Patient performance-based plan parameter optimization for prostate cancer in tomotherapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment Planning

Background:

• Tomotherapy is an advanced radiation therapy technique.
• Treatment planning parameter optimization is crucial for effective cancer treatment.
• Prostate cancer patients' performance status influences treatment tolerance.

Purpose of the Study:

• To evaluate how treatment planning parameters affect tomotherapy plan quality for prostate cancer.
• To identify optimal parameter combinations for patients with varying performance statuses (ECOG 2-3).

Main Methods:

• Generated 27 unique treatment plans per patient by varying field width, pitch, and modulation factor.
• Analyzed plans using dosimetrical indices (e.g., HI, CI, TCI, CN, QF) for target volume assessment.
• Assessed organs at risk (OAR) sparing using dose-volume histograms and Critical Organ Scoring Index (COSI).

Main Results:

• A field width of 1cm yielded superior planning target volume (PTV) and OAR indices but significantly increased treatment time.
• Increasing pitch had minimal impact on treatment time but slightly compromised PTV indices.
• Field width demonstrated the most substantial influence across all evaluated indices, including PTV, OAR, and treatment duration.

Conclusions:

• For patients with good performance status, a 1cm field width, 0.172 pitch, and 1.8 modulation factor are recommended.
• For patients with poor performance status, a 5cm field width, 0.287 pitch, and 3.5 modulation factor are suggested.
• Tailoring tomotherapy parameters based on patient performance status is essential for optimizing treatment outcomes.