In this study, a measurement protocol is presented that improves the precision of dose measurements using a flat-bed document scanner in conjunction with two new GafChromic film models, HS and Prototype A EBT exposed to 6 MV photon beams. We established two sources of uncertainties in dose measurements, governed by measurement and calibration curve fit parameters contributions. We have quantitatively assessed the influence of different steps in the protocol on the overall dose measurement uncertainty. Applying the protocol described in this paper on the Agfa Arcus II flat-bed document scanner, the overall one-sigma dose measurement uncertainty for an uniform field amounts to 2% or less for doses above around 0.4 Gy in the case of the EBT (Prototype A), and for doses above 5 Gy in the case of the HS model GafChromic film using a region of interest 2 X 2 mm2 in size.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1118/1.1929253 | DOI Listing |
Phys Med
March 2018
Unidad de Radioneurocirugía, Instituto Nacional de Neurología y Neurocirugía, Insurgentes sur 3877, La Fama, Tlalpan 14269, Cd. de México, Mexico.
Flatbed scanners are the most frequently used reading instrument for radiochromic film dosimetry because its low cost, high spatial resolution, among other advantages. These scanners use a fluorescent lamp and a CCD array as light source and detector, respectively. Recently, manufacturers of flatbed scanners replaced the fluorescent lamp by light emission diodes (LED) as a light source.
View Article and Find Full Text PDFMed Phys
April 2015
Department of Radiology, Boston University Medical Center, Boston, Massachusetts 02118.
Purpose: To investigate the impact of x-ray beam energy, exposure intensity, and flat-bed scanner uniformity and spatial resolution on the precision of computed tomography (CT) beam width measurements using Gafchromic XR-QA2 film and an off-the-shelf document scanner.
Methods: Small strips of Gafchromic film were placed at isocenter in a CT scanner and exposed at various x-ray beam energies (80-140 kVp), exposure levels (50-400 mA s), and nominal beam widths (1.25, 5, and 10 mm).
Med Phys
June 2013
Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Purpose: To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (XVI) (Version R4.5) and on board imager (OBI) (Version 1.
View Article and Find Full Text PDFMed Phys
February 2012
Department of Radiation Oncology, McLaren Regional Medical Center, Flint, MI 48532, USA.
Purpose: One of the fundamental parameters used for dose calculation is percentage depth-dose, generally measured employing ionization chambers. There are situations where use of ion chambers for measuring depth-doses is difficult or problematic. In such cases, radiochromic film might be an alternative.
View Article and Find Full Text PDFMed Phys
February 2012
Department Of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Purpose: In this study, the relevant characteristics of the new Gafchromic XRQA2 film for its application in measuring kV cone beam computed tomography (CBCT) image doses were thoroughly investigated.
Methods: The film was calibrated free in air to air kerma levels between 0 and 9 cGy using 120 kVp photon beams produced by the x-ray volume imager. Films were scanned using transmission and reflection scanning modes with the Epson Expression 10000 XL flat-bed document scanner.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!