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Iramina H, Nakamura M, Sasaki M, Mizowaki T. Performance of cone-beam computed tomography imaging during megavoltage beam irradiation under phase-gated conditions. Phys Med 2024; 123:103409. [PMID: 38870644 DOI: 10.1016/j.ejmp.2024.103409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 05/23/2024] [Accepted: 06/10/2024] [Indexed: 06/15/2024] Open
Abstract
PURPOSE Target positions should be acquired during beam delivery for accurate lung stereotactic body radiotherapy. We aimed to perform kilovoltage (kV) imaging during beam irradiation (intra-irradiation imaging) under phase-gated conditions and evaluate its performance. METHODS Catphan 504 and QUASAR respiratory motion phantoms were used to evaluate image quality and target detectability, respectively. TrueBeam STx linac and the Developer Mode was used. The imaging parameters were 125 kVp and 1.2 mAs/projection. Flattened megavoltage (MV) X-ray beam energies 6, 10 and 15 MV and un-flattened beam energies 6 and 10 MV were used with field sizes of 5 × 5 and 15 × 15 cm2 and various frame rates for intra-irradiation imaging. In addition, using a QUASAR phantom, intra-irradiation imaging was performed during intensity-modulated plan delivery. The root-mean-square error (RMSE) of the CT-number for the inserted rods, image noise, visual assessment, and contrast-to-noise ratio (CNR) were evaluated. RESULTS The RMSEs of intra-irradiation cone-beam computed tomography (CBCT) images under gated conditions were 50-230 Hounsfield Unit (HU) (static < 30 HU). The noise of the intra-irradiation CBCT images under gated conditions was 15-35 HU, whereas that of the standard CBCT images was 8.8-27.2 HU. Lower frame rates exhibited large RMSEs and noise; however, the iterative reconstruction algorithm (IR) was effective at improving these values. Approximately 7 fps with the IR showed an equivalent CNR of 15 fps without the IR. The target was visible on all the gated intra-irradiation CBCT images. CONCLUSION Several image quality improvements are required; however, intra-irradiated CBCT images showed good visual target detection.
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Affiliation(s)
- Hiraku Iramina
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Mitsuhiro Nakamura
- Department of Advanced Medical Physics, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Makoto Sasaki
- Division of Clinical Radiology Service, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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Lankinen L, Kulmala A, Lehtomäki J, Harju A. The delivery assessment for small targets on Halcyon radiotherapy system - Measured and calculated dose comparison. J Appl Clin Med Phys 2024; 25:e14407. [PMID: 38775807 PMCID: PMC11163489 DOI: 10.1002/acm2.14407] [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: 12/13/2023] [Revised: 03/18/2024] [Accepted: 04/01/2024] [Indexed: 06/11/2024] Open
Abstract
BACKGROUND With the ever-increasing requirements of accuracy and personalization of radiotherapy treatments, stereotactic radiotherapy (SRT) with volumetric modulated arc therapy (VMAT) on O-ring Halcyon radiotherapy system could potentially provide a fast, safe, and feasible treatment option. PURPOSE The purpose of this study was to assess the delivery of Halcyon VMAT plans for small targets. METHODS Well-defined VMAT-SRT plans were created on Halcyon radiotherapy system with the stacked and staggered dual-layer MLC design for the film measurement set-up and the target sizes and shapes designed to emulate the targets of the stereotactic treatments. The planar dose distributions were acquired with film measurements and compared to a current clinical reference dose calculation with AcurosXB (v18.0, Varian Medical Systems) and to Monte Carlo simulations. With the collapsed arc versions of the VMAT-SRT plans, the uncertainty in dose delivery due to the multileaf collimator (MLC) without the gantry rotation could be separated and analyzed. RESULTS The target size was mainly limited by the resolution originated from the design of the MLC leaves. The results of the collapsed arc versions of the plans show good consistency among measured, calculated, and simulated dose distributions. With the full VMAT plans, the agreement between calculated and simulated dose distributions was consistent with the collapsed arc versions. The measured dose distribution agreed with the calculated and simulated dose distributions within the target regions, but considerable local differences were observed in the margins of the target. The largest differences located in the steep gradient regions presumably originating from the deviation of the isocenter. CONCLUSIONS The potential of the Halcyon radiotherapy system for VMAT-SRT delivery was evaluated and the study revealed valuable insights on the machine characteristics with the delivery.
