The talon removable head frame system for stereotactic radiosurgery/radiotherapy: measurement of the repositioning accuracy

Salter, Bill J.; Fuß, Martin; Vollmer, Dennis G.; Sadeghi, Amir; Bogaev, Christopher A.; Cheek, D; Herman, Terence S.; Hevezi, James M.

doi:10.1016/s0360-3016(01)01670-4

Cited by 62 publications

(34 citation statements)

References 13 publications

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“…In SRS/SRT treatments with high dose per fraction, it is critical to have accurate localization, effective and reproducible immobilization, and steep dose falloff around the tumor in order to achieve local tumor control and spare normal tissue. Several stereotactic systems have been employed by different vendors to accurately immobilize these patients during the treatment 3 , 4 , 5 , 6 . However these SRS/SRT treatments usually involve invasive immobilization, such as metal frames or rings fixed to the patient's skull, which provides rigid immobilization and reproducible stereotactic coordinate system 1 , 7 .…”

Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling

Keeling

Hossain

Jin

et al. 2016

J Applied Clin Med Phys

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The purpose of this study is to evaluate patient setup accuracy and quantify individual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head‐and‐neck masks, simulated with Brainlab localizer and planned with iPlan treatment planning system. Stereoscopic X‐ray images (XC) are acquired and registered to corresponding digitally reconstructed radiographs using bony‐anatomy matching to calculate 6D translational and rotational shifts. When the shifts are within tolerance (0.7 mm and 1°), treatment is initiated. Otherwise corrections are applied and additional X‐rays (XV) are acquired to verify that patient position is within tolerance. The uncertainties from the mask, localizer, IR ‐frame, X‐ray imaging, MV, and kV isocentricity are quantified individually. Mask uncertainty (translational: lateral, longitudinal, vertical; rotational: pitch, roll, yaw) is the largest and varies with patients in the range false(−2.07−3.71mm,−5.82−5.62mm,−5.84−3.61mm;−2.10−2.40∘,−2.23−2.60∘,and−2.7−3.00∘false) obtained from mean of XC shifts for each patient. Setup uncertainty in IR positioning (0.88, 2.12, 1.40 mm, and 0.64°, 0.83°, 0.96°) is extracted from standard deviation of XC. Systematic uncertainties of the frame (0.18, 0.25, −1.27mm, −0.32∘, 0.18°, and 0.47°) and localizer (−0.03, −0.01, 0.03 mm, and −0.03∘, 0.00°, −0.01∘) are extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the MV radiotherapy machine are (0.27, 0.24, 0.34 mm) and kV imager (0.15, −0.4, 0.21 mm). A statistical model is developed to evaluate the individual and cumulative systematic and random positioning uncertainties induced by the different hardware and software components of the 6D ExacTrac system. The uncertainties from the mask, localizer, IR frame, X‐ray imaging, couch, MV linac, and kV imager isocentricity are quantified using statistical modeling.PACS number(s): 87.56.B‐, 87.59.B‐

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Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling

Keeling

Hossain

Jin

et al. 2016

J Applied Clin Med Phys

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“…Not all standard treatment tables allow rotational corrections; therefore, strategies for six‐degrees‐of‐freedom (DOF) corrections have been discussed and included the use of a combination of collimator, gantry, and/or the implementation of a robotic couch 19 , 20 , 21 , 22 , 23 . Soete et al (21) have proven that this 6 DOF patient setup correction improves the patient setup accuracy, and other authors reported experiences about the relevance of rotational shift when patients received high precision radiotherapy 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 …”

Section: Introductionmentioning

confidence: 99%

Adaptive optimization by 6 DOF robotic couch in prostate volumetric IMRT treatment: rototranslational shift and dosimetric consequences

