Influence of optimizing protocol choice on the integral dose value in prostate radiotherapy planning by dynamic...

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Dynamic radiotherapy techniques (IMRT, VMAT, HT) can lead to low-dose deposition in large body areas, potentially harming healthy cells.
• Minimizing the irradiated low-dose region is crucial while ensuring adequate target volume dose coverage.

Purpose of the Study:

• To compare integral dose values calculated for dynamic radiotherapy treatment plans.
• To evaluate two distinct optimization protocols for radiotherapy planning.

Main Methods:

• Analyzed 90 external beam radiotherapy plans across three techniques: IMRT, VMAT, and helical tomotherapy (HT).
• Plans were prepared using either a classic optimization protocol or a rings optimization protocol.
• The rings optimization protocol was specifically designed to reduce normal tissue low doses.

Main Results:

• Integral dose values varied based on irradiation geometry, technique, and the optimization protocol used.
• The application of the rings optimization protocol resulted in a decrease in normal tissue integral dose (NTID).

Conclusions:

• An alternative optimization protocol, beyond the classic one, can effectively limit low-dose irradiation areas.
• NTID can be reduced in dynamic radiotherapy techniques without compromising clinical constraints for organs at risk (OAR) and planning target volumes (PTV).