## Manually Fine-Tuning the Calibraton

After the automated optimization and surface annealing processes are complete you will need to manually fine tune the model parameters.

Click the **Calibrate Manually** tab. Adjust the parameters using the sliders followed by the bumper arrows to minimize the RMS% error of the fit of the central axis profile to the measured data over the range 0..10 mm.

- Manual fine-tuning is an iterative process. Begin by adjusting the
**Dose Calibration**slider until the dose profile curve passes through the 5 mm measurement point. - Next, adjust the
**Crossover**slider to minimize the RMS error in the range 0..5 mm. - Next, adjust the
**Nearfield slope**slider to minimize the RMS error in the range 0..5 mm. - Next, adjust the
**Anisotropy shift**slider to minimize the RMS error in the range 0..5 mm. - Next, adjust the
**Anisotropy threshold**slider to minimize the RMS error in the range 0..5 mm. - Next, adjust the
**Farfield power**slider to minimize the RMS error in the range 0..10 mm. - Next, adjust the
**Farfield threshold**slider to minimize the RMS error in the range 0..10 mm. - Next, adjust the
**Dose Calibration**slider to minimize the RMS error in the range 0..5 mm. - Repeat steps 2-8 until the RMS error over the range 0..10 mm can no longer be reduced. Optional: try varying the order of the steps to see if any further reduction is possible.
- Lastly, adjust the
**Anisotropy bias**slider to further minimize the RMS error in the range 0..5 mm. - Repeat steps 2-10 until the RMS error in the range 0..10 mm can no longer be reduced.
- It is typically possible to achieve a central axis RMS error of under 2% over the range 0..10 mm.
- You may optionally return to the Surface Measurements section and repeat the simulated annealing followed by repeated manual fine-tuning to see if the RMS error between calculated and surface measurements can be further reduced.
- Click the
**Save File As...**button to**save the plaque file**.

For this example, simulated annealing of the surface strength distribution, followed by manual fine tuning, eventually achieved a near-surface RMS % error of about 5.1 and a central axis RMS % error of about 1.4 over the range 0..10 mm between the patch source model calculations and measurements.

Note that the BEBIG points are normalized to a value of 100 at the center whereas the PS isodose lines are normalized to 1.0.

All dosimetry has been normalized to 1.0 on the central axis of the plaque at 1 mm from the surface of the plaque, the same normalization point as the BEBIG near-surface measurements.