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Park J, Gagneur JD, Chungbin SJ, Rong Y, Lim SB, Chan MF. Resolving signal drift in the wall-mounted camera of the RGSC system. J Appl Clin Med Phys 2024; 25:e14291. [PMID: 38306504 PMCID: PMC10929989 DOI: 10.1002/acm2.14291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 01/10/2024] [Accepted: 01/16/2024] [Indexed: 02/04/2024] Open
Abstract
PURPOSE To present a modified calibration method to reduce signal drift due to table sagging in Respiratory Gating for Scanner (RGSC) systems with a wall-mounted camera. MATERIALS AND METHODS Approximately 70 kg of solid water phantoms were evenly distributed on the CT couch, mimicking the patient's weight. New calibration measurements were performed at 9 points at the combination of three lateral positions, the CT isocenter and ±10 cm laterally from the isocenter, and three longitudinal locations, the CT isocenter and ±30 cm or ±40 cm from the isocenter. The new calibration was tested in two hospitals. RESULTS Implementing the new weighed calibration method at the extended distance yielded improved results during the DIBH scan, reducing the drift to within 1 from 3 mm. The extended calibration positions exhibited similarly reduced drift in both hospitals, reinforcing the method's robustness and its potential applicability across all centers. CONCLUSION This proposed solution aims to minimize the systematic error in radiation delivery for patients undergoing motion management with wall-mounted camera RGSC systems, especially in conjunction with a bariatric CT couchtop.
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Affiliation(s)
- Jeonghoon Park
- Department of Medical PhysicsMemorial Sloan Kettering Cancer CenterBasking RidgeNew JerseyUSA
| | | | | | - Yi Rong
- Department of Radiation OncologyMayo ClinicPhoenixArizonaUSA
| | - Seng Boh Lim
- Department of Medical PhysicsMemorial Sloan Kettering Cancer CenterBasking RidgeNew JerseyUSA
| | - Maria F. Chan
- Department of Medical PhysicsMemorial Sloan Kettering Cancer CenterBasking RidgeNew JerseyUSA
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Lucido JJ, Penoncello GP, Laughlin BS, Armstrong MD, Lo SG, Rivera JN, Tang X, Chungbin SJ, Breen WG, Mangold AR, Comfere NI, Lester SC, Rule WG, Deufel CL, Foster MG. Development and Dosimetric Characterization of a Customizable Shield for Subtotal Skin Electron Beam Therapy. Adv Radiat Oncol 2023; 8:101289. [PMID: 37457824 PMCID: PMC10344686 DOI: 10.1016/j.adro.2023.101289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/08/2023] [Indexed: 07/18/2023] Open
Abstract
Purpose Purpose: Subtotal skin electron beam therapy may be an option for patients with cutaneous lymphoma receiving radiation therapy to treat large areas of their skin but may benefit from sparing specific areas that may have had previous radiation therapy, are of specific cosmetic concern, and/or show no evidence of disease. We report here on the design, implementation, and dosimetric characteristics of a reusable and transparent customizable shield for use with the large fields used to deliver total skin electron beam therapy at extended distance with a conventional linear accelerator. Methods and Materials A shield was designed and manufactured consisting of acrylic blocks that can be mounted on a steel frame to allow patient-specific shielding. The dosimetry of the device was measured using radiochromic film. Results The shield is easy to use and well-tolerated for patient treatment, providing minimal electron transmission through the shield with a sharp penumbra at the field edge, with no increase in x-ray dose. We report on the dosimetry of a commercial device that has been used to treat more than 30 patients to date. Conclusions The customizable shield is well suited to providing patient-specific shielding for subtotal skin electron beam therapy.
