Dosimetric comparison of M6 CyberKnife plans optimized with Precision and RayStation 12A treatment planning systems.

Purpose: Treatment planning for CyberKnife (CK) (Accuray, USA) can be performed with Precision (Accuray, USA) or RayStation (RS) (RaySearch Laboratories, Sweden) treatment planning systems (TPS). RaySearch recently released a new version of the CK module in RS 12A. The objective of the study was to compare plan quality between RS 12A and Precision.

Investigating ultra-high dose rate water radiolysis using the Geant4-DNA toolkit and a Geant4 model of the Oriatron eRT6 electron linac.

Ultra-high dose rate FLASH radiotherapy, a promising cancer treatment approach, offers the potential to reduce healthy tissue damage during radiotherapy. As the mechanisms underlying this process remain unknown, several hypotheses have been proposed, including the altered production of radio-induced species under ultra-high dose rate (UHDR) conditions. This study explores realistic irradiation scenarios with various dose-per-pulse and investigates the role of pulse temporal structure.

Hybrid ultra-high and conventional dose rate treatments with electrons and photons for the clinical transfer of FLASH-RT to deep-seated targets: A treatment planning study.

Purpose: This study explores the dosimetric feasibility and plan quality of hybrid ultra-high dose rate (UHDR) electron and conventional dose rate (CDR) photon (HUC) radiotherapy for treating deep-seated tumours with FLASH-RT.

Methods: HUC treatment planning was conducted optimizing a broad UHDR electron beam (between 20-250 MeV) combined with a CDR VMAT for a glioblastoma, a pancreatic cancer, and a prostate cancer case. HUC plans were based on clinical prescription and fractionation schemes and compared against clinically delivered plans.

The system of radiological protection and the UN sustainable development goals.

In 2015 the United Nations issued 17 Sustainable Development Goals (SDGs) addressing a wide range of global social, economic, and environmental challenges. The main goal of this paper is to provide an understanding of how the current System of Radiological Protection relates to these SDGs. In the first part it is proposed that the current System of Radiological Protection is implicitly linked to sustainable development.

Validation of MLC leaf open time calculation methods for PSQA in adaptive radiotherapy with tomotherapy units.

Background: Treatment delivery safety and accuracy are essential to control the disease and protect healthy tissues in radiation therapy. For usual treatment, a phantom-based patient specific quality assurance (PSQA) is performed to verify the delivery prior to the treatment. The emergence of adaptive radiation therapy (ART) adds new complexities to PSQA.

Sensitivity of automated and manual treatment planning approaches to contouring variation in early-breast cancer treatment.

Purpose: One of the advantages of integrating automated processes in treatment planning is the reduction of manual planning variability. This study aims to assess whether a deep-learning-based auto-planning solution can also reduce the contouring variation-related impact on the planned dose for early-breast cancer treatment.

Methods: Auto- and manual plans were optimized for 20 patients using both auto- and manual OARs, including both lungs, right breast, heart, and left-anterior-descending (LAD) artery.

Very high-energy electron therapy as light-particle alternative to transmission proton FLASH therapy - An evaluation of dosimetric performances.

Purpose: Clinical translation of FLASH-radiotherapy (RT) to deep-seated tumours is still a technological challenge. One proposed solution consists of using ultra-high dose rate transmission proton (TP) beams of about 200-250 MeV to irradiate the tumour with the flat entrance of the proton depth-dose profile. This work evaluates the dosimetric performance of very high-energy electron (VHEE)-based RT (50-250 MeV) as a potential alternative to TP-based RT for the clinical transfer of the FLASH effect.

A combined approach for the calculation of activation yields and the characterization of materials for a medical cyclotron.

Cyclotrons for the production of radiopharmaceuticals have become important tools in modern nuclear medicine. At the end of their lifecycles, such installations have to be dismantled and any activated materials must be treated according to the local radiation protection legislation. Using a simulation model, we have developed a non-destructive approach for the radiological characterization of components inside and around an IBA Cyclone 18/9 cyclotron.

Comparison of volumetric modulated arc therapy and helical tomotherapy for prostate cancer using Pareto fronts.

Background: Studies comparing different radiotherapy treatment techniques-such as volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT)-typically compare one treatment plan per technique. Often, some dose metrics favor one plan and others favor the other, so the final plan decision involves subjective preferences. Pareto front comparisons provide a more objective framework for comparing different treatment techniques.

Clinical implementation of deep learning-based automated left breast simultaneous integrated boost radiotherapy treatment planning.

Background And Purpose: Automation in radiotherapy treatment planning aims to improve both the quality and the efficiency of the process. The aim of this study was to report on a clinical implementation of a Deep Learning (DL) auto-planning model for left-sided breast cancer.

Materials And Methods: The DL model was developed for left-sided breast simultaneous integrated boost treatments under deep-inspiration breath-hold.

Activity standardisation of Si at IRA-METAS.

This work explores the primary activity standardisation of Si as part of the SINCHRON project that aims at filling the geochronological dating gap by making a new precise measurement of the half-life of this nuclide. The stability of some of the radioactive test solutions, providing Si as hexafluorosilicic acid (HSiF), was monitored over long periods, pointing to the adequate sample composition and vial type to ensure stability. These solutions were standardised using liquid scintillation counting with the triple to double coincidence ratio (TDCR) technique and the CIEMAT-NIST efficiency tracing (CNET) method.

Influence of optimisation parameters on directly deliverable Pareto fronts explored for prostate cancer.

Purpose: In inverse radiotherapy treatment planning, the Pareto front is the set of optimal solutions to the multi-criteria problem of adequately irradiating the planning target volume (PTV) while reducing dose to organs at risk (OAR). The Pareto front depends on the chosen optimisation parameters whose influence (clinically relevant versus not clinically relevant) is investigated in this paper.

