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Dosimeters are devices that are capable of providing a quantitative and reproducible measurement of absorbed dose through a change in one or more of the physical properties of the dosimeters in response to the exposure to ionizing radiation energy (Mod Ali, 2007). A dosimetry system consists of dosimeters, measurement instruments and their associated reference standards, and procedures for using the system. The measuring instrument must be well characterized, so that it gives reproducible and accurate results.
The selection of an appropriate dosimetry system will depend on a variety of factors, including the dose range needed to achieve a particular technological objective, cost, availability, and ease of use. A variety of dosimetry systems are available. Reference standard dosimeters are dosimeters of high metrological quality that can be used to calibrate other dosimeters. In turn, they need to be calibrated against a primary standard. They must have a radiation response that is accurately measurable, and the response must have a well-defined functional relationship with the absorbed dose. Commonly used reference dosimeters include Fricke, ceric–cerous, dichromate, ethanol–monochlorobenzene (ECB), and alanine dosimeters. Routine (or working) dosimeters are used in radiation facilities for dose mapping and for process monitoring under quality control. They must be frequently calibrated against reference dosimeters, because they may not be sufficiently stable and independent from environmental or radiation field conditions. Commonly used routine dosimeters include poly (methyl methacrylate) (PMMA) or perspex, radiochromic, cellulose triacetate (CTA) films, ceric–cerous, and ECB dosimeters. Dosimetric accuracy of the order of 5–10% is generally considered to be necessary for the effective control of the sterilization process.
The selection of an appropriate dosimetry system will depend on a variety of factors, including the dose range needed to achieve a particular technological objective, cost, availability, and ease of use. A variety of dosimetry systems are available. Reference standard dosimeters are dosimeters of high metrological quality that can be used to calibrate other dosimeters. In turn, they need to be calibrated against a primary standard. They must have a radiation response that is accurately measurable, and the response must have a well-defined functional relationship with the absorbed dose. Commonly used reference dosimeters include Fricke, ceric–cerous, dichromate, ethanol–monochlorobenzene (ECB), and alanine dosimeters. Routine (or working) dosimeters are used in radiation facilities for dose mapping and for process monitoring under quality control. They must be frequently calibrated against reference dosimeters, because they may not be sufficiently stable and independent from environmental or radiation field conditions. Commonly used routine dosimeters include poly (methyl methacrylate) (PMMA) or perspex, radiochromic, cellulose triacetate (CTA) films, ceric–cerous, and ECB dosimeters. Dosimetric accuracy of the order of 5–10% is generally considered to be necessary for the effective control of the sterilization process.
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