Capintec CAPTUS 2000, Owner'S Manual

Page: 73 / 206

CAPINTEC, INC CAPTUS
®
2000
return you to the previous screen without saving any count data. Note that when the room
background is measured after the capsule count, it is always only measured once.
Choose the correct type of dose, either capsule or liquid from the Dose Form box. Selecting
Capsule will result in the word capsule count on the results report. By selecting Liquid, the
term dosage will be substituted in any report for the word capsule. Choosing a dose form
only affects the wording of the results report, and has no effect on the measurement process
or calculations.
The Predose Measurements box can enable or disable the predose measurement option.
The predose option should be enabled whenever a patient has received radioactive material
before an uptake procedure is to be performed. When Enabled is selected, and the count
sequence initiated, a screen will appear and ask the user, “Perform Predose Measurement?
Yes. No.” If
Yes is selected, then a measurement of the patient’s thigh and neck should be
performed before any thyroid uptake radiopharmaceutical is administered. These predose
measurements will be subtracted from subsequent thyroid uptake measurements. If
No is
selected, then the Predose measurement will be omitted. If Disabled is selected from the
option box, then predose measurements will be omitted.
NOTE: The thyroid uptake predose measurement part of the CAPTUS
®
2000 software has a
peak finding algorithm that searches for the photopeak that corresponds to the particular
isotope (I-123, I-131, or Tc99m) that will be administered for the thyroid uptake as defined in
the protocol. If the peak is not found, a message will appear stating that no residual activity
was found. If a peak is found, the predose measurement records and subtracts the count
information from the same Region of Interest as the isotope that will be administered. The
predose measurement count rate will also be decay corrected using the same half life as the
isotope chosen for the thyroid uptake. Therefore, the predose measurement should only be
used when the previously administered isotope is the same isotope that will be used for the
thyroid uptake. For example, the predose measurement can be used for thyroid cancer
patients who have been treated with I-131 for tumor oblation, and then have a subsequent I-
131 thyroid uptake performed to evaluate the efficacy of the treatment.
Isotope
Select the isotope to be administered from the isotope drop down box as appears in Figure
6-8. The choices are I-123, I-131, or Tc99m.
Figure 6-8
July 00 THYROID UPTAKE 6-7