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Li J, Yang L, Yao X, Xu L, Zhao L, Bai F. A retrospective study on improving the accuracy of radiotherapy for patients with breast cancer with lymph node metastasis using Styrofoam. Radiol Oncol 2024; 58:124-132. [PMID: 38183274 PMCID: PMC10878773 DOI: 10.2478/raon-2024-0001] [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: 05/16/2023] [Accepted: 08/15/2023] [Indexed: 01/08/2024] Open
Abstract
BACKGROUND To retrospectively analyze the accuracy of radiotherapy using cone beam computed tomography (CBCT), Styrofoam fixation, and breast bracket fixation in the chest wall target area and supraclavicular lymphatic drainage area (supraclavicular target area) of patients with breast cancer.and compare the setting efficiency and comfort satisfaction. PATIENTS AND METHODS A total of 65 patients with postoperative lymphatic metastasis of breast cancer, including 36 cases of Styrofoam fixation and 29 cases of breast bracket fixation, were recruited from March 2021 to August 2022 and retrospectively analyzed. All the patients underwent CBCT scans weekly, and the setup errors of the chest wall and supraclavicular target volume were compared and recorded. The planning target volume (PTV) margins of the two groups were calculated using the correlation MPTV = 2.5Σ + 0.7σ. The setup time and comfort satisfaction scores of the two groups were recorded and analyzed. The correlations among errors in each direction were analyzed using the Pearson correlation analysis. RESULTS There was a significant difference in the left-right direction (X) axis of the chest wall target area between the Styrofoam and breast bracket groups (1.59 ± 1.47 mm vs. 2.05 ± 1.64 mm, P = 0.012). There were statistical differences in the ventrodorsal direction (Z) and bed angle of the supraclavicular target area, the data were (1.36 ± 1.27 mm vs. 1.75 ± 1.55 mm, P = 0.046; 0.47 ± 0.47° vs. 0.66 ± 0.59°, P = 0.006, respectively). In the X, Y, and Z directions, the respective PTV margins of the two groups in the chest wall target area were 5.01 mm, 5.99 mm, and 5.47 mm in the Styrofoam group, while those in the breast bracket group were 6.10 mm, 6.34 mm, and 6.10 mm, respectively. Moreover, the PTV margins of the supraclavicular target in the three directions were 3.69 mm, 3.86 mm, and 4.28 mm in the Styrofoam group, while those in the breast bracket group were 3.99 mm, 3.72 mm, and 5.45 mm, respectively. The setup time of the two groups was 3.4 ± 1.1 min and 5.5 ± 3.1 min (P = 0.007). The subjective comfort satisfaction scores of the two groups were 27.50 ± 1.24 and 25.44 ± 1.23 (P < 0.001). CONCLUSIONS The application of Styrofoam fixation in radiotherapy of breast cancer in the supraclavicular lymph node area has several advantages as compared to breast bracket fixation, including higher positioning accuracy, smaller external expansion boundary, improved work efficiency, and patients' comfort, which might provide a reference for clinical work.
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Affiliation(s)
- Jie Li
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China
| | - Lin Yang
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China
| | - Xiaowei Yao
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China
| | - Linlin Xu
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China
| | - Lina Zhao
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China
| | - Fei Bai
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China
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Xu H, Zhang Z, Tian B, Li X, Bian Y, Liang X, Bo C. Evaluation of corrective effect of 6 degree of freedom couch on setup errors in intensity modulated radiotherapy for postoperative rectal cancer patients. Front Oncol 2023; 13:1030599. [PMID: 36816975 PMCID: PMC9929531 DOI: 10.3389/fonc.2023.1030599] [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: 10/05/2022] [Accepted: 01/11/2023] [Indexed: 02/04/2023] Open
Abstract
Objective To explore the corrective effect of 6 degree of freedom couch on rotation errors in intensity modulated radiotherapy (IMRT) for postoperative rectal cancer patients, further to probe into the clinical application value of 6 degree of freedom couch in radiotherapy. Methods From January 1, 2020 to December 1, 2020, 30 patients with rectal cancer receiving postoperative intensity modulated radiotherapy in The First Hospital of Hebei Medical University were included in this retrospective study. The setup error values in all direction of patients before and after 6 degree of freedom correction were collected during each radiotherapy session. Results In this study, a total of 382 data before and after the correction of 6 degree of freedom couch were collected. It was found that the setup errors in the Y direction gradually increased, was maximal in the third week, and then became smaller, and the setup errors in the other directions increased with the extension of radiotherapy time and reached the maximum at the 5th week. In the translation direction, the setup errors value in Z direction occurred more frequently than that in X and Y directions between the range of 0.21-0.80 cm. In the rotation direction, the setup errors value in rotation X direction occurred more frequently than that in rotation Y and Z directions between the range of 0.21°-2.99°. In addition, after the correction of the 6 degree of freedom couch in real time, the setup errors in patients were significantly reduced in all directions (P < 0.05). Conclusion In summary, it was recommended to clinically use 6 degree of freedom couch combined with IMRT for real-time correction of placement errors in patients with rectal cancer undergoing radiotherapy. At the same time, it was necessary to observe the tumor size and body weight changes of patients on the 5th week. If necessary, radiotherapy positioning and planning should be performed in time.
