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Pruthi DS, Nagpal P, Pandey M. Effectiveness of 6D couch with daily cone beam computed tomography in reducing PTV margins for glioblastoma multiforme. J Neurosci Rural Pract 2023; 14:78-83. [PMID: 36891114 PMCID: PMC9943941 DOI: 10.25259/jnrp_2_2022] [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: 09/07/2022] [Accepted: 09/11/2022] [Indexed: 11/04/2022] Open
Abstract
Objectives Image-guided radiotherapy maximizes therapeutic index of brain irradiation by reducing setup errors during treatment. The aim of study was to analyze setup errors in the radiation treatment of glioblastoma multiforme and if decrease in planning target volume (PTV), margin is feasible using daily cone beam CT (CBCT) and 6D couch correction. Materials and Methods Twenty-one patients (630 fractions of radiotherapy) were studied in which corrections were made in 6° of freedom. We determined setup errors, impact of setup errors of initial three fractions CBCT versus rest of the treatment with daily CBCT, and mean difference in setup errors with or without application of 6D couch and volumetric benefit of reduction of PTV margin from 0.5 cm to 0.3 cm. Results The mean shift in the conventional directions, namely, vertical, longitudinal, and lateral was 0.17 cm, 0.19 cm, and 0.11 cm. There was significant change in vertical shift when first three fractions were compared with rest of the treatment with daily CBCT. When the effect of 6D couch was nullified, all directions showed increased error with longitudinal shift being significant. The number of setup errors of magnitude >0.3 cm was more significant when only conventional shifts were applied as compared with 6D couch. There was significant decrease in volume of brain parenchyma irradiated when margin of PTV was reduced from 0.5 cm to 0.3 cm. Conclusion Daily CBCT along with 6D couch correction can reduce setup error which allows reduction in PTV margin during radiotherapy planning in turn improving the therapeutic index.
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Affiliation(s)
| | - Puneet Nagpal
- Department of Radiation Oncology, Action Cancer Hospital, New Delhi, India
| | - Manish Pandey
- Department of Radiation Oncology, Action Cancer Hospital, New Delhi, India
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Rojas-López JA, Díaz Moreno RM, Venencia CD. Use of genetic algorithm for PTV optimization in single isocenter multiple metastases radiosurgery treatments with Brainlab Elements™. Phys Med 2021; 86:82-90. [PMID: 34062337 DOI: 10.1016/j.ejmp.2021.05.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/15/2021] [Accepted: 05/22/2021] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To optimize PTV margins for single isocenter multiple metastases stereotactic radiosurgery through a genetic algorithm (GA) that determines the maximum effective displacement of each target (GTV) due to rotations. METHOD 10 plans were optimized. The plans were created with Elements Multiple Mets™ (Brainlab AG, Munchen, Germany) from a predefined template. The mean number of metastases per plan was 5 ± 2 [3,9] and the mean volume of GTV was 1.1 ± 1.3 cc [0.02, 5.1]. PTV margin criterion was based on GTV-isocenter distance and target dimensions. The effective displacement to perform specific rotational combination (roll, pitch, yaw) was optimized by GA. The original plans were re-calculated using the PTV optimized margin and new dosimetric variations were obtained. The Dmean, D99, Paddick conformity index (PCI), gradient index (GI) and dose variations in healthy brain were studied. RESULTS Regarding targets located shorter than 50 mm from the isocenter, the maximum calculated displacement was 2.5 mm. The differences between both PTV margin criteria were statistically significant for Dmean (p = 0.0163), D99 (p = 0.0439), PCI (p = 0.0242), GI (p = 0.0160) and for healthy brain V12 (p = 0.0218) and V10 (p = 0.0264). CONCLUSION The GA allows to determine an optimized PTV margin based on the maximum displacement. Optimized PTV margins reduce the detriment of dosimetric parameters. Greater PTV margins are associated with an increase in healthy brain volume.
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Saenz D, Papanikolaou N, Zoros E, Pappas E, Reiner M, Chew LT, Lim HY, Hancock S, Nebelsky A, Njeh C, Anagnostopoulos G. Robustness of single-isocenter multiple-metastasis stereotactic radiosurgery end-to-end testing across institutions. JOURNAL OF RADIOSURGERY AND SBRT 2021; 7:223-232. [PMID: 33898086 PMCID: PMC8055241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
The accuracy of stereotactic radiosurgery (SRS) to multiple metastases with a single-isocenter using high definition dynamic radiosurgery (HDRS) was evaluated across institutions. An SRS plan was delivered at six HDRS-capable institutions to an anthropomorphic phantom consisting of point, film, and 3D-gel dosimeters. Direct dose comparison and gamma analysis were used to evaluate the accuracy. Point measurements averaged across institutions were within 1.2±0.5%. The average gamma passing rate in the film was 96.6±2.2% (3%/2 mm). For targets within 4 cm of the isocenter, the 3D dosimetric gel gamma passing rate averaged across institutions was >90% (3%/2 mm). The targeting accuracy of high definition dynamic radiosurgery assessed by geometrical offset of the center of dose distributions across multiple institutions in this study was within 1 mm for targets within 4 cm of isocenter. Across variations in clinical practice, comparable dosimetry and localization is possible with this treatment planning and delivery technique.
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Affiliation(s)
- Daniel Saenz
- University of Texas Health Science Center, San Antonio, TX, USA
| | | | - Emmanouil Zoros
- National and Kapodistrian University of Athens Medical School, Athens, Greece
| | | | | | | | | | - Sam Hancock
- Southeast Health, Cape Girardeau, Missouri, USA
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Shiinoki T, Fujii F, Yuasa Y, Nonomura T, Fujimoto K, Sera T, Tanaka H. Analysis of dosimetric impact of intrafraction translation and rotation during respiratory‐gated stereotactic body radiotherapy with real‐time tumor monitoring of the lung using a novel six degrees‐of‐freedom robotic moving phantom. Med Phys 2020; 47:3870-3881. [DOI: 10.1002/mp.14369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/02/2020] [Accepted: 06/23/2020] [Indexed: 12/26/2022] Open
Affiliation(s)
- Takehiro Shiinoki
- Department of Radiation Oncology Graduate School of Medicine Yamaguchi University 1‐1‐1 Minamikogushi Ube Yamaguchi755‐8505Japan
| | - Fumitake Fujii
- Department of Mechanical Engineering Graduate School of Science and Technology for Innovation Yamaguchi University 2‐16‐1 Tokiwadai Ube Yamaguchi755‐8611Japan
| | - Yuki Yuasa
- Department of Radiation Oncology Graduate School of Medicine Yamaguchi University 1‐1‐1 Minamikogushi Ube Yamaguchi755‐8505Japan
| | - Tatsuki Nonomura
- Department of Mechanical Engineering Graduate School of Science and Technology for Innovation Yamaguchi University 2‐16‐1 Tokiwadai Ube Yamaguchi755‐8611Japan
| | - Koya Fujimoto
- Department of Radiation Oncology Graduate School of Medicine Yamaguchi University 1‐1‐1 Minamikogushi Ube Yamaguchi755‐8505Japan
| | - Tatsuhiro Sera
- Department of Radiological Technology Yamaguchi University Hospital 1‐1‐1 Minamikogushi Ube Yamaguchi755‐8505Japan
| | - Hidekazu Tanaka
- Department of Radiation Oncology Graduate School of Medicine Yamaguchi University 1‐1‐1 Minamikogushi Ube Yamaguchi755‐8505Japan
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Swinnen ACC, Öllers MC, Loon Ong C, Verhaegen F. The potential of an optical surface tracking system in non-coplanar single isocenter treatments of multiple brain metastases. J Appl Clin Med Phys 2020; 21:63-72. [PMID: 32237274 PMCID: PMC7324699 DOI: 10.1002/acm2.12866] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/23/2020] [Accepted: 02/24/2020] [Indexed: 12/25/2022] Open
Abstract
To evaluate the accuracy of a commercial optical surface tracking (OST) system and to demonstrate how it can be implemented to monitor patient positioning during non‐coplanar single isocenter stereotactic treatments of brain metastases. A 3‐camera OST system was used (Catalyst HD™, C‐RAD) on a TruebeamSTx with a 6DoF couch. The setup accuracy and agreement between the OST system, and CBCT and kV‐MV imaging at couch angles 0° and 270°, respectively, were examined. Film measurements at 3 depths in the Rando‐Alderson phantom were performed using a single isocenter non‐coplanar VMAT plan containing 4 brain lesions. Setup of the phantom was performed with CBCT at couch 0° and subsequently monitored by OST at other couch angles. Setup data for 7 volunteers were collected to evaluate the accuracy and reproducibility of the OST system at couch angles 0°, 45°, 90°, 315°, and 270°. These results were also correlated to the couch rotation offsets obtained by a Winston‐Lutz (WL) test. The Rando‐Alderson phantom, as well as volunteers, were fixated using open face masks (Orfit). For repeated tests with the Rando‐Alderson phantom, deviations between rotational and translational isocenter corrections for CBCT and OST systems are always within 0.2° (pitch, roll, yaw), and 0.1mm and 0.5mm (longitudinal, lateral, vertical) for couch positions 0° and 270°, respectively. Dose deviations between the film and TPS doses in the center of the 4 lesions were −1.2%, −0.1%, −0.0%, and −1.9%. Local gamma evaluation criteria of 2%/2 mm and 3%/1 mm yielded pass rates of 99.2%, 99.2%, 98.6%, 89.9% and 98.8%, 97.5%, 81.7%, 78.1% for the 4 lesions. Regarding the volunteers, the mean translational and rotational isocenter shift values were (0.24 ± 0.09) mm and (0.15 ± 0.07) degrees. Largest isocenter shifts were found for couch angles 45˚ and 90˚, confirmed by WL couch rotation offsets. Patient monitoring during non‐coplanar VMAT treatments of brain metastases is feasible with submillimeter accuracy.
