biodex ATOMLAB 500, Руководство по эксплуатации и обслуживанию, Страница: 104 / 212

4. From the semi-automated decay setup options screen, the user can perform the
test using any of several methods including:
•
Normalized reading by hours: allows the user to set the reading interval at a set
number of hours and set the time to be used for the normalized reading. As an
example using Tc99m, an appropriate number of hours for a normalized reading
would be 30 hours.
•
Normalized reading by half-life of the isotope selected: allows the user to set the
reading interval by half-life and select the half-life reading to be used as the
normalized reading.
Note: An appropriate normalized reading by half life is to use the fifth half life of
the isotope.
•
Averaging calculation method with readings at a set number of hours: allows the
user to set the number of hours between readings before the system calculates
the results using the averaging method described in Appendix J, Linearity.
•
Averaging calculation method by half-life: allows the user to set the number of
half-lives between readings before the system calculates the results.
5.
Select the desired variance calculation method by touching the appropriate radio button.
6.
Select the desired reading interval units by touching the appropriate radio button.
7. The Automated Ends Below field displays the default activity to end the automated
portion of the test. If the value displayed is not appropriate, touch the <Automated
Ends Below> field and use the <
▲
> and <
▼
> keys to adjust the activity to be
between 50 and 500 µCi at which point the automated portion of the test should
end. The system defaults to 100 µCi.
8.
Touch the <Test Ends Below> field and enter the activity level at which the test
should be ended. Touch <Accept> to record this value and return to the Semi-
Automated Decay Setup Options screen.
9.
When all setup options have been addressed on the semi-automated decay setup
options screen, touch <Accept> to record all settings and return to the Semi-
Automated Decay Test screen. The live detector reading is displayed in red on the
screen. If necessary, touch <Zero Background> to perform a Zero Background
reading at this point.
Figure 6.53. Semi-Automated Decay Test Screen Displaying Measured Activity in
Red.