A new method of readout in radiochromic film dosimetry

Kellermann, P.O.; Ertl, Adolf; Gornik, E.

doi:10.1088/0031-9155/43/8/018

Cited by 19 publications

(15 citation statements)

References 18 publications

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“…Therefore target adjustments were not necessary ͑see Table I͒. Film and diode dose profile measurements of the unplugged 4 mm collimator helmet of the Leksell Gamma Knife TM , model B, shows a symmetrical dose beam profile in the xy plane. 32 In model B the sources are arranged symmetrically in such a way that the dose profile along the x and y axis is identical.…”

Section: Resultsmentioning

confidence: 99%

Quality assurance for the Leksell gamma unit: Considering magnetic resonance image‐distortion and delineation failure in the targeting of the internal auditory canal

et al. 1999

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Our aim in this study was to distinguish quantitatively between the localization accuracy of a commercially available stereotactic fixation device as claimed by the manufacturer and the target accuracy as measured by a user, applying neuroradiologic imaging in Gamma Knife planning and phantom irradiation. Missing the target is the most serious possible failure in Gamma Knife and Linac therapy. To reduce this risk, we developed a quality control algorithm and designed a phantom. To evaluate the accuracy of the targeting procedure with a Leksell Gamma unit, and to experience the possible errors in all procedural steps, irradiations of phantoms were performed, using the so-called "unknown" targeting method. Accuracy is defined by the extent of spatial deviation of the irradiated target from the calculated target. Digital imaging was used for therapy planning. GafChromic films, which had been irradiated while affixed to a specially developed phantom, were used for measuring the precision of the radiation unit. A series of MR images (in two plains: transverse and coronal) was acquired sequentially to image the three-dimensional (3-D) volume of the phantom. The results obtained for isocentric accuracy of the Leksell Gamma unit, model B, were in good agreement to the calculated position. The observed spatial deviations between calculated and irradiated targets is less than 1 mm. The newly designed phantom and quality control algorithm are useful in quality assurance measurements of stereotactic radiation therapy.

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Section: Resultsmentioning

confidence: 99%

Quality assurance for the Leksell gamma unit: Considering magnetic resonance image‐distortion and delineation failure in the targeting of the internal auditory canal

et al. 1999

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“…Until recently, most of the experience using radiochromic film was based on Gafchromic MD-55 and HS, which were relatively insensitive to radiation. 86,87,[96][97][98][99][100][101][102][103] The dose sensitivity was too low for the film to be practical for routine clinical IMRT measurements. Recently, a highsensitivity radiochromic film ͑Gafchromic EBT͒ was introduced that has OD sensitivity similar to the radiographic Kodak EDR-2 film.…”

Section: Iib1 Filmmentioning

confidence: 99%

“…95,105,[131][132][133][134] For IMRT commissioning, radiochromic film can be used to acquire beam profiles that will be used for modeling beam penumbra. 99,133 It can also be used to measure relative output factors for very small fields 100,133,[135][136][137] and can be used to measure phantombased IMRT dose distributions, for example, dose distribution measurements that will be used to verify the treatment planning system's programming of the linear accelerator delivery parameters ͑"monitor unit outputs"͒.…”

Section: Iib1 Filmmentioning

confidence: 99%

Dosimetry tools and techniques for IMRT

et al. 2011

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Intensity modulated radiation therapy ͑IMRT͒ poses a number of challenges for properly measuring commissioning data and quality assurance ͑QA͒ radiation dose distributions. This report provides a comprehensive overview of how dosimeters, phantoms, and dose distribution analysis techniques should be used to support the commissioning and quality assurance requirements of an IMRT program. The proper applications of each dosimeter are described along with the limitations of each system. Point detectors, arrays, film, and electronic portal imagers are discussed with respect to their proper use, along with potential applications of 3D dosimetry. Regardless of the IMRT technique utilized, some situations require the use of multiple detectors for the acquisition of accurate commissioning data. The overall goal of this task group report is to provide a document that aids the physicist in the proper selection and use of the dosimetry tools available for IMRT QA and to provide a resource for physicists that describes dosimetry measurement techniques for purposes of IMRT commissioning and measurement-based characterization or verification of IMRT treatment plans. This report is not intended to provide a comprehensive review of commissioning and QA procedures for IMRT. Instead, this report focuses on the aspects of metrology, particularly the practical aspects of measurements that are unique to IMRT. The metrology of IMRT concerns the application of measurement instruments and their suitability, calibration, and quality control of measurements. Each of the dosimetry measurement tools has limitations that need to be considered when incorporating them into a commissioning process or a comprehensive QA program. For example, routine quality assurance procedures require the use of robust field dosimetry systems. These often exhibit limitations with respect to spatial resolution or energy response and need to themselves be commissioned against more established dosimeters. A chain of dosimeters, from secondary standards to field instruments, is established to assure the quantitative nature of the tests. This report is intended to describe the characteristics of the components of these systems; dosimeters, phantoms, and dose evaluation algorithms. This work is the report of AAPM Task Group 120.

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“…Die Farbdichte wächst im Allgemeinen nicht linear als Funktion der Dosis, da das Absorptionsspektrum mit der Dosis variiert und bei hohen Dosen Sättigung eintritt [7,12]. Deshalb wird die Sensitivitätsfunktion möglichst genau und aus praktischen Gründen mit möglichst wenigen Parametern durch eine Abbildungen 3a bis 3d.…”

Section: Empfindlichkeitsfunktionunclassified