Radiation Medicine Commons^™

Fluoroscopic Demonstration Of Thoracic Tumor Immobilization With High Frequency Percussive Ventilation, Cristian Solano, Ina M. Sala, Beverly Maurer, Ronald Levitin, Thomas M. Guerrero

Posters

INTRODUCTION
High frequency percussive ventilation (HFPV) is a novel immobilization technique that utilizes high frequency low tidal volume ventilation to produce endotracheal percussion. In a previous departmental study of chest wall motion immobilization, it was found that volunteers were able to tolerate HFPV for varying lengths of time – from a few to tens of minutes. By investigating a novel process to immobilize the chest wall, and thus thoracic tumors, it can allow for more localized radiation delivery and reduction of healthy tissue irradiation.

Development Of A Deep Neural Network For Synthesis Of Non-Contrast Cranial T1-Weighted Magnetic Resonance Imaging, Agueda M. Taylor, Evan Porter, Thomas Guerrero

Posters

INTRODUCTION
Although 122 out of 1000 people in the US have MRI’s done each year, there are over 4 million with contraindications that subsequently forgo the diagnostic benefits. Studies in recent years have implemented artificial intelligence (AI) algorithms such as deep neural networks (DNN) for production of synthetic medical imaging. The goals of this project are to develop a DNN, specifically a Generative Adversarial Network (GAN) that will predict synthetic Cranial T1 Weighted MRI from non-contrast CT, and to evaluate the model quality.

Functional Lung Segmentation From Computed Tomography Images Using Deep Learning, Duyen M. Quach, Evan Porter, Thomas M. Guerrero

Posters

INTRODUCTION
Functional avoidance treatment planning allows radiation oncologists to intentionally minimize radiation dose to higher-functioning lung areas while favoring radiation dose towards lower-functioning regions. This treatment planning method has been shown to reduce pulmonary toxicity for patients receiving radiation therapy. Functional lung information, traditionally ventilation or perfusion SPECT scans, is required to plan for functional avoidance.

Evaluating The Impact Of Software Distortion Correction On Target Doses In Cranial Stereotactic Radiosurgery, Sharjil Shamim, Zachary Seymour

Posters

INTRODUCTION
Brainlab’s Elements suite proposed a novel MR distortion correction method based on CT imaging. This involves registration of sub-volumes from MR imaging to generate single continuous deformation field maps, creating a corrected MR image set. No literature currently exists studying the impact of software correction on target dose for cranial stereotactic radiosurgery. In this study, we aim to evaluate the impact of Brainlab distortion correction on radiation target dose compared to original treatment plans without distortion correction.

The Prognostic Significance Of Glucose-6-Phosphate Dehydrogenase As A Biomarker In Head And Neck Squamous Cell Carcinomas Treated With Conventional Chemoradiation, Kenneth H. Barker, Barbara L. Pruetz, Jessica D. Arden, Thomas J. Quinn, George D. Wilson

Posters

INTRODUCTION
The prognosis of patients with head and neck squamous cell carcinoma (HNSCC) treated with chemoradiation can be predicted using p16 as a surrogate biomarker of Human Papilloma Virus (HPV) status, but a subset of patients continues to do poorly despite a positive or negative p16 status. This project attempted to identify another biomarker, glucose-6-phosphate dehydrogenase (G6PD) as a marker for prognosis in HNSCC patients. Radiation induces oxidative damage to destroy tumor cells, and G6PD is a key enzyme involved in protecting cells from oxidative damage. The goal of this project was to identify a prognostic biomarker that would aid …

Atr-Mediated Cd47 And Pd-L1 Upregulation Restricts Radiotherapy-Induced Immune Priming And Abscopal Responses In Colorectal Cancer, Cheng-En Hsieh, Cheng-En Hsieh

Dissertations and Theses (Open Access)

Radiotherapy of colorectal cancer (CRC) can prime adaptive immunity against tumor-associated antigen (TAA)-expressing CRC cells systemically. However, incidences of abscopal tumor remission are extremely rare, and the post-irradiation immune escape mechanisms in CRC remain elusive. We report that CRC cells utilize a common DNA repair signaling pathway — ATR/Chk1/STAT3 — to upregulate both CD47 and PD-L1 in response to radiotherapy, which through engagement of SIRPα and PD-1 suppresses the capacity of antigen-presenting cells to phagocytose them thereby preventing TAA cross-presentation and innate immune activation. This post-irradiation CD47 and PD-L1 upregulation can be observed across various human solid tumor cells. Concordantly, …