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Affiliation(s)
| | | | - Chin Loon Ong
- Department of Radiation Oncology, HagaZiekenhuis, Den Haag, the Netherlands
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6
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Independent 6D quality assurance of stereotactic radiotherapy repositioning on linacs. Cancer Radiother 2020; 24:199-205. [PMID: 32165115 DOI: 10.1016/j.canrad.2020.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/21/2020] [Accepted: 01/27/2020] [Indexed: 12/31/2022]
Abstract
PURPOSE A high level of accuracy while positioning the patient is mandatory for frameless stereotactic radiotherapy (SRT), as large doses in multiple fractions can be delivered near organs at risk. The objective of this study is to propose an end-to-end quality assurance method to verify that submillimetre alignment can be achieved with stereotactic conventional linacs. METHODS We used a TrueBeam® linear accelerator equipped with a 6DOF robotic couch. The "ISO Cube" phantom was used with a homemade stand designed to generate known translational and rotational offsets. A reference CT scan was performed with straight alignment of the phantom. The procedure introduced 1.6° angular offset for the couch pitch and roll, at various gantry angles. The couch base was also moved between 0° and 270°. We compared the results with the daily machine performance check tests (MPC, Varian). RESULTS The mean isocentre size, MV and kV imager offsets were found to agree to within 0.1mm, 0.1mm and 0.3mm respectively, and were in close agreement between the methods. For a total four months data collection period, the mean deviation between requested and measured 6DOF couch shifts was 0.6mm and 0.2°. Errors on field size were smaller than 1mm for 97.7% of the 324 data points. CONCLUSION Results demonstrate that the linac equipped with a 6DOF robotic positioner and CBCT imaging satisfies requirements for SRT. Our methodology, based on a modified Winston-Lutz quality control, allowed us to quantitatively assess end-to-end accuracy of a linac in order to safely deliver SRT.
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7
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Afzalifar A, Mowlavi AA, Mohammadi M. Performance of a linear accelerator couch positioning quality control task using an electronic portal imaging device. Radiol Phys Technol 2020; 13:195-200. [PMID: 32078138 DOI: 10.1007/s12194-020-00557-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 10/25/2022]
Abstract
Short and semi-automated quality assurance (QA) programs are becoming one of the most popular and highly demanding tasks in radiotherapy. The current research investigates the accuracy of a four degrees of freedom (4DoF) medical linear accelerator couch positioning with a fast and accurate method based on images acquired using an electronic portal imaging device (EPID). An accurate EPID QA phantom and a proper in-house code were used. A Siemens medical linear accelerator equipped with an a-Si EPID was used to acquire portal images. For verifying the mechanical performance of the EPID positioning, EPID sensitivity, and accuracy of the code response from the image processing point of view were investigated. To characterize the results, three deviations in the phantom positioning were deliberately created. The translational and rotational displacements of the treatment couch were then evaluated. The loading effect on the treatment couch was then investigated. The results of prerequisite tests, including the mechanical performance of the EPID, and the sensitivity and accuracy of the recognition codes, were assessed. The results were found to be within the tolerance range reported at AAPM TG-142. The mean deviations of the tests between expected and measured displacements by 4DoF treatment couch were found to be 0.13° ± 0.11°, 0.12 ± 0.17 mm, 0.17 ± 0.13 mm, and 0.04 ± 0.09 mm for rotational, longitudinal, lateral, and vertical shifts, respectively. The results showed that the proposed method is a reliable and fast approach to find the uncertainties occurring intreatment couch positioning.
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Affiliation(s)
- A Afzalifar
- Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran
| | - A A Mowlavi
- Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran.,ICTP, Associate Federation Scheme,, Medical Physics Field, Trieste, Italy
| | - M Mohammadi
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia. .,School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
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8
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Shimizu H, Sasaki K, Aoyama T, Matsushima S, Isomura T, Fukuma H, Tachibana H, Kodaira T. Development of twist‐correction system for radiotherapy of head and neck cancer patients. J Appl Clin Med Phys 2019; 20:128-134. [PMID: 31222881 PMCID: PMC6612693 DOI: 10.1002/acm2.12667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 04/04/2019] [Accepted: 05/05/2019] [Indexed: 11/09/2022] Open
Abstract
To propose a concept for correcting the twist between the head and neck and the body frequently occurring in radiotherapy patients and to develop a prototype device for achieving this. Furthermore, the operational accuracy of this device under no load was evaluated. We devised a concept for correcting the twist of patients by adjustment of the three rotation (pitch, roll, and yaw) angles in two independent plates connected by a joint (fulcrum). The two plates (head and neck plate and body plate) rotate around the fulcrum by adjusting screws under each of them. A prototype device was created to materialize this concept. First, after all adjusting screws were set to the zero position, the rotation angle of each plate was measured by a digital goniometer. Repeatability was evaluated by performing 20 repeated measurements. Next, to confirm the rotational accuracy of each plate of the prototype device, the calculated rotation angles for 20 combinations of patterns of traveled distances of the adjusting screws were compared with those measured by the digital goniometer and cone‐beam computed tomography (CT). The repeatability (standard deviation: SD) of the pitch, roll, and yaw angles of the head and neck plate was 0.04°, 0.05°, and 0.03°, and the repeatability (SD) of the body plate was 0.05°, 0.04°, and 0.04°, respectively. The mean differences ± SD between the calculated and measured pitch, roll, and yaw angles for the head and neck plate with the digital goniometer were 0.00 ± 0.06°, −0.01 ± 0.06°, and −0.04 ± 0.04°, respectively. The differences for the body plate were −0.03 ± 0.04°, 0.03 ± 0.05°, and 0.02 ± 0.05°, respectively. Results of the cone‐beam CT were similar to those of the digital goniometer. The prototype device exhibited good performance regarding the rotational accuracy and repeatability under no load. The clinical implementation of this concept is expected to reduce the residual error of the patient position due to the twist.
