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Northway SK, Vallejo BM, Liu L, Hansen EE, Tang S, Mah D, MacEwan IJ, Urbanic JJ, Chang C. A quantitative framework for patient-specific collision detection in proton therapy. J Appl Clin Med Phys 2024; 25:e14247. [PMID: 38131514 PMCID: PMC11005990 DOI: 10.1002/acm2.14247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/28/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Beam modifying accessories for proton therapy often need to be placed in close proximity of the patient for optimal dosimetry. However, proton treatment units are larger in size and as a result the planned treatment geometry may not be achievable due to collisions with the patient. A framework that can accurately simulate proton treatment geometry is desired. PURPOSE A quantitative framework was developed to model patient-specific proton treatment geometry, minimize air gap, and avoid collisions. METHODS The patient's external contour is converted into the International Electrotechnique Commission (IEC) gantry coordinates following the patient's orientation and each beam's gantry and table angles. All snout components are modeled by three-dimensional (3D) geometric shapes such as columns, cuboids, and frustums. Beam-specific parameters such as isocenter coordinates, snout type and extension are used to determine if any point on the external contour protrudes into the various snout components. A 3D graphical user interface is also provided to the planner to visualize the treatment geometry. In case of a collision, the framework's analytic algorithm quantifies the maximum protrusion of the external contour into the snout components. Without a collision, the framework quantifies the minimum distance of the external contour from the snout components and renders a warning if such distance is less than 5 cm. RESULTS Three different snout designs are modeled. Examples of potential collision and its aversion by snout retraction are demonstrated. Different patient orientations, including a sitting treatment position, as well as treatment plans with multiple isocenters, are successfully modeled in the framework. Finally, the dosimetric advantage of reduced air gap enabled by this framework is demonstrated by comparing plans with standard and reduced air gaps. CONCLUSION Implementation of this framework reduces incidence of collisions in the treatment room. In addition, it enables the planners to minimize the air gap and achieve better plan dosimetry.
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Affiliation(s)
- Stephen K. Northway
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
| | - Bailey M. Vallejo
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
| | - Lawrence Liu
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
| | - Emily E. Hansen
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
| | - Shikui Tang
- Texas Center for Proton TherapyIrvingTexasUSA
| | - Dennis Mah
- ProCure Proton Therapy CenterSomersetNew JerseyUSA
| | - Iain J. MacEwan
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
| | - James J. Urbanic
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
| | - Chang Chang
- Department of Radiation Medicine and Applied SciencesUniversity of California at San DiegoLa JollaCaliforniaUSA
- California Protons Cancer Therapy CenterSan DiegoCaliforniaUSA
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Hamilton T, Zhang J, Wolf J, Kayode O, Higgins KA, Bradley J, Yang X, Schreibmann E, Roper J. Lung SBRT treatment planning: a study of VMAT arc selection guided by collision check software. Med Dosim 2023; 48:82-89. [PMID: 36750392 DOI: 10.1016/j.meddos.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 12/05/2022] [Accepted: 01/10/2023] [Indexed: 02/08/2023]
Abstract
To evaluate the effects of arc geometry on lung stereotactic body radiation therapy (SBRT) plan quality, using collision check software to select safe beam angles. Thirty lung SBRT cases were replanned 10Gy x 5 using 4 volumetric modulated arc therapy (VMAT) geometries: coplanar lateral (cpLAT), coplanar oblique (cpOBL), noncoplanar lateral (ncpLAT) and noncoplanar oblique (ncpOBL). Lateral arcs spanned 180° on the affected side whereas the 180° oblique arcs crossed midline to spare healthy tissues. Couch angles were separated by 30° on noncoplanar plans. Clearance was verified with Radformation CollisionCheck software. Optimization objectives were the same across the four plans for each case. Planning target volume (PTV) coverage was set to 95% and then plans were evaluated for dose conformity, healthy tissue doses, and monitor units. Clinically treated plans were used to benchmark the results. The volumes of the 25%, 50% and 75% isodoses were smaller with noncoplanar than coplanar arcs. The volume of the 50% isodose line relative to the PTV (CI50%) was as follows: clinical 3.75±0.72, cpLAT 3.39 ± 0.37, cpOBL 3.36 ± 0.34, ncpLAT 3.02 ± 0.21 and ncpOBL 3.02 ± 0.22. The Wilcoxon signed rank test with Bonferroni correction showed p < 0.005 in all CI50% comparisons except between the cpLat and cpObl arcs and between the ncpLat and ncpObl arcs. The best lung sparing was achieved using ncpObl arcs, which was statistically significant (p < 0.001) compared with the other four plans at V12.5Gy, V13.5Gy and V20Gy. Chest wall V30Gy was significantly better using noncoplanar arcs in comparison to the other plan types (p < 0.001). The best heart sparing at V10Gy from the ncpOBL arcs was significant compared with the clinical and cpLat plans (p < 0.005). Arc geometry has a substantial effect on lung SBRT plan quality. Noncoplanar arcs were superior to coplanar arcs at compacting the dose distribution at the 25%, 50% and 75% isodose levels, thereby reducing the dose to healthy tissues. Further healthy tissue sparing was achieved using oblique arcs that minimize the pathlength through healthy tissues and avoid organs at risk. The dosimetric advantages of the noncoplanar and oblique arcs require careful beam angle selection during treatment planning to avoid collisions during treatment, which may be facilitated by commercial software.
