Radiation Medicine Commons^™

Develop A Novel Beam Orientation Optimization Algorithm For Let (Linear Energy Transfer) Incorporated Impt (Intensity Modulated Proton Therapy) (Imptlet, R Dao, Y Qian, Xiaoqiang Li, H Quan, Xuanfeng Ding, G Liu

Conference Presentation Abstracts

Purpose: To improve the dose and LET distribution in the IMPTLET, we introduce a new optimization algorithm to search for the optimal beam orientation and count through the arc trajectory (BOC-IMPTLET). Methods: We introduce kmeans clustering analysis in the BOC-IMPTLET algorithm by analyzing the distribution of LET in the target from the full arc trajectory. The optimal of cluster count was used as beam count, which was determined based on the SSE (Sum of Square Error) value and the angle of the corresponding centroid of each cluster was used as beam orientation, respectively. The BOC-IMPTLET algorithm was implemented in the …

Comparison Of Vmat Beam Complexity With Different Mlc Collimator Rotation And Their Impact On Psqa Pass Rates, David T. To, Michael G. Snyder, Jian Liang

Conference Presentation Abstracts

Purpose: I t has been previously shown that utilizing a collimator angle of ±45° has demonstrated a reduction in MU and VMAT beam complexity. Studies have demonstrated this for VMAT prostate plans with small sample size. In this study we evaluate multiple collimator angles with a larger sample size and different treatment sites. Methods: A total of 17273 VMAT beams were evaluated with beam collimator rotations of 0°, ±5°, ±10°, ±15°, ±30°, ±45°, and ±90°. QA Gamma pass rates for our institution use a 3%/2mm criteria 10% threshold with 95% limit pass rate utilizing Sun Nuclear ArcCheck (helical diode array). …

Predicting Tumor Voxel Dose-Response Using Deep Learning On Serial Fdg-Pet Feedback Images, Shupeng Chen, Di Yan, An Qin, Rohan Deraniyagala, Daniel Krauss, Peter Chen, Craig Stevens

Conference Presentation Abstracts

Purpose: Tumor voxel dose-response matrix (DRM) can be assessed using a series of FDG-PET/CT feedback images acquired during radiotherapy. Predicting the tumor voxel DRM earlier is crucial for treatment adaptation. However, it is also challenging due to FDG fluctuation in tumor cells. This study investigated the feasibility of predicting DRM during early treatment weeks using deep learning (DL). Methods: FDG-PET images were acquired at the pretreatment (preTx), the 2nd and 4th weeks during chemo-radiotherapy (35×2Gy) from 50 head and neck patients. The reference value of tumor voxel DRM (DRMref), representing the average metabolic change ratio during the treatment, was determined …

Internal Lead Shielding For Clinical Electron Treatments, Patrick N. Mcdermott

Conference Presentation Abstracts

Purpose: Electron beams are often used to treat superficial lesions of the lip, cheek, nose and ear. Lead is frequently used to block distal structures. It is customary to place an internal bolus of low atomic number in between the tissue and the lead to reduce electron backscatter from the lead. Space for the lead and the internal bolus is quite limited. The current method, recommended by TG25, for estimating the thickness of the lead plus internal bolus is not self-consistent and leads to a larger than necessary thickness. Furthermore, this method uses an older expression for the electron backscatter …

A Novel Planning Framework For The Efficient Spot-Scanning Proton Arc Therapy Via The Particle Swarm Optimization (Sparc-Particle Swarm), Y Qian, R Dao, G Liu, Xiaoqiang Li, H Quan, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: The delivery efficiency is the bottleneck of spot-scanning proton arc therapy (SPArc) because of the numerous energy layers (EL) ascending switches. This study aims to develop a new algorithm to mitigate the need of EL ascending via water equivalent thickness (WET) sector selection followed by the particle swarm optimization (SPArc- particle swarm). Methods: SPArc- particle swarm divided the full arc trajectory into the optimal sectors based on the K-means clustering analysis of the relative mean WET. Within the sector, particle swarm optimization was used to minimize the total energy switch time, in which it optimized the energy selection integrated …

Linac-Based Srs Treatments Slow Down Unnecessarily Due To Parked Leaf Optimization, Brian Loughery, Cory S. Knill, Raminder P. Sandhu, Lifeng Lin, Jian Liang