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Affiliation(s)
- Linda Lankinen
- Varian Medical Systems, a Siemens Healthineers CompanyHelsinkiFinland
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Antti Kulmala
- Clinical Research Institute HUCH Ltd.HelsinkiFinland
| | - Jouko Lehtomäki
- Varian Medical Systems, a Siemens Healthineers CompanyHelsinkiFinland
| | - Ari Harju
- Varian Medical Systems, a Siemens Healthineers CompanyHelsinkiFinland
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Sarkar B, Pradhan A. Setup time analysis for stereotactic body radiotherapy in O-ring linear accelerator without rotational correction. Radiol Phys Technol 2024; 17:527-535. [PMID: 38526690 DOI: 10.1007/s12194-024-00791-0] [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: 10/17/2023] [Revised: 02/10/2024] [Accepted: 02/14/2024] [Indexed: 03/27/2024]
Abstract
This study analyse setup time (ST) and frequency of on-board imaging for stereotactic abdomen (liver, stomach), lung, and spine radiotherapy in the absence of automatic rotational correction. Total 53 stereotactic body radiotherapy (SBRT) patients, 28 of abdomen, 19 lung, and 6 spine treated for 230 sessions in O-ring gantry accelerator were evaluated for ST analysis. The mean setup time for all patients, abdomen, lung, and spine cases were 7.7 ± 7.4 min, 9.2 ± 9.2 min, 6.3 ± 4.1 min, and 5.5 ± 3.3 min, respectively. Median number CBCT was 2. 96% of cases had a CBCT between 1 and 3, and 9 (4%) had ≥ 4 CBCTs. Overall, 38.1%, 35.5%, 22.1%, 2.2%, and 2.2% of setup time fall into window of 0-5 min, 5-10 min, 10-20 min, 20-30 min, and > 30 min. Most difficult challenge is to negotiate with unknown rotational errors. It will be easy to dealt with them without automatic rotational correction if values are known.
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Affiliation(s)
- Biplab Sarkar
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India.
- Department of Physics, GLA University, Mathura, Uttar Pradesh, 281406, India.
| | - Anirudh Pradhan
- Centre for Cosmology, Astrophysics and Space Science (CCASS), GLA University, Mathura, Uttar Pradesh, 281406, India
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Gonzalez Y, Visak J, Overman L, Liao CY, Yen A, Zhuang T, Cai B, Godley A, Zhang Y, Timmerman R, Iyengar P, Westover K, Parsons D, Lin MH. Beyond conventional bounds: Surpassing system limits for stereotactic ablative (SAbR) lung radiotherapy using CBCT-based adaptive planning system. J Appl Clin Med Phys 2024:e14375. [PMID: 38712917 DOI: 10.1002/acm2.14375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 03/27/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024] Open
Abstract
PURPOSE Online adaptive radiotherapy relies on a high degree of automation to enable rapid planning procedures. The Varian Ethos intelligent optimization engine (IOE) was originally designed for conventional treatments so it is crucial to provide clear guidance for lung SAbR plans. This study investigates using the Ethos IOE together with adaptive-specific optimization tuning structures we designed and templated within Ethos to mitigate inter-planner variability in meeting RTOG metrics for both online-adaptive and offline SAbR plans. METHODS We developed a planning strategy to automate the generation of tuning structures and optimization. This was validated by retrospective analysis of 35 lung SAbR cases (total 105 fractions) treated on Ethos. The effectiveness of our planning strategy was evaluated by comparing plan quality with-and-without auto-generated tuning structures. Internal target volume (ITV) contour was compared between that drawn from CT simulation and from cone-beam CT (CBCT) at time of treatment to verify CBCT image quality and treatment effectiveness. Planning strategy robustness for lung SAbR was quantified by frequency of plans meeting reference plan RTOG constraints. RESULTS Our planning strategy creates a gradient within the ITV with maximum dose in the core and improves intermediate dose conformality on average by 2%. ITV size showed no significant difference between those contoured from CT simulation and first fraction, and also trended towards decreasing over course of treatment. Compared to non-adaptive plans, adaptive plans better meet reference plan goals (37% vs. 100% PTV coverage compliance, for scheduled and adapted plans) while improving plan quality (improved GI (gradient index) by 3.8%, CI (conformity index) by 1.7%). CONCLUSION We developed a robust and readily shareable planning strategy for the treatment of adaptive lung SAbR on the Ethos system. We validated that automatic online plan re-optimization along with the formulated adaptive tuning structures can ensure consistent plan quality. With the proposed planning strategy, highly ablative treatments are feasible on Ethos.
