Recording and reporting of ultra-high dose rate "FLASH" delivery for preclinical and clinical settings.

Treatments at ultra-high dose rate (UHDR) have the potential to improve the therapeutic index of radiation therapy (RT) by sparing normal tissues compared to conventional dose rate irradiations. Insufficient and inconsistent reporting in physics and dosimetry of preclinical and translational studies may have contributed to a reproducibility crisis of radiobiological data in the field. Consequently, the development of a common terminology, as well as common recording, reporting, dosimetry, and metrology standards is required.

Monte Carlo simulations of microdosimetry and radiolytic species production at long time post proton irradiation using GATE and Geant4-DNA.

Background: Radiobiological effectiveness of radiation in cancer treatment can be studied at different scales (molecular till organ scale) and different time post irradiation. The production of free radicals and reactive oxygen species during water radiolysis is particularly relevant to understand the fundamental mechanisms playing a role in observed biological outcomes. The development and validation of Monte Carlo tools integrating the simulation of physical, physico-chemical and chemical stages after radiation is very important to maintain with experiments.

Prognostic Factors of Mandibular Osteoradionecrosis Including Accurate Colocalization of Avulsions and Dosimetric Dental Mapping Software, a Case-control Study.

Purpose: Osteoradionecrosis (ORN) of the mandible remains a significant complication in the intensity modulated radiation therapy (IMRT) era. Dental dose cannot be predicted from heterogeneous IMRT dose distributions; mandibular dose metrics cannot guide dentist avulsion decisions in high-risk ORN situations. Using a mapping tool to report dental root dose, avulsions, and ORN sites, we re-examined ORN risk factors in a case-control study.

Methodology for small animals targeted irradiations at conventional and ultra-high dose rates 65 MeV proton beam.

As part of translational research projects, mice may be irradiated on radiobiology platforms such as the one at the ARRONAX cyclotron. Generally, these platforms do not feature an integrated imaging system. Moreover, in the context of ultra-high dose-rate radiotherapy (FLASH-RT), treatment planning should consider potential changes in the beam characteristics and internal movements in the animal.

[Prevention, diagnosis and management of osteoradionecrosis: Where do we stand?].

Osteoradionecrosis (ORN) is a late secondary iatrogenic complication of external radiotherapy for cancers of the upper aero-digestive tract. Despite the systematization of intensity-modulated radiotherapy and its potential for preserving salivary secretion and limiting the dose delivered to the supporting bone, ORN remains a feared and frequent complication. The objective of this literature review was to provide an overview of the management of ORN and to determine the key points that would make it possible to improve patient care.

["New Modalities in Cancer Imaging and Therapy" XVth edition of the workshop organized by the network "Tumor Targeting, Imaging, Radiotherapies" of the Cancéropôle Grand-Ouest, 5-8 October 2022, France].

The fifteenth edition of the international workshop organized by the "Tumour Targeting and Radiotherapies network" of the Cancéropôle Grand-Ouest focused on the latest advances in internal and external radiotherapy from different disciplinary angles: chemistry, biology, physics, and medicine. The workshop covered several deliberately diverse topics: the role of artificial intelligence, new tools for imaging and external radiotherapy, theranostic aspects, molecules and contrast agents, vectors for innovative combined therapies, and the use of alpha particles in therapy.

Insights on the carbon footprint of radiotherapy in France.

The French healthcare system is responsible for 8% of the national footprint. Achieving a net zero emissions scenario will require a 4-5 fold decrease of carbon emissions in the coming years. The carbon footprint of radiation therapy has not been specifically studied to date.

Voxel-wise analysis: A powerful tool to predict radio-induced toxicity and potentially perform personalised planning in radiotherapy.

Dose - volume histograms have been historically used to study the relationship between the planned radiation dose and healthy tissue damage. However, this approach considers neither spatial information nor heterogenous radiosensitivity within organs at risk, depending on the tissue. Recently, voxel-wise analyses have emerged in the literature as powerful tools to fully exploit three-dimensional information from the planned dose distribution.

