Differences in effective dose and energy imparted estimation from PA-AP, RLAT-LLAT projections in pediatric full spine x-ray examination using the Monte Carlo technique.

Effective dose (E) and energy imparted (epsilon) can be used to quantify the risk of radiation-induced carcinogenesis or hereditary effects arising from radiographic exposures. When the children are examined or treated for idiopathic scoliokyphosis it is important to estimate E and epsilon in the patients due to full spine x-ray examination. The aim of this study is to calculate E and epsilon in the case of children of 5 and 10 years old who undergo full spine x-ray examination using the Monte Carlo approach. Dose area product (DAP) and entrance surface dose (ESD) were also used. AP, PA, RLAT, LLAT projections are simulated by using appropriate energy spectra. According to the results, the effective dose (E) and the energy imparted (epsilon) are smaller at PA projection than AP, although for spine the opposite occurs, in agreement with previous studies. On the other hand, E and epsilon do not differ statistically among RLAT and LLAT projections. Moreover, the role of lung and bone as tissue inhomogeneities in epsilon is shown to be very important.

Assessment of patient radiation doses during transcatheter closure of ventricular and atrial septal defects with Amplatzer devices.

The purpose of this study was to estimate the radiation dose to which children are exposed during cardiac catheterizations for the treatment of ventricular and atrial septal defects. Radiation doses were estimated for 46 children aged 1-18 years. These children were treated for secundum atrial septal defects (ASD group) for perimembranous ventricular septal defects (VSD group) or underwent a routine diagnostic catheterization (diagnostic group). Thermoluminescent dosimeters (TLDs) were attached in locations, representing the lateral entrance dose, the posterior entrance dose, the thyroid dose, and the gonad dose, respectively. A dose area product (DAP) meter was also attached externally on the posterior-anterior (PA) tube to give a direct value in cGy cm(2) for each procedure. The patient's entrance dose from the PA field ranged from 1.5 to 185.0 mGy for all patients, while the lateral entrance dose varied from 0.9 to 204 mGy. Radiation exposure to the thyroid and the gonads was found to vary from 0.4 to 8.3 and 0.1 to 2.1 mGy, respectively. The DAP meter recorded DAP values for the posterior tube, between 46 and 3,700 cGy cm(2). The mean effective dose was found to be 7.7, 16.2, and 33.3 mSv for the diagnostic, the ASD, and the VSD group, respectively. Very strong correlation was found between the DAP values and the entrance radiation dose measured with TLDs. The mean entrance dose received from therapeutic cardiac catheterizations using the Amplatzer devices was found approximately twice the dose received from a diagnostic one. Even for the most complex procedures, the maximum entrance dose was at least 10 times lower than the threshold, associated with skin erythema.