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Affiliation(s)
- Yesenia Gonzalez
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Justin Visak
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Luke Overman
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Chien-Yi Liao
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Allen Yen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Tingliang Zhuang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Bin Cai
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Andrew Godley
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Yuanyuan Zhang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York City, New York, USA
| | - Robert Timmerman
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Puneeth Iyengar
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York City, New York, USA
| | - Kenneth Westover
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York City, New York, USA
| | - David Parsons
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mu-Han Lin
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Medical Artificial Intelligence and Automation Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Fujimoto D, Takatsu J, Hara N, Oshima M, Tomihara J, Segawa E, Inoue T, Shikama N. Dosimetric comparison of four-dimensional computed tomography based internal target volume against variations in respiratory motion during treatment between volumetric modulated arc therapy and three-dimensional conformal radiotherapy in lung stereotactic body radiotherapy. Radiol Phys Technol 2024; 17:143-152. [PMID: 37930563 DOI: 10.1007/s12194-023-00757-8] [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: 04/09/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/07/2023]
Abstract
This study focused on the dosimetric impact of variations in respiratory motion during lung stereotactic body radiotherapy (SBRT). Dosimetric comparisons between volumetric modulated arc therapy (VMAT) and three-dimensional conformal radiotherapy (3DCRT) were performed using four-dimensional computed tomography (4DCT)-based internal target volumes (ITV). We created retrospective plans for ten patients with lung cancer who underwent SBRT using 3DCRT and VMAT techniques. A Delta4 Phantom + (ScandiDos, Uppsala, Sweden) was used to evaluate the dosimetric robustness of 4DCT-based ITV against variations in respiratory motion during treatment. We analyzed respiratory motion during treatment. Dose-volume histogram parameters were evaluated for the 95% dose (D95%) to the planning target volume (PTV) contoured on CT images obtained under free breathing. The correlations between patient respiratory parameters and dosimetric errors were also evaluated. In the phantom study, the average PTV D95% dose differences for all fractions were - 2.9 ± 4.4% (- 16.0 - 1.2%) and - 2.0 ± 2.8% (- 11.2 - 0.7%) for 3DCRT and VMAT, respectively. The average dose difference was < 3% for both 3DCRT and VMAT; however, in 5 out of 42 fractions in 3DCRT, the difference in PTV D95% was > 10%. Dosimetric errors were correlated with respiratory amplitude and velocity, and differences in respiratory amplitude between 4DCT and treatment days were the main factors causing dosimetric errors. The overall average dose error of the PTV D95% was small; however, both 3DCRT and VMAT cases exceeding 10% error were observed. Larger errors occurred with amplitude variation or baseline drift, indicating limited robustness of 4DCT-based ITV.
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Affiliation(s)
- Daimu Fujimoto
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Jun Takatsu
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Naoya Hara
- Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo, 113-8431, Japan
| | - Masaki Oshima
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Jun Tomihara
- Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo, 113-8431, Japan
| | - Eisuke Segawa
- Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo, 113-8431, Japan
| | - Tatsuya Inoue
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
- Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba, 279-0021, Japan
| | - Naoto Shikama
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
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Bogowicz M, Lustermans D, Taasti VT, Hazelaar C, Verhaegen F, Fonseca GP, van Elmpt W. Evaluation of a cone-beam computed tomography system calibrated for accurate radiotherapy dose calculation. Phys Imaging Radiat Oncol 2024; 29:100566. [PMID: 38487622 PMCID: PMC10937948 DOI: 10.1016/j.phro.2024.100566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
Background and purpose Dose calculation on cone-beam computed tomography (CBCT) images has been less accurate than on computed tomography (CT) images due to lower image quality and discrepancies in CT numbers for CBCT. As increasing interest arises in offline and online re-planning, dose calculation accuracy was evaluated for a novel CBCT imager integrated into a ring gantry treatment machine. Materials and methods The new CBCT system allowed fast image acquisition (5.9 s) by using new hardware, including a large-size flat panel detector, and incorporated image-processing algorithms with iterative reconstruction techniques, leading to accurate CT numbers allowing dose calculation. In this study, CBCT- and CT-based dose calculations were compared based on three anthropomorphic phantoms, after CBCT-to-mass-density calibration was performed. Six plans were created on the CT scans covering various target locations and complexities, followed by CBCT to CT registrations, copying of contours, and re-calculation of the plans on the CBCT scans. Dose-volume histogram metrics for target volumes and organs-at-risk (OARs) were evaluated, and global gamma analyses were performed. Results Target coverage differences were consistently below 1.2 %, demonstrating the agreement between CT and re-calculated CBCT dose distributions. Differences in Dmean for OARs were below 0.5 Gy for all plans, except for three OARs, which were below 0.8 Gy (<1.1 %). All plans had a 3 %/1mm gamma pass rate > 97 %. Conclusions This study demonstrated comparable results between dose calculations performed on CBCT and CT acquisitions. The new CBCT system with enhanced image quality and CT number accuracy opens possibilities for off-line and on-line re-planning.