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Xue J, Jin S, Zhang H, Zou K, Sheng J, Tang J, Zhao W, Yang P, Tang L, Lv X, Lv L. A simplified non-coplanar volumetric modulated arc therapy for the whole brain radiotherapy with hippocampus avoidance. Front Oncol 2023; 13:1143564. [PMID: 37152035 PMCID: PMC10155751 DOI: 10.3389/fonc.2023.1143564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/24/2023] [Indexed: 05/09/2023] Open
Abstract
Purpose To evaluate the feasibility of using a simplified non-coplanar volumetric modulated arc therapy (NC-VMAT) and investigate its dosimetric advantages compared with intensity modulated radiation therapy (IMRT) and coplanar volumetric modulated arc therapy (C-VMAT) for hippocampal-avoidance whole brain radiation therapy (HA-WBRT). Methods Ten patients with brain metastase (BM) were included for HA-WBRT. Three treatment plans were generated for each case using IMRT, C-VMAT, and NC-VMAT, respectively. Results The dosimetric results of the three techniques complied roughly with the RTOG 0933 criteria. After dose normalization, the V30Gy of whole brain planned target volume (WB-PTV) in all the plans was controlled at 95%. Homogeneity index (HI) of WB-PTV was significantly reduced in NC-VMAT (0.249 ± 0.017) over IMRT (0.265 ± 0.020, p=0.005) and C-VMAT (0.261 ± 0.014, p=0.020). In terms of conformity index (CI), NC-VMAT could provide a value of 0.821 ± 0.010, which was significantly superior to IMRT (0.788 ± 0.019, p<0.001). According to D2% of WB-PTV, NC-VMAT could provide a value of 35.62 ± 0.37Gy, significantly superior to IMRT (36.43 ± 0.65Gy, p<0.001). According to D50% of WB-PTV, NC-VMAT can achieve the lowest value of 33.18 ± 0.29Gy, significantly different from IMRT (33.47 ± 0.43, p=0.034) and C-VMAT (33.58 ± 0.37, p=0.006). Regarding D2%, D98%, and Dmean of hippocampus, NC-VMAT could control them at 15.57 ± 0.18Gy, 8.37 ± 0.26Gy and 11.71 ± 0.48Gy, respectively. D2% and Dmean of hippocampus for NC-VMAT was significantly lower than IMRT (D2%: 16.07 ± 0.29Gy, p=0.001 Dmean: 12.18 ± 0.33Gy, p<0.001) and C-VMAT (D2%: 15.92 ± 0.37Gy, p=0.009 Dmean: 12.21 ± 0.54Gy, p<0.001). For other organs-at-risk (OARs), according to D2% of the right optic nerves and the right lenses, NC-VMAT had the lowest values of 31.86 ± 1.11Gy and 7.15 ± 0.31Gy, respectively, which were statistically different from the other two techniques. For other organs including eyes and optic chiasm, NC-VMAT could achieve the lowest doses, different from IMRT statistically. Conclusion The dosimetry of the three techniques for HA-WBRT could roughly comply with the proposals from RTOG 0933. After dose normalization (D95%=30Gy), NC-VMAT could significantly improve dose homogeneity and reduce the D50% in the brain. Besides, it can reduce the D2% of the hippocampus, optic nerves, and lens. With this approach, an efficient and straightforward plan was accomplished.
