implantation

Recent years have seen a great increase in electrophysiological cardiac procedures number and radiological systems are constantly improved to obtain good image quality by upgrading technological performance. Even if patient benefits are clear, these procedures expose patients to X-rays for a long fluoroscopic time; the result is progressively higher patient radiation exposure, both in local skin areas (for example, the skin of the back) and in terms of effective dose and related risks. In order to evaluate the mean patient dosimetric parameters, we have analyzed 30 biventricular implantable cardioverter defibrillators (ICD) procedures, measuring DAP (dose area product) during the entire procedure and registering all geometrical and physical data that are necessary to reconstruct, via a Monte Carlo simulation, the dosimetric quantities for ICD therapy. For this reason, for each patient we have collected all X-ray spectrum data (such as kV, mA and time during fluoroscopy and fluorography) related to irradiation geometry (such as focus-to-patient distance, X-ray tube angulations, dimension of X-ray field of view) to obtain a “cumulative dataset” that permit to simulate the intervention. Using a Monte Carlo code, we have evaluated the dose for each patient (both organ dose as effective dose, to obtain “dosimetrical indexes” for the procedure) to produce a statistical analysis that can be compared with other interventional therapies (for examples, hemodynamic procedures as stent implantation, angiography, percutaneous transluminal coronary angioplasty, etc.). Even if the dose variability between patient data is great, primary due to the complexity of the ICD insertion, our results demonstrate that patient dose indexes for this particular electrophysiology procedures are not significantly different from the X-ray guided hemodynamic therapies.