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Affiliation(s)
- Hidetoshi Shimizu
- Department of Radiation Oncology Aichi Cancer Center Hospital Aichi Japan
- Graduate School of Radiological Technology Gunma Prefectural College of Health Sciences Gunma Japan
| | - Koji Sasaki
- Graduate School of Radiological Technology Gunma Prefectural College of Health Sciences Gunma Japan
| | - Takahiro Aoyama
- Department of Radiation Oncology Aichi Cancer Center Hospital Aichi Japan
| | - Shigeru Matsushima
- Department of Diagnostic and Interventional Radiology Aichi Cancer Center Hospital Aichi Japan
| | - Taiki Isomura
- Department of Radiation Oncology Aichi Cancer Center Hospital Aichi Japan
| | - Hiroshi Fukuma
- Department of Radiology Nagoya City University Hospital Aichi Japan
| | - Hiroyuki Tachibana
- Department of Radiation Oncology Aichi Cancer Center Hospital Aichi Japan
| | - Takeshi Kodaira
- Department of Radiation Oncology Aichi Cancer Center Hospital Aichi Japan
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Usui K, Isobe A, Hara N, Muroi T, Sajiki O, Ogawa K, Shikama N, Sasai K. Development of a rotational set-up correction device for stereotactic head radiation therapy: A performance evaluation. J Appl Clin Med Phys 2019; 20:206-212. [PMID: 31112364 PMCID: PMC6560248 DOI: 10.1002/acm2.12616] [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] [Received: 10/15/2018] [Revised: 03/11/2019] [Accepted: 04/27/2019] [Indexed: 11/10/2022] Open
Abstract
We developed a new head supporting device to provide accurate correction of rotational setup during image-guided radiation therapy (IGRT), evaluating its correction performance and the efficacy of dose distribution in stereotactic radiotherapy (SRT) using a helical tomotherapy (HT) system. The accuracy of rotational motion was measured using an electronic inclinometer; we compared device angles and measurement values from 0.0° to 3.0°. The correction accuracy was investigated based on the distance between rotational centers in the device and on megavoltage computed tomography (MVCT); the correction values were compared using distances in the range of 0.0-9.0 cm using a head phantom with a rotational error of 1.5°. For an SRT with a simultaneous integrated boost plan and a rotational error of 3.0° in yaw angle using a head phantom, and for a single-isocenter SRT for multiple brain metastases in the data of three patients, dosimetric efficacy of the HT unit was evaluated for calculated dose distributions with MVCT after rotational correction. This device can correct pitch and yaw angles within 0.3° and can be corrected to within 0.5° for each rotational angle according to the result of MVCT correction regardless of the rotational center position. In the head phantom study, the device had a beneficial impact on rotational correction; D99% for the target improved by approximately 10% with rotational correction. Using patient data with the device, the mean difference based on the treatment planning data was 0.3% for D99% and -0.1% for coverage index to the target. Our rotational setup correction device has high efficacy, and can be used for IGRT.
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Affiliation(s)
- Keisuke Usui
- Department of Radiation Oncology, Juntendo University, Tokyo, Japan
| | - Akira Isobe
- Department of Radiology, Juntendo University Hospital, Tokyo, Japan
| | - Naoya Hara
- Department of Radiology, Juntendo University Hospital, Tokyo, Japan
| | - Tomoya Muroi
- Department of Radiology, Juntendo University Hospital, Tokyo, Japan
| | | | - Koichi Ogawa
- Faculty of Science and Engineering, Hosei University, Tokyo, Japan
| | - Naoto Shikama
- Department of Radiation Oncology, Juntendo University, Tokyo, Japan
| | - Keisuke Sasai
- Department of Radiation Oncology, Juntendo University, Tokyo, Japan
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A study for the dosimetric evaluation of rotational setup error for
lung stereotactic body radiation therapy. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396918000250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractPurposeTo investigate the necessity of rotational shifts by considering dosimetric
impact of rotational errors on stereotactic body radiation therapy
(SBRT).Materials and methods20 lung patients with the lesion size <5 cm treated with SBRT have
been selected for dosimetric analysis. Three-dimensional dose has been
rotationally shifted (±1°, ±3°,
±5° for pitch, roll and yaw) and overlaid to the original
computed tomography images. The dose–volume histograms of
18-rotational plans of each patient were compared to those of the original
plan.ResultsNo significant dosimetric differences were observed in target coverage. For
all of the cases up to 5° in any couch angle dose differences of
D99 and D95 were
<3%. Variations of conformity index were observed to be less
than 0·05. None of the organ at risk doses exceeded the dose limit.
The V20 differences of the ipsilateral and the
total lungs were less than 0·4%.ConclusionIt has been found to be unnecessary to perform rotational shifts up to
5° for lung SBRT treatments; the translational shift is sufficient
for the cases used in this study. This method may be applied and tested
after planning and before treatment initiation to rule out exceptionally
extreme cases.
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11
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Sadeghi P, Lincoln J, Avila Ruiz EA, Robar JL. A novel intra-fraction motion monitoring system for stereotactic radiosurgery: proof of concept. ACTA ACUST UNITED AC 2018; 63:165019. [DOI: 10.1088/1361-6560/aad643] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Using Smaller-Than-Standard Radiation Treatment Margins Does Not Change Survival Outcomes in Patients with High-Grade Gliomas. Pract Radiat Oncol 2018; 9:16-23. [PMID: 30195927 DOI: 10.1016/j.prro.2018.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/10/2018] [Accepted: 06/04/2018] [Indexed: 01/16/2023]
Abstract
PURPOSE The number of studies that evaluate treatment margins for high grade gliomas (HGG) are limited. We hypothesize that patients with HGG who are treated with a gross tumor volume (GTV) to planning tumor volume (PTV) expansion of ≤1 cm will have progression-free survival (PFS) and overall survival (OS) rates similar to those treated in accordance with standard protocols by the Radiation Therapy Oncology Group or European Organisation for Research and Treatment of Cancer. Furthermore, the PFS and OS of subgroups within the study population will have equivalent survival outcomes with GTV1-to-PTV1 margins of 1.0 cm and 0.4 cm. METHODS AND MATERIALS Treatment plans and outcomes for patients with pathologically confirmed HGG were analyzed (n = 267). Survival (PFS and OS) was calculated from the time of the first radiation treatment and a χ2 test or Fisher exact test was used to calculate the associations between margin size and patient characteristics. Survival was estimated using Kaplan-Meier and compared using the log-rank test. All analyses were performed on the univariate level. RESULTS The median PFS and OS times were 10.6 and 19.1 months, respectively. By disease, the median PFS and OS times were 8.6 and 16.1 months for glioblastoma and 26.7 and 52.5 months for anaplastic glioma. The median follow-up time was 18.3 months. The treatment margin had no effect on outcome and the 1.0 cm GTV1-PTV1 margin subgroup (n = 212) showed median PFS and OS times of 10.7 and 19.1 months, respectively, and the 0.4 cm margin subgroup (n = 55) 10.2 and 19.3 months, respectively. In comparison with the standard treatment with 2 cm to 3 cm margins, there was not a significant difference in outcomes. CONCLUSIONS There is no apparent difference in survival when utilizing smaller versus larger margins as defined by the guidelines of the Radiation Therapy Oncology Group and European Organisation for Research and Treatment of Cancer. Although there remains no class I evidence that outcomes after treatment with smaller margins are identical to those after treatment with larger margins, this large series with long-term follow up suggests that a reduction of the margins is safe and further investigation is warranted.
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Sarkar V, Paxton A, Szegedi MW, Zhao H, Huang L, Nelson G, Huang YHJ, Su F, Rassiah-Szegedi P, Salter BJ. An evaluation of the consistency of shifts reported by three different systems for non-coplanar treatments. JOURNAL OF RADIOSURGERY AND SBRT 2018; 5:323-330. [PMID: 30538893 PMCID: PMC6255716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/06/2018] [Indexed: 06/09/2023]
Abstract
Treatment of intra-cranial lesions sometimes requires a non-coplanar beam configuration. One of the most commonly used IGRT modalities, kV conebeam CT, cannot typically be used when large couch rotations are introduced. However, multiple other systems allow for imaging/tracking the patient for such situations. This work compares shift consistency from three independent systems, namely Varian's Advanced Imaging, Brainlab's Exactrac and Varian's OSMS, all installed on the same linear accelerator. After a phantom was first positioned using conebeam CT, the three systems were used to determine shifts at different couch positions. This was done with and without intentional shifts inserted in the original phantom position. Results show that the difference in shifts between the three systems was never more than 0.7 mm (average of 0.2 mm, standard deviation of 0.2 mm). These results confirm that all three systems are equivalent to within 1 mm and may potentially be uses interchangeably, especially in cases where the PTV margin is on the order of 1 mm.
