A Pilot Study of Simulation-Free Hippocampal-Avoidance Whole Brain Radiation Therapy Using Diagnostic MRI-Based and Online Adaptive Planning.

Purpose: We aimed to demonstrate the clinical feasibility and safety of simulation-free hippocampal avoidance whole brain radiation therapy (HA-WBRT) in a pilot study (National Clinical Trial 05096286).

Methods And Materials: Ten HA-WBRT candidates were enrolled for treatment on a commercially available computed tomography (CT)-guided linear accelerator with online adaptive capabilities. Planning structures were contoured on patient-specific diagnostic magnetic resonance imaging (MRI), which were registered to a CT of similar head shape, obtained from an atlas-based database (AB-CT).

Cardiac radiation improves ventricular function in mice and humans with cardiomyopathy.

Background: Rapidly dividing cells are more sensitive to radiation therapy (RT) than quiescent cells. In the failing myocardium, macrophages and fibroblasts mediate collateral tissue injury, leading to progressive myocardial remodeling, fibrosis, and pump failure. Because these cells divide more rapidly than cardiomyocytes, we hypothesized that macrophages and fibroblasts would be more susceptible to lower doses of radiation and that cardiac radiation could therefore attenuate myocardial remodeling.

trial of simulation-free hippocampal-avoidance whole brain adaptive radiotherapy.

Background And Purpose: Hippocampal-avoidance whole brain radiotherapy (HA-WBRT) can be a time-consuming process compared to conventional whole brain techniques, thus potentially limiting widespread utilization. Therefore, we evaluated the clinical feasibility, via dose-volume metrics and timing, by leveraging a computed tomography (CT)-based commercial adaptive radiotherapy (ART) platform and workflow in order to create and deliver patient-specific, simulation-free HA-WBRT.

Materials And Methods: Ten patients previously treated for central nervous system cancers with cone-beam computed tomography (CBCT) imaging were included in this study.

Functional network disorganization and cognitive decline following fractionated whole-brain radiation in mice.

Cognitive dysfunction following radiotherapy (RT) is one of the most common complications associated with RT delivered to the brain, but the precise mechanisms behind this dysfunction are not well understood, and to date, there are no preventative measures or effective treatments. To improve patient outcomes, a better understanding of the effects of radiation on the brain's functional systems is required. Functional magnetic resonance imaging (fMRI) has shown promise in this regard, however, compared to neural activity, hemodynamic measures of brain function are slow and indirect.

Initial clinical experience building a dual CT- and MR-guided adaptive radiotherapy program.

Introduction: Our institution was the first in the world to clinically implement MR-guided adaptive radiotherapy (MRgART) in 2014. In 2021, we installed a CT-guided adaptive radiotherapy (CTgART) unit, becoming one of the first clinics in the world to build a dual-modality ART clinic. Herein we review factors that lead to the development of a high-volume dual-modality ART program and treatment census over an initial, one-year period.

Clinical application of a template-guided automated planning routine.

Purpose: Determine the dosimetric quality and the planning time reduction when utilizing a template-based automated planning application.

Methods: A software application integrated through the treatment planning system application programing interface, QuickPlan, was developed to facilitate automated planning using configurable templates for contouring, knowledge-based planning structure matching, field design, and algorithm settings. Validations are performed at various levels of the planning procedure and assist in the evaluation of readiness of the CT image, structure set, and plan layout for automated planning.

Heart Sparing Radiotherapy Techniques in Breast Cancer: A Focus on Deep Inspiration Breath Hold.

Adjuvant radiation therapy is a critical component of breast cancer management. However, when breast cancer patients receive incidental radiation to the heart, there is an increased risk of cardiac disease and mortality. This is most common for patients with left-sided breast cancers and those receiving nodal irradiation as part of treatment.

RapidPlan hippocampal sparing whole brain model version 2-how far can we reduce the dose?

Whole-brain radiotherapy has been the standard palliative treatment for patients with brain metastases due to its effectiveness, availability, and ease of administration. Recent clinical trials have shown that limiting radiation dose to the hippocampus is associated with decreased cognitive toxicity. In this study, we updated an existing Knowledge Based Planning model to further reduce dose to the hippocampus and improve other dosimetric plan quality characteristics.