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Affiliation(s)
- Tyrone Hamilton
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA.
| | - Jiahan Zhang
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Jonathan Wolf
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Oluwatosin Kayode
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Kristin A Higgins
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Jeffrey Bradley
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Xiaofeng Yang
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Eduard Schreibmann
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
| | - Justin Roper
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Georgia 30322 USA
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3
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Wilson L, Rohe R, Lenards N, Hunzeker A, Tobler M, Zeiler S, Fellows A. Minimizing clearance issues with prone breast patients on Varian linear accelerators through isocenter placement. Med Dosim 2021; 46:319-323. [PMID: 33903005 DOI: 10.1016/j.meddos.2021.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/11/2021] [Indexed: 11/19/2022]
Abstract
The prone position is frequently used for breast irradiation in an effort to minimize dose to normal tissue and reduce skin toxicities. Immobilization required for prone breast irradiation can cause collision issues with the linear accelerator, disrupting treatment and negatively affecting the patient experience. The purpose of this retrospective study was to determine if an isocenter location guideline could be developed to prevent collisions with the prone breast immobilization device and gantry head, while still creating a clinically acceptable treatment plan. Clearance isocenter guidelines were established by measuring clearance between the Civco Horizon breast board and Varian linear accelerator. Fourteen patients with known clearance issues at a single institution were selected for this study and re-planned using clearance isocenter guidelines. Collision plans were compared to clearance plans created within the established clearance threshold through the institutions breast treatment guidelines based on arm II of the Radiation Therapy Oncology Group (RTOG) 1005 recommendations. Researchers in this study demonstrated clinical relevance by establishing that a clearance isocenter location guideline can be developed to prevent collisions with the prone breast immobilization and gantry head, while still creating a clinically acceptable treatment plan.
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Affiliation(s)
- Lauren Wilson
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA.
| | - Rob Rohe
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA
| | - Nishele Lenards
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA
| | - Ashley Hunzeker
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA
| | - Matt Tobler
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA
| | - Sabrina Zeiler
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA
| | - Ashley Fellows
- Medical Dosimetry Program at the University of Wisconsin-La Crosse, La Crosse, WI 54601 USA
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4
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Wang YJ, Yao JS, Lai F, Cheng JCH. CT-Based Collision Prediction Software for External-Beam Radiation Therapy. Front Oncol 2021; 11:617007. [PMID: 33777756 PMCID: PMC7991715 DOI: 10.3389/fonc.2021.617007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/26/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose Beam angle optimization is a critical issue for modern radiotherapy (RT) and is a challenging task, especially for large body sizes and noncoplanar designs. Noncoplanar RT techniques may have dosimetric advantages but increase the risk of mechanical collision. We propose a software solution to accurately predict colliding/noncolliding configurations for coplanar and noncoplanar beams. Materials and Methods Individualized software models for two different linear accelerators were built to simulate noncolliding gantry orientations for phantom/patient subjects. The sizes and shapes of the accelerators were delineated based on their manuals and on-site measurements. The external surfaces of the subjects were automatically contoured based on computed tomography (CT) simulations. An Alderson Radiation Therapy phantom was used to predict the accuracy of spatial collision prediction by the software. A gantry collision problem encountered by one patient during initial setup was also used to test the validity of the software. Results: In the comparison between the software estimates and on-site measurements, the noncoplanar collision angles were all predicted within a 5-degree difference in gantry position. The confusion matrix was calculated for each of the two empty accelerator models, and the accuracies were 98.7% and 97.3%. The true positive rates were 97.7% and 96.9%, while the true negative rates were 99.8% and 97.9%, respectively. For the phantom study, the collision angles were predicted within a 5-degree difference. The software successfully predicted the collision problem encountered by the breast cancer patient in the initial setup position and generated shifted coordinates that were validated to correspond to a noncolliding geometry. Conclusion The developed software effectively and accurately predicted collisions for accelerator-only, phantom, and patient setups. This software may help prevent collisions and expand the range of spatially applicable beam angles.
