Interactive dose shaping part 2: proof of concept study for six prostate patients

Area of Science:

• Radiation Oncology
• Medical Physics
• Image-Guided Therapy

Background:

• Intensity-Modulated Radiation Therapy (IMRT) planning requires balancing target coverage and organ-at-risk (OAR) sparing.
• Real-time, local dose adjustments during IMRT planning are challenging.
• A hierarchical, sequential approach to dose modification and recovery is proposed.

Purpose of the Study:

• To assess the feasibility of Interactive Dose Shaping (IDS) as a new IMRT planning strategy.
• To evaluate IDS for prostate cancer treatment planning using a small cohort.
• To determine if IDS can achieve comparable or superior plan quality to conventional methods in real-time.

Main Methods:

• Developed and utilized IDS tools within the Dynaplan treatment planning software.
• Created IMRT plans for six prostate cancer patients using the IDS strategy.
• Compared IDS plans against conventionally optimized, clinically approved plans (9 beams, co-planar).
• Physician-guided selection of IDS plans based on target coverage and OAR sparing trade-offs.

Main Results:

• IDS plans achieved comparable target coverage and OAR sparing to conventional plans.
• Mean dose differences were 0.0 Gy (boost) and 1.2 Gy (PTV).
• D98% and D2% differences were -1.1 Gy and 1.1 Gy, respectively.
• Treatment plan generation time ranged from 15-45 minutes, with local adaptations under one second.
• Average non-tumor integral dose increased by 16.4%.

Conclusions:

• IDS is a feasible IMRT planning strategy for prostate cancer, enabling rapid, local dose adjustments.
• The approach shows promise for improving treatment planning efficiency and plan quality.
• Further development is needed to address the observed increase in integral dose.