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Shields LBE, Malkawi A, Daniels MW, Rao AJ, Plato BM, Yao TL, Howe JN, Spalding AC. Frameless image-guided linear accelerator (LINAC) stereotactic radiosurgery for medically refractory trigeminal neuralgia: Clinical outcomes in 116 patients. Surg Neurol Int 2024; 15:181. [PMID: 38840612 PMCID: PMC11152532 DOI: 10.25259/sni_101_2024] [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: 02/11/2024] [Accepted: 05/04/2024] [Indexed: 06/07/2024] Open
Abstract
Background Frameless image-guided radiosurgery (IGRS) is an effective and non-invasive method of treating patients who are unresponsive to medical management for trigeminal neuralgia (TN). This study evaluated the use of frameless IGRS to treat patients with medically refractory TN. Methods We performed a retrospective review of records of 116 patients diagnosed with TN who underwent frameless IGRS using a linear accelerator (LINAC) over 10 years (March 2012-February 2023). All patients had failed medical management for TN. Facial pain was graded using the Barrow Neurological Institute (BNI) scoring system. Each patient received a BNI score before frameless IGRS and following treatment. Failure was defined as a BNI score IV-V at the last follow-up and/or undergoing a salvage procedure following IGRS. Results All patients had a BNI score of either IV or V before the frameless IGRS. The mean follow-up duration for all 116 patients following IGRS was 44.1 months. Most patients (81 [69.8%]) had not undergone surgery (microvascular decompression [MVD] or rhizotomy) or stereotactic radiosurgery (SRS) for TN before frameless IGRS. A total of 41 (35.3%) patients underwent a salvage procedure (MVD, rhizotomy, or an additional IGRS) following frameless IGRS. The mean duration between the initial frameless IGRS and salvage procedure was 20.1 months. At the last follow-up, a total of 110 (94.8%) patients had a BNI score of I-III. No complications were reported after the frameless IGRS. The BNI score at the last follow-up was lower compared to the initial BNI for patients regardless of prior intervention (P < 0.001). Patients who failed IGRS had a higher BNI score at the last follow-up compared to those who did not fail IGRS (2.8 vs. 2.5, P = 0.05). Patients with pain relief had a shorter follow-up compared to those with pain refractory to SRS (38.0 vs. 55.1, P = 0.005). Conclusion In this large cohort of patients with medically refractory TN, frameless IGRS resulted in durable pain control in the majority of patients without any toxicity.
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Affiliation(s)
- Lisa B. E. Shields
- Norton Healthcare, Norton Neuroscience Institute, Louisville, Kentucky, United States
| | - Azzam Malkawi
- Norton Neuroscience Institute, Norton Healthcare, Norton Cancer Institute, Louisville, Kentucky, United States
| | - Michael W. Daniels
- Department of Bioinformatics and Biostatistics, University of Louisville, School of Public Health and Information Sciences, Louisville, Kentucky, United States
| | - Abigail J. Rao
- Norton Healthcare, Norton Neuroscience Institute, Louisville, Kentucky, United States
| | - Brian M. Plato
- Norton Healthcare, Norton Neuroscience Institute, Louisville, Kentucky, United States
| | - Tom L. Yao
- Norton Healthcare, Norton Neuroscience Institute, Louisville, Kentucky, United States
| | - Jonathan N. Howe
- Norton Neuroscience Institute, Norton Healthcare, Norton Cancer Institute, Louisville, Kentucky, United States
| | - Aaron C. Spalding
- Norton Neuroscience Institute, Norton Healthcare, Norton Cancer Institute, Louisville, Kentucky, United States
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Kim TH, Cho MS, Shin DS, Shin DH, Kim S. Development of a Real-Time Thermoplastic Mask Compression Force Monitoring System Using Capacitive Force Sensor. Front Robot AI 2022; 9:778594. [PMID: 35875702 PMCID: PMC9298856 DOI: 10.3389/frobt.2022.778594] [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: 09/20/2021] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: Thermoplastic masks keep patients in an appropriate position to ensure accurate radiation delivery. For a thermoplastic mask to maintain clinical efficacy, the mask should wrap the patient's surface properly and provide uniform pressure to all areas. However, to our best knowledge, no explicit method for achieving such a goal currently exists. Therefore, in this study, we intended to develop a real-time thermoplastic mask compression force (TMCF) monitoring system to measure compression force quantitatively. A prototype system was fabricated, and the feasibility of the proposed method was evaluated. Methods: The real-time TMCF monitoring system basically consists of four force sensor units, a microcontroller board (Arduino Bluno Mega 2560), a control PC, and an in-house software program. To evaluate the reproducibility of the TMCF monitoring system, both a reproducibility test using a micrometer and a setup reproducibility test using a head phantom were performed. Additionally, the reproducibility tests of mask setup and motion detection tests were carried out with a cohort of six volunteers. Results: The system provided stable pressure readings in all 10 trials during the sensor unit reproducibility test. The largest standard deviation (SD) among trials was about 36 gf/cm2 (∼2.4% of the full-scale range). For five repeated mask setups on the phantom, the compression force variation of the mask was less than 39 gf/cm2 (2.6% of the full-scale range). We were successful in making masks together with the monitoring system connected and demonstrated feasible utilization of the system. Compression force variations were observed among the volunteers and according to the location of the sensor (among forehead, both cheekbones, and chin). The TMCF monitoring system provided the information in real time on whether the mask was properly pressing the human subject as an immobilization tool. Conclusion: With the developed system, it is possible to monitor the effectiveness of the mask in real time by continuously measuring the compression force between the mask and patient during the treatment. The graphical user interface (GUI) of the monitoring system developed provides a warning signal when the compression force of the mask is insufficient. Although the number of volunteers participated in the study was small, the obtained preliminary results suggest that the system could ostensibly improve the setup accuracy of a thermoplastic mask.
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Affiliation(s)
- Tae-Ho Kim
- Proton Therapy Center, National Cancer Center, Goyang, South Korea
| | - Min-Seok Cho
- Department of Radiation Oncology, Yongin Severance Hospital, Yongin, South Korea
| | - Dong-Seok Shin
- Proton Therapy Center, National Cancer Center, Goyang, South Korea
| | - Dong Ho Shin
- Proton Therapy Center, National Cancer Center, Goyang, South Korea
| | - Siyong Kim
- Department of Radiation Oncology, Virginia Commonwealth University, Virginia, VA, United States
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Papp J, Simon M, Csiki E, Kovács Á. CBCT Verification of SRT for Patients With Brain Metastases. Front Oncol 2022; 11:745140. [PMID: 35127470 PMCID: PMC8807635 DOI: 10.3389/fonc.2021.745140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe aim of our work is to demonstrate the role of image guidance and volumetric imaging in stereotactic radiotherapy (SRT) of brain metastases.MethodsBetween 2018 and 2020, 106 patients underwent intracranial stereotactic radiotherapy. 10 patients with metastatic brain tumors treated with SRT were randomly selected and included in our study model. Patients were scanned pre- and post-treatment with cone beam CT. Total of 100 verifications of 50 stereotaxic treatments were performed and analyzed.ResultsPopulation mean X, Y, Z values were -0.13 cm, -0.04 cm, -0.03 cm, respectively, rotation values 0.81°, 0.51°, 0.46°, respectively. Systematic error components for translational displacements pre corrections were as follows: 0.14 cm for X, 0.13 cm for Y and 0.1 cm for Z. Systematic error components of the post-treatment HR 3D CBCTs were as follows: 0.01 cm for X, 0.06 cm for Y and 0.04 cm for Z.ConclusionsPopulation mean values close to 0 confirmed that there is no systematic variation in our system and the accuracy of our equipment and tools is reliable. HR 3D CBCT scans performed pre SRTs further refine patient and target volume setting, support medical decision making and eliminate the possibility of gross error.
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Affiliation(s)
- Judit Papp
- Department of Oncoradiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Mihály Simon
- Department of Oncoradiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Emese Csiki
- Department of Oncoradiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Árpád Kovács
- Department of Oncoradiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Health Sciences, Faculty of Health Sciences, University of Pécs, Pécs, Hungary
- *Correspondence: Árpád Kovács,
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Brain Linac-Based Radiation Therapy: "Test Drive" of New Immobilization Solution and Surface Guided Radiation Therapy. J Pers Med 2021; 11:jpm11121351. [PMID: 34945823 PMCID: PMC8709255 DOI: 10.3390/jpm11121351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 01/17/2023] Open
Abstract
AIM To test inter-fraction reproducibility, intrafraction stability, technician aspects, and patient/physician's comfort of a dedicated immobilization solution for Brain Linac-based radiation therapy (RT). METHODS A pitch-enabled head positioner with an open-face mask were used and, to evaluate inter- and intrafraction variations, 1-3 Cone-Beam Computed Tomography (CBCT) were performed. Surface Guided Radiation Therapy (SGRT) was used to evaluate intrafraction variations at 3 time points: initial (i), final (f), and monitoring (m) (before, end, and during RT). Data regarding technician mask aspect were collected. RESULTS Between October 2019 and April 2020, 69 patients with brain disease were treated: 45 received stereotactic RT and 24 conventional RT; 556 treatment sessions and 863 CBCT's were performed. Inter-fraction CBCT mean values were longitudinally 0.9 mm, laterally 0.8 mm, vertically 1.1 mm, roll 0.58°, pitch 0.59°, yaw 0.67°. Intrafraction CBCT mean values were longitudinally 0.3 mm, laterally 0.3 mm, vertically 0.4 mm, roll 0.22°, pitch 0.33°, yaw 0.24°. SGRT intrafraction mean values were: i_, m_, f_ longitudinally 0.09 mm, 0.45 mm, 0.31 mm; i_, m_, f_ laterally 0.07 mm, 0.36 mm, 0.20 mm; i_, m_, f_ vertically 0.06 mm, 0.31 mm, 0.22 mm; i_, m_, f_ roll 0.025°, 0.208°, 0.118°; i_, m_, f_ pitch 0.036°, 0.307°, 0.194°; i_, m_, f_ yaw 0.039°, 0.274°, 0.189°. CONCLUSIONS This immobilization solution is reproducible and stable. Combining CBCT and SGRT data confirm that 1 mm CTV-PTV margin for Linac-based SRT was adequate. Using open-face mask and SGRT, for conventional RT, radiological imaging could be omitted.
