A Monte Carlo study on quantifying the amount of dose reduction by shielding the superficial organs of an Iranian 11-year-old boy

Abstract

A method for minimizing organ dose during computed tomography examinations is the use of shielding to protect superficial organs. There are some scientific reports that usage of shielding technique reduces the surface dose to patients with no appreciable loss in diagnostic quality. Therefore, in this Monte Carlo study based on the phantom of a 11-year-old Iranian boy, the effect of using an optimized shield on dose reduction to body organs was quantified. Based on the impact of shield on image quality, lead shields with thicknesses of 0.2 and 0.4 mm were considered for organs exposed directly and indirectly in the scan range, respectively. The results showed that there is 50%–62% reduction in amounts of dose for organs located fully or partly in the scan range at different tube voltages and modeling the true location of all organs in human anatomy, especially the ones located at the border of the scan, range affects the results up to 49%.

Pulmonary embolism in pregnant patients: Assessing organ dose to pregnant phantom and its fetus during lung imaging

“…These data may be used to estimate absorbed doses to maternal and fetal organs during CTPA given the measured CTDI vol for the tube parameter values used.where K is the ratio of mAs per rotation to 100 mAs. The measured CTDI vol of CT scanner used in this study was provided in Table …”

“…The measured CTDI vol of CT scanner used in this study was provided in Table I. 38 Furthermore, the organ dose coefficients (mGy/ 100 MBq) were estimated for those patients undergo V/Q SPECT using MAA for perfusion phase and DTPA or technegas for ventilation phase (supplementary data). To obtain the absorbed dose, one simply needs to multiply the dose coefficient by the ratio of applied activity to 100 MBq.…”

The effects of simulating a realistic eye model on the eye dose of an adult male undergoing head computed tomography

“…Therefore, it was possible to apply both *F8 tally divided by mass and also F6 tally for dose estimations. However, to test the validity of the kerma approximation in small volumes that exist in the geometry of the Nogueira (Akhlaghi et al 2016) eye model, besides photons, electrons were also tracked using the tallies + F6, F6, and *F8 divided by mass. The discrepancies between the outcomes of the tallies were less than 1%, so in this study, the F6:p tally (track length estimate of photon energy deposition) was used for organ dose calculations.…”

“…The third cylinder defined a build-up cap with a diameter of 1.37 cm, which was modeled as polyacetal plastic with a mass density of 1.43 g.cm −3 (Lee et al 2011). Figure 3 displays the CTDI phantom and the ion chamber used for model validation (Akhlaghi et al 2016).…”

Bismuth-silicon and bismuth-polyurethane composite shields for breast protection in chest computed tomography examinations

“…[ 4 ] Numerous investigations have reported the use of high atomic number (Z) shielding materials such as lead and bismuth to attenuate X-rays and γ -rays. [ 5 6 ]…”