M J Butson

..8 and 1.9 times more sensitive than MD-55-1 and MD-55-2 films, respectively. At the absorption peak yielding the maximum optical density change, HS was found to be approximately 0.2 to 0.25 times the sensitivity of EDR-2...

..The results have shown that the MOSFET device can adequately measure peripheral doses, which would be beneficial for in vivo dose assessments in radiotherapy...

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..When these charge reading are compared to the Dmax readings of the same polarity it is found that these polarity effects are minimal for the calculation of percentage dose results with variations being less than 1% of maximum...

..These variations are largest at the skin surface and reduce with depth. The use of a multi leaf collimator for blocking removes extra skin dose caused by the Perspex block trays with decreasing SSD...

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..077 OD units per kGy. The film can be an ideal dosimeter for areas where high dose levels need to be measured...

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..To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size...

..Due to this high dose response that is achievable, the five layer HS could be used in applications where small doses are delivered to certain areas and a low dependence of energy response is required for measurement...

..The film produces a relatively high dose sensitivity with up to 0.25 OD units per Gy change at 672 nm at 100 kVp x-ray energy. Variations in dose sensitivity can be achieved by varying wavelength analysis...

..The film provides adequate relative absorbed dose measurement for clinical radiotherapy x-ray assessment in the 1-2 Gy dose range which with further investigation may be useful for fractionated radiotherapy dose assessment...

..XR type-R film is ideal for a quantitative dosimeter in the low energy range due to its relative energy independence and high sensitivity compared to conventional radiochromic film...

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..This feature may be of use for measurement of integrated UV exposure from fluorescent lights when required and produces a quantifiable history of total exposure...

..As all new film batches should be calibrated for sensitivity upon arrival this should not be of concern...

..g. 7.5% at 900 nm and 12.5% at 1000 nm) and are wavelength dependent. The changes produced by the water are relatively independent of the exposure time to water from 5 s up to 1 h or whether the water exposure occurred...

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..Our results have shown that a 0.3 optical density change with RTQA film provides a colour change level useable for accurate alignment procedures..

..Thus it is most efficient to have a densitometer with a light source suitable for radiochromic film, which can also be used with radiographic film...

..The MOSFET does have the advantage of returning a relatively immediate dosimetric result after irradiation...

..As such, providing the same orientation of EBT film when scanning for dosimetric analysis becomes an essential part of EBT film dosimetry...

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..3mm) of one film piece. GAFCHROMIC EBT, Radiochromic film provides a very simple and easy method for measurement and verification of BSF for x-ray energies commonly used for superficial x-ray therapy...

..Gafchromic EBT film provides an adequate measure of penumbral dose for high energy x-ray beams...

..5 minutes for 30 Gy applied dose to complete as opposed to 12 minutes for a dual field x-ray field irradiation at our centre. Electron beams can be used to satisfactorily irradiate blood and blood products in a minimal amount of time...

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..Radiochromic film seems to be an adequate detector for dosimetry in a water phantom where high spatial resolution is needed and angle of beam incidence at the point of interest is important...

..95+/-2.6 Gy for two standard deviations. Like currently available 'irradiated' film labels, the radiochromic film also serves as a visible reminder that the blood products have been irradiated...

..This matches well with beam qualities for diagnostic computed topography applications...

..Results have shown that a large variation in skin dose is delivered under the dressing depending on the amount of material directly above it as defined by the silicon mesh outline...

..3%); however, results show that the blood glucose meter, which would be available in any haematology department, produces an adequate measure of gafchromic film optical density for blood irradiation dosimetry...

..The results also show the difference is reduced for a larger applicator, probably because the applicator scatter component reaching the in-air measurement point is reduced...

..Beyond this angle it is assumed that beam attenuation through the phantom and inverse square fall-off is causing the surface dose to reduce...

..As such, if the treatment type results in a more rigorously positioned patient on the treatment couch, the wave nature of skin dose delivery may need to be taken into account...

..The film provides an adequate measurement and visually qualitative assessment of radiation exposure for levels in the range of 0 to 200 R...

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..We recommend that a polarization test be performed on a densitometry system to establish the extent of its polarization properties before accurate dosimetry is performed with radiographic film...

..6-0.7 for the same effective energies. This type of film has been optimized for use in diagnostic energy ranges producing a relatively uniform dose response in the 30 keV to 70 keV range...

..This weak dependence provides significantly higher accuracy of dose measurements under conditions of varying spectral quality of X-ray beams, which are common in radiation therapy...

..With the help of this film, it was shown that the output factor for a 0.5 x 0.5 cm(2) field is 0.60+/-0.03 (2SD) relative to the 10 x 10 cm(2) field...

..Radiochromic film has been found to accurately measure dose under eye shield in phantom treatments...

..2 mm.Conclusion: The stack dosimeter can provide useful in vivo information such as the position of a diverging beam edge for treatments around critical structures such as eyes during the first fraction of treatment...

..The multilayer Gafchromic film detector provided adequate skin dose assessment within one fraction of treatment for in vivo results...

..Also, calibration films must be read out with the same post-irradiation time to further enhance the accuracy of dosimetry...

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