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Ong CL, Giaj-Levra N, Nicosia L, Figlia V, Tomasini D, Franken EM, Alongi F. Intra-fraction and Inter-fraction analysis of a dedicated immobilization device for intracranial radiation treatment. Radiat Oncol 2020; 15:200. [PMID: 32811519 PMCID: PMC7437162 DOI: 10.1186/s13014-020-01639-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/10/2020] [Indexed: 11/25/2022] Open
Abstract
Background Immobilization devices are crucial to minimize patient positioning uncertainties in radiotherapy (RT) treatments. Accurate inter and intra-fraction motions is particularly important for intracranial and stereotactic radiation treatment which require high precision in dose delivery. Recently, a new immobilization device has been developed specifically for the radiation treatment of intracranial malignancies. To date, no data are available on the use of this device in daily clinical practice. The aim of this study is to investigate the intra and inter-fraction variations, patient comfort and radiographer confidence of the immobilization system from two distinct institutions: HagaZiekenhuis, Den Haag, Netherlands and IRCCS Ospedale Sacro Cuore Don Calabria, Negrar, Italy. Material and method Sixteen patients (10 diagnosed with brain metastases and 6 with primary central nervous systemic tumor) from IRCCS Ospedale Sacro Cuore Don Calabria and 17 patients (all diagnosed with brain metastases tumor) from HagaZiekenhuis were included in this study. The median target volume was 436 cc (range 3.2–1628 cc) and 4.58 cc (range 0.4–27.19 cc) for IRCCS and Haga, respectively. For patients treated in IRCCS Sacro Cuore Don Calabria, the median dose prescription was 30 Gy (range 27–60 Gy) and median number of fractions 10 (range 3–30). In Haga the median dose prescription was 21 Gy (range 8–21 Gy) and the median number of fraction was 1 (range 1–3). The immobilization device was assembled during CT simulation. A short interview to the patient regarding the device’s comfort level was conducted at the end of the simulation procedure. Additionally, simulation setup time and radiographer (RTT) procedures (i.e. mask preparation) were evaluated. Prior to radiation treatment delivery, an automatic rigid match on the cranial bones between cone beam computed tomography (CBCT) and planning-CT was performed. A couch shift was performed subsequently. An extra post-treatment CBCT was acquire after the treatment delivery. This post-treatment CBCT was matched with pre-treatment CBCT to identify any possible intra-fraction motion. All online matches were validated by experienced radiation oncologist or RTT. A total of 126 CBCT’s were analyzed offline by radiation oncologist/medical physicist. The data of the pre-treatment CBCT match was used to quantify inter-fraction motion. The post-treatment CBCT was matched with pre-treatment CBCT to identify any possible intra-fraction motion. Results During the molding of the mask, all patients responded positive to the comfort. Median time required by the RTTs to assemble the immobilization system was 9 min (range 6–12 min). In terms of comfort, all patients reported a good-to high level of satisfaction. The RTTs also respond positively towards the use of the locking mechanism and clips. Results of positioning uncertainties were comparable between the two institutes. The mean inter-fraction motion for all translational and rotational directions were < 2 mm (SD < 4 mm) and < 0.5°(SD < 1.5°), respectively, while the mean intra-fraction motions were < 0.4 mm (SD < 0.6 mm) and 0.3° (SD < 0.5°). Conclusions This study demonstrates the efficacy and feasibility of the immobilization device in the intracranial radiation treatment. Both patient comfort and preparation time by RTTs are considered adequate. In combination with online daily imaging procedure, this device can achieve submillimeter accuracy required for intracranial and stereotactic treatments.
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Affiliation(s)
- Chin Loon Ong
- Department of Radiotherapy, HagaZiekenhuis, Den Haag, The Netherlands
| | - Niccolò Giaj-Levra
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A.Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy.
| | - Luca Nicosia
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A.Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy
| | - Vanessa Figlia
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A.Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy
| | - Davide Tomasini
- Radiation Oncology Department, ASST Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | - Eric M Franken
- Department of Radiotherapy, HagaZiekenhuis, Den Haag, The Netherlands
| | - Filippo Alongi
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A.Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy.,University of Brescia, Brescia, Italy
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Dincoglan F, Beyzadeoglu M, Sager O, Oysul K, Sirin S, Surenkok S, Gamsiz H, Uysal B, Demiral S, Dirican B. Image-Guided Positioning in Intracranial Non-Invasive Stereotactic Radiosurgery for the Treatment of Brain Metastasis. TUMORI JOURNAL 2018; 98:630-5. [DOI: 10.1177/030089161209800514] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Aims and background The aim of the study was to examine the feasibility of non-invasive image-guided radiosurgery to improve patient comfort and quality of life in stereotactic radiosurgery planning and treatment of patients with brain metastasis. Precise immobilization is a rule of thumb for stereotactic radiosurgery. Non-invasive immobilization techniques have the potential of improved quality of life compared with invasive procedures. Methods and study design A total of 92 lesions from 42 patients with brain metastasis were included in the study. After immobilization with a thermoplastic mask and a bite-block unlike the invasive frame-based procedure, planning computed tomography images were acquired and fused with magnetic resonance images. After contouring, intensity-modulated stereotactic radiosurgery (IM-SRS) planning was done, and the patients were re-immobilized on the treatment couch for the therapy procedures. While patients were on the treatment couch, kilovoltage-cone beam computed tomography images were acquired to determine setup errors and achieve on-line correction and then repeated after on-line correction to confirm precise tumor localization. The patients then underwent single-fraction definitive treatment. Results For the 92 lesions treated, mean ± SD values of translational setup corrections in X (lateral), Y (longitudinal), and Z (vertical) dimensions were 0.7 ± 0.7 mm, 0.8 ± 0.7 mm, and 0.6 ± 0.5 mm, and rotational set-up corrections were 0.5 ± 1.1°, 0.06 ± 1.1°, and -0.1 ± 1.1° in X (pitch), Y (roll), and Z (yaw), respectively. The mean three-dimensional correction vector was 1.2 ± 1.1 mm. Conclusions Non-invasive image-guided radiosurgery for brain metastasis is feasible, and the non-invasive treatment approach can be routinely used in clinical practice to improve patientís quality of life.
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Affiliation(s)
- Ferrat Dincoglan
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Murat Beyzadeoglu
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Omer Sager
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Kaan Oysul
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Sait Sirin
- Neurosurgery Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Serdar Surenkok
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Hakan Gamsiz
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Bora Uysal
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Selcuk Demiral
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
| | - Bahar Dirican
- Radiation Oncology Department, Gulhane Military Faculty of Medicine, Ankara, Turkey
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Hypofractionated stereotactic radiosurgery for treatment of cerebral arteriovenous malformations: outcome analysis with use of the modified arteriovenous malformation scoring system. J Clin Neurosci 2016; 29:155-61. [DOI: 10.1016/j.jocn.2015.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 12/12/2015] [Indexed: 11/19/2022]
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Bendok BR, Rahme RJ, Aoun SG, El Ahmadieh TY, El Tecle NE, Batjer HH, Fishman AJ. Enhancement of the subtemporal approach by partial posterosuperior petrosectomy with hearing preservation. Neurosurgery 2014; 10 Suppl 2:191-9; discussion 199. [PMID: 24476903 DOI: 10.1227/neu.0000000000000300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The microsurgical management of aneurysms in the interpeduncular and ambient cisterns remains challenging. The classic subtemporal approach has several limitations. OBJECTIVE To present a modification of this approach that allows for broader exposure with hearing preservation. METHODS We retrospectively reviewed our clinical database between August 2007 and February 2012 for all patients who underwent a modified subtemporal partial posterosuperior petrosectomy. Clinical data, complications, and postoperative head computed tomography (CT) scans were analyzed. Improvement in the angle of view acquired by the new approach was measured using the OsiriX 3-D rendering software and was compared with that obtained from the subtemporal approach. Similar methods were used to study improvement in the angle of view in head CT scans of randomly selected control patients. RESULTS Five patients underwent a modified subtemporal approach for posterior circulation aneurysm clipping. All patients were women with a mean age of 49.8 years. Mean aneurysm size was 5.75 mm. Mean improvement in the angle of view was 17.52° in the study group (n = 5) and 11.7° in the control group (n = 10). Hearing was completely preserved in 3 patients. One patient had a subclinical conductive hearing loss, and 1 patient was not assessed formally at follow-up, but had no hearing concerns. No neurological sequelae were recorded. CONCLUSION Our modified subtemporal approach appears to be safe and provides an increased angle of view with minimal additional operative time and with low risk to hearing. This approach may expand this surgical corridor and reduce the need for temporal lobe retraction.
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Affiliation(s)
- Bernard R Bendok
- *Department of Neurological Surgery, Northwestern University Feinberg School of Medicine and McGaw Medical Center, Chicago, Illinois; ‡Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas; §Department of Otology-Neurotology and Cranial Base Surgery, Cadence Neuroscience Institute at Central DuPage Hospital, Winfield, Illinois
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Li G, Lovelock DM, Mechalakos J, Rao S, Della-Biancia C, Amols H, Lee N. Migration from full-head mask to "open-face" mask for immobilization of patients with head and neck cancer. J Appl Clin Med Phys 2013; 14:243-54. [PMID: 24036878 PMCID: PMC5714571 DOI: 10.1120/jacmp.v14i5.4400] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/20/2013] [Accepted: 04/29/2013] [Indexed: 11/23/2022] Open
Abstract
To provide an alternative device for immobilization of the head while easing claustrophobia and improving comfort, an “open‐face” thermoplastic mask was evaluated using video‐based optical surface imaging (OSI) and kilovoltage (kV) X‐ray radiography. A three‐point thermoplastic head mask with a precut opening and reinforced strips was developed. After molding, it provided sufficient visible facial area as the region of interest for OSI. Using real‐time OSI, the head motion of ten volunteers in the new mask was evaluated during mask locking and 15 minutes lying on the treatment couch. Using a nose mark with reference to room lasers, forced head movement in open‐face and full‐head masks (with a nose hole) was compared. Five patients with claustrophobia were immobilized with open‐face masks, set up using OSI and kV, and treated in 121 fractions, in which 61 fractions were monitored during treatment using real‐time OSI. With the open‐face mask, head motion was found to be 1.0 ± 0.6 mm and 0.4° ± 0.2° in volunteers during the experiment, and 0.8 ± 0.3 mm and 0.4° ± 0.2° in patients during treatment. These agree with patient motion calculated from pre‐/post‐treatment OSI and kV data using different anatomical landmarks. In volunteers, the head shift induced by mask‐locking was 2.3 ± 1.7 mm and 1.8° ± 0.6°, and the range of forced movements in the open‐face and full‐head masks were found to be similar. Most (80%) of the volunteers preferred the open‐face mask to the full‐head mask, while claustrophobic patients could only tolerate the open‐face mask. The open‐face mask is characterized for its immobilization capability and can immobilize patients sufficiently (< 2 mm) during radiotherapy. It provides a clinical solution to the immobilization of patients with head and neck (HN) cancer undergoing radiotherapy, and is particularly beneficial for claustrophobic patients. This new open‐face mask is readily adopted in radiotherapy clinic as a superior alternative to the standard full‐head mask. PACS numbers: 87.19.xj, 87.63.L‐, 87.59.‐e, 87.55.tg, 87.55.‐x
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Affiliation(s)
- Guang Li
- Memorial Sloan-Kettering Cancer Center.
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Barbosa NA, da Rosa LAR, Batista DVS, Carvalho AR. Development of a phantom for dose distribution verification in Stereotactic Radiosurgery. Phys Med 2013; 29:461-9. [DOI: 10.1016/j.ejmp.2013.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/14/2012] [Accepted: 01/03/2013] [Indexed: 11/28/2022] Open
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Initial clinical experience with a frameless and maskless stereotactic radiosurgery treatment. Pract Radiat Oncol 2012; 2:54-62. [DOI: 10.1016/j.prro.2011.04.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 04/18/2011] [Accepted: 04/21/2011] [Indexed: 11/23/2022]
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12
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Theelen A, Martens J, Bosmans G, Houben R, Jager JJ, Rutten I, Lambin P, Minken AW, Baumert BG. Relocatable fixation systems in intracranial stereotactic radiotherapy. Accuracy of serial CT scans and patient acceptance in a randomized design. Strahlenther Onkol 2011; 188:84-90. [PMID: 22194025 DOI: 10.1007/s00066-011-0018-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 06/28/2011] [Indexed: 12/25/2022]
Abstract
PURPOSE The goal was to provide a quantitative evaluation of the accuracy of three different fixation systems for stereotactic radiotherapy and to evaluate patients' acceptance for all fixations. METHODS A total of 16 consecutive patients with brain tumours undergoing fractionated stereotactic radiotherapy (SCRT) were enrolled after informed consent (Clinical trials.gov: NCT00181350). Fixation systems evaluated were the BrainLAB® mask, with and without custom made bite-block (fixations S and A) and a homemade neck support with bite-block (fixation B) based on the BrainLAB® frame. The sequence of measurements was evaluated in a randomized manner with a cross-over design and patients' acceptance by a questionnaire. RESULTS The mean three-dimensional (3D) displacement and standard deviations were 1.16 ± 0.68 mm for fixation S, 1.92 ± 1.28 and 1.70 ± 0.83 mm for fixations A and B, respectively. There was a significant improvement of the overall alignment (3D vector) when using the standard fixation instead of fixation A or B in the craniocaudal direction (p = 0.037). Rotational deviations were significantly less for the standard fixation S in relation to fixations A (p = 0.005) and B (p = 0.03). EPI imaging with off-line correction further improved reproducibility. Five out of 8 patients preferred the neck support with the bite-block. CONCLUSION The mask fixation system in conjunction with a bite-block is the most accurate fixation for SCRT reducing craniocaudal and rotational movements. Patients favoured the more comfortable but less accurate neck support. To optimize the accuracy of SCRT, additional regular portal imaging is warranted.
