Does digital acquisition reduce patients' skin dose in cardiac interventional procedures? An experimental study.

OBJECTIVE It is necessary to reduce the exposure doses from both fluoroscopy and angiocardiography. Pulsed fluoroscopy clearly reduces patients' exposure. By contrast, whether digital acquisition reduces patients' exposure is not clear. This study simulated the skin radiation doses of patients in cardiac catheterization laboratories with various radiography systems used in percutaneous transluminal coronary angioplasty to determine whether digital acquisition reduces patient exposure as compared with cine film recording. MATERIALS AND METHODS The entrance surface doses with cineangiography and fluoroscopy of acrylic phantoms were compared for 11 radiography systems at seven facilities; each performs more than 100 cardiac intervention procedures per year. The entrance surface dose for an acrylic plate (20 cm thick) was measured using a skin-dose monitor. RESULTS The maximum dose exceeded the minimum dose by 6.44 times for cineangiography and by 3.42 times for fluoroscopy. The entrance surface dose with acrylic plate was lower with digital-only acquisition (mean +/- SD, 3.07 +/- 0.84 mGy/sec) than with film recording (6.00 +/- 3.04 mGy/sec). By contrast, the entrance surface frame dose, after correction for the cine frame rate, tended to be higher with digital acquisition than with film recording (0.210 +/- 0.053 vs 0.179 +/- 0.058 mGy/frame, respectively). CONCLUSION. The entrance surface dose was approximately 50% less with digital-only acquisition than with film recording. However, after correcting the dose for cine frame rate, filmless acquisition did not in itself reduce the exposure. For the surface dose to be reduced for cardiac interventional radiography, even with digital filmless radiography systems, a low recording speed is necessary for angiocardiography.