Integration Of Biomedical Imaging And Translational Approaches For Management Of Head And Neck Cancer, Abdallah Mohamed, Abdallah Mohamed

Dissertations and Theses (Open Access)

The aim of the clinical component of this work was to determine whether the currently available clinical imaging tools can be integrated with radiotherapy (RT) platforms for monitoring and adaptation of radiation dose, prediction of tumor response and disease outcomes, and characterization of patterns of failure and normal tissue toxicity in head and neck cancer (HNC) patients with potentially curable tumors. In Aim 1, we showed that the currently available clinical imaging modalities can be successfully used to adapt RT dose based-on dynamic tumor response, predict oncologic disease outcomes, characterize RT-induced toxicity, and identify the patterns of disease failure. We …

Feasibility Of Acute Hematologic Toxicity Model-Based Patient Selection For Proton Beam Therapy, P Liu, X Cao, X Gao, S Shang, J Liu, Z Wang, Xuanfeng Ding

Conference Presentation Abstracts

Purpose or Objective To investigate the potential clinical benefit of utilizing IMPT to reduce acute hematologic toxicity for locally advanced nonsmall cell lung cancer (NSCLC) patients and explore the feasibility of a model-based patient selection approach via the normal tissue complication probability (NTCP). Materials and Methods Twenty patients with locally advanced NSCLC were enrolled.[ld1] Volumetric modulated arc photon therapy (VMAT) and intensity-modulated proton therapy (IMPT) plans were generated with a prescription dose of 60 Gy in 30 fractions. A wide range of cases with varied tumor size, location, stations of metastatic lymph nodes were selected to represent the general cancer …

Feasibility Of Utilizing Spot-Scanning Proton Arc (Sparc) Therapy For Whole Lung Irradiation, Lewei Zhao, Gang Liu, An Qin, Di Yan, Craig Stevens, Xiaoqiang Li, Rohan Deraniyagala, Xuanfeng Ding

Conference Presentation Abstracts

Purpose or Objective We reported the first feasibility study of utilizing spot-scanning arc therapy (SPArc) whole lung irradiation for a pediatric patient to reduce cardiac toxicity. Materials and Methods A 13 year-old patient with metastatic Ewing sarcoma treated with Volumetric Modulated Arc Therapy (VMAT) in our institution was selected (Figure 1A). The clinical VMAT plan used three 360-deg arcs with 6 MV based on the Elekta HD. Intensity Modulated Proton Therapy (IMPT) plan was generated using 2 iso and 4 treatment fields (Figure 1B) based on the single field optimization approach in a clinical treatment planning system (TPS) (RayStation version …

Mri-Based Synthetic Ct Images For Impt Treatment Planning Of Nasopharyngeal Carcinoma Patients, Shupeng Chen, Y Peng, Y Liu, C Zhao, X Deng, An Qin, Di Yan, Craig Stevens, Rohan Deraniyagala, Xuanfeng Ding

Conference Presentation Abstracts

Purpose or Objective To investigate the feasibility of using an MRI-based synthetic CT image (SCT) generated via a generative adversarial network (GAN) for intensity-modulated proton therapy (IMPT) treatment planning of nasopharyngeal carcinoma (NPC) patients. Materials and Methods T1-weighted MR images and paired CT (PCT) images were obtained from 158 NPC patients with radiotherapy immobilization. Deformable image registration was performed between each MR and PCT image for each patient to create an MR-CT pair. Thirteen pairs were randomly chosen as independent test sets and the remaining 145 pairs (10 for validation and 135 for training) were used to build a conditional …

Lymphocyte Depletion Rate As A Biomarker Of Radiation Dose To Circulating Lymphocytes During Fractionated Partial-Body Radiation Therapy, Susannah G Ellsworth, Anirudh Yalamanchali, Tim Lautenschlaeger, Stuart A Grossman, Clemens Grassberger, Steven H Lin, Radhe Mohan

Faculty, Staff and Student Publications

Purpose: Radiation causes exponential depletion of circulating lymphocyte populations; in turn, radiation-induced lymphopenia is associated with worse survival for many solid tumors, possibly owing to attenuated antitumor immune responses. Identifying reliable and reproducible methods of calculating the radiation dose to circulating immune cells may facilitate development of techniques to reduce the risk and severity of radiation-induced toxic effects to circulating lymphocytes.

