A High-Throughput Neurosphere-Based Colony Formation Assay to Test Drug and Radiation Sensitivity of Different Patient-Derived Glioblastoma Lines.

The gold standard assay for radiation response is the clonogenic assay, a normalized colony formation assay (CFA) that can capture a broad range of radiation-induced cell death mechanisms. Traditionally, this assay relies on two-dimensional (2D) cell culture conditions with colonies counted by fixing and staining protocols. While some groups have converted these to three-dimensional (3D) conditions, these models still utilize 2D-like media compositions containing serum that are incompatible with stem-like cell models such as brain tumor initiating cells (BTICs) that form self-aggregating spheroids in neural stem cell media.

Knowledge-based planning, multicriteria optimization, and plan scorecards: A winning combination.

Background And Purpose: The ESTRO 2023 Physics Workshop hosted the Fully-Automated Radiotherapy Treatment Planning (Auto-RTP) Challenge, where participants were provided with CT images from 16 prostate cancer patients (6 prostate only, 6 prostate + nodes, and 4 prostate bed + nodes) across 3 challenge phases with the goal of automatically generating treatment plans with minimal user intervention. Here, we present our team's winning approach developed to swiftly adapt to both different contouring guidelines and treatment prescriptions than those used in our clinic.

Materials And Methods: Our planning pipeline comprises two main components: 1) auto-contouring and 2) auto-planning engines, both internally developed and activated via DICOM operations.

Longitudinal brain volumetrics in glioma survivors.

Objective: Radiation therapy (RT) is used selectively for patients with low-grade glioma (LGG) given the concerns for potential cognitive effects in survivors, but prior cognitive outcome studies among LGG survivors have had inconsistent findings. Translational studies that characterize changes in brain anatomy and physiology after treatment of LGG may help to both contextualize cognitive findings and improve the overall understanding of radiation effects in normal brain tissue. This study aimed to investigate the hypothesis that patients with LGG who are treated with RT will experience greater brain volume loss than those who do not receive RT.

Prospective Evaluation of Automated Contouring for CT-Based Brachytherapy for Gynecologic Malignancies.

Purpose: The use of deep learning to auto-contour organs at risk (OARs) in gynecologic radiation treatment is well established. Yet, there is limited data investigating the prospective use of auto-contouring in clinical practice. In this study, we assess the accuracy and efficiency of auto-contouring OARs for computed tomography-based brachytherapy treatment planning of gynecologic malignancies.

Characterization of Photon Intensity Modulated Radiation Therapy Robustness in Patients With Prostate Cancer as a Proposed Benchmark for Proton Therapy Robustness Evaluation.

Purpose: Robustness evaluation is increasingly used in particle therapy planning to assess clinical target volume (CTV) coverage in the setting of setup and range uncertainty. However, no clear standard exists as to an acceptable degree of plan robustness. The aim of this study is to quantify x-ray robustness parameters, as this could inform proton planning when held to a similar standard.

Automated evaluation for rapid implementation of knowledge-based radiotherapy planning models.

Purpose: Knowledge-based planning (KBP) offers the ability to predict dose-volume metrics based on information extracted from previous plans, reducing plan variability and improving plan quality. As clinical integration of KBP is increasing there is a growing need for quantitative evaluation of KBP models. A .

Prostate Stereotactic Body Radiation Therapy With a Focal Simultaneous Integrated Boost: 5-Year Toxicity and Biochemical Recurrence Results From a Prospective Trial.

Purpose: Stereotactic body radiation therapy (SBRT) is increasingly used as a definitive treatment option for patients with prostate adenocarcinoma. The aim of this study was to assess the late toxicity, patient-reported quality of life outcomes, and biochemical recurrence rates after prostate SBRT with simultaneous integrated boost (SIB) targeting lesions defined by magnetic resonance imaging (MRI).

Methods And Materials: Patients were eligible if they had biopsy-proven low- or intermediate-risk prostate adenocarcinoma, one or more focal lesions on MRI, and an MRI-defined total prostate volume of <120 mL.

Improving Communication of Peer-Review Conference Outcomes: A Practical Experience.

Purpose: The aim of this work was to describe the design and implementation of a more robust workflow for communicating outcomes from a peer-review chart rounds conference. We also provide information regarding cycle times, plan revisions, and other key metrics that we have observed since initial implementation.

