Validation of an in vivo transit dosimetry algorithm using Monte Carlo simulations and ionization chamber measurements.

Purpose: Transit dosimetry is a safety tool based on the transit images acquired during treatment. Forward-projection transit dosimetry software, as PerFRACTION, compares the transit images acquired with an expected image calculated from the DICOM plan, the CT, and the structure set. This work aims to validate PerFRACTION expected transit dose using PRIMO Monte Carlo simulations and ionization chamber measurements, and propose a methodology based on MPPG5a report.

PRIMO Monte Carlo software as a tool for commissioning of an external beam radiotherapy treatment planning system.

Background: The purpose was to validate the PRIMO Monte Carlo software to be used during the commissioning of a treatment planning system (TPS).

Materials And Methods: The Acuros XB v. 16.

Gamma passing rates of daily EPID transit images correlate to PTV coverage for breast cancer IMRT treatment plans.

Purpose: The use of the transit image obtained with the electronic portal-imaging device (EPID) is becoming an extended method to perform in-vivo dosimetry. The transit images acquired during each fraction can be compared with a predicted image, if available, or with a baseline image, usually the obtained in the first fraction. This work aims to study the dosimetric impact of the failing fractions and to evaluate the appropriateness of using a baseline image in breast plans.

Treatment time of image-guided radiotherapy with a Halcyon 2.0 system.

Introduction: The treatment fraction time is a key indicator of the external beam radiotherapy process. The Halcyon system was designed to improve the clinical workflow, according to the manufacturer (Varian Medical Systems). Few works studied the actual delivery efficiency of the Halcyon system.

Monte Carlo-based independent dose verification of radiosurgery HyperArc plans.

Purpose: To investigate the feasibility of using the free PRIMO Monte Carlo software for independent dose check of cranial SRS plans designed with the Varian HyperArc (HA) technique.

Materials And Methods: In this study, the PRIMO Monte Carlo software v. 0.

Clinical Experience in Prostate Ultrahypofractionated Radiation Therapy With an Online Adaptive Method.

Purpose: This study aimed to describe the feasibility of the online adaptive radiation therapy (oART) method developed at the Hospital Quirónsalud Barcelona for prostate cancer, using a standard C-arm linear accelerator (linac) and without the support of artificial intelligence.

Methods And Materials: The first 18 patients treated at the Hospital Quirónsalud Barcelona with the developed oART method were included. An ultrahypofractionated radiation therapy scheme consisting of 7 × 6.

Monte Carlo simulation of conical collimators for stereotactic radiosurgery with a 6 MV flattening-filter-free photon beam.

Purpose: Conical collimators, or cones, are tertiary collimators that attach to a radiotherapy linac and are suited for the stereotactic radiosurgery treatment of small brain lesions. The small diameter of the most used cones makes difficult the acquisition of the dosimetry data needed for the commissioning of treatment planning systems. Although many publications report dosimetric data of conical collimators for stereotactic radiosurgery, most of the works use different setups, which complicates comparisons.

PRIMO Monte Carlo software benchmarked against a reference dosimetry dataset for 6 MV photon beams from Varian linacs.

Background: The software PRIMO for the Monte Carlo simulation of radiotherapy linacs could potentially act as a independent calculation system to verify the calculations of treatment planning systems. We investigated the suitability of the PRIMO default beam parameters to produce accurate dosimetric results for 6 MV photon beams from Varian Clinac 2100 linacs and 6 MV flattening-filter-free photon beams from Varian TrueBeam linacs.

Methods: Simulation results with the DPM algorithm were benchmarked against a published reference dosimetry dataset based on point measurements of 25 dosimetric parameters on a large series of linacs.

Assessment of the Monitor Unit Objective tool for VMAT in the Eclipse treatment planning system.

Aim: This work aims to achieve the highest possible monitor units (MU) reduction using the tool included in the Eclipse treatment planning system, while preserving the plan quality.

Background: The treatment planning system Eclipse (Varian Medical Systems, Palo Alto, CA) includes a control mechanism for the number of monitor units of volumetric modulated arc therapy (VMAT) plans, named the MU Objective tool.

Material And Methods: Forty prostate plans, 20 gynecological plans and 20 head and neck plans designed with VMAT were retrospectively studied.

Absorbed dose distributions from ophthalmic Ru/ Rh plaques measured in water with radiochromic film.

Purpose: Brachytherapy with Ru/ Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of Ru/ Rh plaques used solid phantoms.

Technical Note: Monte Carlo study of Ru/ Rh ophthalmic plaques including the Rh gamma spectrum.

Purpose: To assess the influence of the Rh gamma spectrum on the Monte Carlo simulation of Ru/ Rh ophthalmic plaques, which has been neglected without a quantitative estimation in all previous publications.

Methods: Simulations were run with the penelope 2014 Monte Carlo code for radiation transport. Depth-dose distributions in water were simulated for the plaque models CCA, CCC, CCX and CIA.

Investigating the spatial accuracy of CBCT-guided cranial radiosurgery: A phantom end-to-end test study.

Purpose: To evaluate the spatial accuracy of a frameless cone-beam computed tomography (CBCT)-guided cranial radiosurgery (SRS) using an end-to-end (E2E) phantom test methodology.

Methods And Materials: Five clinical SRS plans were mapped to an acrylic phantom containing a radiochromic film. The resulting phantom-based plans (E2E plans) were delivered four times.

Experimental HPGe coaxial detector response and efficiency compared to Monte Carlo simulations.

The peak efficiency for photons hitting the frontal surface of a medium volume n-type HPGe coaxial detector is mapped using acutely collimated beams of energies between 31 and 383 keV from a (133)Ba radioactive source. Simulated values obtained with the Monte Carlo radiation transport code penelope, using a model that respected actual detector dimensions and physical constants while varying dead-layer thicknesses, allowed us to fit the experimental results in the detector bulk but not near its rim. The spectra of a (137)Cs source were measured using the detector shielded from the natural background radiation, with and without a broad angle collimator.