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Affiliation(s)
- A Theelen
- Department of Radiation-Oncology (MAASTRO), GROW (School for Oncology & Developmental Biology), Maastricht University Medical Centre, Dr Tanslaan 12, 6229, Maastricht, The Netherlands
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Minniti G, Scaringi C, Clarke E, Valeriani M, Osti M, Enrici RM. Frameless linac-based stereotactic radiosurgery (SRS) for brain metastases: analysis of patient repositioning using a mask fixation system and clinical outcomes. Radiat Oncol 2011; 6:158. [PMID: 22085700 PMCID: PMC3253058 DOI: 10.1186/1748-717x-6-158] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 11/16/2011] [Indexed: 11/21/2022] Open
Abstract
Purpose To assess the accuracy of patient repositioning and clinical outcomes of frameless stereotactic radiosurgery (SRS) for brain metastases using a stereotactic mask fixation system. Patients and Methods One hundred two patients treated consecutively with frameless SRS as primary treatment at University of Rome Sapienza Sant'Andrea Hospital between October 2008 and April 2010 and followed prospectively were involved in the study. A commercial stereotactic mask fixation system (BrainLab) was used for patient immobilization. A computerized tomography (CT) scan obtained immediately before SRS was used to evaluate the accuracy of patient repositioning in the mask by comparing the isocenter position to the isocenter position established in the planning CT. Deviations of isocenter coordinates in each direction and 3D displacement were calculated. Overall survival, brain control, and local control were estimated using the Kaplan-Meier method calculated from the time of SRS. Results The mean measured isocenter displacements were 0.12 mm (SD 0.35 mm) in the lateral direction, 0.2 mm (SD 0.4 mm) in the anteroposterior, and 0.4 mm (SD 0.6 mm) in craniocaudal direction. The maximum displacement of 2.1 mm was seen in craniocaudal direction. The mean 3D displacement was 0.5 mm (SD 0.7 mm), being maximum 2.9 mm. The median survival was 15.5 months, and 1-year and 2-year survival rates were 58% and 24%, respectively. Nine patients recurred locally after SRS, with 1-year and 2-year local control rates of 91% and 82%, respectively. Stable extracranial disease (P = 0.001) and KPS > 70 (P = 0.01) were independent predictors of survival. Conclusions Frameless SRS is an effective treatment in the management of patients with brain metastases. The presented non-invasive mask-based fixation stereotactic system is associated with a high degree of patient repositioning accuracy; however, a careful evaluation is essential since occasional errors up to 3 mm may occur.
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Affiliation(s)
- Giuseppe Minniti
- Department of Radiation Oncology, Sant' Andrea Hospital, University Sapienza, Rome, Italy.
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Fukuda A. Pretreatment setup verification by cone beam CT in stereotactic radiosurgery: phantom study. J Appl Clin Med Phys 2010; 11:3162. [PMID: 21081872 PMCID: PMC5720422 DOI: 10.1120/jacmp.v11i4.3162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 06/07/2010] [Accepted: 07/05/2010] [Indexed: 11/23/2022] Open
Abstract
Kilovoltage cone beam computed tomography (CBCT) imaging may be useful in verifying patient position in stereotactic radiosurgery (SRS). To evaluate its efficacy, we investigated isocenter differences in the radiation beam and CBCT with respect to the achievable setup of a conventional frame-based SRS system. A verification phantom constructed from two plastic boards and Gafchromic-EBT film (4 × 4 cm²) pricked with a pin, was scanned by simulation CT. An isocenter at the tip of pin was planned in the treatment planning system and positioned using stereotactic coordinates. Star-shot irradiation was performed to evaluate the difference between the radiation isocenter and the target (pinhole). CBCT rotation of 200° with a micro multileaf collimator (m3) was performed and measured the isocenter difference between CBCT and the target (tip of pin) by comparing relative coordinates. Data acquisition was performed 13 times on different days and differences were analyzed by calculating mean and standard deviation. The mean difference between the radiation beam and the target (pinhole) and between radiation beam and CBCT isocenter, were 0.6 ± 0.2 mm and 0.8 ± 0.1 mm, respectively. The setup accuracy of conventional stereotactic coordinates and the isocenter accuracy of CBCT complied with AAPM Report No. 54.
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Affiliation(s)
- Atsushi Fukuda
- Department of Radiology, Shiga Medical Center for Children, Moriyama City, Shiga,
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Kim YJ, Cho KH, Kim JY, Lim YK, Min HS, Lee SH, Kim HJ, Gwak HS, Yoo H, Lee SH. Single-dose versus fractionated stereotactic radiotherapy for brain metastases. Int J Radiat Oncol Biol Phys 2010; 81:483-9. [PMID: 20800386 DOI: 10.1016/j.ijrobp.2010.05.033] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 05/25/2010] [Accepted: 05/25/2010] [Indexed: 11/16/2022]
Abstract
PURPOSE To evaluate the efficacy of stereotactic radiotherapy in patients with brain metastases by comparing two different treatment regimens, single-dose radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT). METHODS AND MATERIALS Between November 2003 and December 2008, 98 patients with brain metastases were included. Fifty-eight patients were treated with SRS, and forty were treated with FSRT. Fractionated stereotactic radiotherapy was used for large lesions or lesions located near critical structures. The median doses were 20 Gy for the SRS group and 36 Gy in 6 fractions for the FSRT group. RESULTS With a median follow-up period of 7 months, the median survival was 7 months for all patients, with a median of 6 months for the SRS group and 8 months for the FSRT group (p = 0.89). Local progression-free survival (LPFS) rates at 6 months and 1 year were 81% and 71%, respectively, for the SRS group and 97% and 69%, respectively, for the FSRT group (p = 0.31). Despite the fact that FSRT was used for large lesions and lesions in adverse locations, LPFS was not inferior to SRS. Toxicity was more frequently observed in the SRS group than in the FSRT group (17% vs. 5%, p = 0.05). CONCLUSIONS Because patients treated with FSRT exhibited similar survival times and LPFS rates with a lower risk of toxicity in comparison to those treated with SRS, despite the fact that FSRT was used for large lesions and lesions in adverse locations, we find that FSRT can particularly be beneficial for patients with large lesions or lesions located near critical structures. Further investigation is warranted to determine the optimal dose/fractionation.
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Affiliation(s)
- Yeon-Joo Kim
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
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Wilbert J, Guckenberger M, Polat B, Sauer O, Vogele M, Flentje M, Sweeney RA. Semi-robotic 6 degree of freedom positioning for intracranial high precision radiotherapy; first phantom and clinical results. Radiat Oncol 2010; 5:42. [PMID: 20504338 PMCID: PMC2890022 DOI: 10.1186/1748-717x-5-42] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 05/26/2010] [Indexed: 11/28/2022] Open
Abstract
Background To introduce a novel method of patient positioning for high precision intracranial radiotherapy. Methods An infrared(IR)-array, reproducibly attached to the patient via a vacuum-mouthpiece(vMP) and connected to the table via a 6 degree-of-freedom(DoF) mechanical arm serves as positioning and fixation system. After IR-based manual prepositioning to rough treatment position and fixation of the mechanical arm, a cone-beam CT(CBCT) is performed. A robotic 6 DoF treatment couch (HexaPOD™) then automatically corrects all remaining translations and rotations. This absolute position of infrared markers at the first fraction acts as reference for the following fractions where patients are manually prepositioned to within ± 2 mm and ± 2° of this IR reference position prior to final HexaPOD-based correction; consequently CBCT imaging is only required once at the first treatment fraction. The preclinical feasibility and attainable repositioning accuracy of this method was evaluated on a phantom and human volunteers as was the clinical efficacy on 7 pilot study patients. Results Phantom and volunteer manual IR-based prepositioning to within ± 2 mm and ± 2° in 6DoF was possible within a mean(± SD) of 90 ± 31 and 56 ± 22 seconds respectively. Mean phantom translational and rotational precision after 6 DoF corrections by the HexaPOD was 0.2 ± 0.2 mm and 0.7 ± 0.8° respectively. For the actual patient collective, the mean 3D vector for inter-treatment repositioning accuracy (n = 102) was 1.6 ± 0.8 mm while intra-fraction movement (n = 110) was 0.6 ± 0.4 mm. Conclusions This novel semi-automatic 6DoF IR-based system has been shown to compare favourably with existing non-invasive intracranial repeat fixation systems with respect to handling, reproducibility and, more importantly, intra-fraction rigidity. Some advantages are full cranial positioning flexibility for single and fractionated IGRT treatments and possibly increased patient comfort.
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Affiliation(s)
- Jürgen Wilbert
- Department of Radiation Oncology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
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Minniti G, Valeriani M, Clarke E, D'Arienzo M, Ciotti M, Montagnoli R, Saporetti F, Enrici RM. Fractionated stereotactic radiotherapy for skull base tumors: analysis of treatment accuracy using a stereotactic mask fixation system. Radiat Oncol 2010; 5:1. [PMID: 20070901 PMCID: PMC2823752 DOI: 10.1186/1748-717x-5-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 01/13/2010] [Indexed: 11/20/2022] Open
Abstract
Background To assess the accuracy of fractionated stereotactic radiotherapy (FSRT) using a stereotactic mask fixation system. Patients and Methods Sixteen patients treated with FSRT were involved in the study. A commercial stereotactic mask fixation system (BrainLAB AG) was used for patient immobilization. Serial CT scans obtained before and during FSRT were used to assess the accuracy of patient immobilization by comparing the isocenter position. Daily portal imaging were acquired to establish day to day patient position variation. Displacement errors along the different directions were calculated as combination of systematic and random errors. Results The mean isocenter displacements based on localization and verification CT imaging were 0.1 mm (SD 0.3 mm) in the lateral direction, 0.1 mm (SD 0.4 mm) in the anteroposterior, and 0.3 mm (SD 0.4 mm) in craniocaudal direction. The mean 3D displacement was 0.5 mm (SD 0.4 mm), being maximum 1.4 mm. No significant differences were found during the treatment (P = 0.4). The overall isocenter displacement as calculated by 456 anterior and lateral portal images were 0.3 mm (SD 0.9 mm) in the mediolateral direction, -0.2 mm (SD 1 mm) in the anteroposterior direction, and 0.2 mm (SD 1.1 mm) in the craniocaudal direction. The largest displacement of 2.7 mm was seen in the cranio-caudal direction, with 95% of displacements < 2 mm in any direction. Conclusions The results indicate that the setup error of the presented mask system evaluated by CT verification scans and portal imaging are minimal. Reproducibility of the isocenter position is in the best range of positioning reproducibility reported for other stereotactic systems.
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Affiliation(s)
- Giuseppe Minniti
- Department of Radiation Oncology, Sant' Andrea Hospital, University La Sapienza, via di Grottarossa 1035-1039, 00189, Rome, Italy.