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Affiliation(s)
- Juan Xue
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Sunian Jin
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Hongtao Zhang
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Kun Zou
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Junxiu Sheng
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Jinhai Tang
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Wanying Zhao
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Ping Yang
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Lufan Tang
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
| | - Xiupeng Lv
- The Department of Radiation Oncology, First Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
- *Correspondence: Xiupeng Lv, ; Li Lv,
| | - Li Lv
- The Department of Pathology, Second Affiliated Hospital, Dalian Medical University, Dalian, Liaoning, China
- *Correspondence: Xiupeng Lv, ; Li Lv,
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Hua W, Xu B, Zhang X, Zhang X, Chen T. Setup error and residual error analysis of ExacTrac X-ray image guidance system in stereotactic radiotherapy for brain metastases. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2022. [DOI: 10.1016/j.jrras.2022.100474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Positioning error analysis of the fraxion localization system in the intracranial stereotactic radiotherapy of tumors. Clin Transl Oncol 2020; 23:43-47. [PMID: 32462396 DOI: 10.1007/s12094-020-02382-y] [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: 03/18/2020] [Accepted: 05/10/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To investigate positioning error analysis of the Fraxion localization system in the intracranial stereotactic radiotherapy of tumors. METHODS 64 patients were divided into two groups: a control group (36 patients with the standard thermoplastic mask) and a model group (28 patients with the Fraxion localization system). 3D images of the treated position were obtained by cone-beam computed tomography (CBCT). Positioning errors were obtained by, respectively, registering these two sets of CBCT images to planning CT images, using a 6°-freedom robotic patient positioning system (HexaPOD Evo RT System). The changes in positioning errors with the Fraxion localization system and with the standard thermoplastic mask were analyzed. RESULTS CBCT scan results of the model group showed that the mean of linear error of three directions [superior-inferior (SI), lateral (LAT), and anterior-posterior (AP)] was 0.710 ± 0.676 mm, 0.817 ± 0.687 mm, and 0.710 ± 0.685 mm, respectively. The corresponding PTV was 1.23 mm, 1.26 mm, and 1.36 mm. The differences between the 3D images and the planned CT images were significant (p < 0.001). CONCLUSION The Fraxion radiotherapy system can not only improve the positioning accuracy and reduce positioning errors but also narrow the PTV margin and reduce the radiated volume of normal tissue.
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Wack LJ, Exner F, Wegener S, Sauer OA. The impact of isocentric shifts on delivery accuracy during the irradiation of small cerebral targets-Quantification and possible corrections. J Appl Clin Med Phys 2020; 21:56-64. [PMID: 32196950 PMCID: PMC7286018 DOI: 10.1002/acm2.12854] [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: 09/23/2019] [Revised: 01/26/2020] [Accepted: 02/07/2020] [Indexed: 11/13/2022] Open
Abstract
Purpose To assess the impact of isocenter shifts due to linac gantry and table rotation during cranial stereotactic radiosurgery on D98, target volume coverage (TVC), conformity (CI), and gradient index (GI). Methods Winston‐Lutz (WL) checks were performed on two Elekta Synergy linacs. A stereotactic quality assurance (QA) plan was applied to the ArcCHECK phantom to assess the impact of isocenter shift corrections on Gamma pass rates. These corrections included gantry sag, distance of collimator and couch axes to the gantry axis, and distance between cone‐beam computed tomography (CBCT) isocenter and treatment beam (MV) isocenter. We applied the shifts via script to the treatment plan in Pinnacle 16.2. In a planning study, isocenter and mechanical rotation axis shifts of 0.25 to 2 mm were applied to stereotactic plans of spherical planning target volumes (PTVs) of various volumes. The shifts determined via WL measurements were applied to 16 patient plans with PTV sizes between 0.22 and 10.4 cm3. Results ArcCHECK measurements of a stereotactic treatment showed significant increases in Gamma pass rate for all three measurements (up to 3.8 percentage points) after correction of measured isocenter deviations. For spherical targets of 1 cm3, CI was most severely affected by increasing the distance of the CBCT isocenter (1.22 to 1.62). Gradient index increased with an isocenter‐collimator axis distance of 1.5 mm (3.84 vs 4.62). D98 (normalized to reference) dropped to 0.85 (CBCT), 0.92 (table axis), 0.95 (collimator axis), and 0.98 (gantry sag), with similar but smaller changes for larger targets. Applying measured shifts to patient plans lead to relevant drops in D98 and TVC (7%) for targets below 2 cm3 treated on linac 1. Conclusion Mechanical deviations during gantry, collimator, and table rotation may adversely affect the treatment of small stereotactic lesions. Adjustments of beam isocenters in the treatment planning system (TPS) can be used to both quantify their impact and for prospective correction of treatment plans.