Chiesa

Placidi

Azario

et al. 2015

J Applied Clin Med Phys

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The purpose of this study was to investigate the magnitude and dosimetric relevance of translational and rotational shifts on IGRT prostate volumetric‐modulated arc therapy (VMAT) using Protura six degrees of freedom (DOF) Robotic Patient Positioning System. Patients with cT3aN0M0 prostate cancer, treated with VMAT simultaneous integrated boost (VMAT‐SIB), were enrolled. PTV2 was obtained adding 0.7 cm margin to seminal vesicles base (CTV2), while PTV1 adding to prostate (CTV1) 0.7 cm margin in all directions, except 1.2 cm, as caudal margin. A daily CBCT was acquired before dose delivery. The translational and rotational displacements were corrected through Protura Robotic Couch, collected and applied to the simulation CT to obtain a translated CT (tCT) and a rototranslated CT (rtCT) on which we recalculated the initial treatment plan (TP). We analyzed the correlation between dosimetric coverage, organs at risk (OAR) sparing, and translational or rotational displacements. The dosimetric impact of a rototranslational correction was calculated. From October 2012 to September 2013, a total of 263 CBCT scans from 12 patients were collected. Translational shifts were <5mm in 81% of patients and the rotational shifts were <2∘ in 93% of patient scans. The dosimetric analysis was performed on 172 CBCT scans and calculating 344 VMAT‐TP. Two significant linear correlations were observed between yaw and the V20 femoral heads and between pitch rotation and V50 rectum (p<0.001); rototranslational correction seems to impact more on PTV2 than on PTV1, especially when margins are reduced. Rotational errors are of dosimetric significance in sparing OAR and in target coverage. This is relevant for femoral heads and rectum because of major distance from isocenter, and for seminal vesicles because of irregular shape. No correlation was observed between translational and rotational errors. A study considering the intrafractional error and the deformable registration is ongoing.PACS number: 87.55.de

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“…A sequence of experimental maneuvers was carried out in order to evaluate: first, the capability of the system to maintain a paraspinal target in the same 3D space from setup to the end of a radiotherapy treatment session (spatial accuracy) and second, its ability to relocate a paraspinal target to the same 3D space coordinates obtained after the initial setup following several mount and dismount device maneuvers (repositioning accuracy) [6][7][8] .…”

Section: Localization Technique Of the Fiducial Mark And Experimentalmentioning

confidence: 99%

“…We defined an 'experimental event' as the collection of maneuvers that consists of repositioning the rat in the device, subsequently obtaining X-ray tomograms and simulating a treatment session. We performed between 6 and 8 events for each rat, thereby obtaining s n and r n values [7,9] .…”

Section: Localization Technique Of the Fiducial Mark And Experimentalmentioning

confidence: 99%

See 1 more Smart Citation

A Novel Stereotactic Device for Spinal Irradiation in Rats Designed for a Linear Accelerator

Galván¹,

Lárraga‐Gutiérrez²,

Celis³

et al. 2010

Stereotact Funct Neurosurg

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Objective: Our purpose was to report the design and positioning accuracy testing of a stereotactic device designed for a linear accelerator to perform spinal radiosurgery in rats. Methods: To define the spatial and repositioning accuracy of the device, we measured the 3-dimensional (3D) translation of a paraspinal fiducial mark implanted by microsurgery in 5 Wistar rats during a sequence of setups and treatment simulations, thus obtaining final 3D translation vectors and maximum displacements. Results: For spatial accuracy, the differential coordinate translations were 0.8 ± 0.3, 0.6 ± 0.2 and 0.5 ± 0.1 mm in the x-, y- and z-directions, respectively. The median magnitude of the 3D vector was 1.3 mm (σ = 0.2 mm), with a maximum error of 2.2 mm. The differential coordinate translation for the repositioning accuracy showed values of 1.4 ± 0.3, 1.3 ± 0.3 and 0.8 ± 0.1 mm for the x-, y- and z-coordinates, resulting in a 3D displacement vector of 2.2 mm (σ = 0.2 mm) and a maximum displacement error of 3.6 mm. Conclusions: Using a linear accelerator, our novel stereotactic device provides accurate immobilization and repositioning of paraspinal structures under experimental conditions in rats.

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The talon removable head frame system for stereotactic radiosurgery/radiotherapy: measurement of the repositioning accuracy

Cited by 62 publications

References 13 publications

Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling

Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling

Adaptive optimization by 6 DOF robotic couch in prostate volumetric IMRT treatment: rototranslational shift and dosimetric consequences

A Novel Stereotactic Device for Spinal Irradiation in Rats Designed for a Linear Accelerator

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