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Affiliation(s)
| | - Didier Lustermans
- Corresponding author at: Postbox 3035, 6202 NA Maastricht, The Netherlands.
| | - Vicki Trier Taasti
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Colien Hazelaar
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Frank Verhaegen
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Gabriel Paiva Fonseca
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Wouter van Elmpt
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
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Hernández KVD, Unterkirhers S, Schneider U. Quality assessment of automatically planned O-Ring linac SBRT plans for pelvic lymph node metastases, finding the optimal minimum target size by comparison with robotic SBRT. J Appl Clin Med Phys 2023; 24:e14143. [PMID: 37738649 PMCID: PMC10691630 DOI: 10.1002/acm2.14143] [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: 02/20/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 09/24/2023] Open
Abstract
PURPOSE The purpose of this study is to assess the quality of automatic planned O-Ring Halcyon linac SBRT plans for pelvic lymph node metastases and to establish an absolute PTV volume threshold as a plan quality prediction criterion. Compliance of the plans to institutional SBRT plan evaluation criteria and differences in plan quality and treatment delivery times between Halcyon Linac and CyberKnife robotic SBRT were evaluated. METHODS Twenty-one CyberKnife treatment plans were replanned for Halcyon. Prescription doses range was 26-40 Gy in mean three fractions. The mean/median planning target volume was 4.0/3.6 cm3 . Institutional criteria for the plan evaluation were: New Conformity Index (NCI), Conformity Index (CI), Modified Gradient Index (MGI), selectivity index reciprocal (PIV/TVPIV ), and the target coverage by prescription isodose (%PIV). Statistical analysis based on the receiver operating characteristic (ROC) curve was used to determine a plan quality predictor threshold of the PTV volume. Comparative analysis of normal tissue complication probabilities (NTCP) was used to assess the risk of toxicity in healthy tissues. RESULTS Seventy-one percent (n = 15)/95% (n = 20) of Halcyon and 81% (n = 17)/100% (n = 21) of CK plans fulfilled all ideal/tolerance criteria. For PTVs above a found optimal threshold of 2.6 cm3 (71%, n = 15), no statistically significant difference was observed between the CI, NCI, PIV/TVPIV , and MGI indexes of both groups, while the coverage (%PIV) was statistically but not clinically significantly different between cohorts. Significantly shorter delivery times are expected with Halcyon. No significant differences in NTCP were observed. CONCLUSION All but one automatically optimized Halcyon treatment plans demonstrated ideal or acceptable performance. PTV threshold of 2.6 cm3 can be used as decision criteria in clinical settings. The results of our study demonstrated the promising performance of the Halcyon for pelvic SBRT, although plan-specific QA is required to verify machine performance during plan delivery.
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Affiliation(s)
| | | | - Uwe Schneider
- Science FacultyUniversity of ZürichZürichSwitzerland
- Medical PhysicsRadiotherapy HirslandenZürichSwitzerland
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Pokhrel D, Misa J, McCarthy S, Yang ES. Two novel stereotactic radiotherapy methods for locally advanced, previously irradiated head and neck cancers patients. Med Dosim 2023; 49:114-120. [PMID: 37867087 DOI: 10.1016/j.meddos.2023.09.003] [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: 07/21/2023] [Revised: 09/08/2023] [Accepted: 09/22/2023] [Indexed: 10/24/2023]
Abstract
To determine the feasibility and utility of conebeam CT-guided stereotactic radiotherapy for locally recurrent, previously irradiated head and neck cancer (HNC) patients on the Halcyon, a ring delivery system (RDS). This research aims to quantify plan quality, treatment delivery accuracy, and overall efficacy by comparing against novel clinical TrueBeam HyperArc method. Ten recurrent HNC patients who were treated at our institution on TrueBeam (6MV-FFF) for 30 to 40 Gy in 3 to 5 fractions with noncoplanar HyperArc plans were re-planned on Halcyon (6MV-FFF). These plans were re-planned with the same Acuros-based dose engine. Additionally, we used site-specific full/partial coplanar VMAT arcs. PTV coverage, mean dose to GTV, maximum dose to organs-at-risk (OAR), beam-on time (BOT), and quality assurance (QA) results were investigated and compared. Halcyon provided highly conformal HNC SRT plans with slightly superior mean PTVD99 coverage (96.7% vs 95.5%, p = 0.071), and slightly lower mean GTV dose (37.8 Gy vs 38.2 Gy, p = 0.241) when compared to the HyperArc plans. Differences in plan conformality and maximum dose to OARs were statistically insignificant. Due to Halcyon's coplanar geometry, D2cm was significantly higher (p = 0.001) but Halcyon did result in a reduced normal brain dose by 1 Gy on average and up to 5.2 Gy in some cases. Halcyon provided similar patient-specific QA pass rates with a 2%/2mm gamma criteria (98.2% vs 98.5%) and independent in-house Monte Carlo second check results (97.7% vs 98.2%), suggesting identical treatment delivery accuracy. Halcyon plans resulted in slightly longer beam-on time (3.16 vs 2.30 minutes, p = 0.010), however door-to-door patient time is expected to be <10 minutes. Compared to clinical TrueBeam HyperArc, Halcyon SRT plans provided similar plan quality and treatment delivery accuracy with a potentially faster overall treatment using fully automated patient setup and verification. Rapid delivery of recurrent HNC SRT may reduce intrafraction motion errors while also improving patient compliance and comfort. To provide high-quality of HNC SRT similar to HyperArc, we recommend Halcyon users consider commissioning this novel method. This method will be useful for remote and underserved patient cohorts including Halcyon-only clinics as well.
