Adult neurogenesis improves spatial information encoding in the mouse hippocampus.

Adult neurogenesis is a unique form of neuronal plasticity in which newly generated neurons are integrated into the adult dentate gyrus in a process that is modulated by environmental stimuli. Adult-born neurons can contribute to spatial memory, but it is unknown whether they alter neural representations of space in the hippocampus. Using in vivo two-photon calcium imaging, we find that male and female mice previously housed in an enriched environment, which triggers an increase in neurogenesis, have increased spatial information encoding in the dentate gyrus.

Validation and reproducibility of in vivo dosimetry for pencil beam scanned FLASH proton treatment in mice.

Purpose: To investigate quality assurance (QA) techniques for in vivo dosimetry and establish its routine uses for proton FLASH small animal experiments with a saturated monitor chamber.

Methods And Materials: 227 mice were irradiated at FLASH or conventional (CONV) dose rates with a 250 MeV FLASH-capable proton beamline using pencil beam scanning to characterize the proton FLASH effect on abdominal irradiation and examining various endpoints. A 2D strip ionization chamber array (SICA) detector was positioned upstream of collimation and used for in vivo dose monitoring during irradiation.

Pulsed reduced-dose rate re-irradiation for patients with recurrent grade 2 gliomas.

Background: Patients with grade 2 glioma exhibit highly variable survival. Re-irradiation for recurrent disease has limited mature clinical data. We report treatment results of pulsed reduced-dose rate (PRDR) radiation for patients with recurrent grade 2 glioma.

A comprehensive pre-clinical treatment quality assurance program using unique spot patterns for proton pencil beam scanning FLASH radiotherapy.

Background: Quality assurance (QA) for ultra-high dose rate (UHDR) irradiation is a crucial aspect in the emerging field of FLASH radiotherapy (FLASH-RT). This innovative treatment approach delivers radiation at UHDR, demanding careful adoption of QA protocols and procedures. A comprehensive understanding of beam properties and dosimetry consistency is vital to ensure the safe and effective delivery of FLASH-RT.

Evaluation of multiple-vendor AI autocontouring solutions.

Background: Multiple artificial intelligence (AI)-based autocontouring solutions have become available, each promising high accuracy and time savings compared with manual contouring. Before implementing AI-driven autocontouring into clinical practice, three commercially available CT-based solutions were evaluated.

Materials And Methods: The following solutions were evaluated in this work: MIM-ProtégéAI+ (MIM), Radformation-AutoContour (RAD), and Siemens-DirectORGANS (SIE).

Design and implementation of automated notification systems and an electronic whiteboard for radiation therapy planning monitoring.

Purpose: Radiotherapy (RT) treatment and treatment planning is a complex process prepared and delivered by a multidisciplinary team of specialists. Efficient communication and notification systems among different team members are therefore essential to ensure the safe, timely delivery of treatments to patients.

Method: To address this issue, we developed and implemented automated notification systems and an electronic whiteboard to track every CT simulation, contouring task, the new-start schedule, and physician's appointments and tasks, and notify team members of overdue and missing tasks and appointments.

Radiosensitization beyond DNA damage: Monte Carlo simulations of realistic nanomaterial biodistributions.

We investigated cellular distribution of a tumor-specific gadolinium chelate in 4T1 and U87 cancer cells with the goal to generate more realistic geometries for Monte Carlo simulations of radiation interaction with nanoparticles in cells. Cells were exposed to the agent in-vitro for 30 minutes to 72 hours before being fixed and imaged using transmission electron microscopy. Initially, electron-dense areas consistent with gadolinium were observable throughout the cytoplasm.

Case Report: Bilateral targeted intraoperative radiotherapy: a safe and effective alternative for synchronous bilateral breast cancer.

Background: The incidence of bilateral breast cancer (BBC) ranges from 1.4% to 11.8%.

Experience with intraoperative radiation therapy in an urban cancer center.

Background/objective: Intra-operative radiation therapy (IORT) is a newer partial breast irradiation technique that has been well studied in 2 large randomized trials, the TARGIT-A and ELIOT trials. We initiated our IORT program in 2018 in the context of a registry trial, and aim to report our early results thus far.

Methods: We instituted an IORT practice using Intrabeam® low energy 50kVp x-rays for selected breast cancer cases in 2018.

Implementation of novel measurement-based patient-specific QA for pencil beam scanning proton FLASH radiotherapy.

Background: Several studies have shown pencil beam scanning (PBS) proton therapy is a feasible and safe modality to deliver conformal and ultra-high dose rate (UHDR) FLASH radiation therapy. However, it would be challenging and burdensome to conduct the quality assurance (QA) of the dose rate along with conventional patient-specific QA (psQA).

Purpose: To demonstrate a novel measurement-based psQA program for UHDR PBS proton transmission FLASH radiotherapy (FLASH-RT) using a high spatiotemporal resolution 2D strip ionization chamber array (SICA).

Reproducibility study of Monte Carlo simulations for nanoparticle dose enhancement and biological modeling of cell survival curves.