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Affiliation(s)
- Yu-Jen Wang
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Department of Radiation Oncology, Fu Jen Catholic University Hospital, New Taipei City, Taiwan.,School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Jia-Sheng Yao
- Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Feipei Lai
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Jason Chia-Hsien Cheng
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Division of Radiation Oncology, Departments of Oncology, National Taiwan University Hospital, Taipei, Taiwan.,Graduate Institutes of Oncology, Taipei, Taiwan.,Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
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Hueso-González F, Wohlfahrt P, Craft D, Remillard K. An open-source platform for interactive collision prevention in photon and particle beam therapy treatment planning. Biomed Phys Eng Express 2020; 6:055013. [PMID: 33444244 DOI: 10.1088/2057-1976/aba442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We present an open-source platform to aid medical dosimetrists in preventing collisions between gantry head and patient or couch during photon or particle beam therapy treatment planning. This generic framework uses the native scripting interface of the particular planning software to import STL files of the treatment machine elements. These are visualized in 3D together with the contoured or scanned patient surface. A graphical dialog with sliders allows the interactive rotation of the gantry and couch, with real-time feedback. To prevent a future replanning, treatment planners can assess in advance and exclude beam angles resulting in a potential risk of collision. The software platform is publicly available on GitHub and has been validated for RayStation with actual patient plans. Furthermore, the incorporation of the complete patient geometry was tested with a 3D surface scan of a full-body phantom performed with a handheld smartphone. With this study, we aim at minimizing the risk of replanning due to collisions and thus of treatment delays and unscheduled consumption of manpower. The clinical workflow can be streamlined at no cost already at the treatment planning stage. By ensuring a real-time verification of the plan feasibility, the script might boost the use of optimal couch angles that a planner might shy away from otherwise.
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Affiliation(s)
- F Hueso-González
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
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Setiawan CT, Landrigan-Ossar M. Pediatric Anesthesia Outside the Operating Room: Case Management. Anesthesiol Clin 2020; 38:587-604. [PMID: 32792186 DOI: 10.1016/j.anclin.2020.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Anesthesiology teams care for children in diverse locations, including diagnostic and interventional radiology, gastroenterology and pulmonary endoscopy suites, radiation oncology units, and cardiac catheterization laboratories. To provide safe, high-quality care, anesthesiologists working in these environments must understand the unique environmental and perioperative considerations and risks involved with each remote location and patient population. Once these variables are addressed, anesthesia and procedural teams can coordinate to ensure that patients and families receive the same high-quality care that they have come to expect in the operating room. This article also describes some of the considerations for anesthetic care in outfield locations.
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Affiliation(s)
- Christopher Tan Setiawan
- Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Anesthesiology, Children's Medical Center, 1935 Medical District Drive, Dallas, TX 75235, USA
| | - Mary Landrigan-Ossar
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Harvard Medical School, Boston, MA, USA.
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7
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Islam N, Kilian-Meneghin J, deBoer S, Podgorsak M. A collision prediction framework for noncoplanar radiotherapy planning and delivery. J Appl Clin Med Phys 2020; 21:92-106. [PMID: 32559004 PMCID: PMC7484832 DOI: 10.1002/acm2.12920] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 04/21/2020] [Accepted: 04/22/2020] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Noncoplanar radiotherapy can provide significant dosimetric benefits. However, clinical implementation of such techniques is not fully realized, partially due to the absence of a collision prediction tool integrated into the clinical workflow. In this work, the feasibility of developing a collision prediction system (CPS) suitable for integration into clinical practice has been investigated. METHODS The CPS is based on a geometric model of the Linear Accelerator (Linac), and patient morphology acquired at the simulator using a combination of the planning CT scan and 3-D vision camera (Microsoft, Kinect) data. Physical dimensions of Linac components were taken to construct a geometric model. The Linac components include the treatment couch, gantry, and imaging devices. The treatment couch coordinates were determined based on a correspondence among the CT couch top, Linac couch, and the treatment isocenter location. A collision is predicted based on dot products between vectors denoting points in Linac components and patient morphology. Collision test cases were simulated with the CPS and experimentally verified using ArcCheck and Rando phantoms to simulate a patient. RESULTS For 111 collision test cases, the sensitivity and specificity of the CPS model were calculated to be 0.95 and 1.00, respectively. The CPS predicted collision states that left conservative margins, as designed, relative to actual collision locations. The average difference between the predicted and measured collision states was 2.3 cm for lateral couch movements. The predicted couch rotational position for a collision between the gantry and a patient analog differed from actual values on average by 3.8°. The magnitude of these differences is sufficient to account for interfractional patient positioning variations during treatment. CONCLUSION The feasibility of developing a CPS using geometric models and standard vector algebra has been investigated. This study outlines a framework for potential clinical implementation of a CPS for noncoplanar radiotherapy.
