Dosimetry Calc

Whole body dosimetry data can be estimated using VivoQuant's Dosimetry Calc tool in conjunction with the third party application OLINDA (Organ Level INternal Dose Assessment). The Dosimetry Calc tool calculates the cumulative activity per unit activity administered (units in uCi-hr/uCi) which is the required input to the OLINDA application for dosimetry calculations.

The cumulative activity per unit activity administered is estimated using the following area under the curve (AUC) method. The tool uses a curve fitting algorithm which fits the experimental isotope's exponential decay curve to the percent injected dose per gram (% ID/g) vs time curve of the experimental data. The AUC is calculated using trapezoidal approximations for experimental measurements, and the remaining AUC is calculated using the analytical solution to the definite integral.

The data is then stored in a .CSV file that can be copied into the OLINDA application.

NOTE: Before continuing ensure that a "Remainder Body ROI" has been created. This is a required data point for the OLINDA application.

Getting There

To access the Dosimetry Calc tool the 3D ROI Tool must be active. Go to the Advanced Modules tab, then move down to Dosimetry Calc

Function

Getting Started

Start the tool by selecting 'Export Quantification'.

Once the tool starts, a spreadsheet will appear and request for you to fill in missing information from the study. This can either be done in VivoQuant or in another spreadsheet software.

Tip: It is likely easier to make changes in batch in a spreadsheet software.

The column labeled 'Group' asks for the group number. This allows for multiple groups to be used at once.

The column labeled 'Time Point' asks for the time point of the study for each frame. The time units can be manipulated using the drop down menu on the bottom left of the window or manually in another spreadsheet software.

The column labeled 'Injected Dose' asks for the initial injected dose.

Once the spreadsheet is complete, save the information as an easily accessible .CSV file. In VivoQuant you may append an existing .CSV file or start a new one.

Using the AUC Calculation

Go to the Advanced Modules tab, then select Dosimetry Calc -> AUC Calculation.

Click "Load Spreadsheet" in the top left corner of the dialog box, and call the spreadsheet you created in the last section. In the 'Dosimetry Isotope' drop down menu, select the isotope that was used in the experiment. If the isotope used is not listed, open the file 'isotopes.txt' located in the VivoQuant install directory (default is C:\Program Files\inviCRO\VivoQuant\) and add the isotope information.

It is important to ensure you select the correct isotope because the Dosimetry Calc tool uses a curve fit algorithm and extrapolates using only isotope-specific radioactive decay information.

Next click "Update Plot" and enter in the initial percent injected doses assumed for each of the ROIs.

The Plot should now appear next to the table in the window

Click "OK" button at the bottom of the window and save as another .CSV file

This data is now ready to be used in the OLINDA software