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NCINM User Manual
NCI Dosimetry System for Nuclear Medicine
Current documented release: NCINM3.20260510
[Screenshot placeholder: NCINM3 main window overview]
The National Cancer Institute Dosimetry System for Nuclear Medicine (NCINM) is a reference internal dosimetry program developed by the National Cancer Institute (NCI) for estimating organ absorbed doses and effective dose from nuclear medicine procedures.
NCINM3 uses pre-calculated S values and, when available, predefined biokinetic data to calculate organ doses for selected computational human phantoms. The current release includes NCI, ICRP, and fetus phantom libraries, with mother-to-fetus S values for fetal dose calculations. It supports population-based dose evaluation, benchmarking, and research workflows. It is not intended for patient-specific clinical decision support.
| Step | Description |
|---|---|
| 1 | Select the phantom library and available phantom characteristics |
| 2 | Select a radionuclide or radiopharmaceutical, depending on the selected phantom library |
| 3 | Enter administered activity |
| 4 | Review or edit the source-region table |
| 5 | Review the target-organ dose output table |
| 6 | Optionally select source-region rows and click Export S Values |
NCINM3 supports three phantom libraries:
- NCI phantoms
- ICRP phantoms
- Fetus phantoms
Each library has its own tab. Select the desired phantom library first, then choose the available phantom characteristics for that library.
For NCI and ICRP phantoms, select sex and age. The age radio-button captions are:
- 0
- 1
- 5
- 10
- 15
- 35
The 35-year selection corresponds to the adult phantom.
For fetus phantoms, select gestational age:
- 8 weeks
- 10 weeks
- 15 weeks
- 20 weeks
- 25 weeks
- 30 weeks
- 35 weeks
- 38 weeks
Fetus calculations represent maternal source regions irradiating fetal target organs using mother-to-fetus S values.
The phantom display updates automatically when the phantom library, sex, or age selection is changed.
[Screenshot placeholder: NCI phantom tab with sex and age controls]
[Screenshot placeholder: ICRP phantom tab with sex and age controls]
[Screenshot placeholder: Fetus phantom tab with gestational age controls]
NCINM3 provides two calculation pathways.
Use the Radionuclide tab when source-region residence times or cumulated activities are known and will be entered manually.
Select the radionuclide from the popup menu, then enter source-region residence times or cumulated activities in the source-region table.
The radionuclide library contains 1070 radionuclides with photon and/or electron emissions based on ICRP Publication 107 radiation spectrum data.
For fetus phantom calculations, use this tab and enter maternal source-region data manually. In this mode, source regions correspond to maternal organs and target regions correspond to fetal organs.
[Screenshot placeholder: Radionuclide tab and popup menu]
Use the Radiopharmaceutical tab when predefined biokinetic data should be loaded automatically for NCI or ICRP phantom calculations.
When a radiopharmaceutical is selected, NCINM3 identifies the matching radionuclide from the leading radionuclide name in the radiopharmaceutical text and automatically loads the corresponding source-region residence-time data.
For fetus phantom calculations, this tab is intentionally blank because pregnancy-specific radiopharmaceutical biokinetic models are not currently defined.
[Screenshot placeholder: Radiopharmaceutical tab and popup menu]
Administered activity can be entered in MBq or mCi. The two fields are linked:
- Entering MBq and pressing Enter updates mCi using
1 mCi = 37 MBq - Entering mCi and pressing Enter updates MBq
The default activity is:
| Unit | Default |
|---|---|
| MBq | 3700 |
| mCi | 100 |
[Screenshot placeholder: Administered activity inputs]
The source-region table has column headers:
| Column | Purpose |
|---|---|
| Source | Source organ or region |
| Resid Time h | Residence time in hours |
| Cum Act MBq-s | Cumulated activity in MBq-s |
For radionuclide-based calculations, users enter residence time or cumulated activity manually. NCINM3 converts between them using:
cumulated activity (MBq-s) = administered activity (MBq) x residence time (h) x 3600
For radiopharmaceutical-based calculations, source-region residence times are loaded automatically after the radiopharmaceutical is selected. This pathway is available for NCI and ICRP phantom calculations.
For fetus phantom calculations, source regions are maternal organs. The fetus library includes 70 maternal source regions, including placenta and amniotic fluid, plus a remainder source. Enter the source-region residence times or cumulated activities manually.
Rows with non-zero residence time are shaded automatically. If the residence time is changed back to zero, the row returns to the default background.
For S-value export, select one or more source-region rows in this table. There is no separate S-value export column.
[Screenshot placeholder: Source-region table with shaded non-zero rows]
The target-region output table has column headers:
| Column | Purpose |
|---|---|
| Target | Target organ or tissue |
| Mass g | Target-organ mass in grams |
| Dose mGy | Absorbed dose in mGy |
| Dose/Act mGy/MBq | Absorbed dose per administered activity |
NCINM3 calculates dose from S values, administered activity, and source-region residence time. Effective dose is reported in the final row for NCI and ICRP phantom calculations.
For fetus phantom calculations, the output table reports absorbed dose to fetal target organs using mother-to-fetus S values.
[Screenshot placeholder: Target-organ dose output table]
To export S values:
- Select one or more source-region rows in the source-region table.
- Click Export S Values.
- Save the generated CSV file.
The exported file contains S values in mGy/MBq-s for the selected source
regions and the currently selected phantom. For fetus phantoms, the exported
values are mother-to-fetus S values for the selected maternal source regions and
fetal target organs. The CSV columns are Source Region, Target Region, and
S Value (mGy/MBq-s).
Click Clear Tables to reset administered activity to the default values, clear source-region residence times and cumulated activities, clear dose output, and refresh the phantom display.