Single-Isocenter, Multiple-Target Abdominal Cone-Beam Computed Tomography (CBCT)-Guided Online Adaptive Stereotactic Body Radiotherapy (SBRT).

Stereotactic body radiotherapy (SBRT) is increasingly being prescribed for treating patients with multiple metastases, especially in the setting of oligometastatic disease. Treating multiple targets presents unique challenges in radiotherapy planning and delivery, including practical considerations relating to treatment time, resource allocation, and treatment planning complexity. Treating targets in a common isocenter reduces the time required for treatment and simplifies planning, but historically, it has often not been feasible due to inter- and intra-fractional variation in relative target positions.

Dosimetric evaluation of a novel modular cell irradiation platform for multi-modality in vitro studies including high dose rate brachytherapy.

Purpose: High dose-rate (HDR) brachytherapy is integral for the treatment of numerous cancers. Preclinical studies involving HDR brachytherapy are limited. We aimed to describe a novel platform allowing multi-modality studies with clinical HDR brachytherapy and external beam irradiators, establish baseline dosimetry standard of a preclinical orthovoltage irradiator, to determine accurate dosimetric methods.

Millimeter wave-based patient setup verification and motion tracking during radiotherapy.

Background: Position verification and motion monitoring are critical for safe and precise radiotherapy (RT). Existing approaches to these tasks based on visible light or x-ray are suboptimal either because they cannot penetrate obstructions to the patient's skin or introduce additional radiation exposure. The low-cost mmWave radar is an ideal solution for these tasks as it can monitor patient position and motion continuously throughout the treatment delivery.

Script-based implementation of automatic grid placement for lattice stereotactic body radiation therapy.

Background And Purpose: Spatially fractionated radiation therapy (SFRT) has demonstrated promising clinical response in treating large tumors with heterogeneous dose distributions. Lattice stereotactic body radiation therapy (SBRT) is an SFRT technique that leverages inverse optimization to precisely localize regions of high and lose dose within disease. The aim of this study was to evaluate an automated heuristic approach to sphere placement in lattice SBRT treatment planning.

Inter-fractional portability of deep learning models for lung target tracking on cine imaging acquired in MRI-guided radiotherapy.

MRI-guided radiotherapy systems enable beam gating by tracking the target on planar, two-dimensional cine images acquired during treatment. This study aims to evaluate how deep-learning (DL) models for target tracking that are trained on data from one fraction can be translated to subsequent fractions. Cine images were acquired for six patients treated on an MRI-guided radiotherapy platform (MRIdian, Viewray Inc.

A Dose Accumulation Assessment of Alignment Errors During Spatially Fractionated Radiation Therapy.

Purpose: Spatially fractionated radiation therapy (SFRT) techniques produce high-dose peaks and low-dose valleys within a tumor. Lattice stereotactic body radiation therapy (SBRT) is a form a SFRT delivered across 5 fractions. Because of the high spatial dose gradients associated with SFRT, it is critical for fractionated SFRT patients to be aligned correctly for treatment.

Simulation study of a novel small animal FLASH irradiator (SAFI) with integrated inverse-geometry CT based on circularly distributed kV X-ray sources.

Ultra-high dose rate (UHDR) radiotherapy (RT) or FLASH-RT can potentially reduce normal tissue toxicity. A small animal irradiator that can deliver FLASH-RT treatments similar to clinical RT treatments is needed for pre-clinical studies of FLASH-RT. We designed and simulated a novel small animal FLASH irradiator (SAFI) based on distributed x-ray source technology.

A stochastic control approach to intrafraction motion management in intensity-modulated radiotherapy.

The goal of this research is to demonstrate proof-of-principle for managing intrafraction motion via feedback control of delivered dose to achieve dosimetry comparable to respiratory gating without compromising delivery efficiency.. We develop a stochastic control approach for step-and-shoot intensity-modulated radiotherapy (IMRT) in which the cumulative delivered dose and future trajectory of intrafraction motion are dynamically estimated by combining pre-treatment four-dimensional computed tomography imaging and intrafraction respiratory-motion surrogates.

: A Tool for the Detection of Annotated and Novel Small RNAs.

Existing small noncoding RNA analysis tools are optimized for processing short sequencing reads (17-35 nucleotides) to monitor microRNA expression. However, these strategies under-represent many biologically relevant classes of small noncoding RNAs in the 36-200 nucleotides length range (tRNAs, snoRNAs, etc.).

LITE SABR M1: Planning design and dosimetric endpoints for a phase I trial of lattice SBRT.

Purpose: Lattice stereotactic body radiation therapy (SBRT) is a form of spatially fractionated radiation therapy (SFRT) using SBRT methods. This study reports clinical dosimetric endpoints achieved for Lattice SBRT plans delivering 20 Gy in 5 fractions to the periphery of a tumor with a simultaneous integrated boost (SIB) of 66.7 Gy, as part of a prospective Phase I clinical trial (NCT04133415).

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.

Development of a storage phosphor imaging system for proton pencil beam spot profile determination.

Purpose: Accurate two-dimensional (2D) profile measurements at submillimeter precision are necessary for proton beam commissioning and periodic quality assurance (QA) purposes and are currently performed at our institution with a commercial scintillation detector (Lynx PT) with limited means for independent checks. The purpose of this work was to create an independent dosimetry system consisting of an in-house optical scanner and a BaFBrI:Eu storage phosphor dosimeter by: (a) determining the optimal settings for the optical scanner, (b) measuring 2D proton spot profiles with the storage phosphors, and (c) comparing them to similar measurements using a commercial scintillation detector.

Methods: An in-house 2D laboratory optical scanner was constructed and spatially calibrated for accurate 2D photostimulated luminescence (PSL) dosimetry.