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Pasquier D, Dubus F, Castelain B, Delplanque M, Bernier V, Buchheit I, Kerr C, Santoro I, Huchet A, Causse N, Lartigau E. Évaluation par tomodensitométrie du repositionnement en radiothérapie stéréotaxique fractionnée cérébrale. Cancer Radiother 2009; 13:446-50. [DOI: 10.1016/j.canrad.2009.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 04/29/2009] [Accepted: 05/10/2009] [Indexed: 11/25/2022]
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Coscia G, Vaccara E, Corvisiero R, Cavazzani P, Ruggieri FG, Taccini G. Fractionated stereotactic radiotherapy: A method to evaluate geometric and dosimetric uncertainties using radiochromic films. Med Phys 2009; 36:2870-80. [DOI: 10.1118/1.3134246] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Masi L, Casamassima F, Polli C, Menichelli C, Bonucci I, Cavedon C. Cone beam CT image guidance for intracranial stereotactic treatments: comparison with a frame guided set-up. Int J Radiat Oncol Biol Phys 2008; 71:926-33. [PMID: 18514784 DOI: 10.1016/j.ijrobp.2008.03.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 03/01/2008] [Accepted: 03/03/2008] [Indexed: 11/17/2022]
Abstract
PURPOSE An analysis is performed of the setup errors measured by a kV cone beam computed tomography (CBCT) for intracranial stereotactic radiotherapy (SRT) patients immobilized by a thermoplastic mask and a bite-block and positioned using stereotactic coordinates. We evaluated the overall positioning precision and accuracy of the immobilizing and localizing systems. The potential of image-guided radiotherapy to replace stereotactic methods is discussed. METHODS AND MATERIALS Fifty-seven patients received brain SRT. After a frame-guided setup, before each fraction (131 fractions), a CBCT was acquired and the detected displacements corrected online. Translational and rotational errors were analyzed calculating overall mean and standard deviation. A separate analysis was performed for bite-block (in conjunction with mask) and for simple thermoplastic mask. Interobserver variability for CBCT three-dimensional registration was assessed. The residual error after correction and intrafractional motion were calculated. RESULTS The mean module of the three-dimensional displacement vector was 3.0 +/- 1.4 mm. Setup errors for bite block and mask were smaller (2.9 +/- 1.3 mm) than those for thermoplastic mask alone (3.2 +/- 1.5 mm), but statistical significance was not reached (p = 0.15). Interobserver variability was negligible. The maximum margin calculated for residual errors and intra fraction motion was small but not negligible (1.57 mm). CONCLUSIONS Considering the detected setup errors, daily image guidance is essential for the efficacy of SRT treatments when mask immobilization is used, and even when a bite-block is used in conjunction. The frame setup is still used as a starting point for the opportunity of rotational corrections. Residual margins after on-line corrections must be evaluated.
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Affiliation(s)
- Laura Masi
- Medical Physics Department, Casa di Cura S Chiara, Firenze, Italy.
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Pasciuti K, Iaccarino G, Soriani A, Bruzzaniti V, Marzi S, Gomellini S, Arcangeli S, Benassi M, Landoni V. DVHs evaluation in brain metastases stereotactic radiotherapy treatment plans. Radiother Oncol 2008; 87:110-5. [PMID: 18207593 DOI: 10.1016/j.radonc.2007.12.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2007] [Revised: 12/12/2007] [Accepted: 12/13/2007] [Indexed: 11/16/2022]
Abstract
PURPOSE The aim of this work is to report a retrospective study of radiobiological indicators based on Dose-Volume Histograms analysis obtained by stereotactic radiotherapy treatments. METHODS AND MATERIALS Fifty-five patients for a total of sixty-seven brain metastases with a mean target volume of 8.49 cc were treated by Dynamic Conformal Arc Therapy (DCAT) and Intensity-Modulated Stereotactic Radiotherapy (IMRST). The Delivered prescription dose was chosen on the basis of tumor size and location so as to ensure a 100% isodose coverage to the target volume. RESULTS The treatment plans reported a mean value of 10% and 2.19% for the inhomogeneity and conformal index, respectively. The F factor showed we overdosed sixty-three patients delivering an additional 7% dose more than calculated values. The radiobiological parameters: TCP and NTCP showed a complete tumor control limiting the organs at risk damage. CONCLUSION One goal of stereotactic radiotherapy is to design a treatment plan in which the steep dose gradient achievable minimizes the amount of radiation delivered outside the tumor region. This technique allows to deliver a much larger dose to the target without exceeding the radiation-related tolerance of normal tissues and improving patients' quality of life.
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Affiliation(s)
- Katia Pasciuti
- Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome, Italy.
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Hoh DJ, Liu CY, Chen JCT, Pagnini PG, Yu C, Wang MY, Apuzzo MLJ. CHAINED LIGHTNING, PART II. Neurosurgery 2007; 61:433-46; discussion 446. [PMID: 17881954 DOI: 10.1227/01.neu.0000290888.54578.f5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
THE FUNDAMENTAL PRINCIPLE in the radiosurgical treatment of neurological conditions is the delivery of energy to a lesion with minimal injury to surrounding structures. The development of radiosurgical techniques from Leksell's original design has focused on the refinement of various methodologies to achieve energy containment within a target. This article is the second in a series reviewing the evolution of radiosurgical instruments with respect to issues of energy beam generation and delivery for improved conformal therapy.
Continuing with concepts introduced in an earlier article, this article examines specific aspects of beam delivery and the emergence of stereotactic radiosurgery as a measure for focusing energy beams within a target volume. The application of stereotactic principles and devices to gamma ray and linear accelerator-based energy sources provides the methodology by which energy beams are generated and targeted precisely in a focal lesion. Advanced technological systems are reviewed, including fixed beams, dynamic radiosurgery, multileaf collimation, beam shaping, and robotics as various approaches for manipulating beam delivery. Radiosurgical instruments are also compared with regard to mechanics, geometry, and dosimetry. Finally, new radiosurgical designs currently on the horizon are introduced. In exploring the complex history of radiosurgery, it is evident that the discovery and rediscovery of ideas invariably leads to the development of innovative technology for the next generation.
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Affiliation(s)
- Daniel J Hoh
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA.
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Aoki M, Abe Y, Kondo H, Hatayama Y, Kawaguchi H, Fujimori A, Suzaki K, Seino M, Morita T, Souma M, Tsushima T, Takanashi S. Clinical outcome of stereotactic body radiotherapy of 54 Gy in nine fractions for patients with localized lung tumor using a custom-made immobilization system. ACTA ACUST UNITED AC 2007; 25:289-94. [PMID: 17634882 DOI: 10.1007/s11604-007-0141-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 03/06/2007] [Indexed: 12/25/2022]
Abstract
PURPOSE The aim of this study was to investigate the clinical outcome of stereotactic body radiotherapy (SBRT) of 54 Gy in nine fractions for patients with localized lung tumor using a custom-made immobilization system. METHODS AND MATERIALS The subjects were 19 patients who had localized lung tumor (11 primaries, 8 metastases) between May 2003 and October 2005. Treatment was conducted on 19 lung tumors by fixed multiple noncoplanar conformal beams with a standard linear accelerator. The isocentric dose was 54 Gy in nine fractions. The median overall treatment time was 15 days (range 11-22 days). All patients were immobilized by a thermo-shell and a custom-made headrest during the treatment. RESULTS The crude local tumor control rate was 95% during the follow-up of 9.4-39.5 (median 17.7) months. In-field recurrence was noted in only one patient at the last follow-up. The Kaplan-Meier overall survival rate at 2 years was 89.5%. Grade 1 radiation pneumonia and grade 1 radiation fibrosis were observed in 12 of the 19 patients. Treatment-related severe early and late complications were not observed in this series. CONCLUSION The stereotactic body radiotherapy of 54 Gy in nine fractions achieved acceptable tumor control without any severe complications. The results suggest that SBRT can be one of the alternatives for patients with localized lung tumors.
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Affiliation(s)
- Masahiko Aoki
- Department of Radiology, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
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Jin JY, Ryu S, Faber K, Mikkelsen T, Chen Q, Li S, Movsas B. 2D/3D Image fusion for accurate target localization and evaluation of a mask based stereotactic system in fractionated stereotactic radiotherapy of cranial lesions. Med Phys 2006; 33:4557-66. [PMID: 17278807 DOI: 10.1118/1.2392605] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study was to evaluate the accuracy of a two-dimensional (2D) to three-dimensional (3D) image-fusion-guided target localization system and a mask based stereotactic system for fractionated stereotactic radiotherapy (FSRT) of cranial lesions. A commercial x-ray image guidance system originally developed for extracranial radiosurgery was used for FSRT of cranial lesions. The localization accuracy was quantitatively evaluated with an anthropomorphic head phantom implanted with eight small radiopaque markers (BBs) in different locations. The accuracy and its clinical reliability were also qualitatively evaluated for a total of 127 fractions in 12 patients with both kV x-ray images and MV portal films. The image-guided system was then used as a standard to evaluate the overall uncertainty and reproducibility of the head mask based stereotactic system in these patients. The phantom study demonstrated that the maximal random error of the image-guided target localization was +/-0.6 mm in each direction in terms of the 95% confidence interval (CI). The systematic error varied with measurement methods. It was approximately 0.4 mm, mainly in the longitudinal direction, for the kV x-ray method. There was a 0.5 mm systematic difference, primarily in the lateral direction, between the kV x-ray and the MV portal methods. The patient study suggested that the accuracy of the image-guided system in patients was comparable to that in the phantom. The overall uncertainty of the mask system was +/-4 mm, and the reproducibility was +/-2.9 mm in terms of 95% CI. The study demonstrated that the image guidance system provides accurate and precise target positioning.
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Affiliation(s)
- Jian-Yue Jin
- Department of Radiation Oncology, Henry Ford Hospital, 2799 W Grand Boulevard, Detroit, Michigan 48202, USA.
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Georg D, Bogner J, Dieckmann K, Pötter R. Is mask-based stereotactic head-and-neck fixation as precise as stereotactic head fixation for precision radiotherapy? Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.05.075] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kunieda E, Deloar HM, Kitamura M, Kawaguchi O, Shiba H, Takeda A, Kawase T, Seki S, Shigematsu N, Kubo A. Rotational and translational reproducibility of newly developed Leksell frame-based relocatable fixation system. RADIATION MEDICINE 2006; 24:503-10. [PMID: 17058144 DOI: 10.1007/s11604-006-0066-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Accepted: 05/18/2006] [Indexed: 05/12/2023]
Abstract
PURPOSE The aim of this study was to evaluate three-dimensional movement of the cranium in a relocatable frame using positions of anatomical landmarks obtained from repeated quality-assurance (QA) computed tomography (CT) studies. MATERIALS AND METHODS We analyzed 17 series of QA-CT data representing five patients who underwent stereotactic radiotherapy for treatment of acoustic neurinoma. Helical-CT scans with 1-mm collimation were obtained at the time of treatment planning and during the course of treatment. The right and left short processes of the incus and the top of the crista galli were used as the three anatomical reference points. RESULTS Fluctuations in distance among the reference points were all <1 mm. The translational displacements for these points were <2 mm, with standard deviations (SD) of <2 mm. A plane that included all three reference points was defined as the reference plane. To investigate the direction of cranial rotation for each QA-CT scan, unit normal vectors of the reference plane were obtained. Three-dimensional analyses indicated that cranial rotation was greatest along the X-axis, followed by the Y-axis, with the least rotation along the Z-axis. CONCLUSION The result suggested that movement of the craniocaudal axis in the sagittal plane was a major factor behind displacement of the cranium.