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Affiliation(s)
- Damodar Pokhrel
- Department of Radiation Medicine, Medical Physics Graduate Program, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
| | - Josh Misa
- Department of Radiation Medicine, Medical Physics Graduate Program, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Shane McCarthy
- Department of Radiation Medicine, Medical Physics Graduate Program, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Eddy S Yang
- Department of Radiation Medicine, Medical Physics Graduate Program, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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Huang Y, Liu Z. Dosimetric performance evaluation of the Halcyon treatment platform for stereotactic radiotherapy: A pooled study. Medicine (Baltimore) 2023; 102:e34933. [PMID: 37682167 PMCID: PMC10489306 DOI: 10.1097/md.0000000000034933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 08/04/2023] [Indexed: 09/09/2023] Open
Abstract
With the advancement of radiotherapy equipment, stereotactic radiotherapy (SRT) has been increasingly used. Among the many radiotherapy devices, Halcyon shows promising applications. This article reviews the dosimetric performance such as plan quality, plan complexity, and gamma passing rates of SRT plans with Halcyon to determine the effectiveness and safety of Halcyon SRT plans. This article retrieved the last 5 years of PubMed studies on the effectiveness and safety of the Halcyon SRT plans. Two authors independently reviewed the titles and abstracts to decide whether to include the studies. A search was conducted to identify publications relevant to evaluating the dosimetric performance of SRT plans on Halcyon using the key strings Halcyon, stereotactic radiosurgery, SRT, stereotactic body radiotherapy, and stereotactic ablative radiotherapy. A total of 18 eligible publications were retrieved. Compared to SRT plans on the TrueBeam, the Halcyon has advantages in terms of plan quality, plan complexity, and gamma passing rates. The high treatment speed of SRT plans on the Halcyon is impressive, while the results of its plan evaluation are also encouraging. As a result, Halcyon offers a new option for busy radiotherapy units while significantly improving patient comfort in treatment. For more accurate results, additional relevant publications will need to be followed up in subsequent studies.
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Affiliation(s)
- Yangyang Huang
- Department of Radiotherapy, the Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zongwen Liu
- Department of Radiotherapy, the Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Sarkar B, Biswal SS, Shahid T, Ghosh T, Bhattacharya J, De A, Mukherjee M, Ganesh T, Cozzi L. Comparative dosimetric analysis of volumetric modulated arc therapy based craniospinal irradiation plans between Halcyon ring gantry and TrueBeam C-arm linear accelerator. Sci Rep 2023; 13:3430. [PMID: 36859485 PMCID: PMC9977918 DOI: 10.1038/s41598-023-30429-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
This study evaluates the volumetric modulated arc therapy (VMAT) dosimetric comparison between Halcyon ring gantry and TrueBeam c-arm linear accelerators for craniospinal irradiation (CSI) of the neuro-axis. 25 patients, who received treatment for medulloblastoma and primitive neuro-ectodermal tumors between 2018 and 2021, were planned for VMAT in True Beam (TB), and Halcyon (HAL) linear accelerators using 6 MV unflattened (FFF) photon beams (HALFFF and TBFFF). Dose-volume statistics for the target and organs at risk (OARs) and the total number of monitoring units (MUs) in the treatment plans were compared which included dose received by 95% PTV volume (V95%), volume receiving ≥ 107% dose, homogeneity index (HI), conformity index (PI), MU and dose spillage (D10%, D30%, D50%, D70%, D90%). In all 26 OARs were considered of which five were serial and the remaining were parallel structures. For the former, the dose received by 0.2 cm3, volume = D0.2 cm3) were evaluated and for the latter mean dose were evaluated. Both arms were statistically compared with paired sample t-test with a significant value of ≤ 0.05. 11 patients received treatment with the Halcyon and the rest 14 in the TrueBeam C-arm linear accelerator. Patients in the low- and intermediate-risk category (n = 13) received 23.4 Gy in 13 fractions. The remaining patients were in the high-risk category and received 35 Gy in 21 fractions or 36 Gy in 20 fractions. For HALFFF and TBFFF, PTVV95% were 97.5 ± 0.8% and 97.4 ± 0.9% respectively (p = 0.371) while the V107% were 0.6 ± 0.4% and 0.5 ± 0.5 respectively (p = 0.504). However, the number of monitoring units showed statistical significance (p < 0.001) with values of 1331.9 ± 243.4 MU and 1089 ± 206.7 MU respectively for the HAL and TB plans. The differences in spillage dose were also statistically significant, favouring HAL plans at D30% (p = 0.002), D50% (p < 0.001), D70% (p = 0.039), and D90% (p = 0.01) level except for D10% (p = 0.090). Conformity index also showed statistical significance with PI_HAL = 0.9 ± 0.02 and PI_TB = 0.89 ± 0.03 (p = 0.029). For 10 of the 21 parallel structures, the mean dose differences were statistically significant in favouring of HAL plans. Halcyon based VMAT CSI plans are dosimetrically superior in terms of organ dose, especially for the large organs, and offer lower spillage doses than the TrueBeam plans. Plans generated by both linear accelerators are suitable for the patients' treatments.