Methods and materials: Patient-specific lymphocyte loss rates were derived from a clinical data set including 684 adult patients with solid tumors. Multivariable linear regression was used to model the relationship between the lymphocyte loss rate and physical parameters of …

Contralateral Control Rate With Unilateral Proton Beam Radiotherapy For Oropharyngeal Scc: A Multi-Institutional Prospective Study From The Proton Collaborative Group, Aleksander Vayntraub, Thomas Quinn, John Chang, Noah Kalman, Sanford Katz, James Urbanic, Arpi Thukral, Jason Molitoris, Craig Stevens, Rohan Deraniyagala

Conference Presentation Abstracts

Introduction: Select patients with oropharyngeal SCC are candidates for unilateral radiation therapy. We sought to investigate if ipsilateral targeting leads to increased contralateral recurrences. Methods: We queried the PCG database for patients treated with unilateral proton RT for head and neck SCC from 2015 – 2020 at 12 institutions. DICOMs were evaluated to ensure dose delivered matched a unilateral proton treatment plan. Demographic, clinical and pathological, toxicity and dosimetry information were compiled. Results: We found 43 cases treated with unilateral proton RT. 94% (n¼16) of recurrent cases received prior radiation. Oropharyngeal sites included tonsillar fossa (n¼32), and base of tongue …

The First Modeling Of The Spot-Scanning Proton Arc(Sparc) Delivery Sequence And Investigating Its Efficiency Improvement, Xuanfeng Ding, Gang Liu, Lewei Zhao, Rohan Deraniyagala, Craig Stevens, Di Yan, Xiaoqiang Li

Conference Presentation Abstracts

Purpose: Introduce an experimental approach to model a precise prototype arc system and quantitatively assess its efficiency improvement in the routine proton clinical operation. Methods: The SPArc delivery sequence model(DSMSPArc) includes two kinds of parameters:(1) mechanical parameters. (2) irradiation parameters. Log files and an independent gantry inclinometer were used to derive the irradiation parameters through a series of test plans. The in-house DSMSPArc was established by fitting both mechanical and irradiation parameters. Eight SPArc plans from different disease sites were used to validate the model’s accuracy. To assess the treatment efficiency improvement, the DSMSPArc was used to simulate the SPArc …

A Direct Machine-Specific Parameters Incorporated Spot-Scanning Proton Arc (Sparc) Algorithm, Gang Liu, Lewei Zhao, Di Yan, Xiaoqiang Li, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: To address the challenges of generating a deliverable and efficient spot-scanning proton arc (SPArc) plan for a proton therapy system. We developed a novel SPArc optimization algorithm (SPArcDMSP) by directly incorporating machinespecific parameters such as mechanical constraints and delivery sequence. Method and Material: A SPArc delivery sequence model (DSMarc) was built based on the machine-specific parameters of the prototype arc delivery system IBA ProteusONEt. The SPArcDMSP resamples and adjusts each control point’s delivery speed based on the DSMarc calculation through the iterative approach (Fig1). Users could set the expected delivery time and gantry max acceleration as a mechanical constraint …

A Quantitative Dose Pertubation Comparison Study Between Gold And Platinum Visicoil Fiducial Markers In Proton Beam Therapy, Xuanfeng Ding, Gang Liu, Weili Zheng, Jessica Vadas, Xiaoqiang Li, Lewei Zhao, An Qin, Daniel Krauss, Di Yan

Conference Presentation Abstracts

Purpose: To quantitatively investigate the dose perturbations difference between gold and platinum VISICOILTM fiducial markers in proton beam therapy Method: Gold and platinum VISICOILTM fiducial markers with two different dimensions were tested, including 0.35 & 0.5mm in diameter and 5mm in length. Total four kinds of markers. Gafchromic EBT2 was used to measure dose perturbations along the beam path in a ‘‘sandwich’’ setup (Figure 1). Dose perturbation was reported in each depth (0.3mm, 1.65mm, 3.00mm, 5.40mm, 7.80mm, 10.20mm, 12.60mm, 18.15mm). Relative proton stopping power relative to water were calculated through National Institute of Standards and Technology database and SRIM (version …