Methods And Materials: A multidisciplinary team of stakeholders including physicians, physicists, and dosimetrists developed a revised peer-review workflow that addressed key needs to improve the prior process.

Patterns of Failure and Optimal Treatment Paradigm for Large, Inoperable, Node-Negative Non-small Cell Lung Cancer.

Objectives: The ideal non-operative treatment for patients with large, node-negative non-small cell lung cancer (NSCLC) is poorly defined. To inform optimal treatment paradigms for this cohort, we examined patterns of failure and the impact of radiation therapy (RT) and chemotherapy receipt.

Materials And Methods: Node-negative NSCLC patients with 5+ cm primary tumors receiving definitive RT at our institution were identified.

Stereotactic body radiation therapy with simultaneous integrated boost for prostate cancer: does MRI-targeted biopsy alter the boost field?

Introduction: We aim to investigate if the addition of MRI-US fusion biopsy (FB) can aid in radiation planning and alter the boost field in cases of stereotactic body radiation therapy (SBRT) for prostate cancer with a simultaneous integrated boost (SIB) to a magnetic resonance imaging (MRI)-defined intraprostatic lesion.

Materials And Methods: Patients undergoing SBRT with SIB for biopsy-proven prostatic adenocarcinoma and a pre-radiation MRI were retrospectively reviewed. 36.

Code Wisely: Risk assessment and mitigation for custom clinical software.

Purpose: The task of software development has become an increasing part of the medical physicist's role. Many physicists who are untrained in the best practices of software development have begun creating scripts for clinical use. There is an increasing need for guidance for both developers and medical physicists to code wisely in the clinic.

A Holographic Augmented Reality Guidance System for Patient Alignment: A Feasibility Study.

Purpose To evaluate the accuracy of an augmented reality holographic guidance system for potential use in patient alignment in radiotherapy applications. Methods A cubic phantom was scanned on a CT simulator and a 3D mesh was extracted using the Eclipse Scripting API. An application was created for the Microsoft HoloLens to allow users to see the scanned mesh as a hologram overlaid in the treatment vault.

Transition From Manual to Automated Planning and Delivery of Volumetric Modulated Arc Therapy Stereotactic Radiosurgery: Clinical, Dosimetric, and Quality Assurance Results.

Purpose: Properly planned single isocenter volumetric modulated arc therapy (VMAT) radiosurgery plans exhibit high quality and efficiency. We report here the largest clinical experience to date, to our knowledge, comparing manual planning with a new automated platform designed to standardize and simplify radiosurgery planning and delivery processes.

Methods: We treated 693 patients with single isocenter VMAT radiosurgical plans generated by either our conventional manual (mVMAT) or a recently implemented automated (HyperArc) technique.

Accuracy of dose-volume metric calculation for small-volume radiosurgery targets.

Purpose: For stereotactic radiosurgery (SRS), accurate evaluation of dose-volume metrics for small structures is necessary. The purpose of this study was to compare the DVH metric capabilities of five commercially available SRS DVH analysis tools (Eclipse, Elements, Raystation, MIM, and Velocity).

Methods: DICOM RTdose and RTstructure set files created using MATLAB were imported and evaluated in each of the tools.

Technical Note: Use of automation to eliminate shift errors.

Purpose: To create automated tools within the treatment planning system (TPS) that eliminate the common error pathway of providing incorrect shift instructions to therapists.

Materials/methods: Two scripts were created within the TPS using the Eclipse API (Varian Medical Systems, Palo Alto, CA). One script detects whether or not the user origin has been placed correctly at the intersection of the simulation markers while the other calculates a shift instruction sheet that can be printed for treatment.

Technical Note: An open source solution for improving TG-263 compliance.

Purpose: Compliance with TG-263 nomenclature standards can be challenging. We introduce an open source solution to this problem and evaluate its impact on compliance within our institution.

Materials/methods: The TG-236 nomenclature standards were implemented in our clinic in two phases.

Using a whiteboard web application for tracking treatment workflow metrics for dosimetrists and physicians.

We present a framework for collecting data which elucidates detailed clinical flow timelines for different treatment sites, modalities, planners, and physicians in radiotherapy treatments. A web based tool, the Whiteboard, was developed which allows communication between the physicians and staff about the current state of the radiotherapy treatment plan and provides detailed time data for each stage of the patient's journey from simulation to treatment. Detailed timestamped data was collected over a period of 6 years which included 22 discrete steps of the treatment planning process.