A reconstruction approach for proton computed tomography by modeling the integral depth dose of the scanning proton pencil beam.

Purpose: To present a proton computed tomography (pCT) reconstruction approach that models the integral depth dose (IDD) of the clinical scanning proton beam into beamlets. Using a multilayer ionization chamber (MLIC) as the imager, the proposed pCT system and the reconstruction approach can minimize extra ambient neutron dose and simplify the beamline design by eliminating an additional collimator to confine the proton beam.

Methods: Monte Carlo simulation was applied to digitally simulate the IDDs of the exiting proton beams detected by the MLIC.

Technical Report: Development and Implementation of an Open Source Template Interpretation Class Library for Automated Treatment Planning.

Purpose: Widespread implementation of automated treatment planning in radiation therapy remains elusive owing to variability in clinic and physician preferences, making it difficult to ensure consistent plan parameters. We have developed an open-source class library with the aim to improve efficiency and consistency for automated treatment planning in radiation therapy.

Methods And Materials: An open-source class library has been developed that interprets clinical templates within a commercial treatment planning system into a treatment plan for automated planning.

Quantification of gold nanoparticle photon radiosensitization from direct and indirect effects using a complete human genome single cell model based on Geant4.

Purpose: To investigate the radiosensitization properties of gold nanoparticles (GNPs) and better understand the intricate deoxyribonucleic acid (DNA) damage induction mechanisms involved in GNP-aided radiotherapy, a single cell model with complete human genome based on the Geant4 Monte Carlo toolkit was applied.

Materials And Methods: A Geant4-DNA model was implemented to simulate direct and indirect DNA damage generated in the physical and chemical stages. In the physical stage, a mixed-physics approach was taken by using Geant4-DNA in water and Livermore in gold.

Spatially fractionated stereotactic body radiation therapy (Lattice) for large tumors.

Purpose: Stereotactic body radiation therapy (SBRT) has demonstrated clinical benefits for patients with metastatic and/or unresectable cancer. Technical considerations of treatment delivery and nearby organs at risk can limit the use of SBRT in large tumors or those in unfavorable locations. Spatially fractionated radiation therapy (SFRT) may address this limitation because this technique can deliver high-dose radiation to discrete subvolume vertices inside a tumor target while restricting the remainder of the target to a safer lower dose.

Spread-out Bragg peak proton FLASH irradiation using a clinical synchrocyclotron: Proof of concept and ion chamber characterization.

Purpose: The purpose of this work is to (a) demonstrate the feasibility of delivering a spread-out Bragg peak (SOBP) proton beam in ultra-high dose rate (FLASH) using a proton therapy synchrocyclotron as a major step toward realizing an experimental platform for preclinical studies, and (b) evaluate the response of four models of ionization chambers in such a radiation field.

Methods: A clinical Mevion HYPERSCAN synchrocyclotron was adjusted for ultra-high dose rate proton delivery. Protons with nominal energy of 230 MeV were delivered in pulses with temporal width ranging from 12.

Application programming interface guided QA plan generation and analysis automation.

Purpose: Linear accelerator quality assurance (QA) in radiation therapy is a time consuming but fundamental part of ensuring the performance characteristics of radiation delivering machines. The goal of this work is to develop an automated and standardized QA plan generation and analysis system in the Oncology Information System (OIS) to streamline the QA process.

Methods: Automating the QA process includes two software components: the AutoQA Builder to generate daily, monthly, quarterly, and miscellaneous periodic linear accelerator QA plans within the Treatment Planning System (TPS) and the AutoQA Analysis to analyze images collected on the Electronic Portal Imaging Device (EPID) allowing for a rapid analysis of the acquired QA images.

Modeling double-strand breaks from direct and indirect action in a complete human genome single cell Geant4 model.

The aim of this work is to develop and validate a computational model to investigate direct and indirect DNA damage by directly quantifying DNA strand breaks. A detailed geometrical target model was created in the Monte Carlo toolkit Geant4 to represent the nucleus of a single human cell with complete human genome. A calculation framework to simulate double-strand breaks (DSBs) was implemented using this single cell model in the Geant4-DNA extension.

