Direct aperture optimization-based intensity-modulated radiotherapy for whole breast irradiation

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Intensity-modulated radiation therapy (IMRT) is a common technique for whole breast irradiation.
• Standard IMRT (beamlet-optimized) and 3D conformal radiotherapy (3D-CRT) have limitations in dose distribution and planning efficiency.
• Direct aperture optimization (DAO) is a novel approach to IMRT planning.

Purpose of the Study:

• To compare the technical and dosimetric advantages of DAO-IMRT against standard IMRT and 3D-CRT for whole breast irradiation.
• To evaluate the efficacy of DAO-IMRT in both supine and prone patient positions.
• To assess improvements in dose coverage, uniformity, and organ-at-risk sparing.

Main Methods:

• Retrospective planning study involving 15 breast cancer patients (10 supine, 5 prone).
• DAO-IMRT plans were created and compared with standard beamlet-optimized IMRT and 3D-CRT plans.
• All plans utilized opposed tangential beam arrangements for whole breast treatment.

Main Results:

• DAO-IMRT plans were equivalent or superior to 3D-CRT and standard IMRT in all cases.
• DAO-IMRT achieved higher dose uniformity (UI) and lower lung V20 in supine patients compared to both other techniques.
• DAO-IMRT demonstrated superior UI in prone patients and significantly reduced planning time and monitor units.
• Planning time for DAO-IMRT was ~75% less than 3D-CRT; monitor units were ~60% less than beamlet-IMRT.

Conclusions:

• DAO-IMRT significantly improves dose distribution quality for whole breast irradiation.
• DAO-IMRT enhances both planning and delivery efficiency for supine and prone breast cancer treatment.
• This technique represents a valuable advancement in radiation therapy for breast cancer patients.