Page 23 of Radiation Medicine QA Solutions 2008/2009 by PTW

radiation therapy absolute dosimetry equipment radioactive check devices unisoft dosimetry software radioactive check devices for air density correction and constancy checks of therapy dosemeters features make it possible to perform air density corrections when using vented ionization chambers check proper functioning and constancy of the complete dosemeter two types for thimble and flat chambers are available include encapsulated low activity of 33 mbq type t48012 resp 20 mbq 90sr type t48010 the radioactive check devices are recommended for high precision dosimetry they enable medical physicists to check the stability of ionization chamber response and to determine air density correction factors for sealed in-vivo ionization chambers the use of a radioactive check device is mandatory iec 60731 check readings should be done each time before starting a dose measurement the chamber calibration certificate includes the reference reading under standard conditions the check reading will decrease over time due to the decay of the activity the 90sr half-value time is 28.7 years both check devices include shielding containers and the check device t48012 is supplemented by a thermometer for controlling the check device temperature various holding devices for the adaptation of different ion chambers are available due to the arrangement of the radioactive source of the check device model t48012 the measuring volume of the inserted thimble chamber is irradiated from all directions the cylindrical source of the check device model t48010 is placed near to the entrance window of flat ion chambers by means of the appropriate holding device the source t48012 is equivalent to iso class c64444 the source t48010 is equivalent to class c6x444 the dose rate in 10 cm distance is below 1 µsv/h with cover closed please observe the national regulations for transport and use of radioactive material before shipping we need a confirmation certifying that the purchaser is allowed to handle the radioactive sources software for radiation therapy dosimetry according to international dosimetry protocols features determines chamber correction factors and calculates absorbed dose to water put out data in worksheet format two versions are available to support all established international therapy dosimetry protocols the unisoft software is designed to determine the absorbed dose to water of high-energy photon and electron radiation out of dosemeter readings from ionization chambers based on 60co calibrations unisoft software edition 2000 supports the aapm tg-51 and iaea trs-398 therapy dosimetry protocols by calculating the relevant correction factors for air density polarity effect saturation effect radiation quality and displacement a software module to control the dose meter and to position the detector is included unisoft software edition 1997 includes the iaea trs-277 aapm tg-21 and tg-25 and din 6800-2 therapy dosimetry protocols unisoft features ionization chamber libraries to store chamber data necessary for the determination of correction factors dosimetry worksheets can be defined for different dosimetry protocols beam qualities types of ionization chambers and two kinds of air density correction ordering information s100009 unisoft software edition 2000 s100001 unisoft software edition 1997 unidos unidos e universal dosemeter page 14 unidoswebline universal dosemeter page 13 multidos multi channel dosemeter page 34 tandem dual channel electrometer page 15 radiation detectors pages 16 to 21 radioactive check devices page 23 mephysto mc2 software page 52 ordering information t48012 radioactive check device for thimble chambers t48010 radioactive check device for flat chambers chamber/check source holding devices upon request ionization chambers pages 16 to 22 23

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