SU-E-T-546: Cumulative Dose Evaluation for Head and Neck Cancers

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Head and neck cancer treatment requires precise radiation delivery.
• Adaptive treatment planning aims to improve accuracy by accounting for anatomical changes during therapy.
• New technologies are needed to assess these changes effectively.

Purpose of the Study:

• To evaluate a prototype Varian Eclipse™ system with DART™ technology for analyzing adaptive treatment planning needs.
• To assess structure volume changes, displacements, and dose deviations in head and neck cancer patients.

Main Methods:

• Retrospective analysis of 10 head and neck cancer patients treated with daily cone-beam CTs.
• Utilized DART™ technology for retrospective dose accumulation calculations.
• Performed rigid and deformable image registrations to compare daily scans with planning CTs.

Main Results:

• All patients showed parotid gland volume reduction and dose escalation, often with medial displacement.
• Mean parotid volume reduction rate was 0.18 cm³/treatment day.
• Tumor target volumes (GTV, CTV, PTV) also reduced, particularly in the first half of treatment; dose increases were minimal.

Conclusions:

• The prototype DART™ technology shows promise for adaptive treatment planning.
• Clinical integration could lead to improved treatment accuracy and patient care in radiation oncology.
• Further development is needed to fully realize the potential of adaptive radiotherapy.