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Affiliation(s)
- Etsuo Kunieda
- Department of Radiology, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Lightstone AW, Benedict SH, Bova FJ, Solberg TD, Stern RL. Intracranial stereotactic positioning systems: Report of the American Association of Physicists in Medicine Radiation Therapy Committee Task Group No. 68. Med Phys 2005; 32:2380-2398. [PMID: 16121596 DOI: 10.1118/1.1945347] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 04/14/2005] [Accepted: 05/11/2005] [Indexed: 11/07/2022] Open
Abstract
Intracranial stereotactic positioning systems (ISPSs) are used to position patients prior to precise radiation treatment of localized lesions of the brain. Often, the lesion is located in close proximity to critical anatomic features whose functions should be maintained. Many types of ISPSs have been described in the literature and are commercially available. These are briefly reviewed. ISPS systems provide two critical functions. The first is to establish a coordinate system upon which a guided therapy can be applied. The second is to provide a method to reapply the coordinate system to the patient such that the coordinates assigned to the patient's anatomy are identical from application to application. Without limiting this study to any particular approach to ISPSs, this report introduces nomenclature and suggests performance tests to quantify both the stability of the ISPS to map diagnostic data to a coordinate system, as well as the ISPS's ability to be realigned to the patient's anatomy. For users who desire to develop a new ISPS system, it may be necessary for the clinical team to establish the accuracy and precision of each of these functions. For commercially available systems that have demonstrated an acceptable level of accuracy and precision, the clinical team may need to demonstrate local ability to apply the system in a manner consistent with that employed during the published testing. The level of accuracy and precision required of an individual ISPS system is dependent upon the clinical protocol (e.g., fractionation, margin, pathology, etc.). Each clinical team should provide routine quality assurance procedures that are sufficient to support the assumptions of accuracy and precision used during the planning process. The testing of ISPS systems can be grouped into two broad categories, type testing, which occurs prior to general commercialization, and site testing, performed when a commercial system is installed at a clinic. Guidelines to help select the appropriate tests as well as recommendations to help establish the required frequency of testing are provided. Because of the broad scope of different systems, it is important that both the manufacturer and user rigorously critique the system and set QA tests appropriate to the particular device and its possible weaknesses. Major recommendations of the Task Group include: introduction of a new nomenclature for reporting repositioning accuracy; comprehensive analysis of patient characteristics that might adversely affect positioning accuracy; performance of testing immediately before each treatment to establish that there are no gross positioning errors; a general request to the Medical Physics community for improved QA tools; implementation of weekly portal imaging (perhaps cone beam CT in the future) as a method of tracking fractionated patients (as per TG 40); and periodic routine reviews of positioning accuracy.
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Affiliation(s)
- A W Lightstone
- Department of Medical Physics, Toronto-Sunnybrook Regional Cancer Centre, Toronto, Ontario M4N 3M5, Canada.
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Baumert BG, Egli P, Studer S, Dehing C, Davis JB. Repositioning accuracy of fractionated stereotactic irradiation: assessment of isocentre alignment for different dental fixations by using sequential CT scanning. Radiother Oncol 2005; 74:61-6. [PMID: 15683671 DOI: 10.1016/j.radonc.2004.08.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Revised: 07/16/2004] [Accepted: 08/09/2004] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE To quantify the accuracy and reproducibility of patient repositioning in fractionated stereotactic conformal radiotherapy (SCRT) using dental fixations in conjunction with a stereotactic head mask. PATIENTS AND METHODS One hundred and fourteen verification CT scans were performed on 57 patients in order to check set-up alignment. The first scan was done immediately after the first treatment. Twelve patients were checked for alignment accuracy with weekly CT scans over a period of 3-6 weeks, all others had 1-2 scans. Two different dental fixations were used in combination with a non-invasive mask system: an upper jaw support (35 patients) and a customised bite-block (17 patients). Five patients were treated with no additional fixation. Co-registration to the planning CT was used to assess alignment of the isocentre to the reference markers. Additionally, the intra-operator variability of image co-registration was assessed. RESULTS There was a significant improvement of the overall alignment in using the bite-block instead of the upper jaw support (P<0.001). The mean deviation was for the bite-block 2.2+/-1.1 mm (1 SD), for the upper jaw support 3.3+/-1.8 mm and 3.7+/-2.8 mm for the mask alone. Overall isocentre deviations independent of the method of fixation were 2.8 mm (1.7 mm, 1 SD). Displacements in CC direction were significantly less for the bite-block compared to the upper jaw support (P=0.03). The addition of an upper jaw support significantly reduced lateral rotations compared to the mask system alone (P=0.03). The intra-operator variability of image co-registration was 1.59+/-0.49 mm (1 SD). CONCLUSION The reproducibility of patient positioning using a re-locatable head mask system combined with a bite-block is within the reported range for similar devices and is preferable to a simple upper jaw support. In order to further reduce the margin for the planning target volume an intra-oral dental fixation is recommended.
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Affiliation(s)
- Brigitta G Baumert
- Department of Radiation Oncology, University Hospital, Zurich, Switzerland
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Vordermark D, Kölbl O, Ruprecht K, Vince GH, Bratengeier K, Flentje M. Hypofractionated stereotactic re-irradiation: treatment option in recurrent malignant glioma. BMC Cancer 2005; 5:55. [PMID: 15924621 PMCID: PMC1156875 DOI: 10.1186/1471-2407-5-55] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Accepted: 05/30/2005] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Hypofractionated stereotactic radiotherapy (HFSRT) is one salvage treatment option in previously irradiated patients with recurrent malignant glioma. We analyzed the results of HFSRT and prognostic factors in a single-institution series. METHODS Between 1997 and 2003, 19 patients with recurrent malignant glioma (14 glioblastoma on most recent histology, 5 anaplastic astrocytoma) were treated with HFSRT. The median interval from post-operative radiotherapy to HFSRT was 19 (range 3-116) months, the median daily single dose 5 (4-10) Gy, the median total dose 30 (20-30) Gy and the median planning target volume 15 (4-70) ml. RESULTS The median overall survival (OS) was 9.3 (1.9-77.6+) months from the time of HFSRT, 15.4 months for grade III and 7.9 months for grade IV tumors (p = 0.029, log-rank test). Two patients were alive at 34.6 and 77.6 months. OS was longer after a total dose of 30 Gy (11.1 months) than after total doses of <30 Gy (7.4 months; p = 0.051). Of five (26%) reoperations, none was performed for presumed or histologically predominant radiation necrosis. Median time to tumor progression after HFSRT on imaging was 4.9 months (1.3 to 37.3) months. CONCLUSION HFSRT with conservative total doses of no more than 30 Gy is safe and leads to similar OS times as more aggressive treatment schemes. In individual patients, HFSRT in combination with other salvage treatment modalities, was associated with long-term survival.
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Affiliation(s)
- Dirk Vordermark
- Dept. of Radiation Oncology, University of Würzburg, Germany
| | - Oliver Kölbl
- Dept. of Radiation Oncology, University of Würzburg, Germany
| | | | - Giles H Vince
- Dept. of Neurosurgery, University of Würzburg, Germany
| | | | - Michael Flentje
- Dept. of Radiation Oncology, University of Würzburg, Germany
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Robar JL, Clark BG, Schella JW, Kim CS. Analysis of patient repositioning accuracy in precision radiation therapy using automated image fusion. J Appl Clin Med Phys 2005; 6:71-83. [PMID: 15770198 PMCID: PMC5723511 DOI: 10.1120/jacmp.v6i1.1998] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This work describes a rapid and objective method of determining repositioning error during the course of precision radiation therapy using off‐line CT imaging and automated mutual‐information image fusion. The technique eliminates the variability associated with manual identification of anatomical landmarks by observers. A phantom study was conducted to quantify the accuracy of the image co‐registration‐based analysis itself. For CT voxel dimensions of 0.65×0.65×1.0mm3, the method is shown to detect translations with an accuracy of 0.5 mm in the anterior‐posterior and lateral dimensions and 0.8 mm in the superior‐inferior dimension. Phantom rotation in the coronal plane was detected to within 0.5° of expected values. The analysis has been applied to eight radiotherapy patients at two independent clinics, each immobilized by the same system for cranial stereotactic radiotherapy and CT‐imaged once per week over the five‐ to six‐week course of treatment. Among all patients, the ranges of translation in the anterior‐posterior, lateral, and superior‐inferior dimensions were −0.91mmto0.77mm,−0.66mm to1.02mm, and −2.24mm to3.47mm, respectively. Considering all patients and CT scans, the standard deviations of translation were 0.42 mm, 0.47 mm, and 1.36 mm in the anterior‐posterior, lateral, and superior‐inferior dimensions, respectively. The ranges of patient rotation about the superior‐inferior, left‐right, and anterior‐posterior axes were −2.84to2.62°,−1.74°to1.96°, and −1.78°to1.42°, respectively. PACS numbers: 87.53.‐j, 87.53.Kn, 87.53.Ly, 87.53.Xd
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Affiliation(s)
- James L Robar
- Department of Medical Physics, Nova Scotia Cancer Centre, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7, Canada.
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Fuss M, Salter BJ, Cheek D, Sadeghi A, Hevezi JM, Herman TS. Repositioning accuracy of a commercially available thermoplastic mask system. Radiother Oncol 2004; 71:339-45. [PMID: 15172151 DOI: 10.1016/j.radonc.2004.03.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Revised: 02/25/2004] [Accepted: 03/05/2004] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND PURPOSE To evaluate the repositioning accuracy of a commercially available thermoplastic mask system for single dose radiosurgery treatments and fractionated treatment courses. PATIENTS AND METHODS The repositioning accuracy of the Raycast-HP mask system (Orfit Industries, Wijnegem, Belgium) was analyzed. Twenty-two patients that were treated by intensity-modulated radiation therapy (IMRT) or intensity modulated radiosurgery (IMRS) for 43 intracranial lesions, underwent repeated CT imaging during their course of treatment, or as a positional control immediately before radiosurgery. We evaluated multiple anatomical landmark coordinates and their respective shifts in consecutive repeated CT-controls. An iterative optimization algorithm allowed for the calculation of the x, y and z-components of translation of the target isocenter(s) for each repeated CT, as well as rotation in the respective CT data sets. In addition to absolute target isocenter translation, the total magnitude vector (i.e. sum-vector) of isocenter motion was calculated along with patient rotations about the three principle axes. RESULTS Fifty-five control CT datasets were analyzed for the target isocenter's respective position relative to the original treatment planning CT simulation. Mean target isocenter translation was 0.74+/-0.53, 0.75+/-0.60 and 0.93+/-0.78 mm in x, y and z-directions, respectively. Mean rotation about the x, y and z-axes was 0.67+/-0.66, 0.61+/-0.63 and 0.67+/-0.61 degrees, respectively. The respective median and mean magnitude vectors of isocenter translation were 1.28 and 1.59+/-0.84 mm. Analysis of the accuracy of the first setup control, representative of setup accuracy for radiosurgery treatments, compared with setup accuracy throughout a fractionated radiation treatment course were statistically equivalent (P= 0.15) thus indicating no measurable deterioration of setup accuracy throughout the treatment course. CONCLUSIONS The analyzed Orfit thermoplastic mask system performed favorably compared with other mask immobilization systems for which peer-reviewed repositioning data exist. While the performance of the system for fractionated treatment courses was considered to be excellent, use of this mask system for radiosurgery immobilization in our clinic is subject to additional quality assurance measures to prohibit the delivery of treatments with target dislocations larger than 2 mm. The measured data in the present study should enable the users of this system to assign appropriate margins for the generation of planning target volumes.
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Affiliation(s)
- Martin Fuss
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Kivelä T, Tenhunen M, Joensuu T, Tommila P, Joensuu H, Kouri M. Stereotactic radiotherapy of symptomatic circumscribed choroidal hemangiomas. Ophthalmology 2003; 110:1977-82. [PMID: 14522774 DOI: 10.1016/s0161-6420(03)00483-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To determine feasibility of low-dose stereotactic radiotherapy in the treatment of symptomatic circumscribed choroidal hemangioma. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Five consecutive patients with perifoveolar and peripapillary circumscribed choroidal hemangioma and visual symptoms from exudative retinal detachment. METHODS A dose of 20 Gy was delivered stereotactically with linear accelerator. Tumor dimensions were determined by B-scan ultrasonography. MAIN OUTCOME MEASURES Resolution of subretinal fluid, best-corrected visual acuity, and reduction in tumor height. RESULTS Median tumor height at baseline was 2.8 mm (range, 2.0-4.2 mm). Two tumors were subfoveolar, two were juxtafoveolar, and one was extrafoveolar. Cystic macular edema and subretinal fibrosis were present in both eyes with subfoveolar tumor. Exudative retinal detachment resolved within a median of 5 months (response rate, 100%; 95% CI, 48%-100%). Median best-corrected visual acuity was 20/50 (range, 20/22-20/100) at diagnosis and 20/25 (range, 20/20-20/60) 20 months after treatment. Tumor height had decreased a median of 24% (range, 0%-31%) by 6 months and 29% (range, 9%-59%) by 20 months. Secondary retinal pigment epithelial mottling associated with tumor regression occurred in two patients. One eye developed a paracentral scotoma. CONCLUSIONS Stereotactic radiotherapy can be targeted precisely enough to induce regression of subretinal fluid from circumscribed choroidal hemangiomas.