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Affiliation(s)
- J. John Lucido
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | | | | | - Stephanie G. Lo
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Judith N. Rivera
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Xueyan Tang
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | - William G. Breen
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | | | - Scott C. Lester
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - William G. Rule
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona
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Laughlin BS, Anderson JD, Gagneur JD, Chungbin SJ, Bues M, Hobbis D, Fatyga M, Korte SM, Carroll SE, Vora S, Sio TT, Wong WW, Keole SR, Rong Y. Implementation of Photon Treatment Back-Up Workflow at a High-Volume Proton Center: Safety, Quality, and Patient Considerations. Pract Radiat Oncol 2022; 12:e453-e459. [PMID: 35272078 DOI: 10.1016/j.prro.2022.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/11/2022] [Accepted: 01/19/2022] [Indexed: 11/30/2022]
Abstract
A successful proton beam therapy (PBT) center relies heavily on the proper function and maintenance of a proton beam therapy machine. However, when a PBT machine is non-operational, a proton facility is hindered with delays that can potentially lead to inferior treatment outcome due to treatment interruption. The implementation of a workflow for which proton plans are converted to photon plans so that patients can be treated using photon has been a successful strategy to reduce delays and mitigate its impact on patient care. This workflow was established through collaboration of physicians, physicists, dosimetrists, therapists, nurses, and schedulers. A tiered system established by disease site, number of fractions, and individualized circumstances is used to prioritize patients. This article provides an overview of workflow of conversion of PBT to photon when the PBT machine is down. Specific needs of patients undergoing proton beam therapy are addressed.
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Affiliation(s)
- Brady S Laughlin
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Justin D Anderson
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Justin D Gagneur
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Suzanne J Chungbin
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Dean Hobbis
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Mirek Fatyga
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Shawn M Korte
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Sarah E Carroll
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Sujay Vora
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Terence T Sio
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - William W Wong
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Sameer R Keole
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054
| | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic Arizona, 5881 E Mayo Boulevard, Phoenix, Arizona, 85054.
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Serago CF, Chungbin SJ, Buskirk SJ, Ezzell GA, Collie AC, Vora SA. Initial experience with ultrasound localization for positioning prostate cancer patients for external beam radiotherapy. Int J Radiat Oncol Biol Phys 2002; 53:1130-8. [PMID: 12128112 DOI: 10.1016/s0360-3016(02)02826-2] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE Transabdominal ultrasound localization of the prostate gland and its immediate surrounding anatomy has been used to guide the positioning of patients for the treatment of prostate cancer. This process was evaluated in terms of (1) the reproducibility of the ultrasound measurement; (2) a comparison of patient position between ultrasound localization and skin marks determined from a CT treatment planning scan; (3) the predictive indicators of patient anatomy not well suited for ultrasound localization; (4) the measurement of prostate organ displacement resulting from ultrasound probe pressure; and (5) quality assurance measures. METHODS AND MATERIALS The reproducibility of the ultrasound positioning process was evaluated for same-day repeat positioning by the same ultrasound operator (22 patients) and for measurements made by 2 different operators (38 patients). Differences between conventional patient positioning (CT localization with skin markings) and ultrasound-based positioning were determined for 38 patients. The pelvic anatomy was evaluated for 34 patients with pretreatment CT scans to identify predictors of poor ultrasound image quality. The displacement of the prostate resulting from pressure of the ultrasound probe was measured for 16 patients with duplicate CT scans with and without a simulated probe. Finally, daily, monthly, and semiannual quality assurance tests were evaluated. RESULTS Self-verification tests of ultrasound positioning indicated a shift of <3 mm in approximately 95% of cases. Interoperator tests indicated shifts of <3 mm in approximately 80-90% of cases. The mean difference in patient positioning between conventional and ultrasound localization for lateral shifts was 0.3 mm (SD 2.5): vertical, 1.3 mm (SD 4.7 mm) and longitudinal, 1.0 mm (SD 5.1). However, on a single day, the differences were >10 mm in 1.5% of lateral shifts, 7% of longitudinal shifts, and 7% of vertical shifts. The depth to the isocenter, thickness of tissue overlying the bladder, and position of the prostate relative to the pubic symphysis, but not the bladder volume, were significant predictive indicators of poor ultrasound imaging. The pressure of the ultrasound probe displaced the prostate in 7 of the 16 patients by an average distance of 3.1 mm; 9 patients (56%) showed no displacement. Finally, the quality assurance tests detected ultrasound equipment defects. CONCLUSION The ultrasound positioning system is reproducible and may indicate the need for significant positioning moves. Factors that predict poor image quality are the depth to the isocenter, thickness of tissue overlying the bladder, and position of the prostate relative to the pubic symphysis. The prostate gland may be displaced a small amount by the pressure of the ultrasound probe. A quality assurance program is necessary to detect ultrasound equipment defects that could result in patient alignment errors.
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