Filmless Evaluation of the Mechanical Accuracy of the Isocenter in Stereotactic Radiotherapy

Geyer, Peter; Blank, Hilbert; Evers, C.; Leichtner, Thomas; Alheit, H.

doi:10.1007/s00066-007-1659-4

Cited by 10 publications

(13 citation statements)

References 33 publications

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“…In this study, we independently assess the effectiveness of the Varian IsoCal technique. We employ the digital Winston‐Lutz (WL) test method, which has been demonstrated to have submillimeter accuracy 4, 6, 14, 15, 16. This method measures the image center accuracies directly against the radiation isocenter.…”

Section: Introductionmentioning

confidence: 99%

Independent evaluation of the effectiveness of IsoCal in improving image center accuracy on Varian TrueBeam and Clinac machines

Gao

Jiang

et al. 2018

J Applied Clin Med Phys

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Modern medical linear accelerators (linacs) are often equipped with image guidance systems that are capable of megavolt (MV), kilovolt (kV), planar, or volumetric imaging. On Varian TrueBeam linacs, the isocenter accuracies of the imaging systems are calibrated with a procedure named IsoCal. On Clinac series linacs from Varian, installation of IsoCal is optional and the effects of IsoCal on the imaging systems can be turned on or off after the IsoCal procedure is performed. In this study, we report on the effectiveness of IsoCal in improving the coincidence of the image centers with the radiation isocenter, using an independent Winston‐Lutz (WL) method to locate the radiation isocenter. A ball‐bearing phantom was imaged with 2D MV, 2D kV, and cone beam computed radiography systems on two TrueBeam and two Clinac machines. Using the same phantom, digital WL tests with 16 combinations of gantry and collimator angles were performed to locate the radiation isocenter. The offsets between the IsoCal‐calibrated image centers and the WL radiation isocenter were found to be within 0.4 mm on the four linacs in this study. When IsoCal was turned off, the maximal offsets of the image centers were greater than 1.0 mm on the two Clinac machines. The method developed in this study can be used as a vendor‐independent quality assurance tool to assess the isocentricity of the image centers and radiation central axes.

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Section: Introductionmentioning

confidence: 99%

Independent evaluation of the effectiveness of IsoCal in improving image center accuracy on Varian TrueBeam and Clinac machines

Gao

Jiang

et al. 2018

J Applied Clin Med Phys

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“…Despite the progress in neurosurgery, radiotherapy and oncology, recurrences develop in virtually all patients, resulting in poor survival [10,12,22,28,32]. The standard of care for patients with recurrent GBM has not yet been clearly defined.…”

Section: Introductionmentioning

confidence: 99%

Hypofractionated Stereotactic Reirradiation of Recurrent Glioblastomas

et al. 2009

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“…The Winston‐Lutz test was relatively simple ( 2 ) and became quite popular, ( 34 , 36 ) but it was based on films; therefore, it inherited all film‐related problems. The general disadvantages in using films include the cost of films, chemicals and processor maintenance, and occupation of archiving space.…”

Section: Methodsmentioning

confidence: 99%

“…( 23 ) Dust or marks on the film can lead to spikes in images. ( 40 ) The film results for Winston‐Lutz test are not quantitative, ( 26 , 52 , 59 ) and are based on manual evaluations ( 24 , 34 ) and visual inspection — which makes them highly dependent on the skills of the observer. ( 11 , 36 , 52 , 60 ) The uncertainty introduced by operator judgment has been reported to be 0.3 to 0.4 mm, ( 36 , 61 , 62 ) although this could be reduced by scanning the films and using software analysis.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Isocenter verification for linac‐based stereotactic radiation therapy: review of principles and techniques

Rowshanfarzad

Sabet

O’Connor

et al. 2011

J Applied Clin Med Phys

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There have been several manual, semi‐automatic and fully‐automatic methods proposed for verification of the position of mechanical isocenter as part of comprehensive quality assurance programs required for linear accelerator‐based stereotactic radiosurgery/radiotherapy (SRS/SRT) treatments. In this paper, a systematic review has been carried out to discuss the present methods for isocenter verification and compare their characteristics, to help physicists in making a decision on selection of their quality assurance routine.PACS numbers: 87.53.Ly, 87.56.Fc, 87.56.‐v

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Filmless Evaluation of the Mechanical Accuracy of the Isocenter in Stereotactic Radiotherapy

Abstract: Applying the proposed beam arrangements, the Winston-Lutz test can be done by digital and filmless imaging systems, thereby saving time as well.

Cited by 10 publications

References 33 publications

Independent evaluation of the effectiveness of IsoCal in improving image center accuracy on Varian TrueBeam and Clinac machines

Independent evaluation of the effectiveness of IsoCal in improving image center accuracy on Varian TrueBeam and Clinac machines

Hypofractionated Stereotactic Reirradiation of Recurrent Glioblastomas

Isocenter verification for linac‐based stereotactic radiation therapy: review of principles and techniques

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