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Affiliation(s)
- Tero Kivelä
- Oncology and Vitreoretinal Service, Department of Ophthalmology, Helsinki University Central Hospital, Haartmaninkatu 4 C, PL 220, FIN-00029 HUS, Helsinki, Finland
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Baumert BG, Norton IA, Davis JB. Intensity-modulated stereotactic radiotherapy vs. stereotactic conformal radiotherapy for the treatment of meningioma located predominantly in the skull base. Int J Radiat Oncol Biol Phys 2003; 57:580-92. [PMID: 12957272 DOI: 10.1016/s0360-3016(03)00587-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE This study evaluates a possible advantage of intensity-modulated stereotactic radiotherapy (IMSRT) over stereotactic conformal radiotherapy (SCRT) in the treatment of lesions in the base of the skull. METHODS AND MATERIALS Ten patients (7 with a skull base meningioma) planned for routine SCRT were replanned for IMSRT. The criteria for comparison were the same for both methods: optimal dose to the planning target volume (PTV) and optimal sparing of the organs at risk (OAR). For SCRT, sparing of OAR was achieved by conformal avoidance using 5-6 fields. The IMSRT inverse planning process used optimized OAR sparing through user-defined dose constraints. Dose to the PTV and OAR were assessed by dose-volume histograms, maximum dose, 2 conformity indices, and volumes of relevant isodoses. RESULTS The conformity index is consistently higher for IMSRT, the largest improvement being for the multifocal and irregular cases. Volumes of the 90% and 80% isodoses were smaller for IMSRT, whereas the volume of the 30% isodose was larger for IMSRT in 6 cases. The maximum dose was consistently higher for IMSRT (mean values 102% and 108% for SCRT and IMSRT, respectively). Sparing of OAR was better with IMSRT, especially for those OARs situated in or near a concave PTV. CONCLUSIONS In terms of PTV coverage, there is an advantage in using IMSRT for all target shapes, but especially for irregular and concave targets. The dose to OAR is lower with IMSRT, although the volume of normal tissue receiving a low dose can be larger than for SCRT.
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Affiliation(s)
- Brigitta G Baumert
- Department of Radiation Oncology, University Hospital Zurich, Zurich, Switzerland.
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Wong VYW, Tung SY, Leung TW, Ho KHS. CT verification of isocentre relocatability using stereotactic mask fixation system. Clin Oncol (R Coll Radiol) 2003; 15:280-7. [PMID: 12924459 DOI: 10.1016/s0936-6555(03)00091-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS This study introduces a non-invasive method based on computed tomography (CT) verification to ensure patients are accurately positioned before fractionated stereotactic radiotherapy. It enables quality control of mask positioning with reference to the CT images of the treatment plan. MATERIALS AND METHODS A mask system, together with a dental impression moulded mouth bite, was used for patient immobilisation. In order to facilitate relevant image comparison, special alignment during CT localisation was discussed in the study. The accuracy of patient set-up was studied by assessing the isocentre position in relation to the patient's anatomical structure. The planning CT images were applied as a reference and the study was applied to 261 cranial applications. RESULTS The results show that the mean and the maximum overall displacements at the isocentre were 0.7 and 2.5 mm, respectively. The mean and the maximum rotational displacement in the axial plane were 0.56 degrees and 2 degrees, respectively. The mean translational displacement and rotational displacement were close to zero when considering the direction of movement. CONCLUSIONS The results indicate that the systematic error of the mask system and the verification method are minimal. Advantages of this technique include the simple set-up, three-dimensional quantification and short study time (10-15 min). It is therefore practical to implement on a routine basis. Investigation of the ability to relocate the mask is also recommended to justify the required safety margin between the clinical and planning target volumes.
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Affiliation(s)
- V Y W Wong
- Department of Clinical Oncology, Tuen Mun Hospital, Hong Kong, People's Republic of China.
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Gross MW, Spahn U, Engenhart-Cabillic R. Assessment of the accuracy of a conventional simulation for radiotherapy of head and skull base tumors. Technol Cancer Res Treat 2003; 2:345-51. [PMID: 12892518 DOI: 10.1177/153303460300200410] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this prospective study we investigated the absolute accuracy of the conventional simulation in head and skull base tumors. 41 isocenters in 40 consecutive patients with tumors of the head and skull base were included. In all cases a rigid stereotactic mask system was used for non-invasive fixation. The stereotactic ("calculated") coordinates of the isocenter were defined by the treatment planning computer. Each patient underwent a physical simulation using exclusively anatomical reference points to define the "preliminary" isocenter. The displacement between its coordinates and those of the stereotactic target point was recorded in X-, Y- and Z-direction with help of the targeting device, and the spatial error was calculated. Additionally, the patients were stratified by basal or calvarial tumor site to estimate the importance of the basal bone structures in the simulation accuracy. The influence of the learning effect on simulation accuracy was also determined. The results showed an accuracy of set-up at the linac within 1 mm in all three directions as calculated from orthogonal portal films. Mean shift of the isocenter coordinates obtained from physical simulation compared to the calculated stereotactic coordinates was 2.15 mm, 2.54 mm, and 2.69 mm for X-, Y-, and Z-direction, respectively. Mean spatial displacement amounted 5.06 mm, and the median was 4.50 mm. No significant difference could be noted between basal and calvarial location of the isocenter. A significant "learning effect" was observed with a decrease in spatial shift with increasing patient numbers. This effect was stronger in basal lesions, whereas calvarial lesions showed only a minor, insignificant effect. In conclusion, a physical simulation requires a safety margin of 5 mm in PTV definition in addition to other factors, e.g. organ movement.
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Affiliation(s)
- Markus W Gross
- Department of Radiotherapy & Radiooncology, Philipps-University of Marburg, Baldingerstrasse, D-35033 Marburg, Germany.
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Kim KH, Cho MJ, Kim JS, Kim JS, Song CJ, Song SH, Kim SH, Myers L, Kim YE. Isocenter accuracy in frameless stereotactic radiotherapy using implanted fiducials. Int J Radiat Oncol Biol Phys 2003; 56:266-73. [PMID: 12694848 DOI: 10.1016/s0360-3016(03)00088-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE The stereotactic radiotherapy (SRT) system verifies isocenter accuracy in patient space. In this study, we evaluate isocenter accuracy in frameless SRT using implanted cranial gold markers. MATERIALS AND METHODS We performed frameless SRT on 43 intracranial tumor patients between August 1997 and December 2000. The treatment technique was determined by the tumor shape and volume, and by the location of critical organs. The coordinates of anterior-posterior and lateral port film were inputted to ISOLOC software, which calculated (1) the couch moves translation distance required to bring the target point to the isocenter, and (2) the intermarker distance comparisons between the CT study and the treatment machine films. We evaluated the isocenter deviation based on the error between orthogonal film target coordinates and isocenter coordinates. RESULTS The mean treatment isocenter deviations (x, y, z) were -0.03, 0.14, and -0.04 mm, respectively. The systematic component isocenter standard deviations were 0.28, 0.31, and 0.35 mm (1 SD), respectively, and the random component isocenter standard deviations were 0.53, 0.52, and 0.50 mm (1 SD), respectively. CONCLUSIONS The isocenter accuracy in the frameless SRT-implanted fiducial system is highly reliable and is comparable to that of other stereotactic radiosurgery systems.
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Affiliation(s)
- Ki-Hwan Kim
- Department of Therapeutic Radiology, Chungnam National University, Taejon, South Korea
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Stieber VW, Bourland JD, Tome WA, Mehta MP. Gentlemen (and ladies), choose your weapons: Gamma knife vs. linear accelerator radiosurgery. Technol Cancer Res Treat 2003; 2:79-86. [PMID: 12680787 DOI: 10.1177/153303460300200202] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This article compares and contrasts Gamma Knife radiosurgery with linear accelerator-based radiosurgery; where appropriate, Cyberknife technology is discussed. Topics covered are: positioning of the head (invasive versus non-invasive positioning systems); collimator construction; beam properties; beam arrangements; treatment planning; and issues regarding manpower (including a discussion of patient repositioning during treatment), machine availability, and financial considerations.
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Affiliation(s)
- Volker W Stieber
- Department of Radiation Oncology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1030, USA.
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38
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Jaywant SM, Osei EK, Ladak S. Stereotactic radiotherapy in the treatment of ocular melanoma: a noninvasive eye fixation aid and tracking system. J Appl Clin Med Phys 2003; 4:156-61. [PMID: 12777151 PMCID: PMC5724480 DOI: 10.1120/jacmp.v4i2.2531] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ocular melanoma is frequently treated using brachytherapy implants (such as 125I and 60Co plaques or 184Ta wire), surgery, or external beam radiotherapy using small 60Co beams, high energy x-rays, or proton therapy. The last technique, though very expensive, provides improved dose distributions and dose localizations in the treatment of tumours adjacent to critical normal tissues. The technique of fractionated stereotactic radiotherapy is now being used at an increasingly large number of centers in the treatment of lesions in the brain, and the head and neck. This article describes the successful extension of the stereotactic technique to the treatment of ocular melanoma: an eye fixation aid is attached to a noninvasive, relocatable Gill-Thomas-Cosman head frame together with a simple eye-movement tracking system.
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Affiliation(s)
- S. M. Jaywant
- Department of Radiation PhysicsPrincess Margaret Hospital610 University AvenueTorontoOntarioM5G 2M9Canada
| | - E. K. Osei
- Department of Radiation PhysicsPrincess Margaret Hospital610 University AvenueTorontoOntarioM5G 2M9Canada
| | - S. Ladak
- Department of Radiation TherapyPrincess Margaret Hospital610 University AvenueTorontoOntarioM5G 2M9Canada
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Leybovich LB, Sethi A, Dogan N, Melian E, Krasin M, Emami B. An immobilization and localization technique for SRT and IMRT of intracranial tumors. J Appl Clin Med Phys 2002; 3:317-22. [PMID: 12383052 PMCID: PMC5724536 DOI: 10.1120/jacmp.v3i4.2556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2002] [Accepted: 08/06/2002] [Indexed: 11/23/2022] Open
Abstract
A noninvasive localization and immobilization technique that facilitates planning and accurate delivery of both intensity modulated radiotherapy (IMRT) and linac based stereotactic radiotherapy (SRT) of intracranial tumors has been developed and clinically tested. Immobilization of a patient was based on a commercially available Gill-Thomas-Cossman (GTC) relocatable frame. A stereotactic localization frame (LF) with the attached NOMOS localization device (CT pointer) was used for CT scanning of patients. Thus, CT slices contained fiducial marks for both IMRT and SRT. The patient anatomy and target(s) were contoured on a stand-alone CT-based imaging system. CT slices and contours were then transmitted to both IMRT and SRT treatment planning systems (TPSs) for concurrent development of IMRT and SRT plans. The treatment method that more closely approached the treatment goals could be selected. Since all TPSs used the same contour set, the accuracy of competing treatment plans comparison was improved. SRT delivery was done conventionally. For IMRT delivery patients used the SRT patient immobilization system. For the patient setup, the IMRT target box was attached to the SRT LF, replacing the IMRT CT Pointer. A modified and lighter IMRT target box compatible with SRT LF was fabricated. The proposed technique can also be used for planning and delivery of 3D CRT, thus improving its accuracy. Day-to-day reproducibility of the patient setup can be evaluated using a SRT Depth Helmet.
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Affiliation(s)
- Leonid B Leybovich
- Department of Radiation Oncology, Stritch School of Medicine, Loyola University Chicago, 2160 South First Ave., Maywood, Illinois 60153, USA.
