Radiation Medicine Commons^™

Comparison Of Magnetic Resonance Imaging (Mri) And Endoluminal Endoscopic Ultrasound (Eus) For Restaging Rectal Cancer After Neoadjuvant Chemotherapy, Judy Sheffeh, Amr Aref, Mohammed Barawi, Amer Alame, Amer Zeni, Ernesto R. Drelichman, Jasneet S. Bhullar

Conference Presentation Abstracts

Purpose/Background: Given the high incidence and mortality of rectal cancer, accurate staging and restaging are crucial for guiding optimal interventions. However, no consensus exists on the best imaging modality for restaging after neoadjuvant chemoradiotherapy. This study aims to compare MRI and EUS in the restaging of rectal cancer following neoadjuvant chemoradiotherapy.

Methods/Interventions: We conducted a prospective observational study and enrolled patients with rectal cancer. EUS and MRI were performed at diagnosis for initial staging and repeated after neoadjuvant chemotherapy and chemoradiotherapy for restaging. A total of 43 patients were enrolled, with 25 patients (10 males, 15 females) with rectal cancer …

Treatment Outcomes Following Tme For Biologically Unfavorable Locally Advanced Rectal Cancer, Maryam Aleissa, Amr Aref, Hussein Gharib, Ernesto R. Drelichman, Amer Zeni, Amer Alame, Jasneet S. Bhullar

Conference Presentation Abstracts

Purpose/Background: Many centers now offer organ preservation for selected patients with locally advanced rectal cancer. Our group initiated three Phase II trials to assess the safety of this approach in various clinical scenarios. Nonoperative management was recommended only for patients achieving complete clinical response CCR)after total neoadjuvant therapy TNT. Total mesorectal excision TME was advised when CCR was not achieved (primary TME), following residual cancer after Limited Local Excision LLE (completion TME), or after tumor recurrence/regrowth post-LLE or watchful waiting WW (salvage TME). This study examines treatment outcomes following primary or salvage TME in these biologically unfavorable cases.

Methods/Interventions: Each …

Source Model Parameters For Beam Commissioning Of Scanning Proton Therapy Treatment Planning System: Multi-Institutional Survey And Analysis, Chih-Wei Chang, Liyong Lin, Lei Dong, Heng Li, Jan Po Schuemann, Jiajian Shen, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: To create a beamline-specific repository of source model parameters and beam commissioning data for scanning proton therapy (PT) treatment planning system (TPS).

Methods: We surveyed 28 PT centers, collecting beam commissioning source model parameters of diverse beamlines from different vendors: Hitachi, IBA, Varian, Mevion. Parameters included (i) beam meterset calibration in protons per MU, (ii) in-air spot size at isocenter in terms of standard deviation in x- (crossline, σ_x) and y- (inline, σ_y) directions, (iii) in-air angular spread at isocenter in x-direction (θ_x) and y-direction (θ_y). We plotted each parameter as …

Loco-Regional Irradiation In Patients With Biopsy-Proven Axillary Node Involvement At Presentation Who Become Pathologically Node-Negative After Neoadjuvant Chemotherapy: Primary Outcomes Of Nrg Oncology/Nsabp B-51/Rtog 1304, E Mamounas, H Bandos, J White, T Julian, A Khan, S Shaitelman, M Torres, Frank Vicini, P Ganz, Andrew Muskovitz

Conference Presentation Abstracts

No abstract provided.

Nrg-Br008: A Phase Iii Randomized Trial Of Radiotherapy Optimization For Low-Risk Her2-Positive Breast Cancer (Hero), L Braunstein, M Mitchell, H Bandos, W Sikov, A Khan, Peter Chen, P Ganz, R Jagsi, J White, R Cecchini

Conference Presentation Abstracts

Background: Breast radiotherapy (RT) is the standard of care for patients with early-stage breast cancer (BC) who undergo breast-conserving surgery (BCS). However, the magnitude of benefit of RT is less clear in BCS patients with low-risk disease who receive effective systemic therapy. Among patients with early-stage HER2-positive (HER2+) BC, 10-year locoregional recurrence has been reported as low as 1.5% following BCS, adjuvant chemotherapy and HER2-targeted therapy, and RT. Given these exceedingly favorable outcomes, with the addition of HER2-directed therapy, we seek to evaluate the feasibility of omitting RT among patients with early-stage HER2+ BC following BCS and appropriate systemic therapy. …

