Investigations on the beam quality correction factor for ionization chambers in high-energy brachytherapy dosimetry.

. To enhance the investigations on MC calculated beam quality correction factors of thimble ionization chambers from high-energy brachytherapy sources and to develop reliable reference conditions in source and detector setups in water..

Dose prescription for stereotactic body radiotherapy: general and organ-specific consensus statement from the DEGRO/DGMP Working Group Stereotactic Radiotherapy and Radiosurgery.

Purpose And Objective: To develop expert consensus statements on multiparametric dose prescriptions for stereotactic body radiotherapy (SBRT) aligning with ICRU report 91. These statements serve as a foundational step towards harmonizing current SBRT practices and refining dose prescription and documentation requirements for clinical trial designs.

Materials And Methods: Based on the results of a literature review by the working group, a two-tier Delphi consensus process was conducted among 24 physicians and physics experts from three European countries.

Potential and limitations of epitope mapping and molecular targeting in Hymenoptera venom allergy.

Hymenoptera venom (HV) allergy can lead to life threatening conditions by specific IgE (sIgE)-mediated anaphylactic reactions. The knowledge about major allergens from venom of different clinically relevant species increased in the last decades, allowing the development of component-resolved diagnostics in which sIgE to single allergens is analysed. Despite these advances, the precise regions of the allergens that bind to IgE are only known for few HV allergens.

The influence of different versions of FLUKA and GEANT4 on the calculation of response functions of ionization chambers in clinical proton beams.

To investigate the influence of different versions of the Monte Carlo codesgeant4 andflukaon the calculation of overall response functionsof air-filled ionization chambers in clinical proton beams.factors were calculated for six plane-parallel and four cylindrical ionization chambers withgeant4 andfluka. These factors were compared to already published values that were derived using older versions of these codes.

Proton dosimetry in a magnetic field: Measurement and calculation of magnetic field correction factors for a plane-parallel ionization chamber.

Background: The combination of magnetic resonance imaging and proton therapy offers the potential to improve cancer treatment. The magnetic field (MF)-dependent change in the dosage of ionization chambers in magnetic resonance imaging-integrated proton therapy (MRiPT) is considered by the correction factor , which needs to be determined experimentally or computed via Monte Carlo (MC) simulations.

Purpose: In this study, was both measured and simulated with high accuracy for a plane-parallel ionization chamber at different clinical relevant proton energies and MF strengths.

Monte Carlo calculated ionization chamber correction factors in clinical proton beams - deriving uncertainties from published data.

For the update of the IAEA TRS-398 Code of Practice (CoP), global ionization chamber factors (f) and beam quality correction factors (k) for air-filled ionization chambers in clinical proton beams have been calculated with different Monte Carlo codes. In this study, average Monte Carlo calculated f and k factors are provided and the uncertainty of these factors is estimated. Average f factors in monoenergetic proton beams with energies between 60 MeV and 250 MeV were derived from Monte Carlo calculated f factors published in the literature.

A method to implement inter-track interactions in Monte Carlo simulations with TOPAS-nBio and their influence on simulated radical yields following water radiolysis.

In FLASH radiotherapy (dose rates ≥40 Gy s), a reduced normal tissue toxicity has been observed, while maintaining the same tumor control compared to conventional radiotherapy (dose rates ≤0.03 Gy s). This protecting effect could not be fully explained yet.

Determination of the dose rate around a HDR Ir brachytherapy source with the microDiamond and the microSilicon detector.

Purpose: To employ the microDiamond and the microSilicon detector (mDD and mSD, both PTW-Freiburg, Germany) to determine the dose rate around a HDR Ir brachytherapy source (model mHDR-v2r, Elekta AB, Sweden).

Methods: The detectors were calibrated with a Co beam at the PTW Calibration Laboratory. Measurements around the Ir source were performed inside a PTW MP3 water phantom.

Enhancement of the EGSnrc code egs_chamber for fast fluence calculations of charged particles.

Purpose: Simulation of absorbed dose deposition in a detector is one of the key tasks of Monte Carlo (MC) dosimetry methodology. Recent publications (Hartmann and Zink, 2018; Hartmann and Zink, 2019; Hartmann et al., 2021) have shown that knowledge of the charged particle fluence differential in energy contributing to absorbed dose is useful to provide enhanced insight on how response depends on detector properties.

Development, Monte Carlo simulations and experimental evaluation of a 3D range-modulator for a complex target in scanned proton therapy.

The purpose of this work was to develop and manufacture a 3D range-modulator (3D RM) for a complex target contour for scanned proton therapy. The 3D RM is considered to be a viable technique for the very fast dose application in patient-specific tumors with only one fixed energy. The RM was developed based on a tumor from a patient CT and manufactured with high-quality 3D printing techniques with both polymer resin and aluminum.

Cema-based formalism for the determination of absorbed dose for high-energy photon beams.

Purpose: Determination of absorbed dose is well established in many dosimetry protocols and considered to be highly reliable using ionization chambers under reference conditions. If dosimetry is performed under other conditions or using other detectors, however, open questions still remain. Such questions frequently refer to appropriate correction factors.

Investigating the feasibility of TOPAS-nBio for Monte Carlo track structure simulations by adapting GEANT4-DNA examples application.

