Abstract：
:Diode sensitivity variations with temperature (SVWT) have been reported to vary from small negative values up to 0.6% per degrees C. Thus it is possible for diode calibration factors established at room temperature (approximately 20 degrees C) to yield errors in the range of -1% to +9% when diodes are placed on a patient's skin (approximately 30 degrees C) for in vivo entrance dose measurements. In this study we simulated several skin temperatures using a temperature-controlled aluminum surface in contact with a section of Bolus. The internal temperatures of several diodes with different buildup thickness were monitored as a function of time when placed in contact with the heated bolus. Our results indicate that for different combinations of room temperature (18 degrees C-23 degrees C) and patient skin temperature (28 degrees C-34 degrees C) diodes reached 90% of their equilibrium temperature within 3-5 min. In addition, the range of typical skin temperatures was determined by measurements performed on a number of actual patients under clinical conditions. Based on the results of our experiments a protocol was developed to minimize the temperature based errors for in vivo dosimetry.
journal_name
Med Physjournal_title
Medical physicsauthors
Welsh KT,Reinstein LEdoi
10.1118/1.1367862subject
Has Abstractpub_date
2001-05-01 00:00:00pages
844-9issue
5eissn
0094-2405issn
2473-4209journal_volume
28pub_type
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