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Affiliation(s)
- Biplab Sarkar
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India.
| | | | - Tanweer Shahid
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
| | - Tanmoy Ghosh
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
| | - Jibak Bhattacharya
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
| | - Arundhati De
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
| | - Mukti Mukherjee
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
| | | | - Luca Cozzi
- grid.417728.f0000 0004 1756 8807Radiotherapy and Radiosurgery Department, Humanitas Research Hospital and Cancer Center, Via Manzoni 56, 20089 Milan, Rozzano Italy ,grid.452490.eDepartment of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20090 Milan, Italy ,grid.423288.70000 0004 0413 1286Varian Medical Systems, Palo Alto, USA
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11
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Lim R, Penoncello GP, Hobbis D, Harrington DP, Rong Y. Technical note: Characterization of novel iterative reconstructed cone beam CT images for dose tracking and adaptive radiotherapy on L-shape linacs. Med Phys 2022; 49:7715-7732. [PMID: 36031929 DOI: 10.1002/mp.15943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 08/05/2022] [Accepted: 08/10/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cone-beam computed tomography (CBCT) allows for patient setup and positioning, and potentially dose verification or adaptive replanning prior to each treatment delivery. Poor CBCT image quality due to scatter artifacts and patient motion has been a major limiting factor. A new image reconstruction algorithm was recently clinically implemented for improving image quality through iterative reconstruction (iCBCT). PURPOSE This study aims to characterize iCBCT image quality, establish image value (HU)-to-relative electron density (RED) calibration curves for dose calculation, and assess the dosimetric accuracy for different anatomical sites. MATERIAL AND METHODS Both conventional CBCT and iCBCT scans were acquired from a Varian TrueBeam On-Board Imager system. A Catphan 604 phantom was scanned to compare image quality between the traditional Feldkamp-Davis-Kress (FDK) and novel iterative reconstruction techniques. Computerized Imaging Reference Systems (CIRS) electron density phantom was used to construct site-specific HU-RED curves corresponding to various scan settings. The CIRS Dynamic Thorax phantom, Rando pelvis phantom, and BrainLab head phantom were used for assessing dosimetric accuracy calculated on iCBCT images, compared to that on traditional FDK-based CBCT images. All phantoms were scanned on a computed tomography (CT) to obtain baseline HU values for comparison. RESULTS Test results obtained from Catphan showed statistically significant improvement with iCBCT, compared to FDK CBCT. Average HU differences from the baseline CT values were improved to within ±30 HU for iCBCT, compared to FDK CBCT for phantom studies. Dose calculated on iCBCT for both phantoms and patient cases directly using baseline HU-RED calibration from CT showed 0.5%-2.0% accuracy from the baseline dose calculated on CT, which is comparable to doses calculated using site-specific HU-RED calibration curves. CONCLUSION iCBCT provides improved image quality, improved HU accuracy compared to CT baseline, and has potential to provide online dose verification as part of the adaptive radiotherapy workflow directly using the baseline HU-RED calibration curve from CT.