Investigate The Delivery Efficiency Improvement For Sparc Compared To Impt, Peilin Liu, B A. De Jong, S Chang, Lewei Zhao, G Liu, Craig Stevens, Rohan Deraniyagala, E W. Korevaar, J A. Langendijk, Xiaoqiang Li, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: To assess the efficiency improvement of SPArc compared to IMPT in proton clinical operation.Methods: A random clinical operation day at a proton therapy center with a two room system. Aa total of 10 Head & Neck cancer cases treated on Jan 6th, 2021were selected and SPArc plans were generated for all the cases with similar target coverage and dose constraints of organ at risk (OARs). 3% range uncertainties and 3mm setup uncertainties were applied for robust optimization. The log files of clinical IMPT were exported to calculate true treatment delivery time. The machine-specific delivery sequence model was utilized to …

A Comprehensive Investigation Of Linear Energy Transfer Optimization Effectiveness In Intensity-Modulated Proton Therapy Via Alternating Direction Method Of Multipliers (Impt Let-Admm), Q Fan, G Liu, Lewei Zhao, Xiaoqiang Li, Xuanfeng Ding, S Dai

Conference Presentation Abstracts

Linear energy transfer (LET)-guided optimization in intensity-modulated proton therapy (IMPT) via alternating direction method of multipliers (ADMM) has the potential to improve its biological effectiveness (IMPTLET- ADMM), in which the LET distribution in target can be escalated, while the LET distribution in the organs at risk can be mitigated. This study aims to quantitatively investigate the effectiveness of LET optimization in IMPT via ADMM with different solvers in its iteration loop. Methods: The clinical dose-volume-histogram (DVH) constraint noted dose sub-problem and clinical LET -volume-histogram (LVH) constraint noted LET sub-problem are combined to generate a composite objective function, which is available …

Particle Arc Single-Isocenter Stereotactic Radiosurgery Of Multiple Brain Metastases, L Volz, S Mein, T Tessonnier, Peilin Liu, A Mairani, M Durante, Xuanfeng Ding, C Graeff, T Li

Conference Presentation Abstracts

Purpose: To develop spot-scanning proton (SPArc) and heavy ion (SHArc) arc therapy for single-isocenter stereotatic radiosurgery (SISRS) of multiple brain metastases (MBMs). First results achieved with dedicated planning infrastructure are compared to state-of-the -art volumetric modulated photon arc therapy (HA-VMAT). Methods: A multi-institutional collaboration was established to develop bespoke SPArc and SHArc SISRS infrastructure with available research and commercial treatment planning systems. Devised planning and delivery methods considered dedicated energy, spot, and multi-arc selection strategies. SPArc and SHArc (carbon and helium ions) plans were generated for MBM patients exhibiting 3-12 intracranial lesions with GTV volumes between 0.03ccm and 19.8ccm, at …

The Clinical Usability, Efficiency, And Accuracy Of Combining Deep-Learning-Based Synthetic Ct And Auto-Contouring For Daily Cbct-Based Online Adaptive Radiation Therapy, An Qin, J Xu, N O'Connell, Xuanfeng Ding, Shupeng Chen, D Thill

Conference Presentation Abstracts

Purpose: To evaluate the feasibility of deep-learning and CBCT-based online adaptive radiotherapy(ART) in thorax, Head&Neck, and pelvic regions. Methods: The study utilized ADMIRE(Advanced Medical Image Registration Engine), a research software designed to enable fast online ART through: (1)synthetic CT(sCT) generation from CBCT, (2)automatic segmentation of critical organs(OARs), and(3)deformable image registration(DIR) to transfer the target volume. ADMIRE trained a modified Cycle-Generative-Adversarial-Networks with Structural Similarity Index Map(SSIM) loss term to generate sCT, while the auto-segmentation model was based on a 3D-ResUnet with modification. Site-specific models were trained for three anatomic sites: thorax, pelvic, and head&neck, and for both networks. The study included …

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: …

Expansion Of The Detrusor Muscular Ring Surrounding The Bladder Neck On Mri: Moving Beyond The Prostate As An Etiology Of Lower Urinary Tract Symptoms Due To Benign Prostatic Hyperplasia, Kiran Nandalur, David Walker, Hong Ye, Sayf A. Al-Katib, Brian Seifman, David Gangwish, Abhay Dhaliwal, Connor Ervin, Kayla Dobies, Channing Sesoko, Sirisha Nandalur, Bernadette Zwaans, Jennifer Nguyen, Jason Hafron