Conference Presentation Abstracts

Purpose: It was observed on a VersaHD that clinical SRS deliveries created in the Elements treatment planning system (TPS) slowed gantry rotation and dose rate to allow parked MLC leaves to move into position for use in an upcoming control point. Gantry rotation slowed suddenly, visibly backtracking to previous gantry angles. The purpose of this work is to study the effect of parked MLC positioning parameters in Elements on cranial SRS delivery speed and gantry motion on a VersaHD. Methods: To study the effect of parked MLC leaf positions on VersaHD deliverability, cranial SRS plans were generated with different TPS …

Application Of A Novel Optical Tool For Linac Calibrations, Cory S. Knill, Brian Loughery, Raminder P. Sandhu, Lifeng Lin, Mark Stefani

Conference Presentation Abstracts

Purpose: Maintaining a linac within tight stereotactic isocentricity tolerances requires minimizing errors in individual components of the linac. However, while isocentricity can be measured using a Winston-Lutz test, contributions from individual components can be difficult to discern. The disconnect between how individual components contribute to isocentricity can lead to lengthy troubleshooting exercises when isocentricity is outside tolerance. To provide more info rmation to physicists and increase the speed of isocentricity adjustments, a new tool that uses optical tracking to investigate and adjust individual linac components that contribute to isocentricity was tested on three clinical linacs. Methods: The optical tracking tool …

Individual Vmat Beam Complexity Indices Have Limited Predictive Value For Qa Pass-Rates, Jian Liang, Q Liu, David T. To, Michael G. Snyder

Conference Presentation Abstracts

Purpose: Previous studies with sample sizes <400 have indicated that VMAT beam complexity indices may have a relationship with measured QA pass-rates. The aim of this study is to evaluate such relationships on a large scale to further investigate their strength. Methods: Total of 17,273 VMAT QA results across 8 Elekta Agility machines were used in this study. All beams were flattened 6MV or 10MV. Sun Nuclear ArcCheck was used for QA measurements with γ-analysis parameters of 10% threshold, 3% dose difference, 2mm distance to agreement, and 95% passing threshold. A total 214 Beams (1.23%) failed QA. QA distributions in Pinnacle were calculated with 2 degree gantry intervals and a dose grid of 2mm. Four complexity indices (MCSv, MU weighted Segment Area, Segment Area/Perimeter, and Average Leaf Gap) were computed. Spearman’s correlations were evaluated for each, and cut-off values for the indices were sought to indicate values above which no QA failures would be expected. Results: Evaluation of the 4 complexity metrics showed weak correlation with QA pass rates (< ±0.42) with high significance (p < 0.001). When metrics were evaluated independently, cut-off values from correlation plots separated only 0.67%, 0.72%, 2.2%, 6.3% guaranteed passing beams from the total sample, respectively. When evaluating whether anymetric for a given beam exceeded its cut-off, the fraction of guaranteed passing beams rose to only 6.6%. However, when cut-off values for one metric were allowed to be functionally dependent upon another, the fraction of guaranteed passing beams increased. For MU weighted Segment Area andAverage Leaf Gap, a dependent approach separated 19.1% guaranteed passing beams from the sample. Conclusion: Individual complexity metrics have weak predictive utility in assessing plan performance. However, using multiple complexity cut-off functions with dependence upon more than one metric increased the fraction of predicted passing beams by around 300%.

Does Proton Arc Therapy Has Potential Clinical Benefits For Hepatocellular Carcinoma?, Peilin Liu, R Dalfsen, M Soukup, Shupeng Chen, Lewei Zhao, Z Wang, X S. Gao, Thomas Quinn, Craig Stevens, Rohan Deraniyagala, Xiaoqiang Li, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: To investigate the potential clinical benefits and dose-averaged Linear Energy Transfer (LETd) sparing, utilizing proton arc plan for Hepatocellular carcinoma (HCC) patients in comparison with Intensity Modulated Proton Therapy (IMPT). Methods: Ten HCC patients have been retrospectively selected. Two planning groups were created: Proton Arc plans using Monaco ver. 6 and the clinical IMPT plan. Both planning groups used the same robustness parameters. The prescription dose is 67.5 Gy (RBE) in 15 fractions/ 66 GyE in 10 fractions of the Clinical Target Volume (CTV) following clinical IMPT plan. Robustness evaluations were performed to ensure target dose coverage. Normal Tissue …