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Affiliation(s)
- Rebecca Lim
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Gregory P Penoncello
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA.,Department of Radiation Oncology, University of Colorado, Aurora, Colorado, USA
| | - Dean Hobbis
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA
| | | | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA
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12
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Pokhrel D, Webster A, Mallory R, Visak J, Bernard ME, McGarry RC, Kudrimoti M. Feasibility of using ring‐mounted Halcyon Linac for single‐isocenter/two‐lesion lung stereotactic body radiation therapy. J Appl Clin Med Phys 2022; 23:e13555. [PMID: 35128795 PMCID: PMC9121043 DOI: 10.1002/acm2.13555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 01/14/2022] [Accepted: 01/26/2022] [Indexed: 11/07/2022] Open
Affiliation(s)
- Damodar Pokhrel
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Aaron Webster
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Richard Mallory
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Justin Visak
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Mark E. Bernard
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Ronald C. McGarry
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Mahesh Kudrimoti
- Medical Physics Graduate ProgramDepartment of Radiation MedicineUniversity of KentuckyLexingtonKentuckyUSA
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13
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Zheng J, Xia Y, Sun L. A Comprehensive Evaluation of the Application of the Halcyon(2.0) IMRT Technique in Long-Course Radiotherapy for Rectal Cancer. Technol Cancer Res Treat 2022; 21:15330338221074501. [PMID: 35235486 PMCID: PMC8894964 DOI: 10.1177/15330338221074501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective: To evaluate if the Halcyon(2.0) Intensity Modulation Radiotherapy (IMRT) technique has an advantage in the long-course rectal cancer radiotherapy. Methods: A total of 20 clinical IMRT plans of Halcyon(2.0) for long-course (2Gy in 25 fractions) rectal cancer radiotherapy were randomly selected. Based on the parameters of these plans, 20 TrueBeam (with the Millennium 120 MLC) plans were redesigned, respectively. The dosimetry indexes, field complexity parameters, the Gamma Passing Rates (GPR), and the delivery time of the 2 groups of plans were obtained as measures of the plan quality, the modulation complexity, the delivery accuracy, and the delivery efficiency. The differences between the 2 groups of parameters were analyzed, with P < .05 means statistically significant. Results: In terms of dosimetry, there was no significant or clinical difference between the 2 groups in critical dosimetry parameters. The Monitor Unit of the Halcyon(2.0) fields is lower than the TrueBeam fields by 26.39, while the modulation complexity score (MCS), the mean aperture area variability (AAV), and the mean leaf sequence variability (LSV) of the Halcyon(2.0) fields were 23.8%, 20%, and 2.3% larger than those of the TrueBeam fields, respectively. Neither the ArcCheck-based GPRs nor the portal-dosimetry-based GPRs in both 3%/3 mm and 2%/2 mm criteria showed the difference between the Halcyon(2.0) fields and the TrueBeam fields. The Pearson correlation coefficient between GPR(2%/2 mm) and MCS of the Halcyon(2.0) fields was 0.335, while that of the TrueBeam fields was 0.502. The mean total delivery time of the TrueBeam plans was 195.55 ± 22.86 s, while that of Halcyon(2.0) was 124.25 ± 10.42 s (P < .001), which was reduced approximatively by 36%. Conclusion: For long-course rectal cancer radiotherapy, the Halcyon(2.0) IMRT plans behave almost the same in dosimetry and delivery accuracy as the TrueBeam plans. However, the lower MU and the field modulation complexity, combined with the higher delivery efficiency, make Halcyon(2.0) a feasible and reliable platform in long-course radiotherapy for the rectal cancer.
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Affiliation(s)
- Jiajun Zheng
- 26481Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Yuqing Xia
- 26481Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Li Sun
- 26481Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
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14
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Absolute dose measurements for lung gated delivery stereotactic body radiation therapy. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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15
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Visak J, Webster A, Bernard ME, Kudrimoti M, Randall ME, McGarry RC, Pokhrel D. Fast generation of lung SBRT plans with a knowledge-based planning model on ring-mounted Halcyon Linac. J Appl Clin Med Phys 2021; 22:54-63. [PMID: 34562308 PMCID: PMC8598154 DOI: 10.1002/acm2.13427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/23/2021] [Accepted: 09/07/2021] [Indexed: 12/31/2022] Open
Abstract
Purpose To demonstrate fast treatment planning feasibility of stereotactic body radiation therapy (SBRT) for centrally located lung tumors on Halcyon Linac via a previously validated knowledge‐based planning (KBP) model to support offline adaptive radiotherapy. Materials/methods Twenty previously treated non‐coplanar volumetric‐modulated arc therapy (VMAT) lung SBRT plans (c‐Truebeam) on SBRT‐dedicated C‐arm Truebeam Linac were selected. Patients received 50 Gy in five fractions. c‐Truebeam plans were re‐optimized for Halcyon manually (m‐Halcyon) and with KBP model (k‐Halcyon). Both m‐Halcyon and k‐Halcyon plans were normalized for identical or better target coverage than clinical c‐Truebeam plans and compared for target conformity, dose heterogeneity, dose fall‐off, and dose tolerances to the organs‐at‐risk (OAR). Treatment delivery parameters and planning times were evaluated. Results k‐Halcyon plans were dosimetrically similar or better than m‐Halcyon and c‐Truebeam plans. k‐Halcyon and m‐Halcyon plan comparisons are presented with respect to c‐Truebeam. Differences in conformity index were statistically insignificant in k‐Halcyon and on average 0.02 higher (p = 0.04) in m‐Halcyon plans. Gradient index was on average 0.43 (p = 0.006) lower and 0.27 (p = 0.02) higher for k‐Halcyon and m‐Halcyon, respectively. Maximal dose 2 cm away in any direction from target was statistically insignificant. k‐Halcyon increased maximal target dose on average by 2.9 Gy (p < 0.001). Mean lung dose was on average reduced by 0.10 Gy (p = 0.004) in k‐Halcyon and increased by 0.14 Gy (p < 0.001) in m‐Halcyon plans. k‐Halcyon plans lowered bronchial tree dose on average by 1.2 Gy. Beam‐on‐time (BOT) was increased by 2.85 and 1.67 min, on average for k‐Halcyon and m‐Halcyon, respectively. k‐Halcyon plans were generated in under 30 min compared to estimated dedicated 180 ± 30 min for m‐Halcyon or c‐Truebeam plan. Conclusion k‐Halcyon plans were generated in under 30 min with excellent plan quality. This adaptable KBP model supports high‐volume clinics in the expansion or transfer of lung SBRT patients to Halcyon.