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40
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Audet C, Hilts M, Jirasek A, Duzenli C. CT gel dosimetry technique: comparison of a planned and measured 3D stereotactic dose volume. J Appl Clin Med Phys 2002; 3:110-8. [PMID: 11958651 PMCID: PMC5724611 DOI: 10.1120/jacmp.v3i2.2575] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2001] [Accepted: 01/25/2002] [Indexed: 11/23/2022] Open
Abstract
This study presents a 3D dose mapping of complex dose distributions using an x-ray computed tomography (CT) polymer gel dosimetry technique. Two polyacrylamide gels (PAGs) of identical composition were irradiated with the same four arc stereotactic treatment to maximum doses of 15 Gy (PAG1) and 8 Gy (PAG2). The PAGs were CT imaged using a previously defined protocol that involves image averaging and background subtraction to improve image quality. For comparison with the planned isodose distribution, the PAG images were converted to relative dose maps using a CT number-dose calibration curve or simple division. The PAG images were then co-registered with the planning CT images in the BrainLab treatment planning software which automatically provides reconstructed sagittal and coronal images for 3D evaluation of measured and planned dose. The hypo-intense high dose region in both sets of gel images agreed with the planned 80% isodose contour and was shifted by up to 1.5 and 3.0 mm in the axial and reconstructed planes, respectively. This demonstrates the ability of the CT gel technique to accurately localize the high dose region produced by the stereotactic treatment. The resulting agreement of the measured relative dose volume for PAG1 was within 3.0 mm for the 50% and 80% isodose surfaces. However, the dose contrast was too low in PAG2 to allow for accurate definition of measured relative dose surfaces. Thus, a PAG should be irradiated to higher doses if quantitative relative dose information is required. Unfortunately, this implies use of an additional PAG and its CT number dose response since doses greater than 8-10 Gy fall outside the linear regions of the response.
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MESH Headings
- Acrylamides/therapeutic use
- Gels/therapeutic use
- Humans
- Image Processing, Computer-Assisted/instrumentation
- Image Processing, Computer-Assisted/methods
- Imaging, Three-Dimensional/instrumentation
- Imaging, Three-Dimensional/methods
- Polymers/therapeutic use
- Radiation Dosage
- Radiosurgery/instrumentation
- Radiosurgery/methods
- Radiotherapy Dosage
- Radiotherapy Planning, Computer-Assisted/instrumentation
- Radiotherapy Planning, Computer-Assisted/methods
- Radiotherapy, Conformal/instrumentation
- Radiotherapy, Conformal/methods
- Tomography, X-Ray Computed/instrumentation
- Tomography, X-Ray Computed/methods
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Affiliation(s)
- C. Audet
- British Columbia Cancer AgencyBritish ColumbiaCanadaV5Z 4E6
- Palo Alto Medical FoundationPalo AltoCalifornia94305
| | - M. Hilts
- British Columbia Cancer AgencyBritish ColumbiaCanadaV5Z 4E6
| | - A. Jirasek
- British Columbia Cancer AgencyBritish ColumbiaCanadaV5Z 4E6
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverCanadaV5Z 4E6
| | - C. Duzenli
- British Columbia Cancer AgencyBritish ColumbiaCanadaV5Z 4E6
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Dieckmann K, Bogner J, Georg D, Zehetmayer M, Kren G, Pötter R. A linac-based stereotactic irradiation technique of uveal melanoma. Radiother Oncol 2001; 61:49-56. [PMID: 11578728 DOI: 10.1016/s0167-8140(01)00413-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To describe a stereotactic irradiation technique for uveal melanomas performed at a linac, based on a non-invasive eye fixation and eye monitoring system. METHODS For eye immobilization a light source system is integrated in a standard stereotactic mask system in front of the healthy eye: During treatment preparation (computed tomography/magnetic resonance imaging) as well as for treatment delivery, patients are instructed to gaze at the fixation light source. A mini-video camera monitors the pupil center position of the diseased eye. For treatment planning and beam delivery standard stereotactic radiotherapy equipment is used. If the pupil center deviation from a predefined 'zero-position' exceeds 1 mm (for more than 2 s), treatment delivery is interrupted. Between 1996 and 1999 60 patients with uveal melanomas, where (i) tumor height exceeded 7 mm, or (ii) tumor height was more than 3 mm, and the central tumor distance to the optic disc and/or the macula was less than 3 mm, have been treated. A total dose of 60 or 70 Gy has been given in 5 fractions within 10 days. RESULTS The repositioning accuracy in the mask system is 0.47+/-0.36 mm in rostral-occipital direction, 0.75+/-0.52 mm laterally, and 1.12+/-0.96 mm in vertical direction. An eye movement analysis performed for 23 patients shows a pupil center deviation from the 'zero' position<1 mm in 91% of all cases investigated. In a theoretical analysis, pupil center deviations are correlated with GTV 'movements'. For a pupil center deviation of 1 mm (rotation of the globe of 5 degrees ) the GTV is still encompassed by the 80% isodose in 94%. CONCLUSION For treatments of uveal melanomas, linac-based stereotactic radiotherapy combined with a non-invasive eye immobilization and monitoring system represents a feasible, accurate and reproducible method. Besides considerable technical requirements, the complexity of the treatment technique demands an interdisciplinary team continuously dedicated to this task.
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Affiliation(s)
- K Dieckmann
- Department of Radiotherapy and Radiobiology, University of Vienna, General Hospital Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
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42
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Caudrelier JM, Auliard A, Sarrazin T, Gibon D, Coche-Dequéant B, Castelain B. [Comparison of conventional and conformational dosimetry in radiotherapy of cerebral neoplasms]. Cancer Radiother 2001; 5:237-45. [PMID: 11446077 DOI: 10.1016/s1278-3218(01)00098-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE We prospectively compared a conventional treatment planning (PT2D) and 3-dimensional conformal treatment planning (PT3D) for radiotherapy of cerebral tumours. PATIENTS AND METHODS Patients treated between 1/10/98 and 1/4/99 by irradiation for cerebral tumours were analysed. For each case, we planned PT2D using conventional orthogonal x-ray films, and afterward, PT3D using CT scan. Gross tumor volume, planning target volume and normal tissue volumes were defined. Dose was prescribed according to report 50 of the International Commission on Radiation Units and Measurements (ICRU). We compared surfaces of sagittal view targets defined on PT2D and PT3D and called them S2D and S3D, respectively. Irradiated volumes by 90% isodoses (VE-90%) and normal tissue volumes irradiated by 20, 50, 90% isodoses were calculated and compared using Student's paired t-test. RESULTS There was a concordance of 84% of target surfaces defined on PT2D and PT3D. Percentages of target surface under- or-over defined by PT2D were 16 and 13% respectively. VE-90% was decreased by 15% (p = 0.07) with PT3D. Normal brain volume irradiated by 90% isodose was decreased by 27% with PT3D (p = 0.04). CONCLUSION For radiotherapy of cerebral tumors using only coplanar beams, PT3D leads to a reduction of normal brain tissue irradiated. We recommend PT3D for radiotherapy of cerebral tumors, particularly for low-grade or benign tumors (meningiomas, neuromas, etc.).
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Affiliation(s)
- J M Caudrelier
- Département de radiothérapie, centre Oscar-Lambret, BP 307, 59020 Lille, France.
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Karger CP, Jäkel O, Debus J, Kuhn S, Hartmann GH. Three-dimensional accuracy and interfractional reproducibility of patient fixation and positioning using a stereotactic head mask system. Int J Radiat Oncol Biol Phys 2001; 49:1493-504. [PMID: 11286858 DOI: 10.1016/s0360-3016(00)01562-5] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE Conformal radiotherapy in the head and neck region requires precise and reproducible patient setup. The definition of safety margins around the clinical target volume has to take into account uncertainties of fixation and positioning. Data are presented to quantify the involved uncertainties for the system used. METHODS AND MATERIALS Interfractional reproducibility of fixation and positioning of a target point in the brain was evaluated by biplanar films. 118 film pairs obtained at 52 fractions in 4 patients were analyzed. The setup was verified at the actual treatment table position by diagnostic X-ray units aligned to the isocenter and by a stereotactic X-ray localization technique. The stereotactic coordinates of the treated isocenter, of fiducials on the mask, and of implanted internal markers within the patient were measured to determine systematic and random errors. The data are corrected for uncertainty of the localization method. RESULTS Displacements in target point positioning were 0.35 +/- 0.41 mm, 1.22 +/- 0.25 mm, and -0.74 +/- 0.32 mm in the x, y, and z direction, respectively. The reproducibility of the fixation of the patient's head within the mask was 0.48 mm (x), 0.67 mm (y), and 0.72 mm (z). Rotational uncertainties around an axis parallel to the x, y, and z axis were 0.72 degrees, 0.43 degrees, and 0.70 degrees, respectively. A simulation, based on the acquired data, yields a typical radial overall uncertainty for positioning and fixation of 1.80 +/- 0.60 mm. CONCLUSIONS The applied setup technique showed to be highly reproducible. The data suggest that for the applied technique, a safety margin between clinical and planning target volume of 1-2 mm along one axis is sufficient for a target at the base of skull.
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Affiliation(s)
- C P Karger
- Abteilung Medizinische Physik, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
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44
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Baumert BG, Lomax AJ, Miltchev V, Davis JB. A comparison of dose distributions of proton and photon beams in stereotactic conformal radiotherapy of brain lesions. Int J Radiat Oncol Biol Phys 2001; 49:1439-49. [PMID: 11286852 DOI: 10.1016/s0360-3016(00)01422-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE Micromultileaf collimators (mMLC) have recently been introduced to conform photon beams in stereotactic irradiation of brain lesions. Proton beams and stereotactic conformal radiotherapy (SCRT) can be used to tailor the dose to nonspherical targets, as most tumors of the brain are irregularly shaped. Comparative planning of brain lesions using either proton or stereotactically guided photon beams was done to assess the institution's clinically available modality for three-dimensional conformal radiotherapy. METHODS AND MATERIALS For the photon treatment, multiple stereotactically guided uniform intensity beams from a linear accelerator were used, each conformed to a projection of the planning target volume (PTV) by a mMLC. Proton beams were delivered from an isocentrically mounted gantry, using the spot-scanning technique and energy modulation. Seven patients were scanned in a stereotactic frame; target volumes and organs at risk (OAR) were delineated with the help of MR images. Four different lesions were selected: (1) concave, (2) ellipsoid isolated, (3) superficial and close to an organ at risk, and (4) irregular complex. Dose distributions in the PTV and critical structures were calculated using three-dimensional treatment-planning systems, followed by both a quantitative (by dose--volume histogram and conformity index) and qualitative (visual inspection) assessment of the plans. RESULTS A high degree of conformation was achieved with a mMLC and stereotactic uniform intensity beams with comparable conformity indices to protons for 5 out of 7 plans, especially for superficial or spherical lesions. In the cases studied, the conformity index was better for protons than for photons for complex or concave lesions, or when the PTV was in the neighborhood of critical structures. CONCLUSION The results for the cases studied, show that for simple geometries or for superficial lesions, there is no advantage in using protons. However, for complex PTV shapes, or when the PTV is in the vicinity of critical structures, protons seem to be potentially better than the fixed-field photon technique.
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Affiliation(s)
- B G Baumert
- Radiation-Oncology, University Hospital, Zurich, Switzerland.
