the helicopter-borne electromagnetic (hem) frequency-domain exploration method is an airborne electromagnetic (aem) technique that is widely used for vast and rough areas for resistivity imaging. the vast amount of digitized data flowing from the hem method requires an efficient and accurate inversion algorithm. generally, the inverse modelling of hem data in the first step requires a precise a...

Introduction After the publication of Task Group number 43 dose calculation formalism by the American Association of Physicists in Medicine (AAPM), this method has been known as the most common dose calculation method in brachytherapy treatment planning. In this formalism, the water phantom is introduced as the reference dosimetry phantom, while the attenuation coefficient of the sources in the...

PURPOSE To compare gamma knife treatment plans that use skull scaling instrument measurements for skull definition vs. CT based skull definition. METHODS Eight previously treated patients who had head CT scans were randomly selected. Their CT images were imported into Leksell GammaPlan. For each patient, three dose plans were developed: 1. the reference plan. It was planned based on the stand...

A Monte Carlo based inverse treatment planning system (MCI) has been developed which combines arguably the most accurate dose calculation method (Monte Carlo particle transport) with a 'guaranteed' optimization method (simulated annealing). A distribution of photons is specified in the tumour volume; they are transported using an adjoint calculation method to outside the patient surface to buil...

BACKGROUND The study summarised in this report aimed to investigate the interplay between fluence complexity, dose calculation algorithms, dose calculation spatial resolution and delivery characteristics (monitor units, effective field width and dose delivery against dose prediction agreement) was investigated. A sample set of complex planning cases was selected and tested using a commercial tr...

PURPOSE Cone beam CT is increasingly being used for daily patient positioning verification during radiation therapy treatments. The daily use of CBCT could lead to accumulated patient doses higher than the older technique of weekly portal imaging. There have been several studies focusing on measurement or calculation of the patient dose from CBCT recently. METHODS This study investigates the ...

PURPOSE The purpose of this study was to assess the dosimetric equivalence of magnetic resonance (MR)-generated synthetic CT (synCT) and simulation CT for treatment planning in radiotherapy of rectal cancer. METHODS This study was conducted on eleven patients who underwent whole-body PET/MR and PET/CT examination in a prospective IRB-approved study. For each patient synCT was generated from D...

The accuracy of dose calculation is a key challenge in stereotactic body radiotherapy (SBRT) of the lung. We have benchmarked three photon beam dose calculation algorithms--pencil beam convolution (PBC), anisotropic analytical algorithm (AAA), and Acuros XB (AXB)--implemented in a commercial treatment planning system (TPS), Varian Eclipse. Dose distributions from full Monte Carlo (MC) simulatio...