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Affiliation(s)
- Vikren Sarkar
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | - Adam Paxton
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | - Martin W Szegedi
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | - Hui Zhao
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | - Long Huang
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | - Geoff Nelson
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Fanchi Su
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Bill J Salter
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT 84112, USA
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14
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Woods K, Ayan AS, Woollard J, Gupta N. Quality assurance for a six degrees-of-freedom table using a 3D printed phantom. J Appl Clin Med Phys 2017; 19:115-124. [PMID: 29159920 PMCID: PMC5768004 DOI: 10.1002/acm2.12227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/07/2017] [Accepted: 10/17/2017] [Indexed: 12/31/2022] Open
Abstract
Purpose To establish a streamlined end‐to‐end test of a 6 degrees‐of‐freedom (6DoF) robotic table using a 3D printed phantom for periodic quality assurance. Methods A 3D printed phantom was fabricated with translational and rotational offsets and an imbedded central ball‐bearing (BB). The phantom underwent each step of the radiation therapy process: CT simulation in a straight orientation, plan generation using the treatment planning software, setup to offset marks at the linac, registration and corrected 6DoF table adjustments via hidden target test, delivery of a Winston‐Lutz test to the BB, and verification of table positioning via field and laser lights. The registration values, maximum total displacement of the combined Winston‐Lutz fields, and a pass or fail criterion of the laser and field lights were recorded. The quality assurance process for each of the three linacs were performed for the first 30 days. Results Within a 95% confidence interval, the overall uncertainty values for both translation and rotation were below 1.0 mm and 0.5° for each linac respectively. When combining the registration values and other uncertainties for all three linacs, the average deviations were within 2.0 mm and 1.0° of the designed translation and rotation offsets of the 3D print respectively. For all three linacs, the maximum total deviation for the Winston‐Lutz test did not exceed 1.0 mm. Laser and light field verification was within tolerance every day for all three linacs given the latest guidance documentation for table repositioning. Conclusion The 3D printer is capable of accurately fabricating a quality assurance phantom for 6DoF positioning verification. The end‐to‐end workflow allows for a more efficient test of the 6DoF mechanics while including other important tests needed for routine quality assurance.
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Affiliation(s)
- Kyle Woods
- Department of Radiation Oncology, Ohio State University, Columbus, OH, USA
| | - Ahmet S Ayan
- Department of Radiation Oncology, Ohio State University, Columbus, OH, USA
| | - Jeffrey Woollard
- Department of Radiation Oncology, Ohio State University, Columbus, OH, USA
| | - Nilendu Gupta
- Department of Radiation Oncology, Ohio State University, Columbus, OH, USA
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Belcher AH, Liu X, Chmura S, Yenice K, Wiersma RD. Towards frameless maskless SRS through real-time 6DoF robotic motion compensation. Phys Med Biol 2017; 62:9054-9066. [PMID: 29131807 DOI: 10.1088/1361-6560/aa93d2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Stereotactic radiosurgery (SRS) uses precise dose placement to treat conditions of the CNS. Frame-based SRS uses a metal head ring fixed to the patient's skull to provide high treatment accuracy, but patient comfort and clinical workflow may suffer. Frameless SRS, while potentially more convenient, may increase uncertainty of treatment accuracy and be physiologically confining to some patients. By incorporating highly precise robotics and advanced software algorithms into frameless treatments, we present a novel frameless and maskless SRS system where a robot provides real-time 6DoF head motion stabilization allowing positional accuracies to match or exceed those of traditional frame-based SRS. A 6DoF parallel kinematics robot was developed and integrated with a real-time infrared camera in a closed loop configuration. A novel compensation algorithm was developed based on an iterative closest-path correction approach. The robotic SRS system was tested on six volunteers, whose motion was monitored and compensated for in real-time over 15 min simulated treatments. The system's effectiveness in maintaining the target's 6DoF position within preset thresholds was determined by comparing volunteer head motion with and without compensation. Comparing corrected and uncorrected motion, the 6DoF robotic system showed an overall improvement factor of 21 in terms of maintaining target position within 0.5 mm and 0.5 degree thresholds. Although the system's effectiveness varied among the volunteers examined, for all volunteers tested the target position remained within the preset tolerances 99.0% of the time when robotic stabilization was used, compared to 4.7% without robotic stabilization. The pre-clinical robotic SRS compensation system was found to be effective at responding to sub-millimeter and sub-degree cranial motions for all volunteers examined. The system's success with volunteers has demonstrated its capability for implementation with frameless and maskless SRS treatments, potentially able to achieve the same or better treatment accuracies compared to traditional frame-based approaches.
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Affiliation(s)
- Andrew H Belcher
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL 60637-1470, United States of America
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Denton TR, Shields LB, Howe JN, Shanks TS, Spalding AC. Practical considerations of linear accelerator-based frameless extracranial radiosurgery for treatment of occipital neuralgia for nonsurgical candidates. J Appl Clin Med Phys 2017; 18:123-132. [PMID: 28517492 PMCID: PMC5874950 DOI: 10.1002/acm2.12105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/02/2017] [Accepted: 04/10/2017] [Indexed: 12/31/2022] Open
Abstract
Occipital neuralgia generally responds to medical or invasive procedures. Repeated invasive procedures generate increasing complications and are often contraindicated. Stereotactic radiosurgery (SRS) has not been reported as a treatment option largely due to the extracranial nature of the target as opposed to the similar, more established trigeminal neuralgia. A dedicated phantom study was conducted to determine the optimum imaging studies, fusion matrices, and treatment planning parameters to target the C2 dorsal root ganglion which forms the occipital nerve. The conditions created from the phantom were applied to a patient with medically and surgically refractory occipital neuralgia. A dose of 80 Gy in one fraction was prescribed to the C2 occipital dorsal root ganglion. The phantom study resulted in a treatment achieved with an average translational magnitude of correction of 1.35 mm with an acceptable tolerance of 0.5 mm and an average rotational magnitude of correction of 0.4° with an acceptable tolerance of 1.0°. For the patient, the spinal cord was 12.0 mm at its closest distance to the isocenter and received a maximum dose of 3.36 Gy, a dose to 0.35 cc of 1.84 Gy, and a dose to 1.2 cc of 0.79 Gy. The brain maximum dose was 2.20 Gy. Treatment time was 59 min for 18, 323 MUs. Imaging was performed prior to each arc delivery resulting in 21 imaging sessions. The average deviation magnitude requiring a positional or rotational correction was 0.96 ± 0.25 mm, 0.8 ± 0.41°, whereas the average deviation magnitude deemed within tolerance was 0.41 ± 0.12 mm, 0.57 ± 0.28°. Dedicated quality assurance of the treatment planning and delivery is necessary for safe and accurate SRS to the cervical spine dorsal root ganglion. With additional prospective study, linear accelerator-based frameless radiosurgery can provide an accurate, noninvasive alternative for treating occipital neuralgia where an invasive procedure is contraindicated.