An Analytic Model Of The External Beam Dose Rate Effect On Immune Cells In Blood Dosimetry, Lewei Zhao, Peilin Liu, G Liu, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: Radiation therapy is a double-edged sword with regard to its immunomodulatory effect. It is critical to find how it is affected by dose rate. Thus, we developed an analytic model for calculating the number of immune cells receiving radiation. Methods: Suppose the blood is received radiation by constant dose rate. The blood is one-way flow without circulation in the radiation delivery at a constant velocity. Two kinds of lung treatment regimens were considered standard delivery 2Gy per fx total 30fx and hypo-fractionation SBRT 12 Gy per fx total 5 fx. Two different dose rates were simulated for standard treatment: …

Three-Dimensional Microct Imaging Of Mouse Heart Development From Early Post-Implantation To Late Fetal Stages, Nanbing Li-Villarreal, Tara L Rasmussen, Audrey E Christiansen, Mary E Dickinson, Chih-Wei Hsu

Faculty, Staff and Students Publications

Comprehensive detailed characterization of new mouse models can be challenging due to the individual focus involved in developing these models. Often models are engineered to test a specific hypothesis in a limited number of tissues, stages, and/or other contexts. Whether or not the model produces the desired phenotypes, phenotyping beyond the desired context can be extremely work intensive and these studies are often not undertaken. However, the general information resulting from broader phenotyping can be invaluable to the wider scientific community. The International Mouse Phenotyping Consortium (IMPC) and its subsidiaries, like the Knockout Mouse Project (KOMP), has made great strides …

Fiducial Markers Allow Accurate And Reproducible Delivery Of Liver Stereotactic Body Radiation Therapy, Marina Moskalenko, Bernard L. Jones, Adam Mueller, Shirley Lewis, Jay C. Shiao, Sara J. Zakem, Tyler P. Robin, Karyn A. Goodman

Department of Radiation Oncology Faculty Papers

Fiducial markers are utilized for image guided radiotherapy (IGRT) alignment during the delivery of liver stereotactic body radiosurgery (SBRT). There are limited data demonstrating the impact of matching fiducials on the accuracy of liver SBRT. This study quantifies the benefit of fiducial-based alignment and improvements in inter-observer reliability. Nineteen patients with 24 liver lesions were treated with SBRT. Target localization was performed using fiducial markers on cone-beam computed tomography (CBCT). Each CBCT procedure was retrospectively realigned to match both the liver edge and fiducial markers. The shifts were recorded by seven independent observers. Inter-observer variability was analyzed by calculating the …

Comparison Of Clinical And Radiographic Efficacy Of Particles Versus Nbca/Onyx In Middle Meningeal Artery Embolization For Chronic Subdural Hematoma, Jane Khalife, Mohamed Salem, Victoria Wong Murray, Allen Karimov, Brian Jankowitz, Jan Karl Burkhardt, Hamza Shaikh, Daniel Tonetti, Pratit Patel, Tudor Jovin, Ajith Thomas

Rowan-Virtua Research Day

Different embolic materials are utilized in MMA embolization of chronic subdural hematoma per operators’ discretion. We aim to compare the clinical and radiographic efficacy of different embolic materials in a pooled retrospective cohort of two US centers.

Clinical Outcomes Of Immunotherapy Continued Beyond Radiographic Disease Progression In Older Adult Patients With Advanced Non-Small Cell Lung Cancer, Eric K Singhi, Frank Mott, Michelle Worst, Cheuk Hong Leung, J Jack Lee, Brett Carter, Carolyn J Presley, John V Heymach, Mehmet Altan

Faculty, Staff and Student Publications

Immunotherapy is an effective and generally well-tolerated treatment strategy for older adult patients (aged ≥70 years) with advanced non-small cell lung cancer (NSCLC). Unfortunately, most patients who receive immunotherapy eventually exhibit disease progression during treatment. The present study reports on a subset of older adult patients with advanced NSCLC who could effectively continue immunotherapy beyond radiographic disease progression due to perceived clinical benefit. Local consolidative radiotherapy may be used in select older adult patients to prolong the duration of immunotherapy they receive, with a particular consideration of their preexisting co-morbidities, performance status and tolerance of potential toxicities associated with combined …

Tumor Locations Impact On Cardiac Toxicity In Women That Received Partial Breast Irradiation, Sara Diltz, Muayad Almahariq, Joshua Dilworth

Posters

Accelerated partial breast irradiation (APBI) is an appropriate modality for select women with low-risk breast cancer. While APBI delivers radiation dose to a smaller volume of breast tissue compared to whole breast irradiation, dose to the heart and coronary vessels may be relatively high, depending on the proximity of the treatment device to these structures. The primary goal of this study is to determine if the risk of adverse cardiac events depends on tumor location in women receiving APBI.