An atlas-guided automatic planning approach for rectal cancer intensity-modulated radiotherapy.

We try to develop an atlas-guided automatic planning (AGAP) approach and evaluate its feasibility and performance in rectal cancer intensity-modulated radiotherapy. The developed AGAP approach consisted of four independent modules: patient atlas, similar patient retrieval, beam morphing (BM), and plan fine-tuning (PFT) modules. The atlas was setup using anatomy and plan data from Pinnacle auto-planning (P-auto) plans.

Dynamics and extensional rheology of polymer-surfactant association complexes.

Understanding and characterizing the influence of polymers and surfactants on rheology, application, and processing is critical for designing complex fluid formulations for enhanced oil recovery, pharmaceuticals, cosmetics, foods, inks, agricultural sprays, and coatings. It is well-established that the addition of anionic surfactant like sodium dodecyl sulfate (SDS) to an aqueous solution of an oppositely-charged or uncharged polymer like poly(ethylene oxide) (PEO) can result in the formation of the polymer-surfactant association complexes (P0S-ACs) and a non-monotonic concentration-dependent variation in zero shear viscosity. However, the extensional rheology response of polymer-surfactant mixtures remains relatively poorly understood, partially due to characterization challenges that arise for low viscosity, low elasticity fluids, even though the response to strong extensional flows impacts drop formation and many processing operations.

Characterization of Dosimetric Differences in Strut-Adjusted Volume Implant Treatment Plans Calculated With TG-43 Formalism and a Model-Based Dose Calculation Algorithm.

Purpose: To comprehensively characterize dosimetric differences between calculations with a commercial model-based dose calculation algorithm (MBDCA) and the TG-43 formalism in application to accelerated partial breast irradiation (APBI) with the strut-adjusted volume implant (SAVI) applicator.

Methods: Dose for 100 patients treated with the SAVI applicator was recalculated with an MBDCA for comparison to dose calculated via TG-43. For every pair of dose calculations, dose-volume histogram (DVH) metrics including V90%, V95%, V100%, V150%, and V200% for the PTV_EVAL were compared.

Dual-storage phosphor proton therapy dosimetry: Simultaneous quantification of dose and linear energy transfer.

Purpose: To investigate the feasibility of using the high Z storage phosphor material BaFBrI:Eu in conjunction with the low Z storage phosphor material KCl:Eu for simultaneous proton dose and linear energy transfer (LET) measurements by (a) measuring the fundamental optical and dosimetric properties of BaFBrI:Eu , (b) evaluating its compatibility in being readout simultaneously with KCl:Eu dosimeters, and (c) modeling and validating its LET dependence under elevated proton LET irradiation.

Methods: A commercial BaFBrI:Eu storage phosphor detector (Model ST-VI, Fujifilm) was characterized with energy dispersive x-ray spectroscopy (EDS) analysis to obtain its elemental composition. The dosimeters were irradiated using both a Mevion S250 proton therapy unit (at the center of a spread-out Bragg peak, SOBP) and a Varian Clinac iX linear accelerator with the latter being a low LET irradiation.

Long-term Inter-protocol kV CBCT image quality assessment for a ring-gantry linac via automated QA approach.

We develop a fully automated QA process to compare the image quality of all kV CBCT protocols on a Halcyon linac with ring gantry design, and evaluate image quality stability over a 10-month period. A total of 19 imaging scan and reconstruction protocols were characterized with measurement on a newly released QUART phantom. A set of image analysis algorithms were developed and integrated into an automated analysis suite to derive key image quality metrics, including HU value accuracy on density inserts, HU uniformity using the background plate, high contrast resolution with the modulation transfer function (MTF) from the edge profiles, low contrast resolution using the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), slice thickness with the air gap modules, and geometric accuracy with the diameter of the phantom.

Technical Note: Cumulative dose modeling for organ motion management in MRI-guided radiation therapy.

Purpose: To develop a method for continuous online dose accumulation during irradiation in MRI-guided radiation therapy (MRgRT) and to demonstrate its application in evaluating the impact of internal organ motion on cumulative dose.

Methods: An intensity-modulated radiation therapy (IMRT) treatment plan is partitioned into its unique apertures. Dose for each planned aperture is calculated using Monte Carlo dose simulation on each phase of a four-dimensional computed tomography (4D-CT) dataset.

Direct tumor visual feedback during free breathing in 0.35T MRgRT.

To present a tumor motion control system during free breathing using direct tumor visual feedback to patients in 0.35 T magnetic resonance-guided radiotherapy (MRgRT). We present direct tumor visualization to patients by projecting real-time cine MR images on an MR-compatible display system inside a 0.

Quantitative proton radiation therapy dosimetry using the storage phosphor europium-doped potassium chloride.

Purpose: To (a) characterize the fundamental optical and dosimetric properties of the storage phosphor europium-doped potassium chloride for quantitative proton dosimetry, and (b) investigate if its dose radiation response can be described by an analytic radiation transport model.

Methods: Cylindrical KCl:Eu dosimeters with dimensions of 6 mm diameter and 1 mm thickness were fabricated in-house. The dosimeters were irradiated using both a Mevion S250 passive scattering proton therapy system and a Varian Clinac iX linear accelerator.

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.

Treatment Outcome Prediction for Cancer Patients based on Radiomics and Belief Function Theory.

In this study, we proposed a new radiomics-based treatment outcome prediction model for cancer patients. The prediction model is developed based on belief function theory (BFT) and sparsity learning to address the challenges of redundancy, heterogeneity, and uncertainty of radiomic features, and relatively small-sized and unbalanced training samples. The model first selects the most predictive feature subsets from relatively large amounts of radiomic features extracted from pre- and/or in-treatment positron emission tomography (PET) images and available clinical and demographic features.