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Affiliation(s)
- Linda J Wack
- Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany
| | - Florian Exner
- Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany
| | - Sonja Wegener
- Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany
| | - Otto A Sauer
- Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany
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Flores-Martinez E, Cerviño LI, Pawlicki T, Kim GY. Assessment of the use of different imaging and delivery techniques for cranial treatments on the Halcyon linac. J Appl Clin Med Phys 2019; 21:53-61. [PMID: 31738473 PMCID: PMC6964767 DOI: 10.1002/acm2.12772] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/01/2019] [Accepted: 10/14/2019] [Indexed: 11/18/2022] Open
Abstract
Purpose In this work, we investigated the effect on the workflow and setup accuracy of using surface guided radiation therapy (SGRT) for patient setup, megavoltage cone beam CT (MVCBCT) or kilovoltage cone beam CT (kVCBCT) for imaging and fixed IMRT or volumetric‐modulated arc therapy (VMAT) for treatment delivery with the Halcyon linac. Methods We performed a retrospective investigation of 272 treatment fractions, using three different workflows. The first and second workflows used MVCBCT and fixed IMRT for imaging and treatment delivery, and the second one also used SGRT for patient setup. The third workflow used SGRT for setup, kVCBCT for imaging and VMAT for delivery. Workflows were evaluated by comparing the number of fractions requiring repeated imaging acquisitions and the time required for setup, imaging and treatment delivery. Setup position accuracy was assessed by comparing the daily kV‐ or MV‐ CBCT with the planning CT and measuring the residual rotational errors for pitch, yaw and roll angles. Results Without the use of SGRT, the imaging fields were delivered more than once on 11.1% of the fractions, while re‐imaging was necessary in 5.5% of the fractions using SGRT. The total treatment time, including setup, imaging, and delivery, for the three workflows was 531 ± 157 s, 503 ± 130 s and 457 ± 91 s, respectively. A statistically significant difference was observed when comparing the third workflow with the first two. The total residual rotational errors were 1.96 ± 1.29°, 1.28 ± 0.67° and 1.22 ± 0.76° and statistically significant differences were observed when comparing workflows with and without SGRT. Conclusions The use of SGRT allowed for a reduction of re‐imaging during patient setup and improved patient position accuracy by reducing residual rotational errors. A reduction in treatment time using kVCBCT with SGRT was observed. The most efficient workflow was the one including kVCBCT and SGRT for setup and VMAT for delivery.
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Affiliation(s)
- Everardo Flores-Martinez
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, USA
| | - Laura I Cerviño
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, USA
| | - Todd Pawlicki
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, USA
| | - Gwe-Ya Kim
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, USA
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Zani M, Marrazzo L, Calusi S, Talamonti C, Scoccianti S, Greto D, Desideri I, Fusi F, Pallotta S. TomoTherapy treatments of multiple brain lesions: an in-phantom accuracy evaluation. Phys Med Biol 2019; 64:025020. [PMID: 30561374 DOI: 10.1088/1361-6560/aaf977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aim of the present study was to evaluate the accuracy which can be obtained with helical TomoTherapy® (HT, Accuray) systems in the case of multiple intracranial targets treatments. Set-up accuracy was measured, for different registration options and MegaVoltage CT (MVCT) slice thickness, by applying known misalignments to an ad-hoc developed phantom. End-to-end (E2E) tests were performed to assess the delivery accuracy in phantoms containing multiple targets by using radiochromic films: measured dose distribution centroids were compared with physical and calculated target positions on axial and coronal planes. A Gamma index analysis was carried out on planned and measured planar dose maps. The bone and tissue algorithm with the fine MVCT reconstruction grid gave the best results among the automatic options. The most accurate registration modality resulted to be the manual one with a sub-voxel accuracy shifts and a capability in the detection of rotations within 0.3°. For the E2E along the coronal plane (six targets), a mean deviation between measured dose distribution centroids and physical barycenters of 0.6 mm (range 0.1 mm-1.3 mm) was observed. Along the axial plane (five targets), a mean deviation of 1.2 mm (range 0.7 mm-2.1 mm) was found for the centroids shifts. Gamma index (5%, 1 mm, local) passing rates higher than 87.5% between planned and delivered dose distributions were measured. These results demonstrate that multiple brain lesion HT treatments are feasible with an accuracy at least comparable to frameless linac-based delivery, when a set-up capable to assure angular corrections and a reliable patient immobilization is employed.