Methods: Thirty-one prostate cancer patients treated at our clinic were randomly selected.

Activity standardisation of Lu.

Lu decays through low-energy β- and γ-emissions in addition to conversion and Auger electrons. To support the use of this radiopharmaceutical in Switzerland, a Lu solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had no Lu impurity.

Construction and dosimetric characterization of a motorized scanning-slit system for electron FLASH experiments.

Background: Beam scanning is a useful technique for the treatment of large tumors when the primary beam size is limited, which is the case with radiation beams used in FLASH radiotherapy.

Purpose: To optimize beam scanning as a dose delivery method for FLASH radiotherapy, it is necessary to first understand the effects of beam scanning on the FLASH effect. To do so, biological FLASH experiments need to be done using defined beam parameters with beam scanning and compared to the situation without beam scanning.

3D-conformal very-high energy electron therapy as candidate modality for FLASH-RT: A treatment planning study for glioblastoma and lung cancer.

Background: Pre-clinical ultra-high dose rate (UHDR) electron irradiations on time scales of 100 ms have demonstrated a remarkable sparing of brain and lung tissues while retaining tumor efficacy when compared to conventional dose rate irradiations. While clinically-used gantries and intensity modulation techniques are too slow to match such time scales, novel very-high energy electron (VHEE, 50-250 MeV) radiotherapy (RT) devices using 3D-conformed broad VHEE beams are designed to deliver UHDR treatments that fulfill these timing requirements.

Purpose: To assess the dosimetric plan quality obtained using VHEE-based 3D-conformal RT (3D-CRT) for treatments of glioblastoma and lung cancer patients and compare the resulting treatment plans to those delivered by standard-of-care intensity modulated photon RT (IMRT) techniques.

Effect of Conventional and Ultrahigh Dose Rate FLASH Irradiations on Preclinical Tumor Models: A Systematic Analysis.

Purpose: Compared with conventional dose rate irradiation (CONV), ultrahigh dose rate irradiation (UHDR) has shown superior normal tissue sparing. However, a clinically relevant widening of the therapeutic window by UHDR, termed "FLASH effect," also depends on the tumor toxicity obtained by UHDR. Based on a combined analysis of published literature, the current study examined the hypothesis of tumor isoefficacy for UHDR versus CONV and aimed to identify potential knowledge gaps to inspire future in vivo studies.

The general-purpose Geant4 Monte Carlo toolkit and its Geant4-DNA extension to investigate mechanisms underlying the FLASH effect in radiotherapy: Current status and challenges.

FLASH radiotherapy is a promising approach to cancer treatment that offers several advantages over conventional radiotherapy. With this novel technique, high doses of radiation are delivered in a short period of time, inducing the so-called FLASH effect - a phenomenon characterized by healthy tissue sparing without alteration of tumor control. The mechanisms behind the FLASH effect remain unknown.

Vancouver call for action to strengthen expertise in radiological protection worldwide.

Ionising radiation has been used for over a century for peaceful purposes, revolutionising health care and promoting well-being through its application in industry, science, and medicine. For almost as long, the International Commission on Radiological Protection (ICRP) has promoted understanding of health and environmental risks of ionising radiation and developed a protection system that enables the safe use of ionising radiation in justified and beneficial practices, providing protection from all sources of radiation. However, we are concerned that a shortage of investment in training, education, research, and infrastructure seen in many sectors and countries may compromise society's ability to properly manage radiation risks, leading to unjustified exposure to or unwarranted fear of radiation, impacting the physical, mental, and social well-being of our peoples.

Dosimetry in the lungs of α-particles (Po) and β-particles (Pb) present in the tobacco smoke of conventional cigarettes and heated tobacco products.

Tobacco products contain radioactive Pb and Po which can be transferred from the filler to the mainstream smoke. When inhaled, they can contribute to the radioactive dose to the lungs and are suspected to significantly contribute to lung cancer from smoking. Currently, no data are available on the radioactive risk of the heated tobacco products (HTP).

Independent Reproduction of the FLASH Effect on the Gastrointestinal Tract: A Multi-Institutional Comparative Study.

FLASH radiation therapy (RT) is a promising new paradigm in radiation oncology. However, a major question that remains is the robustness and reproducibility of the FLASH effect when different irradiators are used on animals or patients with different genetic backgrounds, diets, and microbiomes, all of which can influence the effects of radiation on normal tissues. To address questions of rigor and reproducibility across different centers, we analyzed independent data sets from The University of Texas MD Anderson Cancer Center and from Lausanne University (CHUV).

Modeling of scavenging systems in water radiolysis with Geant4-DNA.

Purpose: This paper presents the capabilities of the Geant4-DNA Monte Carlo toolkit to simulate water radiolysis with scavengers using the step-by-step (SBS) or the independent reaction times (IRT) methods. It features two examples of application areas: (1) computing the escape yield of HO following a Co γ-irradiation and (2) computing the oxygen depletion in water irradiated with 1 MeV electrons.

Methods: To ease the implementation of the chemical stage in Geant4-DNA, we developed a user interface that helps define the chemical reactions and set the concentration of scavengers.

Time-Integrated Bioavailability Proxy for Actinides in a Contaminated Estuary.

Actinides accumulate within aquatic biota in concentrations several orders of magnitude higher than in the seawater [the concentration factor (CF)], presenting an elevated radiological and biotoxicological risk to human consumers. CFs currently vary widely for the same radionuclide and species, which limits the accuracy of the modeled radiation dose to the public through seafood consumption. We propose that CFs will show less dispersion if calculated using a time-integrated measure of the labile (bioavailable) fraction instead of a specific spot sample of bulk water.