The purpose of this work is to investigate the feasibility of TOPAS-nBio for track structure simulations using tuple scoring and ROOT/Python-based post-processing.There are several example applications implemented in GEANT4-DNA demonstrating track structure simulations. These examples are not implemented by default in TOPAS-nBio.

Monte Carlo calculation of beam quality correction factors in proton beams using FLUKA.

To provide Monte Carlo calculated beam quality correction factors () for monoenergetic proton beams using the Monte Carlo codefluka.The Monte Carlo codeflukawas used to calculate the dose absorbed in a water-filled reference volume and the air-filled cavities of six plane-parallel and four cylindrical ionization chambers. The chambers were positioned at the entrance region of monoenergetic proton beams with energies between 60 and 250 MeV.

Estimating the modulating effect of lung tissue in particle therapy using a clinical CT voxel histogram analysis.

To treat lung tumours with particle therapy, different additional tasks and challenges in treatment planning and application have to be addressed thoroughly. One of these tasks is the quantification and consideration of the Bragg peak (BP) degradation due to lung tissue: as lung is an heterogeneous tissue, the BP is broadened when particles traverse the microscopic alveoli. These are not fully resolved in clinical CT images and thus, the effect is not considered in the dose calculation.

Pediatric classical Hodgkin lymphoma.

Over the past century, classical Hodgkin lymphoma (HL) has been transformed from a uniformly fatal disease to one of the most curable cancers. Given the high cure rate, a major focus of classical HL management is reducing the use of radiation therapy (RT) and chemotherapy agents such as procarbazine and doxorubicin to minimize long-term toxicities. In both North America and Europe, an important philosophy in the management of classical HL is to guide the intensity of treatment according to the risk category of the disease.

Monte Carlo calculation of perturbation correction factors for air-filled ionization chambers in clinical proton beams using TOPAS/GEANT.

Introduction: Current dosimetry protocols for clinical protons using air-filled ionization chambers assume that the perturbation correction factor is equal to unity for all ionization chambers and proton energies. Since previous Monte Carlo based studies suggest that perturbation correction factors might be significantly different from unity this study aims to determine perturbation correction factors for six plane-parallel and four cylindrical ionization chambers in proton beams at clinical energies.

Materials And Methods: The dose deposited in the air cavity of the ionization chambers was calculated with the help of the Monte Carlo code TOPAS/Geant4 while specific constructive details of the chambers were removed step by step.

Monte Carlo simulations and dose measurements of 2D range-modulators for scanned particle therapy.

This paper introduces the concept of a 2D range-modulator as a static device for generating spread-out Bragg peaks at very small distances to the target. The 2D range-modulator has some distinct advantages that can be highly useful for different research projects in particle therapy facilities. Most importantly, it creates an instantaneous, quasi-static irradiation field with only one energy, thus decreasing irradiation time tremendously.

A phantom based evaluation of the dose prediction and effects in treatment plans, when calculating on a direct density CT reconstruction.

In radiation therapy, a Computed Tomography (CT) image is needed for an accurate dose calculation. To allow such a calculation, the CT image values have to be converted into relative electron densities. Thus, standard procedure is to calibrate the CT numbers to relative electron density (RED) by using a phantom with known composition inserts.

Correction to: Effects of the Bragg peak degradation due to lung tissue in proton therapy of lung cancer patients.

Following publication of the original article [1], we have been notified that the below text parts of the Discussion chapter should be changed.

Monte Carlo calculation of beam quality correction factors in proton beams using TOPAS/GEANT4.

To provide Monte Carlo calculated beam quality correction factors (k ) for monoenergetic proton beams using [Formula: see text], a toolkit based on the Monte Carlo code [Formula: see text]. Monte Carlo simulations of six plane-parallel and four cylindrical ionization chambers were carried out. The latest ICRU 90 recommendations on key data for ionizing-radiation dosimetry were used to calculate the electronic stopping powers and to select the mean energy necessary to create an ion pair in air ([Formula: see text]).

Effects of the Bragg peak degradation due to lung tissue in proton therapy of lung cancer patients.

Purpose: To quantify the effects of the Bragg peak degradation due to lung tissue on treatment plans of lung cancer patients with spot scanning proton therapy and to give a conservative approximation of these effects.

Methods And Materials: Treatment plans of five lung cancer patients (tumors of sizes 2.7-46.

Comparison of penh, fluka, and Geant4/topas for absorbed dose calculations in air cavities representing ionization chambers in high-energy photon and proton beams.

Purpose: The purpose of this work is to analyze whether the Monte Carlo codes penh, fluka, and geant4/topas are suitable to calculate absorbed doses and ratios in therapeutic high-energy photon and proton beams.

Methods: We used penh, fluka, geant4/topas, and egsnrc to calculate the absorbed dose to water in a reference water cavity and the absorbed dose to air in two air cavities representative of a plane-parallel and a cylindrical ionization chamber in a 1.25 MeV photon beam and a 150 MeV proton beam - egsnrc was only used for the photon beam calculations.

A Monte Carlo study on the PTW 60019 microDiamond detector.

Purpose: Data on the output correction factor for small photon beam dosimetry of the microDiamond detector manufactured by the company PTW can be found in a variety of papers. Referring either to measurements or to Monte Carlo (MC) calculations, they show substantial disagreements particularly at very small fields. This work reports results of a further MC study aiming at a better understanding of how specific properties of the microDiamond detector are influencing its output correction factor and whether this can explain at least some of the disagreements.