Left Ear

Summary

A CTV under the left ear of a rolled patient.

The CTV abuts the skin surface, and without a bolus, 74% of the target voxels have a minimum depth < 10 mm and 89% have a depth < 15 mm.

With an OptiBol variable-thickness bolus with goal buildup set to 15 mm, 100% of the voxels have depth > 10 mm and 91% have a depth > 15 mm.

Gallery

1. Four-panel view in the p.d software showing an OptiBol with 15 mm goal buildup
2. Axial view of the variable-thickness bolus with 15 mm goal buildup. Red wax was placed in this patient’s ear (as contoured), but the bolus could have been designed to fill that hole as well.
3. Photo of the OptiBol with laser registered inside the alignment guide
4. Depth-volume histograms for the voxels in the underlying CTV shown with no bolus vs. OptiBol 15 mm

Details on Depth-Volume Histograms (Gallery Item 4)

Variable-Thickness OptiBol (Goal 15 mm to Target)

• 100% of the target voxels have min depth ≥ 10 mm (0% target < 10 mm)
• 95% of the target voxels have min depth ≥ 14.25 mm (where 14.25 mm is 95% of goal buildup of 15 mm for this bolus design)
• 91% of the target voxels have min depth ≥ 15 mm

No Bolus

• Only 26% of the target voxels have min depth ≥ 10 mm (74% target < 10 mm)
• Only 12% of the target voxels have min depth ≥ 14.25 mm
• Only 11% of the target voxels have min depth ≥ 15 mm