Fluke Biomedical 35080B - Manual (Page 66)

35080B
Operators Manual
C-2
Use the following procedure to measure kVp on the rhodium anode, rhodium filtration selection of the
DMR.
1. Acquire a Cadmium K-edge Mammo Filter Pack (37355) measurement using the normal method to
determine a value of kVp between 27.5 and 29.5 kVp. This value can be used without correction
resulting in a maximum error of about 1 kVp. For maximum accuracy, use the look-up-table in
Table C-1 to obtain a corrected value of kVp. For example, if the measured value of kVp were
27.8, the actual corrected value would be 28.2 kVp. This correction is due to the slight difference in
response of the Cadmium K-edge Mammo Filter Pack (37355) to the Rh anode, Rh filtration
spectrum as compared to a Mo anode, Mo filtration spectrum.
Table C-1. Look-up-table for Cadmium K-edge Mammo Filter Pack (37355) measurements
made on Rh anode, Rh filtration selection of DMR mammography system. The
equation used for the correction is Corrected kVp = (Uncorrected kVp - 27) x 1.5 +
27
Uncorrected
kVp
Corrected
kVp
Uncorrected
kVp
Corrected
kVp
27.3 27.5 28.2 28.8
27.4 27.6 28.3 29.0
27.5 27.8 28.4 29.1
27.6 27.9 28.5 29.3
27.7 28.1 28.6 29.4
27.8 28.2 28.7 29.6
27.9 28.4 28.8 29.7
28.0 28.5 28.9 29.9
28.1 28.7 29.0 30.0
2. Insert the Linear Mammo Filter Pack (37351) into the Model 35080B kVp Divider and acquire a kVp
measurement using the same generator settings as used for the k-edge measurement in step 1.
Use the look-up-table in Table C-2 to determine the actual kVp of the exposure. For example, if the
measured value were 34.3 kVp, the actual kVp would be 28.7.
3. Determine the k-edge correction value as usual, by subtracting the Linear Mammo Filter Pack
(37351) reading (28.2 in the example) from the measurement obtained with the Cadmium K-edge
Mammo Filter Pack (37355) in step 1 (28.7 in the example). Note that the k-edge correction value
can be positive or negative (the value is (28.2 - 28.7) = -0.5 kVp in this example).