Time-resolved dosimetry for validation of 4D dose calculation in PBS proton therapy.

Four-dimensional dose calculation (4D-DC) is crucial for predicting the dosimetric outcome in the presence of intra-fractional organ motion. Time-resolved dosimetry can provide significant insights into 4D pencil beam scanning dose accumulation and is therefore irreplaceable for benchmarking 4D-DC. In this study a novel approach of time-resolved dosimetry using five PinPoint ionization chambers (ICs) embedded in an anthropomorphic dynamic phantom was employed and validated against beam delivery details.

Dynamic lung phantom commissioning for 4D dose assessment in proton therapy.

Anthropomorphic phantoms mimicking organ and tumor motion of patients are essential for end-to-end testing of motion mitigation techniques in ion beam therapy. In this work a commissioning procedure developed with the in-house designed respiratory phantom ARDOS (Advanced Radiation DOSimetry system) is presented. The phantom was tested and benchmarked for 4D dose verification in proton therapy, which included: characterization of the tissue equivalent materials from computed tomography (CT) imaging, assessment of dose calculation accuracy in critical structures of the phantom, and testing various detectors for proton dosimetry in the ARDOS phantom.

Advanced Radiation DOSimetry phantom (ARDOS): a versatile breathing phantom for 4D radiation therapy and medical imaging.

A novel breathing phantom was designed for being used in conventional and ion-beam radiotherapy as well as for medical imaging. Accurate dose delivery and patient safety are aimed to be verified for four-dimensional (4D) treatment techniques compensating for breathing-induced tumor motion. The phantom includes anthropomorphic components representing an average human thorax.

Multidimensional dosimetry of ¹⁰⁶Ru eye plaques using EBT3 films and its impact on treatment planning.

Purpose: The purpose of this study was to establish a method to perform multidimensional radiochromic film measurements of (106)Ru plaques and to benchmark the resulting dose distributions against Monte Carlo simulations (MC), microdiamond, and diode measurements.

Methods: Absolute dose rates and relative dose distributions in multiple planes were determined for three different plaque models (CCB, CCA, and COB), and three different plaques per model, using EBT3 films in an in-house developed polystyrene phantom and the mcnp6 MC code. Dose difference maps were generated to analyze interplaque variations for a specific type, and for comparing measurements against MC simulations.

[Complex study of the state of the microcirculatory bed at different stages of circulatory failure].

The state of microcirculation was studied on 103 patients with the 1st-3rd degree of circulatory failure due to post-myocardial infarction cardiosclerosis and rheumatic valvular heart disease. The dynamics of the local blood flow in the skin of the left forearm (by the H-clearance method) as well as platelet aggregation ability were studied, conjunctival biomicroscopy and T-V capillaroscopy were performed. Already at early stages, patients with circulatory failure were observed to have changes in the microcirculation accompanied by a decrease in the volume velocity of the tissue (capillary) blood flow.