Stereotactic radiosurgery with MLC-defined arcs: Verification of dosimetry, spatial accuracy, and end-to-end tests.

Purpose: To measure dosimetric and spatial accuracy of stereotactic radiosurgery (SRS) delivered to targets as small as the trigeminal nerve (TN) using a standard external beam treatment planning system (TPS) and multileaf collimator-(MLC) equipped linear accelerator without cones or other special attachments or modifications.

Methods: Dosimetric performance was assessed by comparing computed dose distributions to film measurements. Comparisons included the γ-index, beam profiles, isodose lines, maximum dose, and spatial accuracy.

Assessing the feasibility of single target radiosurgery quality assurance with portal dosimetry.

Purpose: To assess the feasibility of using portal dosimetry (PD) for pre-treatment quality assurance of single target, flattening filter free (FFF), volumetric arc therapy intracranial radiosurgery plans.

Methods: A PD algorithm was created for a 10X FFF beam on a Varian Edge linear accelerator (Varian Inc, Palo Alto, CA, USA). Treatment plans that were previously evaluated with Gafchromic EBT-XD (Ashland, Bridgewater, NJ, USA) film were measured via PD and analyzed with the ARIA Portal Dosimetry workspace.

Prostate Stereotactic Body Radiation Therapy With a Focal Simultaneous Integrated Boost: Acute Toxicity and Dosimetry Results From a Prospective Trial.

Purpose: This study aimed to report the early toxicity results of a prospective clinical trial of prostate stereotactic body radiation therapy (SBRT) to the entire prostate with a simultaneous integrated boost (SIB) to magnetic resonance imaging (MRI)-defined focal lesions.

Methods And Materials: Eligible patients included men with biopsy-proven prostate stage T1c to T2c adenocarcinoma, a Gleason score ≤7, and prostate-specific antigen values of ≤20 ng/mL, who had at least 1 focal lesion visible on MRI and a total prostate volume no greater than 120 cm. SBRT consisted of a dose of 36.

Model for Estimating Power and Downtime Effects on Teletherapy Units in Low-Resource Settings.

Purpose: More than 6,500 megavoltage teletherapy units are needed worldwide, many in low-resource settings. Cobalt-60 units or linear accelerators (linacs) can fill this need. We have evaluated machine performance on the basis of patient throughput to provide insight into machine viability under various conditions in such a way that conclusions can be generalized to a vast array of clinical scenarios.

Subcutaneous adipose tissue characteristics and the risk of biochemical recurrence in men with high-risk prostate cancer.

Purpose/objective(s): To assess subcutaneous adipose tissue characteristics by computed tomography (CT) as potential imaging biomarkers predictive of biochemical recurrence in men with high-risk prostate cancer receiving radiotherapy (RT).

Materials And Methods: This retrospective study included men with high-risk prostate cancer (PSA>20ng/ml, Gleason score ≥8, or clinical extraprostatic extension) treated between 2001 and 2012. All patients received definitive, dose-escalated external beam RT along with a course of neoadjuvant, concurrent, and adjuvant androgen deprivation therapy (ADT).

A priori patient-specific collision avoidance in radiotherapy using consumer grade depth cameras.

Purpose: In this study, we demonstrate and evaluate a low cost, fast, and accurate avoidance framework for radiotherapy treatments. Furthermore, we provide an implementation which is patient specific and can be implemented during the normal simulation process.

Methods: Four patients and a treatment unit were scanned with a set of consumer depth cameras to create a polygon mesh of each object.

Combining Computed Tomography-Based Bone Density Assessment with FRAX Screening in Men with Prostate Cancer.

To investigate the addition of a computed tomography (CT)-based method of osteoporosis screening to FRAX without bone mineral density (BMD) fracture risk assessment in men undergoing radiotherapy for prostate cancer, we reviewed the records of all patients with localized prostate cancer treated with external beam radiotherapy at our institution between 2001 and 2012. The 10-yr probability of hip fracture was calculated using the FRAX algorithm without BMD. The CT attenuation of the L5 trabecular bone (L5) was assessed by contouring the trabecular bone on a single CT slice at the level of the midvertebral body and by averaging the Hounsfield units (HU) of all included voxels.