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Affiliation(s)
- Justin Visak
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Aaron Webster
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mark E Bernard
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mahesh Kudrimoti
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Marcus E Randall
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Ronald C McGarry
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Damodar Pokhrel
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
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16
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Tamihardja J, Razinskas G, Exner F, Richter A, Kessler P, Weick S, Kraft J, Mantel F, Flentje M, Polat B. Comparison of treatment plans for hypofractionated high-dose prostate cancer radiotherapy using the Varian Halcyon and the Elekta Synergy platforms. J Appl Clin Med Phys 2021; 22:262-270. [PMID: 34351055 PMCID: PMC8425948 DOI: 10.1002/acm2.13380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/17/2021] [Accepted: 07/16/2021] [Indexed: 01/23/2023] Open
Abstract
Purpose To compare radiotherapy plans between an O‐ring and a conventional C‐arm linac for hypofractionated high‐dose prostate radiotherapy in terms of plan quality, dose distribution, and quality assurance in a multi‐vendor environment. Methods Twenty prostate cancer treatment plans were irradiated on the O‐ring Varian Halcyon linac and were re‐optimized for the C‐arm Elekta Synergy Agility linac. Dose‐volume histogram metrics for target coverage and organ at risk dose, quality assurance, and monitor units were retrospectively compared. Patient‐specific quality assurance with ion chamber measurements, gamma index analysis, and portal dosimetry was performed using the Varian Portal Dosimetry system and the ArcCHECK® phantom (Sun Nuclear Corporation). Prostate‐only radiotherapy was delivered with simultaneous integrated boost (SIB) volumetric modulated arc therapy (VMAT) in 20 fractions of 2.5/3.0 Gy each. Results For both linacs, target coverage was excellent and plan quality comparable. Homogeneity in PTVBoost was high for Synergy as well as Halcyon with a mean homogeneity index of 0.07 ± 0.01 and 0.05 ± 0.01, respectively. Mean dose for the organs at risk rectum and bladder differed not significantly between the linacs but were higher for the femoral heads and penile bulb for Halcyon. Quality assurance showed no significant differences in terms of ArcCHECK gamma pass rates. Median pass rate for 3%/2 mm was 99.3% (96.7 to 99.8%) for Synergy and 99.8% (95.6 to 100%) for Halcyon. Agreement between calculated and measured dose was high with a median deviation of −0.6% (−1.7 to 0.8%) for Synergy and 0.2% (−0.6 to 2.3%) for Halcyon. Monitor units were higher for the Halcyon by approximately 20% (p < 0.001). Conclusion Hypofractionated high‐dose prostate cancer SIB VMAT on the Halcyon system is feasible with comparable plan quality in reference to a standard C‐arm Elekta Synergy linac.
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Affiliation(s)
- Jörg Tamihardja
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Gary Razinskas
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Florian Exner
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Anne Richter
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Patrick Kessler
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Stefan Weick
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Johannes Kraft
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Frederick Mantel
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Michael Flentje
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
| | - Bülent Polat
- Department of Radiation Oncology, University of Würzburg, Würzburg, Germany
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Pokhrel D, Visak J. Letter to the Editor: In Response to Sarkar et al. J Appl Clin Med Phys 2021; 22:283-285. [PMID: 34043270 PMCID: PMC8200499 DOI: 10.1002/acm2.13277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 11/22/2022] Open
Affiliation(s)
- Damodar Pokhrel
- Department of Radiation Medicine, Medical Physics Graduate program, University of Kentucky, Lexington, KY, USA
| | - Justin Visak
- Department of Radiation Medicine, Medical Physics Graduate program, University of Kentucky, Lexington, KY, USA
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18
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Sarkar B, Ghosh T, Biswal SS, Shahid T, Ganesh T. In regards to Pokhrel et al. Clinical validation of ring-mounted halcyon linac for lung SBRT: Comparison to SBRT-dedicated C-arm linac treatments. JACMP 2021 Jan;22(1):261-70. J Appl Clin Med Phys 2021; 22:281-282. [PMID: 34042272 PMCID: PMC8200508 DOI: 10.1002/acm2.13273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 03/21/2021] [Accepted: 04/16/2021] [Indexed: 11/25/2022] Open
Affiliation(s)
- Biplab Sarkar
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India.,GLA University, Mathura, India
| | - Tanmay Ghosh
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
| | | | - Tanweer Shahid
- Department of Radiation Oncology, Apollo Multispeciality Hospitals, Kolkata, India
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