Improved heterogeneity handling in the collapsed cone dose engine for brachytherapy.

Background: Model-based dose calculation algorithms (MBDCA), such as the Advanced Collapsed cone Engine (ACE) in Oncentra Brachy® can be used to overcome the limitations of the TG-43 formalism. ACE is a point kernel superposition algorithm that calculates the total dose separated into primary, first-scatter, and multiple-scatter dose. Albeit ACE yields accurate results under most circumstances, several studies have reported underestimations of the dose to cortical bone.

Modeling of the direction modulated brachytherapy tandem applicator using the Oncentra Brachy advanced collapsed cone engine.

Purpose: The direction modulated brachytherapy (DMBT) magnetic resonance-compatible tandem applicator, made from a tungsten alloy rod, has six symmetric peripheral grooves, designed specifically to enhance intensity modulation capacity through achieving directional radiation dose profiles. In this work, the directional dose distributions of the DMBT tandem were modeled and calculated with the Oncentra Brachy advanced collapsed cone engine (ACE), which was validated against Monte Carlo (MC) calculations.

Methods And Material: The prototype 3D tandem applicator model was created for use in the Oncentra Brachy treatment planning system.

Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I-125 seeds.

Purpose: To investigate the dose calculation accuracy of the Advanced Collapsed cone Engine (ACE) algorithm for ocular brachytherapy using a COMS plaque loaded with I-125 seeds for two heterogeneous patient tissue scenarios.

Methods: The Oncura model 6711 I-125 seed and 16 mm COMS plaque were added to a research version (v4.6) of the Oncentra Brachy (OcB) treatment planning system (TPS) for dose calculations using ACE.

Beam characterisation of the 1.5 T MRI-linac.

As a prerequisite for clinical treatments it was necessary to characterize the Elekta 1.5 T MRI-linac 7 MV FFF radiation beam. Following acceptance testing, beam characterization data were acquired with Semiflex 3D (PTW 31021), microDiamond (PTW 60019), and Farmer-type (PTW 30013 and IBA FC65-G) detectors in an Elekta 3D scanning water phantom and a PTW 1D water phantom.

Initial evaluation of Advanced Collapsed cone Engine dose calculations in water medium for I-125 seeds and COMS eye plaques.

Purpose: To investigate the dose calculation accuracy in water medium of the Advanced Collapsed cone Engine (ACE) for three sizes of COMS eye plaques loaded with low-energy I-125 seeds.

Methods: A model of the Oncura 6711 I-125 seed was created for use with ACE in Oncentra Brachy (OcB) using primary-scatter separated (PSS) point dose kernel and Task Group (TG) 43 datasets. COMS eye plaque models of diameters 12, 16, and 20 mm were introduced into the OcB applicator library based on 3D CAD drawings of the plaques and Silastic inserts.

Performance evaluation of a collapsed cone dose calculation algorithm for HDR Ir-192 of APBI treatments.

Purpose: Most dose calculations for HDR brachytherapy treatments are based on the AAPM-TG43 formalism. Because patient's anatomy, heterogeneities, and applicator shielding are not considered, the dose calculation based on this formalism is inaccurate in some cases. Alternatively, collapsed cone (CC) methods as well as Monte Carlo (MC) algorithms belong to the model-based dose calculation algorithms, which are expected to improve the accuracy of calculated dose distributions.

Collapsed cone dose calculations for heterogeneous tissues in brachytherapy using primary and scatter separation source data.

Background And Objective: Brachytherapy is a form of radiation therapy using sealed radiation sources inserted within or in the vicinity of the tumor of, e.g., gynecological, prostate or head- and neck cancers.

Biochemical evaluation of the vitamin and iron status of an apparently healthy Dutch free-living elderly population. Comparison with younger adults.

In order to obtain information on "normal" values, the vitamin and iron status have been investigated of an apparently healthy Dutch elderly population, living in their own homes in the centre of the Netherlands. In total 99 women and 99 men (overall mean age 72 yrs) volunteered in the study. By omitting the elderly suffering from one or more diseases as well as those using vitamin supplements, 131 aged people were selected for the biochemical evaluation of the vitamin and iron status of healthy elderly.