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Affiliation(s)
- Travis R. Denton
- The Norton Cancer Institute Radiation CenterNorton HealthcareLouisvilleKYUSA
- Associates in Medical PhysicsLLCGreenbeltMDUSA
| | - Lisa B.E. Shields
- The Norton Cancer Institute Radiation CenterNorton HealthcareLouisvilleKYUSA
- Norton Neuroscience InstituteLouisvilleKYUSA
- The Brain Tumor CenterNorton HealthcareLouisvilleKYUSA
| | - Jonathan N. Howe
- The Norton Cancer Institute Radiation CenterNorton HealthcareLouisvilleKYUSA
- Associates in Medical PhysicsLLCGreenbeltMDUSA
| | - Todd S. Shanks
- The Norton Cancer Institute Radiation CenterNorton HealthcareLouisvilleKYUSA
- Norton Neuroscience InstituteLouisvilleKYUSA
- The Brain Tumor CenterNorton HealthcareLouisvilleKYUSA
| | - Aaron C. Spalding
- The Norton Cancer Institute Radiation CenterNorton HealthcareLouisvilleKYUSA
- Norton Neuroscience InstituteLouisvilleKYUSA
- The Brain Tumor CenterNorton HealthcareLouisvilleKYUSA
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17
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Li J, Shi W, Andrews D, Werner-Wasik M, Lu B, Yu Y, Dicker A, Liu H. Comparison of Online 6 Degree-of-Freedom Image Registration of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Intracranial Radiosurgery. Technol Cancer Res Treat 2017; 16:339-343. [PMID: 28462690 PMCID: PMC5616049 DOI: 10.1177/1533034616683069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
PURPOSE The study was aimed to compare online 6 degree-of-freedom image registrations of TrueBeam cone-beam computed tomography and BrainLab ExacTrac X-ray imaging systems for intracranial radiosurgery. METHODS Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (version 2.5), which is integrated with a BrainLab ExacTrac imaging system (version 6.1.1). The phantom study was based on a Rando head phantom and was designed to evaluate isocenter location dependence of the image registrations. Ten isocenters at various locations representing clinical treatment sites were selected in the phantom. Cone-beam computed tomography and ExacTrac X-ray images were taken when the phantom was located at each isocenter. The patient study included 34 patients. Cone-beam computed tomography and ExacTrac X-ray images were taken at each patient's treatment position. The 6 degree-of-freedom image registrations were performed on cone-beam computed tomography and ExacTrac, and residual errors calculated from cone-beam computed tomography and ExacTrac were compared. RESULTS In the phantom study, the average residual error differences (absolute values) between cone-beam computed tomography and ExacTrac image registrations were 0.17 ± 0.11 mm, 0.36 ± 0.20 mm, and 0.25 ± 0.11 mm in the vertical, longitudinal, and lateral directions, respectively. The average residual error differences in the rotation, roll, and pitch were 0.34° ± 0.08°, 0.13° ± 0.09°, and 0.12° ± 0.10°, respectively. In the patient study, the average residual error differences in the vertical, longitudinal, and lateral directions were 0.20 ± 0.16 mm, 0.30 ± 0.18 mm, 0.21 ± 0.18 mm, respectively. The average residual error differences in the rotation, roll, and pitch were 0.40°± 0.16°, 0.17° ± 0.13°, and 0.20° ± 0.14°, respectively. Overall, the average residual error differences were <0.4 mm in the translational directions and <0.5° in the rotational directions. ExacTrac X-ray image registration is comparable to TrueBeam cone-beam computed tomography image registration in intracranial treatments.
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Affiliation(s)
- Jun Li
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Wenyin Shi
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - David Andrews
- 2 Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, USA
| | - Maria Werner-Wasik
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Bo Lu
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Yan Yu
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Adam Dicker
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Haisong Liu
- 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
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Boman E, Kapanen M, Laaksomaa M, Mäenpää H, Hyödynmaa S, Kellokumpu-Lehtinen PL. Treatment accuracy without rotational setup corrections in intracranial SRT. J Appl Clin Med Phys 2016; 17:86-94. [PMID: 27455488 PMCID: PMC5690032 DOI: 10.1120/jacmp.v17i4.6149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/23/2016] [Accepted: 02/22/2016] [Indexed: 11/30/2022] Open
Abstract
The aim of this study was to evaluate the impact of actual rotational setup errors on dose distributions in intracranial stereotactic radiotherapy (SRT) with different alternatives for treatment position selection. A total of 38 SRT fractions from 18 patients were retrospectively evaluated with rotational setup errors obtained from actual treatments. The planning computed tomography (CT) images were rotated according to online cone‐beam CT (CBCT) images and the dose distribution was recalculated to the rotated CT images using three different patient positionings derived from: 1) an automatic 6D match neglecting rotation correction (Auto6D); 2) an automatic 3D match (Auto3D); and 3) a manual 3D match from actual treatment (Treat3D). The mean conformity index (CI) was 0.92 for the original plans and 0.91 for the Auto6D plans. The mean CI decreased significantly (p<0.01) to 0.78 and 0.80 for the Auto3D and the Treat3D plans, respectively. The mean minimum dose of the planning target volume (PTVmin) was 91.9% of the prescribed dose for the original plans and 92.1% for the Auto6D plans, while for the Auto3D and the Treat3D plans PTVmin decreased significantly (p<0.01) to 78.9% and 80.2%, respectively. No significant differences were seen between the Auto6D and the original treatment plans in terms of the dose parameters. However, the Auto3D and the Treat3D plans were statistically significantly inferior (p<0.01) to the Auto6D and the original plans. In addition, a significant negative correlation (p<0.01,|r|>0.38) was found in the Auto3D and the Treat3D cases between the rotation error and CI, PTVmin or minimum dose of gross tumour volume. In SRT, a treatment plan of comparable quality to 6D rotation correction can be achieved by using 6D registration without a rotational correction in the selection of patient positioning. This was demonstrated for typical rotation errors seen in clinical practice. PACS number(s): 87.55, 87.57
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19
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Wernicke AG, Yondorf MZ, Parashar B, Nori D, Clifford Chao KS, Boockvar JA, Pannullo S, Stieg P, Schwartz TH. The cost-effectiveness of surgical resection and cesium-131 intraoperative brachytherapy versus surgical resection and stereotactic radiosurgery in the treatment of metastatic brain tumors. J Neurooncol 2016; 127:145-53. [DOI: 10.1007/s11060-015-2026-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 12/24/2015] [Indexed: 10/22/2022]
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20
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Sager O, Dincoglan F, Beyzadeoglu M. Stereotactic radiosurgery of glomus jugulare tumors: current concepts, recent advances and future perspectives. CNS Oncol 2015; 4:105-14. [PMID: 25768334 DOI: 10.2217/cns.14.56] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Stereotactic radiosurgery (SRS), a very highly focused form of therapeutic irradiation, has been widely recognized as a viable treatment option in the management of intracranial pathologies including benign tumors, malign tumors, vascular malformations and functional disorders. The applications of SRS are continuously expanding thanks to the ever-increasing advances and corresponding improvements in neuroimaging, radiation treatment techniques, equipment, treatment planning and delivery systems. In the context of glomus jugulare tumors (GJT), SRS is being more increasingly used both as the upfront management modality or as a complementary or salvage treatment option. As its safety and efficacy is being evident with compiling data from studies with longer follow-up durations, SRS appears to take the lead in the management of most patients with GJT. Herein, we address current concepts, recent advances and future perspectives in SRS of GJT in light of the literature.