Assessing The Interplay Effect Based On A Precise Machine-Specific Delivery Sequence And Time For Cyclotron Accelerator Proton Therapy System., Lewei Zhao, Gang Liu, Jiajian Sher, Andrew Lee, Di Yan, Rohan Deraniyagala, Craig Stevens, Xiaoqiang Li, Shikui Tang, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: We proposed an experimental approach to build a precise machine-specific model for standard, volumetric, and layer repainting delivery based on a cyclotron accelerator system. Then, we assessed the interplay effect using a 4D mobile lung target phantom compared to a generic delivery sequence model from West German Proton Therapy Essen (WPE). Methods: The machine delivery log files, from an IBA ProteusPLUSt system, were retrospectively analyzed to quantitatively model energy layer switching time, spot switching time, and spot drill time for standard and volumetric repainting delivery. To quantitatively evaluate the interplay effect, a series of digital thoracic 4DCT image sets …

Coeliac Plexus Radiosurgery For Pain Management In Patients With Advanced Cancer : Study Protocol For A Phase Ii Clinical Trial, Galia Jacobson, Ronen Fluss, Amira Dany-Benshushan, Talia Golan, Tikva Meron, Camilla Zimmermann, Laura A Dawson, Aisling Barry, Marcin Miszczyk, Michael Buckstein, Dayssy Diaz Pardo, Artur Aguiar, Liat Hammer, Adam Dicker, Maoz Ben-Ailan, Ofir Morag, David Hausner, Zvi Symon, Yaacov R Lawrence

Department of Radiation Oncology Faculty Papers

Introduction: Pancreatic cancer is characterised by severe mid-back and epigastric pain caused by tumour invasion of the coeliac nerve plexus. This pain is often poorly managed with standard treatments. This clinical trial investigates a novel approach in which high-dose radiation (radiosurgery) is targeted to the retroperitoneal coeliac plexus nerve bundle. Preliminary results from a single institution pilot trial are promising: pain relief is substantial and side effects minimal. The goals of this study are to validate these findings in an international multisetting, and investigate the impact on quality of life and functional status among patients with terminal cancer.

Methods and …

Clinical Evaluation Of An Auto-Segmentation Tool For Spine Sbrt Treatment, Yingxuan Chen, Yevgeniy Vinogradskiy, Yan Yu, Wenyin Shi, Haisong Lui

Department of Radiation Oncology Faculty Papers

Purpose: Spine SBRT target delineation is time-consuming due to the complex bone structure. Recently, Elements SmartBrush Spine (ESS) was developed by Brainlab to automatically generate a clinical target volume (CTV) based on gross tumor volume (GTV). The aim of this project is to evaluate the accuracy and efficiency of ESS auto-segmentation.

Methods: Twenty spine SBRT patients with 21 target sites treated at our institution were used for this retrospective comparison study. Planning CT/MRI images and physician-drawn GTVs were inputs for ESS. ESS can automatically segment the vertebra, split the vertebra into 6 sectors, and generate a CTV based on the …

Clinical Evaluation Of An Auto-Segmentation Tool For Spine Sbrt Treatment., Yingxuan Chen, Yevgeniy Vinogradskiy, Yan Yu, Wenyin Shi, Haisong Liu

Department of Radiation Oncology Faculty Papers

Purpose: Spine SBRT target delineation is time-consuming due to the complex bone structure. Recently, Elements SmartBrush Spine (ESS) was developed by Brainlab to automatically generate a clinical target volume (CTV) based on gross tumor volume (GTV). The aim of this project is to evaluate the accuracy and efficiency of ESS auto-segmentation.

