Precise radiochromic film dosimetry using a flat-bed document scanner

Abstract

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.

PIXEL-BASED CORRECTION METHOD FOR GAFCHROMIC®EBT FILM DOSIMETRY

“…Hence, accurate readout of film data without distortion is a critical aspect of EBT film dosimetry [2]. However, most commercially available scanners used for readout of EBT film employ a fluorescent lamp as a light source, which leads to light scattering on the active layer of the film [3]. This problem results in a significant distortion in dose conversion with non-uniform responses, even though the uniform dose is originally irradiated onto the film [4].…”

“…Also, corrected doses were compared with profiles measured by an ionization chamber (sensitive volume of 0.03 cm 3 , type 31015, PTW-Feiburg, Germany). In this case, the corrected profiles should be equal to the profiles measured by the ionization chamber because the ionization chamber is a standard dosimeter in the measurement of profiles with a large sized beam.…”

Design and Status of the ELIMED Beam Line for Laser-Driven Ion Beams

“…In order to fulfill all the requirements new detection devices and techniques must be designed and developed. The solution proposed to perform relative and absolute dose measurements implies different alternative approaches, as for instance SEM detectors [18], CR39 solid-state track detectors [19], Gafchromic films [20], transmission ionization chamber for high intense beams [21] and Faraday Cups (FC) [22]. Figure 1 shows a schematic layout of the ELIMED beam line where the elements composing the three different sections are clearly visible in their preliminary design.…”

Dosimetric evaluation of internal shielding in a high-dose-rate skin applicator

“…1, the films were irradiated with the applicator on top of the phantom with a dwell time of the source calculated to deliver a dose to the film at 3 mm depth of about 2 Gy. A flatbed scanner (EPSON 10000XL) was used to scan the films following the recommendations found in a literature [19][20][21]. Briefly, each film was scanned prior to the irradiation and 24 h after the irradiation [22] in order to subtract the background [23].…”