Studying the lung dose uncertainty during chest CT scans using phantoms with statistical lung volumes and shapes

Abstract

In recent years, there has been increasing interest in constructing a series of deformable phantoms which follow the statistical distributions of some anatomical variations, known as ‘statistical phantoms’. The main purpose of this study was to develop statistical phantoms by considering the variations in lung volume and shape, in order to evaluate the lung dose uncertainty for individuals undergoing chest computed tomography. Calculations were performed for 100 statistical lung volume phantoms and 70 statistical lung shape phantoms at tube voltages of 80 and 120 kVp, with the use of Monte Carlo MCNP code. The obtained results indicate that dose fluctuations for low tube voltage (80 kVp) are higher than those at 120 kVp. Moreover, it shows that the impact of statistical variations in lung volume on dose discrepancy (5% to 7%) is higher than the impact of statistical lung shape variations (around 2%).

A Monte Carlo Platform for Characterization of X-Ray Radiation Dose in CT Imaging

“…MC method is the most reliable approach to characterize CT dose values [ 4 ]. The most common MC codes are MCNP [ 5 ], GEANT [ 6 ], FLUKA [ 7 ], and EGSnrc [ 8 ].…”

“…Monte Carlo (MC) method is the most trustworthy approach to estimate and characterize dose values in CT imaging [ 4 ]. The most common international MC codes for simulation of real procedures in the field of medical radiation physics include MCNP [ 5 ], GEANT [ 6 ], FLUKA [ 7 ], and EGSnrc [ 8 ].…”

Evaluation of radiation dose to pediatric models from whole body PET/CT imaging

“…Therefore, a series of contiguous transverse slices with a thickness of 1 cm covered the scan range, and the X‐ray photons were emitted over 360°, normal to each line source. The accuracy of the simulation was previously validated by comparing measured computed tomography dose index values with those obtained by simulation 30,31 . The CT technique was used for attenuation correction and anatomic correlation of the PET findings as stated by Alessio et al 32 .…”

“…The accuracy of the simulation was previously validated by comparing measured computed tomography dose index values with those obtained by simulation. 30,31 The CT technique was used for attenuation correction and anatomic correlation of the PET findings as stated by Alessio et al 32 Therefore, pitch of 1, tube voltage of 120 kVp, and weight-based tube loadings were studied for whole body PET/CT imaging of pediatric patients. Accordingly, tube loadings of 20 mAs for 4, 5, and 6 years old, 25 mAs for 8 years old, and 30 mAs for 11 and 14 years old phantoms were considered in the simulations.…”