First evidence of in vivo effect of FLASH radiotherapy with helium ions in zebrafish embryos.

The ability to reduce toxicity of ultra-high dose rate (UHDR) helium ion irradiation has not been reported in vivo. Here, we tested UHDR helium ion irradiation in an embryonic zebrafish model. Our results show that UHDR helium ions spare body development and reduce spine curvature, compared to conventional dose rate.

Systematic dosimetric evaluation of risk of osteoradionecrosis (DERO): First results of dose reporting for preventing teeth osteoradionecrosis after head and neck irradiation.

Purpose: OsteoRadioNecrosis (ORN) is a late complication of radiation for head and neck cancer. Predicting ORN is a major challenge. We developed DERO (Dosimetric Evaluation of Risk of ORN), a semi-automatic tool which reports doses delivered to tooth-bearing sectors, to guide post-therapeutic dental care.

Ultrahigh-Dose-Rate Proton Irradiation Elicits Reduced Toxicity in Zebrafish Embryos.

Purpose: Recently, ultrahigh-dose-rate radiation therapy (UHDR-RT) has emerged as a promising strategy to increase the benefit/risk ratio of external RT. Extensive work is on the way to characterize the physical and biological parameters that control the so-called "Flash" effect. However, this healthy/tumor differential effect is observable in in vivo models, which thereby drastically limits the amount of work that is achievable in a timely manner.

[What do we need to deliver "online" adapted radiotherapy treatment plans?].

During the joint SFRO/SFPM session of the 2019 congress, a state of the art of adaptive radiotherapy announced a strong impact in our clinical practice, in particular with the availability of treatment devices coupled to an MRI system. Three years later, it seems relevant to take stock of adaptive radiotherapy in practice, and especially the "online" strategy because it is indeed more and more accessible with recent hardware and software developments, such as coupled accelerators to a three-dimensional imaging device and algorithms based on artificial intelligence. However, the deployment of this promising strategy is complex because it contracts the usual time scale and upsets the usual organizations.

[Clinical research in radiation oncology: how to move from the laboratory to the patient?].

Translational research in radiation oncology is undergoing intense development. An increasingly rapid transfer is taking place from the laboratory to the patients, both in the selection of patients who can benefit from radiotherapy and in the development of innovative irradiation strategies or the development of combinations with drugs. Accelerating the passage of discoveries from the laboratory to the clinic represents the ideal of any translational research program but requires taking into account the multiple obstacles that can slow this progress.

["Adaptation of the tumour and its ecosystem to radiotherapies: Mechanisms, imaging and therapeutic approaches" XIVth edition of the workshop organised by the "Vectorisation, Imagerie, Radiothérapies" network of the Cancéropôle Grand-Ouest, 22-25 September 2021, Le Bono, France].

The fourteenth edition of the workshop covered the latest advances in internal and external radiotherapy obtained through a better understanding of the adaptive capacity of the tumor and its microenvironment, from different disciplinary angles, chemistry, biology, physics, and medicine, paving the way for numerous technological innovations. The biological aspects and the contribution of imaging in monitoring and understanding the adaptation of tumors to radiotherapy were presented, before focusing on innovative radiotherapy strategies and machine learning and data-driven techniques. Finally, the challenges were explored in the radiobiology of targeted radionuclide therapy as well as data science and machine learning in radiomics.

Proton Irradiations at Ultra-High Dose Rate vs. Conventional Dose Rate: Strong Impact on Hydrogen Peroxide Yield.

During ultra-high dose rate (UHDR) external radiation therapy, healthy tissues appear to be spared while tumor control remains the same compared to conventional dose rate. However, the understanding of radiochemical and biological mechanisms involved are still to be discussed. This study shows how the hydrogen peroxide (H2O2) production, one of the reactive oxygen species (ROS), could be controlled by early heterogenous radiolysis processes in water during UHDR proton-beam irradiations.