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Affiliation(s)
- Naveed Islam
- State University of New York at Buffalo, Buffalo, NY, USA.,Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Josh Kilian-Meneghin
- State University of New York at Buffalo, Buffalo, NY, USA.,Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Steven deBoer
- State University of New York at Buffalo, Buffalo, NY, USA.,Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Matthew Podgorsak
- State University of New York at Buffalo, Buffalo, NY, USA.,Roswell Park Cancer Institute, Buffalo, NY, USA
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Felefly T, Achkar S, Khater N, Sayah R, Fares G, Farah N, El Barouky J, Azoury F, El Khoury C, Roukoz C, Nehme Nasr D, Nasr E. Collision prediction for intracranial stereotactic radiosurgery planning: An easy-to-implement analytical solution. Cancer Radiother 2020; 24:316-322. [PMID: 32467083 DOI: 10.1016/j.canrad.2020.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/28/2020] [Accepted: 01/31/2020] [Indexed: 02/05/2023]
Abstract
PURPOSE Gantry collision is a concern in linac-based stereotactic radiosurgery (SRS). Without collision screening, the planner may compromise optimal planning, unnecessary re-planning delays can occur, and incomplete treatments may be delivered. To address these concerns, we developed a software for collision prediction based on simple machine measurements. MATERIALS AND METHODS Three types of collision were identified; gantry-couch mount, gantry-couch and gantry-patient. Trigonometric formulas to calculate the distance from each potential point of collision to the gantry rotation axis were generated. For each point, collision occurs when that distance is greater than the gantry head to gantry rotational axis distance. The colliding arc for each point is calculated. A computer code incorporating these formulas was generated. The inputs required are the couch coordinates relative to the isocenter, the patient dimensions, and the presence or absence of a circular SRS collimator. The software outputs the collision-free gantry angles, and for each point, the shortest distance to the gantry or the colliding sector when collision is identified. The software was tested for accuracy on a TrueBEAM® machine equipped with BrainLab® accessories for 80 virtual isocenter-couch angle configurations with and without a circular collimator and a parallelepiped phantom. RESULTS The software predicted the absence of collision for 19 configurations. The mean absolute error between the measured and predicted gantry angle of collision for the remaining 61 cases was 0.86 (0.01-2.49). CONCLUSION This tool accurately predicted collisions for linac-based intracranial SRS and is easy to implement in any radiotherapy facility.
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Affiliation(s)
- T Felefly
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon.
| | - S Achkar
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - N Khater
- Department of Radiation Oncology, Saint-Louis University, Saint-Louis, MO, USA
| | - R Sayah
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - G Fares
- Physics Department, Faculty of Sciences, Saint Joseph University, Beirut, Lebanon
| | - N Farah
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - J El Barouky
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - F Azoury
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - C El Khoury
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - C Roukoz
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - D Nehme Nasr
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
| | - E Nasr
- Department of Radiation Oncology, Hôtel-Dieu de France University Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon
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Miao J, Niu C, Liu Z, Tian Y, Dai J. A practical method for predicting patient-specific collision in radiotherapy. J Appl Clin Med Phys 2020; 21:65-72. [PMID: 32462733 PMCID: PMC7484822 DOI: 10.1002/acm2.12915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/19/2020] [Accepted: 04/27/2020] [Indexed: 11/16/2022] Open
Abstract
Purpose To develop a practical method for predicting patient‐specific collision during the treatment planning process. Materials and method Based on geometry information of the accelerator gantry and the location of plan isocenter, the collision‐free space region could be determined. In this study, collision‐free space region was simplified as a cylinder. Radius of cylinder was equal to the distance from isocenter to the collimator cover. The collision‐free space was converted and imported into treatment planning system (TPS) in the form of region of interest (ROI) which was named as ROISS. Collision was viewed and evaluated on the fusion images of patient's CT and ROIs in TPS. If any points of patient's body or couch fell beyond the safety space, collision would occur. This method was implemented in the Pinnacle TPS. The impact of safety margin on accuracy was also discussed. Sixty‐five plans of clinical patients were chosen for the clinical validation. Results When the angle of couch is zero, the ROISS displays as a series of circles on the cross section of the patient's CT. When the couch angle is not zero, ROISS is a series of ellipses in the transverse view of patient's CT. The ROISS can be generated quickly within five seconds after a single mouse click in TPS. Adding safety margin is an effective measure in preventing collisions from being undetected. Safety margin could increase negative predictive value (NPV) of test cases. Accuracy obtained was 96.3% with the 3 cm safety margin with 100% true positive collision detection. Conclusion This study provides a reliable, accurate, and fast collision prediction during the treatment planning process. Potential collisions can be discovered and prevented early before delivering. This method can integrate with the current clinical workflow without any additional required resources, and contribute to improvement in the safety and efficiency of the clinic.
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Affiliation(s)
- Junjie Miao
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chuanmeng Niu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhiqiang Liu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuan Tian
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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