Methods: Twenty spine SBRT patients with 21 target sites treated at our institution were used for this retrospective comparison study. Planning CT/MRI images and physician-drawn GTVs were inputs for ESS. ESS can automatically segment the vertebra, split the vertebra into 6 sectors, and generate a CTV based on the …

A Measure Of Srs/Srt Plan Quality: Quantitative Limits For Intermediate Dose Spill (R50%) In Linac-Based Delivery, Dharmin D. Desai, Ivan L. Cordrey, Ellis L. Johnson

Radiation Medicine Faculty Publications

Stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) of multiple cranial targets using a single isocenter on conventional C-arm linear accelerators are rapidly developing clinical techniques. However, no universal guidelines for acceptable intermediate dose spill limits are currently available or widely accepted. In this work, we propose an intermediate dose spill guidance range for cranial SRS/SRT delivered on C-arm linacs with MLC collimation for single PTV plans and single isocenter multiple target plans with PTV volumes in the range 0.02–57.9 cm³. We quantify intermediate dose spill with the R50% metric (R50% = volume of 50% of prescription isodose cloud …

Role Of Surgery In Multifocal Glioblastoma, Syeda Kubra Kishwar Jafri, Syed Sarmad Bukhari, Muhammad Shahzad Shamim

Section of Neurosurgery

The management of multifocal glioblastomas is a point of constant discussion amongst neuro-oncologists. Best outcomes in glioblastoma management come from gross total resection (GTR) followed by concomitant radiation and chemotherapy (CCRT). Multifocal disease is resistant to GTR. Conventional management of these lesion is usually biopsy only followed by CCRT. Recent evidence has shown that there may be some benefit to attempting GTR of the largest lesion whenever safe to do so.

Integration Of Liquid Biopsy And Pharmacogenomics For Precision Therapy Of Egfr Mutant And Resistant Lung Cancers, Jill M. Kolesar, Spencer Peh, Levin Thomas, Gayathri Baburaj, Nayonika Mukherjee, Raveena Kantamneni, Shirley Lewis, Ananth Pai, Karthik S. Udupa, Naveena Kumar An, Vivek M. Rangnekar, Mahadev Rao

Pharmacy Practice and Science Faculty Publications

The advent of molecular profiling has revolutionized the treatment of lung cancer by comprehensively delineating the genomic landscape of the epidermal growth factor receptor (EGFR) gene. Drug resistance caused by EGFR mutations and genetic polymorphisms of drug metabolizing enzymes and transporters impedes effective treatment of EGFR mutant and resistant lung cancer. This review appraises current literature, opportunities, and challenges associated with liquid biopsy and pharmacogenomic (PGx) testing as precision therapy tools in the management of EGFR mutant and resistant lung cancers. Liquid biopsy could play a potential role in selection of precise tyrosine kinase inhibitor (TKI) therapies during different phases …

Feasibility Of Using Ring-Mounted Halcyon Linac For Single-Isocenter/Two-Lesion Lung Stereotactic Body Radiation Therapy, Damodar Pokhrel, Aaron Webster, Richard Mallory, Justin Visak, Mark E. Bernard, Ronald C. Mcgarry, Mahesh Kudrimoti

Radiation Medicine Faculty Publications

PURPOSE: To demonstrate the plan quality and delivery efficiency of volumetric-modulated arc therapy (VMAT) with the Halcyon Linac ring delivery system (RDS) in the treatment of single-isocenter/two-lesion lung stereotactic body radiation therapy (SBRT).

MATERIALS/METHODS: Sixteen previously treated non-coplanar VMAT single-isocenter/two-lesion lung SBRT plans delivered with SBRT-dedicated C-arm TrueBeam Linac were selected. Prescribed dose was 50 Gy to each lesion over five fractions with treatment delivery every other day and AcurosXB algorithm as the final dose calculation algorithm. TrueBeam single-isocenter plans were reoptimized for Halcyon Linac with coplanar geometry. Both TrueBeam and Halcyon plans were normalized for identical combined target coverage …

Multi-Center Planning Study Of Radiosurgery For Intracranial Metastases Through Automation (Mc-Prima) By Crowdsourcing Prior Web-Based Plan Challenge Study, M K H Chan, T Gevaert, N Kadoya, J Dorr, R Leung, S Alheet, A Toutaoui, R Farias, M Wong, C Skourou, M Valenti, I Farré, C Otero-Martínez, D O'Doherty, J Waldron, S Hanvey, M Grohmann, Haisong Lui

Department of Radiation Oncology Faculty Papers

Background: Planning radiosurgery to multiple intracranial metastases is complex and shows large variability in dosimetric quality among planners and treatment planning systems (TPS). This project aimed to determine whether autoplanning using the Muliple Brain Mets (AutoMBM) software can improve plan quality and reduce inter-planner variability by crowdsourcing results from prior international planning study.

