Automated calibration adjustment for film dosimetry
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Mar 4, 2003
Grant Date -
N/A
app pub date -
Jan 21, 2000
filing date -
Jan 21, 2000
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
The present invention provides a method of correcting errors in film dosimetry measurements arising from variations in radiographic film processing and manufacturing. The method includes: (1) irradiating separate and distinct areas of one or more calibration films with different radiation dose levels to obtain a first calibration; (2) exposing a non-irradiated portion of at least one (and typically all) of the calibration films to light from an array of standardized light sources to obtain a first optical density step gradient; (3) exposing a non-irradiated portion of subsequent test films to light from the array of standardized light sources to obtain a second optical density step gradient; and (4) modifying the first calibration or optical density values of the test films based on differences between the first and second optical density step gradients. Since the characteristics of each of the standardized light sources vary little from one exposure to the next, any deviations in the optical density step gradient among different films results, presumably, from changes in film processing or differences in film chemistry.
First Claim
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