High Dose Rate Brachytherapy Monotherapy Versus External Beam Radiotherapy With Hdr Brachytherapy Boost For Unfavorable Intermediate Prostate Cancer Patients, Doyle Lang, Benjamin Willen, Daniel J. Krauss, Sirisha R. Nandalur

Posters

Prostate cancer is the most common male malignancy by incidence in the world. Treatment differs by the patient’s risk stratification. For the treatment of unfavorable intermediate-risk prostate cancer, external beam radiotherapy with high-dose-rate brachytherapy boost was the accepted treatment but high-dose-rate brachytherapy as monotherapy has been proposed as a potentially viable treatment option. External beam radiotherapy treatment involves shooting high-energy photons or particle radiation through normal healthy tissue to hit the tumor directly. High-dose-rate brachytherapy involves inserting radioactive seeds into the tumor. Studies are needed to compare toxicity profiles and relative outcomes between the two treatment options.

The Safe And Effective Clinical Deployment Of Artificial Intelligence To Ols, Kelly Nealon

Dissertations and Theses (Open Access)

18 million new cancer cases are diagnosed each year. Roughly half of these patients will be treated with radiation therapy, a complex technique that requires an interdisciplinary team of clinical staff and expensive equipment to be delivered safely. Cancer centers in Low- and Middle-Income Countries (LMIC) have an especially difficult time meeting the demands of radiation therapy as the complexity of treatment techniques increase, with only 37% of patients in these regions having access to the care they need. Artificial Intelligence (AI) based tools are being developed to simplify the treatment planning and quality assurance processes to increase the number …

Improving Dose-Response Correlations For Locally Advanced Nsclc Patients Treated With Imrt Or Pspt, Yulun He

Dissertations and Theses (Open Access)

The standard of care for locally advanced non-small cell lung cancer (NSCLC) is concurrent chemo-radiotherapy. Despite recent advancements in radiation delivery methods, the median survival time of NSCLC patients remains below 28 months. Higher tumor dose has been found to increase survival but also a higher rate of radiation pneumonitis (RP) that affects breathing capability. In fear of such toxicity, less-aggressive treatment plans are often clinically preferred, leading to metastasis and recurrence. Therefore, accurate RP prediction is crucial to ensure tumor coverage to improve treatment outcome. Current models have associated RP with increased dose but with limited accuracy as they …

Multiparametric Magnetic Resonance Imaging Artificial Intelligence Pipeline For Oropharyngeal Cancer Radiotherapy Treatment Guidance, Kareem Wahid

Dissertations and Theses (Open Access)

Oropharyngeal cancer (OPC) is a widespread disease and one of the few domestic cancers that is rising in incidence. Radiographic images are crucial for assessment of OPC and aid in radiotherapy (RT) treatment. However, RT planning with conventional imaging approaches requires operator-dependent tumor segmentation, which is the primary source of treatment error. Further, OPC expresses differential tumor/node mid-RT response (rapid response) rates, resulting in significant differences between planned and delivered RT dose. Finally, clinical outcomes for OPC patients can also be variable, which warrants the investigation of prognostic models. Multiparametric MRI (mpMRI) techniques that incorporate simultaneous anatomical and functional information …

Automating The Radiation Therapy Treatment Planning Process For Pediatric Patients With Medulloblastoma, Soleil Hernandez

Dissertations and Theses (Open Access)

Over the past 50 years, pediatric cancer 5-year survival rates increased from 20% to 80% in high-income countries, however, these trends have not been mirrored in low-and-middle-income countries (LMICs). This is due in part to delayed diagnosis, higher rates of advanced disease at presentation and a growing lack of access to high quality medical personnel and technology necessary to deliver complex treatments.

The long-term goal of this study was to alleviate demanding workflows and increase global access to high-quality pediatric radiation therapy by harnessing the power of artificial intelligence to automate the radiation therapy treatment planning process for pediatric patients …