Conference Presentation Abstracts

Purpose: The etiology of lower urinary tract symptoms secondary to benign prostatic hyperplasia (LUTS/BPH) remains uncertain. The purpose of our study was to quantitatively analyze pelvic anatomic characteristics on magnetic resonance imaging (MRI) to assess for independent factors for symptoms.
*Methods and Materials: This retrospective single-institution study evaluated treatment-naïve men who underwent prostate MRI within 3 months of International Prostate Symptom Score (IPSS) from June 2021 to February 2022. Factors measured on MRI included: detrusor muscular ring surrounding the bladder neck measured as area and alternatively diameter, central gland (CG) mean apparent diffusion coefficient (ADC), levator hiatus (LH) volume, intrapelvic …

Mri-Based Synthetic Ct Images Generated Using 3d Conditional Gan For Impt Treatment Planning, Shupeng Chen, An Qin, Rohan Deraniyagala, Xuanfeng Ding, Y Peng, Y Liu, C Zhao, X Deng

Conference Presentation Abstracts

Purpose: To develop an advanced deep convolutional neural network architecture to generate synthetic CT (SCT) images from MR images for intensity-modulated proton therapy (IMPT) treatment planning of head and neck cancer patients. Methods: T1-weighted MR images and paired CT (PCT) images were obtained from 189 nasopharyngeal cancer (NPC) patients under radiotherapy immobilization. Deformable image registration was performed between MR and PCT images for each patient to create an MR-CT image pair. Thirteen pairs were randomly chosen as independent test sets and the remaining 176 pairs (14 for validation and 162 for training) were used to build two conditional generative adversarial …

Commissioning And Validation Of A Monte Carlo Algorithm For Spine Stereotactic Radiosurgery, C Knill, R Sandhu, B Loughery, L Lin, R Halford, D Drake, M Snyder

Conference Presentation Abstracts

Purpose: A 6FFF Monte Carlo (MC) dose calculation algorithm was commissioned for spine stereotactic radiosurgery (SRS) planning on the Versa HD. Initial model generation, validation, and ensuing model tuning will be presented. Methods: The model was generated by the manufacturer, Brainlab, using both in-air and in-water commissioning measurements of field sizes between 6mm and 400mm on the Versa HD. Initial model validation was performed by simulating a water tank in the planning system, calculating commissioning fields, and comparing calculations to measured data. Model accuracy was quantified for output factors, PDDs, profile sizes, and profile penumbras. Nine previously treated Spine SRS …

A Novel Ultra-High Dose Rate Proton Therapy Technology: Spot-Scanning Proton Arc Therapy Flash (Splash), Gang Liu, Lewei Zhao, Xiaoqiang Li, S Zhang, S Dai, X Lu, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: The flash dose rate on the order of 40 Gy/s has the potential to spare normal tissue with iso-effective tumor growth delay. Meanwhile, the spot-scanning proton arc therapy(SPArc), demonstrated its superior dosimetric conformity and plan robustness compared to the conventional intensity modulated proton therapy(IMPT). To take the full advantage of flash dose rate and the high dose conformity, we introduce a novel optimization and delivery technique, SPArc FLASH (SPLASH). Methods: SPLASH framework was implemented in an open-source proton planning platform (matRad). It optimizes the spot moniter unit(MU) weighting and cyclotron beam current per spot simultaneously. More specifically, it simultaneously …

During-Treatment Imaging Feasibility For Intrafraction Stereotactic Spine Treatment Evaluations, M Liu, D Drake, D Lack, M Sigler, J Sliwinski, K Barton, D To, I Grills, J Liang

Conference Presentation Abstracts

Purpose: On Elekta linacs, cone-beam CTs (CBCT) can be acquired during VMAT delivery to monitor intrafraction motion during treatment. Stereotactic spine treatments can be lengthy, increasing patient motion likelihood during treatment. We evaluated during-treatment CBCT (DT-CBCT) feasibility to assess patient motion for stereotactic spine treatments in place of a mid-treatment CBCT. Methods: CBCTs from seven spine treatments were analyzed retrospectively. Various fractionation schemes were used (16-25Gy delivered in 1-5 fractions). All plans contained two VMAT arcs of 2209.5-13,332.4 MUs with treatment times of 7-58 minutes. Projections from pre-correction CBCTs were combined with post-correction CBCT to simulate patient motion (1cm, 2 …

Evaluation Of 4pi Arc Positioning For Cranial Vmat Srs In Elements, B Loughery, C Knill, R Sandhu, L Lin, Z Seymour

Conference Presentation Abstracts

Purpose: Brainlab’s Elements Cranial VMAT (CVMAT) v3.0 introduces a 4Pi optimization that includes automated gantry and couch positioning alongside collimator optimization. In contrast, v1.5 uses a fixed collimator angle and predefined templates for gantry and couch angles that are manually modified by the planner. This study evaluates the 4Pi generated plans for clinical acceptability in terms of plan quality and delivery accuracy on a VersaHD. Methods: We chose a recent sample of 9 clinical plans that represent our catalog of target locations, fractionation schemes, and target sizes. Cases were replanned in CVMAT v3.0 using 4Pi optimization. These plans were evaluated …