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Affiliation(s)
- Omer Sager
- Department of Radiation Oncology, Gulhane Military Medical Academy, Gn. Tevfik Saglam Cad. 06018, Etlik, Kecioren, Ankara, Turkey
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21
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Martens D, Luesink M, Huizenga H, Pasma KL. eNAL++: a new and effective off-line correction protocol for rotational setup errors when using a robotic couch. J Appl Clin Med Phys 2015; 16:177-185. [PMID: 26699569 PMCID: PMC5690996 DOI: 10.1120/jacmp.v16i6.5583] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 08/26/2015] [Accepted: 07/22/2015] [Indexed: 12/25/2022] Open
Abstract
Cone‐beam CTs (CBCTs) installed on a linear accelerator can be used to provide fast and accurate automatic six degrees of freedom (6DoF) vector displacement information of the patient position just prior to radiotherapy. These displacement corrections can be made with 6DoF couches, which are primarily used for patient setup correction during stereotactic treatments. When position corrections are performed daily prior to treatment, the correction is deemed "online". However, the interface between the first generation 6DoF couches and the imaging software is suboptimal. The system requires the user to select manually the patient and type the match result by hand. The introduction of 6DoF setup correction for treatments, other than stereotactic radiotherapy, is hindered by both the high workload associated with the online protocol and the interface issues. For these reasons, we developed software that fully integrates the 6DoF couch with the linear accelerator. To further reduce both the workload and imaging dose, three off‐line 6DoF correction protocols were analyzed. While the protocols require significantly less imaging, the analysis assessed their ability to reduce the systematic rotation setup correction. CBCT scans were acquired for 19 patients with intracranial meningioma. The total number of CBCT scans was 856, acquired before and after radiotherapy treatment fractions. The patient positions were corrected online using a 6DoF robotic couch. The effects on the residual rotational setup error for three off‐line protocols were simulated. The three protocols used were two known off‐line protocols, the no action level (NAL) and the extended no action level (eNAL), and one new off‐line protocol (eNAL++). The residual setup errors were compared using the systematic and random components of the total setup error. The reduction of the rotational setup error of these protocols was optimized with respect to the required workload (i.e., number of CBCTs required). Rotational errors up to 3.2° were found after initial patient setup. The eNAL++ protocol achieved a reduction of the systematic rotational setup error similar to that of the online protocol (pitch from 0.8° to 0.3°), while requiring 70% fewer CBCTs. With a 6DoF robotic couch, translation, and rotation patient position corrections can be performed off‐line to reduce the systematic setup error, workload, and patient scan dose. PACS numbers: 87.56.Fc, 87.56.Da, 87.57.‐s
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22
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Belcher AH, Liu X, Grelewicz Z, Pearson E, Wiersma RD. Development of a 6DOF robotic motion phantom for radiation therapy. Med Phys 2015; 41:121704. [PMID: 25471951 DOI: 10.1118/1.4900828] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The use of medical technology capable of tracking patient motion or positioning patients along 6 degree-of-freedom (6DOF) has steadily increased in the field of radiation therapy. However, due to the complex nature of tracking and performing 6DOF motion, it is critical that such technology is properly verified to be operating within specifications in order to ensure patient safety. In this study, a robotic motion phantom is presented that can be programmed to perform highly accurate motion along any X (left-right), Y (superior-inferior), Z (anterior-posterior), pitch (around X), roll (around Y), and yaw (around Z) axes. In addition, highly synchronized motion along all axes can be performed in order to simulate the dynamic motion of a tumor in 6D. The accuracy and reproducibility of this 6D motion were characterized. METHODS An in-house designed and built 6D robotic motion phantom was constructed following the Stewart-Gough parallel kinematics platform archetype. The device was controlled using an inverse kinematics formulation, and precise movements in all 6 degrees-of-freedom (X, Y, Z, pitch, roll, and yaw) were performed, both simultaneously and separately for each degree-of-freedom. Additionally, previously recorded 6D cranial and prostate motions were effectively executed. The robotic phantom movements were verified using a 15 fps 6D infrared marker tracking system and the measured trajectories were compared quantitatively to the intended input trajectories. The workspace, maximum 6D velocity, backlash, and weight load capabilities of the system were also established. RESULTS Evaluation of the 6D platform demonstrated translational root mean square error (RMSE) values of 0.14, 0.22, and 0.08 mm over 20 mm in X and Y and 10 mm in Z, respectively, and rotational RMSE values of 0.16°, 0.06°, and 0.08° over 10° of pitch, roll, and yaw, respectively. The robotic stage also effectively performed controlled 6D motions, as well as reproduced cranial trajectories over 15 min, with a maximal RMSE of 0.04 mm translationally and 0.04° rotationally, and a prostate trajectory over 2 min, with a maximal RMSE of 0.06 mm translationally and 0.04° rotationally. CONCLUSIONS This 6D robotic phantom has proven to be accurate under clinical standards and capable of reproducing tumor motion in 6D. Such functionality makes the robotic phantom usable for either quality assurance or research purposes.
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Affiliation(s)
- Andrew H Belcher
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637-1470
| | - Xinmin Liu
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637-1470
| | - Zachary Grelewicz
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637-1470
| | - Erik Pearson
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637-1470
| | - Rodney D Wiersma
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637-1470
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Mancosu P, Reggiori G, Gaudino A, Lobefalo F, Paganini L, Palumbo V, Stravato A, Tomatis S, Scorsetti M. Are pitch and roll compensations required in all pathologies? A data analysis of 2945 fractions. Br J Radiol 2015; 88:20150468. [PMID: 26393283 PMCID: PMC4743463 DOI: 10.1259/bjr.20150468] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/10/2015] [Accepted: 09/16/2015] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE New linear accelerators can be equipped with a 6D robotic couch, providing two additional rotational motion axes: pitch and roll. These shifts in kilo voltage-cone beam CT (kV-CBCT) image-guided radiotherapy (IGRT) were evaluated over the first 6 months of usage of a 6D robotic couch-top, ranking the treatment sites for which the two compensations are larger for patient set-up. METHODS The couch compensations of 2945 fractions for 376 consecutive patients treated on the PerfectPitch™ 6D couch (Varian(®) Medical Systems, Palo Alto, CA) were analysed. Among these patients, 169 were treated for brain, 111 for lung, 54 for liver, 26 for pancreas and 16 for prostate tumours. During the set-up, patient anatomy from planning CT was aligned to kV-CBCT, and 6D movements were executed. Information related to pitch and roll were extracted by proper querying of the Microsoft(®) SQL server (Microsoft Corporation, Redmond, WA) ARIA database (Varian Medical Systems). Mean values and standard deviations were calculated for all sites. Kolmogorov-Smirnov (KS) test was performed. RESULTS Considering all the data, mean pitch and roll adjustments were -0.10° ± 0.92° and 0.12° ± 0.96°, respectively; mean absolute values for both adjustments were 0.58° ± 0.69° and 0.69° ± 0.72°, respectively. Brain treatments showed the highest mean absolute values for pitch and roll rotations (0.73° ± 0.69° and 0.80° ± 0.78°, respectively); the lowest values of 0.36° ± 0.47° and 0.49° ± 0.58° were found for pancreas. KS test was significant for brain vs liver, pancreas and prostate. Collective corrections (pitch + roll) >0.5°, >1.0° and >2.0° were observed in, respectively, 79.8%, 61.0% and 29.1% for brain and 56.7%, 39.4% and 6.7% for pancreas. CONCLUSION Adjustments in all six dimensions, including unconventional pitch and roll rotations, improve the patient set-up in all treatment sites. The greatest improvement was observed for patients with brain tumours. ADVANCES IN KNOWLEDGE To our knowledge, this is the first systematic evaluation of the clinical efficacy of a 6D Robotic couch-top in CBCT IGRT over different tumour regions.
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Affiliation(s)
- Pietro Mancosu
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Giacomo Reggiori
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Anna Gaudino
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Francesca Lobefalo
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Lucia Paganini
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Valentina Palumbo
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Antonella Stravato
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Stefano Tomatis
- Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan, Italy
| | - Marta Scorsetti
- Radiation Oncology Department, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
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Roper J, Chanyavanich V, Betzel G, Switchenko J, Dhabaan A. Single-Isocenter Multiple-Target Stereotactic Radiosurgery: Risk of Compromised Coverage. Int J Radiat Oncol Biol Phys 2015; 93:540-6. [PMID: 26460996 DOI: 10.1016/j.ijrobp.2015.07.2262] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 06/12/2015] [Accepted: 07/09/2015] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine the dosimetric effects of rotational errors on target coverage using volumetric modulated arc therapy (VMAT) for multitarget stereotactic radiosurgery (SRS). METHODS AND MATERIALS This retrospective study included 50 SRS cases, each with 2 intracranial planning target volumes (PTVs). Both PTVs were planned for simultaneous treatment to 21 Gy using a single-isocenter, noncoplanar VMAT SRS technique. Rotational errors of 0.5°, 1.0°, and 2.0° were simulated about all axes. The dose to 95% of the PTV (D95) and the volume covered by 95% of the prescribed dose (V95) were evaluated using multivariate analysis to determine how PTV coverage was related to PTV volume, PTV separation, and rotational error. RESULTS At 0.5° rotational error, D95 values and V95 coverage rates were ≥95% in all cases. For rotational errors of 1.0°, 7% of targets had D95 and V95 values <95%. Coverage worsened substantially when the rotational error increased to 2.0°: D95 and V95 values were >95% for only 63% of the targets. Multivariate analysis showed that PTV volume and distance to isocenter were strong predictors of target coverage. CONCLUSIONS The effects of rotational errors on target coverage were studied across a broad range of SRS cases. In general, the risk of compromised coverage increased with decreasing target volume, increasing rotational error and increasing distance between targets. Multivariate regression models from this study may be used to quantify the dosimetric effects of rotational errors on target coverage given patient-specific input parameters of PTV volume and distance to isocenter.