Monte Carlo-based software for 3D personalized dose calculations in image-guided radiotherapy.

Background And Purpose: Image-guided radiotherapy (IGRT) involves frequent in-room imaging sessions contributing to additional patient irradiation. The present work provided patient-specific dosimetric data related to different imaging protocols and anatomical sites.

Material And Methods: We developed a Monte Carlo based software able to calculate 3D personalized dose distributions for five imaging devices delivering kV-CBCT (Elekta and Varian linacs), MV-CT (Tomotherapy machines) and 2D-kV stereoscopic images from BrainLab and Accuray.

Technical note: Proton beam dosimetry at ultra-high dose rates (FLASH): Evaluation of GAFchromic™ (EBT3, EBT-XD) and OrthoChromic (OC-1) film performances.

Purpose: The ARRONAX cyclotron facility offers the possibility to deliver proton beams from low to ultra-high dose rates (UHDR). As a good control of the dosimetry is a prerequisite of UHDR experimentations, we evaluated in different conditions the usability and the dose rate dependency of several radiochromic films commonly used for dosimetry in radiotherapy.

Methods: We compared the dose rate dependency of three types of radiochromic films: GAFchromic™ EBT3 and GAFchromic™ EBT-XD (Ashland Inc.

Image-guided radiotherapy.

We present the updated recommendations of the French society for oncological radiotherapy on image-guided radiotherapy (IGRT). The objective of the IGRT is to take into account the anatomical variations of the target volume occurring between or during the irradiation fractions, such as displacements and/or deformations, so that the delivered dose corresponds to the planned dose. This article presents the different IGRT devices, their use and quality control, and quantify the possible additional dose generated by each of them.

Voluntary Wheel Running Does Not Enhance Radiotherapy Efficiency in a Preclinical Model of Prostate Cancer: The Importance of Physical Activity Modalities?

Physical activity is increasingly recognized as a strategy able to improve cancer patient outcome, and its potential to enhance treatment response is promising, despite being unclear. In our study we used a preclinical model of prostate cancer to investigate whether voluntary wheel running (VWR) could improve tumor perfusion and enhance radiotherapy (RT) efficiency. Nude athymic mice were injected with PC-3 cancer cells and either remained inactive or were housed with running wheels.

A Monte Carlo Determination of Dose and Range Uncertainties for Preclinical Studies with a Proton Beam.

Proton therapy (PRT) is an irradiation technique that aims at limiting normal tissue damage while maintaining the tumor response. To study its specificities, the ARRONAX cyclotron is currently developing a preclinical structure compatible with biological experiments. A prerequisite is to identify and control uncertainties on the ARRONAX beamline, which can lead to significant biases in the observed biological results and dose-response relationships, as for any facility.

Perineal recurrence of prostate cancer along a brachytherapy needle track: A case report.

Metastatic recurrence in an atypical site, such as the perineum, can occur after prostatectomy, cryotherapy, or brachytherapy, but is uncommon. To our knowledge, this is only the third case of perineal recurrence of prostatic cancer along a low dose rate brachytherapy needle track. A 64-year-old man was referred to an urologist with an increased PSA of 6.

[Management of image guidance doses delivered during radiotherapy].

Image-guided radiotherapy (IGRT) has become a standard irradiation technique to improve the clinical outcome of patients in terms of toxicity and local control due to better targeting of radiation during the irradiation fraction. Positioning imaging systems, whether embedded or not, such as kV for 2×2D acquisitions and especially kVCBCT for 3D acquisitions are however irradiating in a large volume including the target volume but also healthy tissue, with a theoretical risk of increased toxicity and second cancer. It therefore appears very important both to optimize the absorbed dose due to IGRT practice but also to report it, especially in case of kVCBCT.