Nanoparticle-derived radiosensitization has been investigated by several groups using Monte Carlo simulations and biological modeling. In this work we replicated the physical simulation and biological modeling of previously published research for 50 nm gold nanoparticles irradiated with monoenergetic photons, various 250 kVp photon spectra, and spread-out Bragg peak (SOBP) protons. Monte Carlo simulations were performed using TOPAS and used condensed history Penelope low energy physics models for macroscopic dose deposition and interaction with the nanoparticle; simulation of the microscopic dose deposition from nanoparticle secondaries was performed using Geant4-DNA track structure physics.

Impact of respiratory motion on proton pencil beam scanning FLASH radiotherapy: anand phantom measurement study.

. To investigate the effects of respiratory motion on the delivered dose in the context of proton pencil beam scanning (PBS) transmission FLASH radiotherapy (FLASH-RT) by simulation and phantom measurements..

Commissioning a 250 MeV research beamline for proton FLASH radiotherapy preclinical experiments.

Background: The potential reduction of normal tissue toxicities during FLASH radiotherapy (FLASH-RT) has inspired many efforts to investigate its underlying mechanism and to translate it into the clinic. Such investigations require experimental platforms of FLASH-RT capabilities.

Purpose: To commission and characterize a 250 MeV proton research beamline with a saturated nozzle monitor ionization chamber for proton FLASH-RT small animal experiments.

Reducing PTV margins for prostate SBRT with motion compensation and gating techniques.

The purpose of this study is to investigate the dosimetric accuracy of prostate SBRT when motion is considered. To account for target movement, motion compensation and gating techniques were investigated with PTV margins reduced to 2 mm. To allow for dosimetric measurements a Delta4 phantom, Gafchromic film, and Hexamotion motion platform were utilized.

Volumetric changes of the parotid gland during IMRT based on mid-treatment imaging: implications for parotid stem cell sparing strategies in head and neck cancer.

Background: To evaluate the change in parotid glands at mid-treatment during IMRT and the association between radiation dose to the parotid gland stem cell (PGSC) region and patient-reported xerostomia for patients with head and neck cancer (HNC).

Material And Methods: Patients who were treated from 2006-2012 at our institution with patient-reported xerostomia outcomes available at least 9 months following RT were included. PG and PGSC regions were delineated and the dose was estimated from the treatment plan dose distribution, using contours from pre- and mid-treatment CT scans.

Orthovoltage X-Rays Exhibit Increased Efficacy Compared with γ-Rays in Preclinical Irradiation.

Unlabelled: Radionuclide irradiators (137Cs and 60Co) are commonly used in preclinical studies ranging from cancer therapy to stem cell biology. Amidst concerns of radiological terrorism, there are institutional initiatives to replace radionuclide sources with lower energy X-ray sources. As researchers transition, questions remain regarding whether the biological effects of γ-rays may be recapitulated with orthovoltage X-rays because different energies may induce divergent biological effects.

Case Report: Can Targeted Intraoperative Radiotherapy in Patients With Breast Cancer and Pacemakers be the New Standard of Care?

Background: Partial breast irradiation with Intra-operative radiotherapy (IORT) has become a popular management option as opposed to whole breast radiation using external beam radiotherapy for breast cancer patients. While previous studies have highlighted the use of IORT in breast cancer patients, there is a scarcity of literature on the use of IORT in those who also have ipsilateral pacemakers. Thus, the aim of our case report is to highlight the applicability of IORT in breast cancer patients who also have a pacemaker.

Deep Learning-Based Automatic Detection of Brain Metastases in Heterogenous Multi-Institutional Magnetic Resonance Imaging Sets: An Exploratory Analysis of NRG-CC001.

Purpose: Deep learning-based algorithms have been shown to be able to automatically detect and segment brain metastases (BMs) in magnetic resonance imaging, mostly based on single-institutional data sets. This work aimed to investigate the use of deep convolutional neural networks (DCNN) for BM detection and segmentation on a highly heterogeneous multi-institutional data set.

Methods And Materials: A total of 407 patients from 98 institutions were randomly split into 326 patients from 78 institutions for training/validation and 81 patients from 20 institutions for unbiased testing.

A 2D strip ionization chamber array with high spatiotemporal resolution for proton pencil beam scanning FLASH radiotherapy.

Purpose: Experimental measurements of two-dimensional (2D) dose rate distributions in proton pencil beam scanning (PBS) FLASH radiation therapy (RT) are currently lacking. In this study, we characterize a newly designed 2D strip-segmented ionization chamber array (SICA) with high spatial and temporal resolution and demonstrate its applications in a modern proton PBS delivery system at both conventional and ultrahigh dose rates.

Methods: A dedicated research beamline of the Varian ProBeam system was employed to deliver a 250-MeV proton PBS beam with nozzle currents up to 215 nA.

Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline.

Purpose: This guideline provides updated evidence-based recommendations addressing recent developments in the management of patients with brain metastases, including advanced radiation therapy techniques such as stereotactic radiosurgery (SRS) and hippocampal avoidance whole brain radiation therapy and the emergence of systemic therapies with central nervous system activity.

Methods: The American Society for Radiation Oncology convened a task force to address 4 key questions focused on the radiotherapeutic management of intact and resected brain metastases from nonhematologic solid tumors. The guideline is based on a systematic review provided by the Agency for Healthcare Research and Quality.