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Affiliation(s)
- Justin Roper
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia; Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia.
| | - Vorakarn Chanyavanich
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia; Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Gregory Betzel
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia; Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Jeffrey Switchenko
- Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia
| | - Anees Dhabaan
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia; Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia
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Dieterich S, Zwingenberger A, Hansen K, Pfeiffer I, Théon A, Kent MS. INTER- AND INTRAFRACTION MOTION FOR STEREOTACTIC RADIOSURGERY IN DOGS AND CATS USING A MODIFIED BRAINLAB FRAMELESS STEREOTACTIC MASK SYSTEM. Vet Radiol Ultrasound 2015; 56:563-9. [DOI: 10.1111/vru.12271] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 04/05/2015] [Indexed: 12/27/2022] Open
Affiliation(s)
- Sonja Dieterich
- Department of Radiation Oncology; UC Davis School of Medicine; Sacramento CA
| | - Allison Zwingenberger
- Department of Surgical and Radiological Sciences; UC Davis School of Veterinary Medicine 1 Shields Ave; Davis CA
| | - Katherine Hansen
- Department of Surgical and Radiological Sciences; UC Davis School of Veterinary Medicine 1 Shields Ave; Davis CA
| | - Isabella Pfeiffer
- The William R. Prichard Veterinary Medical Teaching Hospital; UC Davis School of Veterinary Medicine 1 Shields Ave; Davis CA
| | - Alain Théon
- Department of Surgical and Radiological Sciences; UC Davis School of Veterinary Medicine 1 Shields Ave; Davis CA
| | - Michael S. Kent
- Department of Surgical and Radiological Sciences; UC Davis School of Veterinary Medicine 1 Shields Ave; Davis CA
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Hypofractionated radiosurgery has a better safety profile than single fraction radiosurgery for large resected brain metastases. J Neurooncol 2015; 123:103-11. [PMID: 25862006 DOI: 10.1007/s11060-015-1767-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 04/02/2015] [Indexed: 11/12/2022]
Abstract
The purpose of this study is to compare the safety and efficacy of single fraction radiosurgery (SFR) with hypofractionated radiosurgery (HR) for the adjuvant treatment of large, surgically resected brain metastases. Seventy-five patients with 76 resection cavities ≥ 3 cm received 15 Gray (Gy) × 1 SFR (n = 40) or 5-8 Gy × 3-5 HR (n = 36). Cumulative incidence of local failure (LF) and radiation necrosis (RN) was estimated accounting for death as a competing risk and compared with Gray's test. The effect of multiple covariates was evaluated with the Fine-Gray proportional hazards model. The most common HR dose-fractionation schedules were 6 Gy × 5 (44%), 7-8 Gy × 3 (36%), and 6 Gy × 4 (8%). The median follow-up was 11 months (range 2-71). HR patients had larger median resection cavity volumes (24.0 vs. 13.3 cc, p < 0.001), planning target volumes (PTV) (37.7 vs. 20.5 cc, p < 0.001), and cavity to PTV expansion margins (2 vs. 1.5 mm, p = 0.002) than SFR patients. Cumulative incidence of LF (95% CI) at 6 and 12-months for HR versus SFR was 18.9% (0.07-0.34) versus 15.9% (0.06-0.29), and 25.6% (0.12-0.42) versus 27.2% (0.14-0.42), p = 0.80. Cumulative incidence of RN (95% CI) at 6 and 12 months for HR vs. SFR was 3.3% (0.00-0.15) versus 10.7% (0.03-0.23), and 10.3% (0.02-0.25) versus 19.2% (0.08-0.34), p = 0.28. On multivariable analysis, SFR was significantly associated with an increased risk of RN, with a HR of 3.81 (95% CI 1.04-13.93, p = 0.043). Hypofractionated radiosurgery may be the more favorable treatment approach for radiosurgery of cavities 3-4 cm in size and greater.
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Denton TR, Shields LBE, Howe JN, Spalding AC. Quantifying isocenter measurements to establish clinically meaningful thresholds. J Appl Clin Med Phys 2015; 16:5183. [PMID: 26103187 PMCID: PMC5690087 DOI: 10.1120/jacmp.v16i2.5183] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/23/2014] [Accepted: 11/23/2014] [Indexed: 11/23/2022] Open
Abstract
A dataset range of isocenter congruency verification tests have been examined from a statistical perspective for the purpose of establishing tolerance levels that are meaningful, based on the fundamental limitation of linear accelerator isocentricity and the demands of a high-precision stereotactic radiosurgery program. Using a laser-defined isocenter, a total of 149 individual isocenter congruency tests were examined with recorded values for ideal spatial corrections to the isocenter test tool. These spatial corrections were determined from radiation exposures recorded on an electronic portal imaging device (EPID) at various gantry, collimator, and treatment couch combinations. The limitations of establishing an ideal isocenter were quantified from each variable which contributed to uncertainty in isocenter definition. Individual contributors to uncertainty, specifically, daily positioning setup errors, gantry sag, multileaf collimator (MLC) offset, and couch walkout, were isolated from isocenter congruency measurements to determine a clinically meaningful isocenter measurement. Variations in positioning of the test tool constituted, on average, 0.38 mm magnitude of correction. Gantry sag and MLC offset contributed 0.4 and 0.16 mm, respectively. Couch walkout had an average degrading effect to isocenter of 0.72 mm. Considering the magnitude of uncertainty contributed by each uncertainty variable and the nature of their combination, an appropriate schedule action and immediate action level were determined for use in analyzing daily isocenter congruency test results in a stereotactic radiosurgery (SRS) program. The recommendations of this study for this linear accelerator include a schedule action level of 1.25 mm and an immediate action level of 1.50mm, requiring prompt correction response from clinical medical physicists before SRS or stereotactic body radiosurgery (SBRT) is administered. These absolute values were derived from considering relative data from a specific linear accelerator and, therefore, represent a means by which a numerical quantity can be used as a test threshold with relative specificity to a particular linear accelerator.
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Affiliation(s)
- Travis R Denton
- The Norton Cancer Institute Radiation Center, Louisville, KY and Associates in Medical Physics, LLC, Greenbelt, MD.
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Naoi Y, Kunishima N, Yamamoto K, Yoda K. A planning target volume margin formula for hypofractionated intracranial stereotactic radiotherapy under cone beam CT image guidance with a six-degrees-of-freedom robotic couch and a mouthpiece-assisted mask system: a preliminary study. Br J Radiol 2014; 87:20140240. [PMID: 25029296 DOI: 10.1259/bjr.20140240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE A planning target volume (PTV) margin formula for hypofractionated intracranial stereotactic radiotherapy (SRT) has been proposed under cone beam CT (CBCT) image guidance with a six-degrees-of-freedom (6-DOF) robotic couch. METHODS CBCT-based registration using a 6-DOF couch reportedly led to negligibly small systematic positioning errors, suggesting that each in-treatment positioning error during the treatment courses for the patients employing this combination was predominantly caused by a random gaussian process. Under this assumption, an anisotropic PTV margin for each axis was formulated based on a gaussian distribution model. 19 patients with intracranial lesions who underwent additional post-treatment CBCT were consecutively selected, to whom stereotactic hypofractionated radiotherapy was delivered by a linear accelerator equipped with a CBCT imager, a 6-DOF couch and a mouthpiece-assisted mask system. Time-averaged patient-positioning errors during treatment were estimated by comparing the post-treatment CBCT with the reference planning CT images. RESULTS It was suggested that each histogram of the in-treatment positioning error in each axis would approach each single gaussian distribution with a mean of zero. The calculated PTV margins in the x, y and z directions were 0.97, 1.30 and 0.88 mm, respectively. CONCLUSION The empirical isotropic PTV margin of 2 mm used in our facility for intracranial SRT was consistent with the margin calculated by the proposed gaussian model. ADVANCES IN KNOWLEDGE We have proposed a PTV margin formula for hypofractionated intracranial SRT under CBCT image guidance with a 6-DOF robotic couch.
