Biodex Medical Systems Quality Assurance Testing of AtomLab
®
Dose Calibrators
July 8, 2004 P/N 107012 Rev. B; © 2004, Sun Nuclear Corp. page 3 of 4
repeated to verify. AtomLab dose calibra-
t
ors have been tested for volume
dependence in beta measurements which
are expected to be worst case and the
results were 0.13 %/ml.
4
Syringe test
1
In a small vial, mix 2.0 ml of a solution of
T
c-99m with an activity concentration
between 1 and 10 mCi/ml.
2 Set out a second small vial containing
non-radioactive saline solution.
3 Draw 0.5 ml of the Tc-99m solution into
the syringe and assay it.
4 Record the volume and activity of the
first assayed sample (Figure 2).
5 Remove the syringe from the calibrator,
d
raw an additional 0.5 ml of non-radio-
active saline into the same syringe (total
volume 1.0 ml), and assay again. Record
the volume and measured activity on
the form.
6 Repeat step 5 twice more until you have
assayed 1.5 ml and 2.0 ml volumes and
recorded them.
7 Assay the vial used to draw saline into
the syringe. If the measured activity is
greater than 1% of the 0.5 ml syringe
assay, Tc99m was lost during filling.
Repeat the procedure.
8 Divide the average activity by the activ-
ity indicated for each volume. The
q
uotient is a volume correction factor.
9 I
f any correction factors are greater than
1
.05 or less than 0.95, it will be neces-
sary to make a correction table that will
allow you to convert from “indicated
activity” to “true activity.” If this is nec-
essary, be sure to label the table
“syringe geometry dependence”, and
note the date of the test as well as the
model number and serial number of the
dose calibrator.
Vial test (30 ml)
1
To test the geometry dependence for a
3
0 ml glass vial, draw 1.0 ml of Tc-99m
solution (between 1 and 10 mCi/ml) into
a syringe and inject it into the vial. Assay
the vial. Record the volume and activity
indicated.
2 R
emove the vial from the calibrator and,
using a clean sy ringe, inject 2. 0 or 3.0 ml
of non-radioactive saline, and assay
again. Record the volume and activity
indicated on the form (Figure 2). Repeat
t
he process until you have assayed a
19.0 ml volume. The entire process
m
ust be completed within ten (10) min-
utes, or, if not, decay-correct the
a
ctivity.
3 Divide the average activity by the activ-
ity indicated for each volume. The
quotient is a volume correction factor.
4 If any correction factors are greater than
1
.05 or less than 0.95, it will be neces-
sary to make a correction table that will
a
llow you to convert from “indicated
activity” to “true activity.” If this is nec-
e
ssary, be sure to label the table “vial
geometry dependence”, and note the
d
ate of the test and the model number
and serial number of the calibrator.
Accuracy
Accuracy means a determination of the
dose calibrator’s absolute error resulting
from a measurement of a suitable NIST-
traceable radionuclide activity. Traceable
sources are available from NIST and from
many radioisotope suppliers. At least two
sources with different principal photon
energies (such as Co-57, Co-60 or Cs-137)
should be used. One should have a princi-
pal photon energy between 100 keV and
500 keV.
1 Press the Background (Bkgnd) button
which zeroes the dose calibrator.
2 Assay a calibrated reference source at
the appropriate setting (i.e., use the Co-
57 setting to assay Co-57). Record the
displayed activity measurement, M, the
date, and the reference source identifi-
cation (nuclide, activity, date of
calibration, serial number, model num-
ber, and manufacturer.)
3 Repeat the procedure for the other cali-
brated reference source.
4 For both sources, decay-correct the ref-
erence source activity value and record
as “true activity.”
5 Calculate activity measurement % error
from:
4. See “Accurate Dose Calibrator Activity Mea-
surement of Y-90 Ibritumomab Tiuxetan,” J. A. Sie-
gel et al, J Nucl Med, 2004, 45:450-454.
AtomLab Dose Calibrator Geometry Test, Model:________________ Serial Number:_______________
Syringe: Type______ Volume_____ Decay correct if test not completed in 10 min.
D
ate Time Volume
(Activity)
v
Volume cf = Avg/(Activity)
v
_
_____ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
Avg: ______
Vial: Type______ Volume_____ Decay correct if test not completed in 10 min.
Date Time Volume
(Activity)
v
Volume cf = Avg/(Activity)
v
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
______ ______ ______ ______ ______
Avg: ______
Figure 2. Sample AtomLab dose calibrator geometry test form
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