Methods: Twenty-four institutions autoplanned with AutoMBM on a five metastases case from a prior international planning competition from which population statistics (means and variances) of 23 dosimetric metrics and resulting composite plan score (maximum score = 150) of other TPS (Eclipse, Monaco, RayStation, iPlan, GammaPlan, MultiPlan) were …

Chronoradiobiology Of Breast Cancer: The Time Is Now To Link Circadian Rhythm And Radiation Biology, Nicolas Nelson, Joseph Lombardo, Lauren Matlack, Alexandria Smith, Kamryn Hines, Wenyin Shi, Nicole L Simone

Department of Radiation Oncology Faculty Papers

Circadian disruption has been linked to cancer development, progression, and radiation response. Clinical evidence to date shows that circadian genetic variation and time of treatment affect radiation response and toxicity for women with breast cancer. At the molecular level, there is interplay between circadian clock regulators such as PER1, which mediates ATM and p53-mediated cell cycle gating and apoptosis. These molecular alterations may govern aggressive cancer phenotypes, outcomes, and radiation response. Exploiting the various circadian clock mechanisms may enhance the therapeutic index of radiation by decreasing toxicity, increasing disease control, and improving outcomes. We will review the body’s natural circadian …

What After Bcg Fails In Non-Muscle Invasive Bladder Cancer?, M Hammad Ather

Section of Urology

No abstract provided.

Corrigendum To: Impact Of Lymphopenia On Survival For Elderly Patients With Glioblastoma: A Secondary Analysis Of The Cctg Ce.6 (Eortc 26062-22061, Trog 08.02) Randomized Clinical Trial., Andrew J Song, Keyue Ding, Iyad Alnahhas, Normand J Laperriere, James Perry, Warren P Mason, Chad Winch, Chris J O'Callaghan, Johan J Menten, Alba A Brandes, Claire Phillips, Michael F Fay, Ryo Nishikawa, David Osoba, J Gregory Cairncross, Wilson Roa, Wolfgang Wick, Wenyin Shi

Department of Radiation Oncology Faculty Papers

[This corrects the article DOI: 10.1093/noajnl/vdab153.].

Radiation Exposure Determination In A Secure, Cloudbased Online Environment, Ben C. Shirley, Eliseos J. Mucaki, Joan H.M. Knoll, Peter Rogan

Biochemistry Publications

Rapid sample processing and interpretation of estimated exposures will be critical for triaging exposed individuals after a major radiation incident. The dicentric chromosome (DC) assay assesses absorbed radiation using metaphase cells from blood. The Automated Dicentric Chromosome Identifier and Dose Estimator System (ADCI) identifies DCs and determines radiation doses. This study aimed to broaden accessibility and speed of this system, while protecting data and software integrity. ADCI Online is a secure web-streaming platform accessible worldwide from local servers. Cloud-based systems containing data and software are separated until they are linked for radiation exposure estimation. Dose estimates are identical to ADCI …

The Use Of Nuclear Medicine In Detecting And Treating Mental Health Diseases, Jena Simmons, Gina Capitano, Walter Kierzkowski

Medical Imaging Senior Posters

Mental health disorders affect over 792 million people around the world, and a leading cause for disability. Mental health disorders include a plethora of conditions that affect mood, thinking and behavior, including but not limited to, depression, dementia, anxiety, autism, and schizophrenia. The most common method of diagnosis is a psychological evaluation, which can lack accuracy if performed as the only method of diagnosis. Nuclear Medicine helps aid in diagnosis of these disorders in conjunction with psychological testing. Brain scans can help determine if there is a pathogenic cause for the symptoms. Brain scans are done utilizing Positron Emission Tomography …

Development Of End-To-End Test Phantom For Stereotactic Radiosurgery Using Alanine Dosimeter, Aungsumalin Intang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Alanine dosimeters are generally used in high-dose dosimetry, while accurate and precise dose delivery verification procedures are important in stereotactic radiosurgery (SRS). Hence, an end-to-end test is required. In addition, no end-to-end SRS test employing an alanine dosimeter has been established in Thailand. The objective of this study was to determine the dose accuracy of SRS VMAT plans in end-to-end test phantom using alanine dosimeter. The electron paramagnetic resonance (EPR) parameters were optimized in the 1-2000 cGy dose range. Following that, suitable parameters were used to investigate the alanine characteristics and estimate the uncertainty in radiation therapy dose range. The …