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 Features
• Self-developing: no processing, no chemicals
• Not light sensitive- no darkroom required
• Unaffected by aqueous fluids- can be immersed in water phantoms
• Energy independent in therapy range
• Tissue equivalent
• No dose rate or dose fractionation effects
• Films can be cut to any size and shape
• Wide dynamic range
• Almost linear dose-density response
• Tough, robust, abrasion-resistant
Gafchromic® Dosimetry Films have been designed for use with gamma, x-rays, electrons, protons, ion beams, alpha particles and neutrons and can be used to measure and map sources of all types covering a wide range of energies down to 5keV, or lower. The active component in Gafchromic® Dosimetry Films is comprised of sub-micron sized crystals of a radiation-sensitive monomer. When the film is exposed to ionizing radiation, a polymerization reaction is initiated, resulting in the production of a blue-colored dye-polymer. The amount of polymer produced and the depth of color change is proportional to the dose absorbed in the active layer. Gafchromic® Dosimetry Films have inherently high spatial resolution, beyond the capability of conventional silver films. Since the polymerization process does not spread from crystal to crystal and there is no post-exposure development process to change the size or shape of the particles, the films are capable of resolution down to the micron range. The spatial resolution is limited principally by the characteristics of the exposure source.
Quantitative Dosimetry
The responses of Gafchromic® Dosimetry Films are dependent upon factors specific to the hospital or laboratory including the energy spectrum of the radiation source, the characteristics of the densitometer, film scanner or other means of measurement, etc. Therefore, the user should determine the dose-density response under the conditions pertaining to their facility. Since the absolute responses of Gafchromic® Dosimetry Films vary from lot to lot, the user should re-measure response when changing the lot number.
For the Characterization, Calibration, Quality Control and Wide-Area Dose Measurement of Therapeutic and Radiological Radiation Sources.
Beam Sources
• Measure field uniformity
• Determine field shape
• Make depth-dose characterizations
• Map fields in 2- and 3-dimensions
• Validate IMRT and stereotactic treatment plans
Isotope Sources
• Characterize depth-dose fields of HDR brachytherapy sources
• Map the activity of LDR brachytherapy seeds
• Verify the operation of intravascular sources
• Design and validate treatments with eye plaques
• Map and measure plaques for implantation
• Map fields inside irradiators
• Map and measure “hot particles”
The color change in Gafchromic® Dosimetry Films may be measured with any densitometer, scanner or spectrophotometer. However, the best response is obtained with instruments that measure at red-light wavelengths in the range of the peak absorbance of the blue dye, i.e. close to 670nm. Examples of such hardware include the Photoelectron Corporation CCD100 Microdensitometer, the Radlink LaserPro 16TM (www.eradlink.com/pdfs/laserpro16.pdf), the Tobias TXP Transmission Densitometer, the Nuclear Associates Radiochromic Densitometer Model 37-443, or any flatbed color scanner.
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