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45
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Wulf J, Hädinger U, Oppitz U, Olshausen B, Flentje M. Stereotactic radiotherapy of extracranial targets: CT-simulation and accuracy of treatment in the stereotactic body frame. Radiother Oncol 2000; 57:225-36. [PMID: 11054527 DOI: 10.1016/s0167-8140(00)00226-7] [Citation(s) in RCA: 205] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND PURPOSE Evaluation of set-up accuracy and analysis of target reproducibility in the stereotactic body frame (SBF), designed by Blomgren and Lax from Karolinska Hospital, Stockholm. Different types of targets were analyzed for the risk of target deviation. The correlation of target deviation to bony structures was analyzed to evaluate the value of bones as reference structures for isocenter verification. MATERIALS AND METHODS Thirty patients with 32 targets were treated in the SBF for primary or metastatic peripheral lung cancer, liver metastases, abdominal and pelvic tumor recurrences or bone metastases. Set-up accuracy and target mobility were evaluated by CT-simulation and port films. The contours of the target at isocenter level, bony structures and body outline were compared by matching the CT-slices for treatment planning and simulation using the stereotactic coordinates of the SBF as external reference system. The matching procedure was performed by using a 3D treatment planning program. RESULTS Set-up accuracy represented by bony structures revealed standard deviations (SD) of 3.5 mm in longitudinal, 2.2 mm in anterior-posterior and 3.9 mm in lateral directions. Target reproducibility showed a SD of 4.4 mm in longitudinal, 3.4 mm ap and 3.3 mm in lateral direction prior to correction. Correlation of target deviation to bones ranged from 33% (soft tissue targets) to 100% (bones). CONCLUSION A security margin of 5 mm for PTV definition is sufficient, if CT simulation is performed prior to each treatment to correct larger target deviations or set-up errors. Isocenter verification relative to bony structures is only safe for bony targets but not for soft tissue targets.
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Affiliation(s)
- J Wulf
- Department of Radiotherapy, University of Würzburg, Josef-Schneider-Strasse 11, D-97080 Würzburg, Germany
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Uematsu M, Shioda A, Suda A, Tahara K, Kojima T, Hama Y, Kono M, Wong JR, Fukui T, Kusano S. Intrafractional tumor position stability during computed tomography (CT)-guided frameless stereotactic radiation therapy for lung or liver cancers with a fusion of CT and linear accelerator (FOCAL) unit. Int J Radiat Oncol Biol Phys 2000; 48:443-8. [PMID: 10974460 DOI: 10.1016/s0360-3016(00)00619-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE To evaluate intrafractional tumor position stability during computed tomography (CT)-guided frameless stereotactic radiation therapy (SRT) for lung or liver cancers, we checked repeated CT scanning, with a fusion of CT and linear accelerator (FOCAL) unit. METHODS AND MATERIALS The FOCAL unit is a combination of a linear accelerator (Linac), CT scanner, X-ray simulator (X-S), and carbon table, and is designed to achieve CT-guided SRT with daily CT positioning followed by immediate irradiation while patients keep reduced shallow respirations. To evaluate intrafractional tumor position stability, 50 lung or liver lesions in 20 patients were checked by repeated CT scanning just before and after irradiation, and the obtained images were compared. RESULTS There was no case with the intrafractional error judged to be greater than 10 mm. In 68% of cases, the intrafractional positioning errors were negligible (0-5 mm). CONCLUSIONS Using the FOCAL unit, SRT for lung or liver cancers could be performed with intrafractional positioning errors not greater than 10 mm.
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Affiliation(s)
- M Uematsu
- Division of Radiation Oncology, National Defense Medical College, Tokorozawa, Saitama, Japan
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Schulte RW, Fargo RA, Meinass HJ, Slater JD, Slater JM. Analysis of head motion prior to and during proton beam therapy. Int J Radiat Oncol Biol Phys 2000; 47:1105-10. [PMID: 10863084 DOI: 10.1016/s0360-3016(00)00551-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE We report on the use of a noninvasive patient motion monitoring system to evaluate the amount of head motion prior to and during proton radiation therapy sessions. METHODS AND MATERIALS Two optical displacement sensors, placed close to the patient's head, were used for online monitoring of the head position, with submillimeter accuracy. Motion data, including the difference between start and end position (Dx) and the maximum displacement during the recorded session (Dx-max), were acquired for pretreatment sessions to analyze alignment radiographs, and for treatment sessions. We have recorded 102 pretreatment and 99 treatment sessions in 16 patients immobilized with a thermoplastic mask, and 44 pretreatment and 56 treatment sessions in 13 patients immobilized with vacuum-assisted dental fixation. To avoid incorrect data analysis due to replicate observations, only 1 pretreatment and 1 treatment session per patient were selected at random for statistical comparison of mean or median motion parameters in different subgroups. RESULTS Both techniques showed similar immobilization efficiencies. The median Dx and Dx-max values were 0. 18 mm and 0.46 mm, respectively, for 16 treatment sessions with mask immobilization, and 0.22 mm and 0.50 mm, respectively, for 13 treatment sessions with dental immobilization. Motion parameters for pretreatment and treatment sessions were not statistically different. CONCLUSION Online verification of patient's head motion is feasible and provides valuable data for confirmation of proper treatment delivery in individual patients, as well as for the evaluation of different immobilization methods.
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Affiliation(s)
- R W Schulte
- Departments of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, CA 92354, USA.
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48
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Vordermark D, Becker G, Flentje M, Richter S, Goerttler-Krauspe I, Koelbl O. Transcranial sonography: integration into target volume definition for glioblastoma multiforme. Int J Radiat Oncol Biol Phys 2000; 47:565-71. [PMID: 10837937 DOI: 10.1016/s0360-3016(00)00565-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Recent studies indicate that transcranial sonography (TCS) reliably displays the extension of malignant brain tumors. The effect of integrating TCS into radiotherapy planning for glioblastoma multiforme (GBM) was investigated herein. METHODS AND MATERIALS Thirteen patients subtotally resected for GBM underwent TCS during radiotherapy planning and were conventionally treated (54 to 60 Gy). Gross tumor volumes (GTVs) and stereotactic boost planning target volumes (PTVs, 3-mm margin) were created, based on contrast enhancement on computed tomography (CT) only (PTV(CT)) or the combined CT and TCS information (PTV(CT+TCS)). Noncoplonar conformal treatment plans for both PTVs were compared. Tumor progression patterns and preoperative magnetic resonance imaging (MRI) were related to both PTVs. RESULTS A sufficient temporal bone window for TCS was present in 11 of 13 patients. GTVs as defined by TCS were considerably larger than the respective CT volumes: Of the composite GTV(CT+TCS) (median volume 42 ml), 23%, 13%, and 66% (medians) were covered by the overlap of both methods, CT only and TCS only, respectively. Median sizes of PTV(CT) and PTV(CT+TCS) were 34 and 74 ml, respectively. Addition of TCS to CT information led to a median increase of the volume irradiated within the 80% isodose by 32 ml (median factor 1.51). PTV(CT+TCS) volume was at median 24% of a "conventional" MRI(T2)-based PTV. Of eight progressions analyzed, three and six occurred inside the 80% isodose of the plans for PTV(CT) and for PTV(CT+TCS), respectively. CONCLUSION Addition of TCS tumor volume to the contrast-enhancing CT volume in postoperative radiotherapy planning for GBM increases the treated volume by a median factor of 1.5. Since a high frequency of marginal recurrences is reported from dose-escalation trials of this disease, TCS may complement established methods in PTV definition.
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Affiliation(s)
- D Vordermark
- Department of Radiation Oncology, University of Wuerzburg, Germany.
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Zavgorodni SF. Treatment planning algorithm corrections accounting for random setup uncertainties in fractionated stereotactic radiotherapy. Med Phys 2000; 27:685-90. [PMID: 10798690 DOI: 10.1118/1.598930] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A number of relocatable head fixation systems have become commercially available or developed in-house to perform fractionated stereotactic radiotherapy (SRT) treatment. The uncertainty usually quoted for the target repositioning in SRT is over 2 mm, more than twice that of stereotactic radiosurgery (SRS) systems. This setup uncertainty is usually accounted for at treatment planning by outlining extra target margins to form the planning target volume (PTV). It was, however, shown by Lo et al. [Int. J. Radiat. Oncol., Biol., Phys. 34, 1113-1119 (1996)] that these extra margins partly offset the radiobiological advantages of SRT. The present paper considers dose calculations in SRT and shows that the dose predictions could be made at least as accurate as in SRS with no extra margins required. It is shown that the dose distribution from SRT can be calculated using the same algorithms as in SRS, with the measured off-axis ratios (OARs) replaced by "effective" OARs. These are obtained by convolving the probability density distribution of the isocenter positions (assumed to be normal) and the original OARs. An additional output correction factor has also been introduced accounting for the isocenter dose reduction (2.4% for a 7 mm collimator) due to the OARs "blurring." Another correction factor accommodates for the reduced (by 1% for 6 MV beam) dose rate at the isocenter due to x-ray absorption in the relocatable mask. Mean dose profiles and the standard deviations of the dose (STD) were obtained through simulating SRT treatment by a combination of normally distributed isocenters. These dose distributions were compared with those calculated using the convolution approach. Agreement of the dose distributions was within 1%. Since standard deviation reduces with the number of fractions, N, as STD/square root(N), the planning predictions in fractionated stereotactic radiotherapy can be made more accurate than in SRS by increasing N and using "effective" OARs along with corrected dose output.
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Affiliation(s)
- S F Zavgorodni
- Department of Medical Physics, Royal Adelaide Hospital, South Australia, Australia.
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50
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Kubo HD, Wilder RB, Pappas CT. Impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans. Int J Radiat Oncol Biol Phys 1999; 44:937-45. [PMID: 10386653 DOI: 10.1016/s0360-3016(99)00041-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE The authors undertook a study to analyze the impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans. METHODS AND MATERIALS Twelve cases involving primary brain tumors, metastases, or arteriovenous malformations that had been planned with BrainLAB's conventional circular collimator-based radiosurgery system were re-planned using a beta-version of BrainLAB's treatment planning software that is compatible with MRC Systems' and BrainLAB's micro-multileaf collimators. These collimators have a minimum leaf width of 1.7 mm and 3.0 mm, respectively, at isocenter. The clinical target volumes ranged from 2.7-26.1 cc and the number of static fields ranged from 3-5. In addition, for 4 prostate cancer cases, 2 separate clinical target volumes were planned using MRC Systems' and BrainLAB's micro-multileaf collimators and Varian's multileaf collimator: the smaller clinical target volume consisted of the prostate gland and the larger clinical target volume consisted of the prostate and seminal vesicles. For the prostate cancer cases, treatment plans were generated using either 6 or 7 static fields. A "PITV ratio," which the Radiation Therapy Oncology Group defines as the volume encompassed by the prescription isodose surface divided by the clinical target volume, was used as a measure of the quality of treatment plans (a PITV ratio of 1.0-2.0 is desirable). Bladder and rectal volumes encompassed by the prescription isodose surface, isodose distributions and dose volume histograms were also analyzed for the prostate cancer patients. RESULTS In 75% of the cases treated with radiosurgery, a PITV ratio between 1.0-2.0 could be achieved using a micro-multileaf collimator with a leaf width of 1.7-3.0 mm at isocenter and 3-5 static fields. When the clinical target volume consisted of the prostate gland, the micro-multileaf collimator with a minimum leaf width of 3.0 mm allowed one to decrease the median volume of bladder and rectum within the prescription isodose surface by 26% and 17%, respectively, compared to the multileaf collimator with a leaf width of 10 mm. Use of the 1.7 mm leaf width micro-multileaf collimator allowed one to decrease the median volume of bladder and rectum within the prescription isodose surface by 48% and 39%, respectively, compared to the multileaf collimator with a leaf width of 10 mm. CONCLUSIONS For most lesions treated with radiosurgery, the use of a micro-multileaf collimator with a leaf width of 1.7-3.0 mm at isocenter and 3-5 static fields allows one to meet the Radiation Therapy Oncology Group guidelines for treatment planning. Both planning and treatment are relatively straightforward with a micro-multileaf collimator, allowing for efficient treatment of non-spherical targets with either stereotactic radiosurgery or fractionated stereotactic radiotherapy. When the clinical target volume consists of the prostate gland, micro-multileaf collimators with a minimum leaf width of 1.7-3.0 mm allow one to spare more bladder and rectum than one can with a multileaf collimator that has a 10-mm leaf width based on an analysis of PITV ratios, isodose distributions, and dose volume histograms.
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Affiliation(s)
- H D Kubo
- Department of Radiation Oncology, University of California, Davis Medical Center, Sacramento, USA.
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