Does Lung Function Imaging Modality Have A Dosimetric Impact On Functional Avoidance Treatment Planning: Assessment Using Prospective Clinical Trial Data, J Belardo, S Zhang, E Castillo, R Castillo, C Rusthoven, B Jones, M Miften, T Guerrero, I Grills, Y Chen

Conference Presentation Abstracts

Purpose: Functional avoidance radiotherapy proposes to use functional imaging to design treatment plans that reduce doses to functional regions of lung. Prospective data has shown that reducing doses to functional lung results in reduced pulmonary toxicity. Various lung function imaging modalities have been proposed for functional avoidance; however, there have been no studies evaluating whether using different imaging modalities results in dosimetrically different functional avoidance plans. The purpose of this study was to quantify the differences in treatment plans as a function of lung function imaging modality. Methods: 25 lung cancer patients enrolled on a prospective trial underwent nuclear medicine …

Development Of A Collision Model For Advanced Proton Treatment Planning And Delivery, Shupeng Chen, Lewei Zhao, Weili Zheng, An Qin, Rohan Deraniyagala, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: A major barrier to implementing advanced proton therapy delivery techniques, such as proton arc/4pi delivery is the unknown characteristics of the collision zones, i.e., the combinations of couch and gantry angles that result in a mechanical collision between the gantry and couch or patient. This study aims to develop a collision model for the determination of patient-specific collision zones to enable safe and deliverable noncoplanar proton therapy treatment planning. Methods: The detailed geometric parameters of the treatment machine including the nozzle, the snout, and the size and the location of the range shifter were measured from an IBA Proteus …

A Novel Technique To Evaluate Skin Toxicity In Breast Cancer Radiotherapy, R Culcasi, M Vlachaki, M Snyder

Conference Presentation Abstracts

Purpose: To evaluate skin toxicity throughout breast radiotherapy by visualizing variations in Eulerian amplified microcirculation and correlating to skin temperature as measured by a thermal camera. Methods: High-resolution monochrome video recordings and thermal images were acquired for four breast cancer patients prior to radiation treatment followed weekly over 3-5 weeks. During these visits, the radiation oncologist assessed the patient’s skin following the CTCAE scoring system. Videos were amplified by a factor of 100 for frequencies near the patient's measured heart rate (as measured by a fingertip pulse oximeter) with a bandwidth of 0.2Hz, based on a technique developed by CSAIL …

Evaluation Of Variables Predicting Pulmonary Function Test (Pft) Changes For Lung Cancer Patients Treated On A Prospective 4dct-Ventilation Functional Avoidance Clinical Trial, Nader Ghassemi, Richard Castillo, Edward Castillo, Bernard L. Jones, Moyed Miften, Brian Kavanaugh, Maria Werner Werner-Wasik, Ryan Miller, Julie Barta, Inga Grills, Thomas Guerrero

Conference Presentation Abstracts

Purpose: Functional avoidance radiotherapy uses functional imaging to reduce pulmonary toxicity by designing radiotherapy plans that reduce doses to the functional lung. A novel form of lung functional imaging uses 4DCT imaging to calculate 4DCT-based lung ventilation (4DCT-ventilation) maps. A phase-II, multi-center, prospective study of 4DCT-ventilation functional avoidance was completed. Pre and post-treatment pulmonary function tests (PFTs) were acquired in order to quantitatively assess pulmonary function change. The purpose of this study is to evaluate which factors predict for PFT changes for patients treated with 4DCT-ventilation functional avoidance radiotherapy. Methods: 56 patients with locally advanced lung cancer receiving radiotherapy were …

Real-Time Tracking Diaphragm Motion On During-Treatment Kv Cone Beam Projection Images Using Resnet50, J Liang, Q Liu, E Porter, D Yan

Conference Presentation Abstracts

Purpose: Diaphragm manifested on Cone Beam projection image has been used as surrogate to monitor lung tumor position. We propose a deep learning method to detect diaphragm apex position of the ipsilateral lung in real-time on KV projections acquired during Lung SBRT delivery. Methods: 7 hypo-lung SBRT patients with right lower lobe tumor were selected in this retrospective study. The imaging projection angle ranges from about -270 to 112 degrees. The right lung diaphragm apex was manually labeled as ground-truth on KV projections acquired during-treatment sessions with 899±167 projections per session. The backbone of our machine learning model is 50 …