A Monte Carlo based analytic model of the in-room neutron ambient dose equivalent for a Mevion gantry-mounted passively scattered proton system.

The goal of this study was to develop a Monte Carlo (MC)-based analytical model that can predict the in-room ambient dose equivalent from a Mevion gantry-mounted passively scattered proton system. The Mevion S250 and treatment vault were simulated using the MCNPX MC code. The results of the in-room neutron dose measurements, using an FHT 762 WENDI-II detector, were employed to benchmark the MC-derived values.

Automated and robust beam data validation of a preconfigured ring gantry linear accelerator using a 1D tank with synchronized beam delivery and couch motions.

Purpose: To develop an efficient and automated methodology for beam data validation for a preconfigured ring gantry linear accelerator using scripting and a one-dimensional (1D) tank with automated couch motions.

Materials And Methods: Using an application programming interface, a program was developed to allow the user to choose a set of beam data to validate with measurement. Once selected the program generates a set of instructions for radiation delivery with synchronized couch motions for the linear accelerator in the form of an extensible markup language (XML) file to be delivered on the ring gantry linear accelerator.

Intracranial Stereotactic Radiation Therapy With a Jawless Ring Gantry Linear Accelerator Equipped With New Dual Layer Multileaf Collimator.

Purpose: To test the feasibility of a simplified, robust, workflow for intracranial stereotactic radiation therapy (SRT) using a ring gantry linear accelerator (RGLA) equipped with a dual-layer stacked, staggered, and interdigitating multileaf collimator.

Materials And Methods: Twenty recent clinical SRT cases treated using a radiosurgery c-arm linear accelerator were anonymized. From these data sets, a new planning workflow was developed and used to replan these cases, which then were compared to their clinical counterparts.

Influence of 0.35 T magnetic field on the response of EBT3 and EBT-XD radiochromic films.

Purpose: To investigate the inconsistency of recent literature on the effect of magnetic field on the response of radiochromic films, we studied the influence of 0.35 T magnetic field on dosimetric response of EBT3 and EBT-XD Gafchromic films.

Methods: Two different models of radiochromic films, EBT3 and EBT-XD, were investigated.

A Monte Carlo-based analytic model of neutron dose equivalent for a mevion gantry-mounted passively scattered proton system for craniospinal irradiation.

Purpose: To calculate in- and out-of-field neutron spectra and dose equivalent, using Monte Carlo (MC) simulation, for a Mevion gantry-mounted passively scattered proton system in craniospinal irradiation. An analytical model based on the MC calculations that estimates in- and out-of-field neutron dose equivalent from proton Craniospinal irradiation (CSI) was also developed.

Methods: The MCNPX MC code was used to simulate a Mevion S250 proton therapy system.

Sensitivity analysis of Monte Carlo model of a gantry-mounted passively scattered proton system.

Purpose: This study aimed to present guidance on the correlation between treatment nozzle and proton source parameters, and dose distribution of a passive double scattering compact proton therapy unit, known as Mevion S250.

Methods: All 24 beam options were modeled using the MCNPX MC code. The calculated physical dose for pristine peak, profiles, and spread out Bragg peak (SOBP) were benchmarked with the measured data.

Lateral head flexion as a noncoplanar solution for ring gantry stereotactic radiosurgery.

Purpose: Ring gantry radiotherapy devices are often limited to deliver beams in the axial plane, severely limiting beam entrance angles and rendering noncoplanar beam delivery impossible. However, a ring gantry geometry greatly simplifies delivery machines and increases the efficiency of treatment with the potential to decrease the overall costs of radiotherapy. This study explores the use of lateral head flexion in order to increase beam entrance angles and extend the available solid angle space for a ring gantry stereotactic radiosurgery (SRS) application.

A novel design of proton computed tomography detected by multiple-layer ionization chamber with strip chambers: A feasibility study with Monte Carlo simulation.

Purpose: Uncertainty in proton range can be reduced by proton computed tomography (CT). A novel design of proton CT using a multiple-layer ionization chamber with two strip ionization chambers on the surface is proposed to simplify the imaging acquisition and reconstruction.

Methods: Two strip ionization chambers facing the proton source were coupled into a multiple-layer ionization chamber (MLIC).