Validation of a Monte Carlo simulated cardiac phantom for planar and SPECT studies.

Purpose: This work aimed to validate Monte Carlo (MC) simulated cardiac phantoms for the evaluation of planar- and SPECT-gated-blood-pool (GBP-P and GBP-S) studies.

Methods: A comparison of gamma camera system performance criteria measurements (energy resolution, spatial resolution, sensitivity) with MC simulations was conducted. Furthermore, the accuracy of measured and simulated volumes of two stereolithography-printed cardiac phantoms (based on 4D-XCAT phantoms) was assessed.

Measured, calculated, and egs_brachy I-125 dose distributions in a gold plaque for retinoblastoma treatment.

Background: This study measured and calculated dose distributions around a unique gold plaque for whole-eye radiotherapy (to treat retinoblastoma). The applicator consists of a pericorneal ring attached to the four extraocular muscles and four legs, each loaded with I-125 seeds. They are inserted beneath the conjunctiva in-between each pair of muscles and attached anteriorly to the ring.

Characterization of Gafchromic™ film response against radionuclide activity.

Purpose: In this study, we used Gafchromic™ film XR-QA2 and RT-QA2 to characterize the film energy response against various radionuclides. We introduce a neutron depletion theoretical model that can describe film response as a function of cumulated activity. The film response was investigated with respect to different backscatter media such as polystyrene, perspex, lead and corrugated fibreboard carton (CFC).

External beam patient dose verification based on the integral quality monitor (IQM) output signals.

Background: The Integral Quality Monitor (IQM) can essentially measure the integral fluence through a segment and provide real-time information about the accuracy of radiation delivery based on comparisons of measured segment signals and pre-calculated reference values. However, the present IQM chamber cannot calculate the dose in the patient.

Aim: This study aims to make use of IQM field output signals to calculate the number of monitor units (MUs) delivered through an arbitrary treatment field in order to convert Monte Carlo (MC)-generated dose distributions in a patient model into absolute dose.

Integral quality monitor (IQM ) signal correction factors for small fields to predict larger irregular segment output signals.

Purpose: To develop a method of correcting for the inaccuracies of small adjoined field segments in their contribution to larger fields in order to get a better match between their combined signals and the measured integral quality monitor (IQM) open field signals. This would enable the pre-calculation of known irregular segment output signals per monitor unit (MU), which would be later useful for patient-based dose calculations for treatment verification during pre-treatment treatment validation using the IQM output signal per MU.

Methods: Small fields exhibit source obscurity and loss of scatter, resulting in smaller signals being measured by the IQM and the subsequent underestimation of IQM output signals of larger segments obtained by combining small segment signals.

Dosimetry Effects Caused by Unilateral and Bilateral Hip Prostheses: A Monte Carlo Case Study in Megavoltage Photon Radiotherapy for Computed Tomography Data without Metal Artifacts.

Background: Hip prostheses (HPs) are routinely used in hip augmentation to replace painful or dysfunctional hip joints. However, high-density and high-atomic-number (Z) inserts may cause dose perturbations in the target volume and interface regions.

Aim: To evaluate the dosimetric influence of various HPs during megavoltage conformal radiotherapy (RT) of the prostate using Monte Carlo (MC) simulations.