Set TG-51 Calibration Conditions

Use Calibration Conditions to describe the reference geometry used for photon and electron measurements.

Photon Calibration

Set:

• Reference Field Size
• Calibration Setup
  • SSD Setup — source-to-surface distance; use this option for the fixed 1000 mm SSD geometry.
  • SAD Setup — source-to-axis distance; use this option for the fixed 1000 mm SAD geometry.

Quadrant normally selects a 100 × 100 mm² reference field when it is available. The displayed SSD and SAD values are fixed, read-only values. Confirm that the displayed field and selected geometry match the measurements you performed.

Electron Calibration

Select the Reference Applicator, then verify that Electron SSD displays the fixed, read-only value of 1000 mm.

The electron protocol is selected when you create the data set with Wizard or Quick Add. See Select or Create a TG-51 Data Set and Understand TG-51 Protocols and Saved Evidence.

The reference applicator is optional when the data set will contain only photon calibrations. Quadrant excludes SRS applicators from this selection.

Update the Conditions

1. Open Calibration > TG-51 > Calibration Conditions.
2. Confirm the selected data set.
3. Select the photon Reference Field Size.
4. Select SSD Setup or SAD Setup.
5. Verify the displayed 1000 mm SSD or SAD value.
6. If electron calibrations are planned, select the Reference Applicator.
7. If electron calibrations are planned, verify that Electron SSD displays 1000 mm and matches the reference-dose measurement.
8. Review the pending changes.
9. Click Save.

Caution

Changing reference conditions can make saved PDD values or calibration results inconsistent with the measurement geometry. Review any recalculation or deletion prompt before continuing.

Confirm the Result

After saving, verify that the photon field and geometry, electron applicator, and electron SSD match the conditions used for the calibration. Confirm that the fixed photon distance and electron SSD are 1000 mm. For Report 385, the calibration wizard separately records the 1000 mm beam-quality SSD and confirms that the reference-dose SSD is within the supported 900–1100 mm range.

Continue with Select a TG-51 Reference Data Set.