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Affiliation(s)
- Y Naoi
- 1 Department of Radiology, Self Defense Forces Central Hospital, Tokyo, Japan
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Li Q, Mu J, Gu W, Chen Y, Ning Z, Jin J, Pei H. Frameless stereotactic body radiation therapy for multiple lung metastases. J Appl Clin Med Phys 2014; 15:4737. [PMID: 25207400 PMCID: PMC5875519 DOI: 10.1120/jacmp.v15i4.4737] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 04/15/2014] [Accepted: 04/05/2014] [Indexed: 12/02/2022] Open
Abstract
Two patients with multiple lung metastases (≥ 5) were treated using frameless stereotactic body radiation therapy (SBRT) on an Elekta Axesse linear accelerator equipped with an interdigitation‐capable multileaf collimator and four‐dimensional cone‐beam CT (4D CBCT). The technique and the early clinical outcomes were evaluated. Patient A with five lung metastases and Patient B with seven lung metastases underwent SBRT (48 Gy/8 fractions for Patient A, 42 Gy/7 fractions for Patient B). The treatments were administered using a 6 MV photon beam. The nominal dose rate was 660 MUs/min. Patients were positioned and immobilized using thermoplastic masks and image guidance was done using 4D CBCT. The targets were delineated on the images of the 4D CT, and the positron emission tomography‐computed tomography (PET‐CT) images were taken as references. A two‐step, volumetric‐modulated arc therapy (VMAT) plan was designed for each patient. Step 1: the lesions in one lung were irradiated by a 210° arc field; Step 2: the rest of the lesions in the other lung were irradiated by a 120° arc field. Plans were evaluated using conformity index (CI) and homogeneity index (HI). Patients were followed up and adverse events were graded according to the Common Terminology Criteria for Adverse Events v4.0 (CTCAE v4.0). The beam‐on time of each treatment was less than 10 min. The CI and HI for the two plans were 0.562, 0.0709 and 0.513, 0.0794, respectively. Pulmonary function deteriorated slightly in both patients, and the patient with seven lung lesions was confirmed to have Grade 1 radiation pneumonitis. The technique was fast, accurate, and well tolerated by patients, and the two‐step plan is a helpful design in reducing the dose to the lungs. PACS numbers: 87.55‐x, 87.56.J‐, 87.56.‐v, 87.56.nk, 87.57.qp
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Affiliation(s)
- Qilin Li
- The First People's Hospital of Changzhou City.
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Nanda R, Dhabbaan A, Janss A, Shu HK, Esiashvili N. The feasibility of frameless stereotactic radiosurgery in the management of pediatric central nervous system tumors. J Neurooncol 2014; 117:329-35. [DOI: 10.1007/s11060-014-1392-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
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Yamoah K, Zaorsky NG, Siglin J, Shi W, Werner-Wasik M, Andrews DW, Dicker AP, Bar-Ad V, Liu H. Spine Stereotactic Body Radiation Therapy Residual Setup Errors and Intra-Fraction Motion Using the Stereotactic X-Ray Image Guidance Verification System. ACTA ACUST UNITED AC 2014; 3:1-8. [PMID: 29333353 PMCID: PMC5766040 DOI: 10.4236/ijmpcero.2014.31001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Purpose To determine the precision of our institution’s current immobilization devices for spine SBRT, ultimately leading to recommendations for appropriate planning margins. Methods We identified 12 patients (25 treatments) with spinal metastasis treated with spine Stereotactic Body Radiation Therapy (SBRT). The Body-FIX system was used as immobilization device for thoracic (T) and lumbar (L) spine lesions. The head and shoulder mask system was used as immobilization device for cervical (C) spine lesions. Initial patient setup used the infrared positioning system with body markers. Stereotactic X-ray imaging was then performed and correction was made if the initial setup error exceeded predetermined institutional tolerances, 1.5 mm for translation and 2° for rotation. Three additional sets of verification X-rays were obtained pre-, mid-, and post-treatment for all treatments. Results Intrafraction motion regardless of immobilization technique was found to be 1.28 ± 0.57 mm. The mean and standard deviation of the variances along each direction were as follows: Superior-inferior, 0.56 ± 0.39 mm and 0.77 ± 0.52 mm, (p = 0.25); Anterior-posterior, 0.57 ± 0.43 mm and 1.14 ± 0.61 mm, (p = 0.01); Left-right, 0.48 ± 0.34 mm and 0.74 ± 0.40 mm, (p = 0.09) respectively. There was a significantly greater difference in the average 3D variance of the BodyFIX as compared to the head and shoulder mask immobilization system, 1.04 ± 0.46 mm and 1.71 ± 0.52 mm; (p = 0.003) respectively. Conclusions Overall, our institution’s image guidance system using stereotactic X-ray imaging verification provides acceptable localization accuracy as previously defined in the literature. We observed a greater intrafraction motion for the head and shoulder mask as compared with the BodyFIX immobilization system, which may be a result of greater C-spine mobility and/or the suboptimal mask immobilization. Thus, better immobilization techniques for C-spine SBRT are needed to reduce setup error and intrafraction motion. We are currently exploring alternative C-spine immobilization techniques to improve set up accuracy and decrease intrafraction motion during treatment.
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Affiliation(s)
- Kosj Yamoah
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
| | - Nicholas G Zaorsky
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA.,Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, USA
| | - Joshua Siglin
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
| | - Wenyin Shi
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
| | - Maria Werner-Wasik
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
| | - David W Andrews
- Department of Neurological Surgery, Jefferson Medical College, Philadelphia, USA
| | - Adam P Dicker
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
| | - Voichita Bar-Ad
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
| | - Haisong Liu
- Department of Radiation Oncology, Jefferson Medical College and Kimmel Cancer Center of Thomas Jefferson University, Philadelphia, USA
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Feasibility of an online adaptive replanning method for cranial frameless intensity-modulated radiosurgery. Med Dosim 2013; 38:291-7. [DOI: 10.1016/j.meddos.2013.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 01/25/2013] [Accepted: 02/26/2013] [Indexed: 11/22/2022]
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Eaton BR, Gebhardt B, Prabhu R, Shu HK, Curran WJ, Crocker I. Hypofractionated radiosurgery for intact or resected brain metastases: defining the optimal dose and fractionation. Radiat Oncol 2013; 8:135. [PMID: 23759065 PMCID: PMC3693888 DOI: 10.1186/1748-717x-8-135] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 06/01/2013] [Indexed: 11/12/2022] Open
Abstract
Background Hypofractionated Radiosurgery (HR) is a therapeutic option for delivering partial brain radiotherapy (RT) to large brain metastases or resection cavities otherwise not amenable to single fraction radiosurgery (SRS). The use, safety and efficacy of HR for brain metastases is not well characterized and the optimal RT dose-fractionation schedule is undefined. Methods Forty-two patients treated with HR in 3-5 fractions for 20 (48%) intact and 22 (52%) resected brain metastases with a median maximum dimension of 3.9 cm (0.8-6.4 cm) between May 2008 and August 2011 were reviewed. Twenty-two patients (52%) had received prior radiation therapy. Local (LC), intracranial progression free survival (PFS) and overall survival (OS) are reported and analyzed for relationship to multiple RT variables through Cox-regression analysis. Results The most common dose-fractionation schedules were 21 Gy in 3 fractions (67%), 24 Gy in 4 fractions (14%) and 30 Gy in 5 fractions (12%). After a median follow-up time of 15 months (range 2-41), local failure occurred in 13 patients (29%) and was a first site of failure in 6 patients (14%). Kaplan-Meier estimates of 1 year LC, intracranial PFS, and OS are: 61% (95% CI 0.53 – 0.70), 55% (95% CI 0.47 – 0.63), and 73% (95% CI 0.65 – 0.79), respectively. Local tumor control was negatively associated with PTV volume (p = 0.007) and was a significant predictor of OS (HR 0.57, 95% CI 0.33 - 0.98, p = 0.04). Symptomatic radiation necrosis occurred in 3 patients (7%). Conclusions HR is well tolerated in both new and recurrent, previously irradiated intact or resected brain metastases. Local control is negatively associated with PTV volume and a significant predictor of overall survival, suggesting a need for dose escalation when using HR for large intracranial lesions.
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Affiliation(s)
- Bree R Eaton
- Department of Radiation Oncology, Winship Cancer Institute, Emory University, 1365 Clifton Rd, NE, Building A, Suite CT 104, Atlanta, GA 30322, USA.
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