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Affiliation(s)
- M Zani
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', Viale Morgagni, 50, 50134 Firenze. Author to whom any correspondence should be addressed
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Tanabe S, Umetsu O, Sasage T, Utsunomiya S, Kuwabara R, Kuribayashi T, Takatou H, Kawaguchi G, Aoyama H. Clinical commissioning of a new patient positioning system, SyncTraX FX4, for intracranial stereotactic radiotherapy. J Appl Clin Med Phys 2018; 19:149-158. [PMID: 30273444 PMCID: PMC6236847 DOI: 10.1002/acm2.12467] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/04/2018] [Accepted: 09/09/2018] [Indexed: 12/04/2022] Open
Abstract
Background & Aims A new real‐time tracking radiotherapy (RTRT) system, the SyncTraX FX4 (Shimadzu, Kyoto, Japan), consisting of four X‐ray tubes and four ceiling‐mounted flat panel detectors (FPDs) combined with a linear accelerator, was installed at Uonuma Kikan Hospital (Niigata, Japan) for the first time worldwide. In addition to RTRT, the SyncTraX FX4 system enables bony structure‐based patient verification. Here we provide the first report of this system's clinical commissioning for intracranial stereotactic radiotherapy (SRT). Materials & Methods A total of five tests were performed for the commissioning: evaluations of (1) the system's image quality; (2) the imaging and treatment coordinate coincidence; and (3) the localization accuracy of cone‐beam computed tomography (CBCT) and SyncTraX FX4; (4) the measurement of air kerma; (5) an end‐to‐end test. Results & Discussion The tests revealed the following. (1) All image quality evaluation items satisfied each acceptable criterion in all FPDs. (2) The maximum offsets among the centers were ≤0.40 mm in all combinations of the FPD and X‐ray tubes (preset). (3) The isocenter localization discrepancies between CBCT and preset #3 in the SyncTraX FX4 system were 0.29 ± 0.084 mm for anterior‐posterior, −0.19 ± 0.13 mm for superior‐inferior, 0.076 ± 0.11 mm for left‐right, −0.11 ± 0.066° for rotation, −0.14 ± 0.064° for pitch, and 0.072±0.058° for roll direction. the Pearson's product‐moment correlation coefficient between the two systems was >0.98 in all directions. (4) The mean air kerma value for preset #3 was 0.11 ± 0.0002 mGy in predefined settings (80 kV, 200 mA, 50 msec). (5) For 16 combinations of gantry and couch angles, median offset value in all presets was 0.31 mm (range 0.14–0.57 mm). Conclusion Our results demonstrate a competent performance of the SyncTraX FX4 system in terms of the localization accuracy for intracranial SRT.
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Affiliation(s)
- Satoshi Tanabe
- Department of Radiation Oncology, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Osamu Umetsu
- Department of Radiation Oncology, Uonuma Kikan Hospital, Niigata, Japan
| | - Toshikazu Sasage
- Department of Radiation Oncology, Uonuma Kikan Hospital, Niigata, Japan
| | - Satoru Utsunomiya
- Department of Radiological Technology, Niigata University Graduate School of Health Sciences, Niigata, Japan
| | - Ryota Kuwabara
- Department of Radiation Oncology, Uonuma Kikan Hospital, Niigata, Japan
| | | | - Hiromasa Takatou
- Department of Radiation Oncology, Uonuma Kikan Hospital, Niigata, Japan
| | - Gen Kawaguchi
- Department of Radiation Oncology, Uonuma Kikan Hospital, Niigata, Japan
| | - Hidefumi Aoyama
- Department of Radiology and Radiation Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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