Comparison of focal boost high dose rate prostate brachytherapy optimisation methods

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• High-dose-rate (HDR) brachytherapy is a key treatment for localized prostate cancer.
• Treatment planning aims to deliver precise radiation doses to the tumor while sparing healthy tissues.
• Defining the target volume, such as the tumor plus margin (F-PTV) or involved sectors, is critical for effective dose delivery.

Purpose of the Study:

• To compare the dosimetric outcomes of two different target volume optimization strategies in HDR prostate brachytherapy.
• To evaluate the efficacy of optimizing radiation dose to the F-PTV versus involved sectors for whole gland treatments with a focal boost.

Main Methods:

• Retrospective analysis of 15 patients undergoing HDR prostate brachytherapy.
• Dosimetric parameters including D90 (minimum dose to 90% of the PTV) and V150 (volume receiving 150% of the prescription dose) were compared.
• Optimization was performed targeting either the F-PTV or involved radioactive seed implant sectors.

Main Results:

• Median F-PTV D90 was 21.0 Gy for F-PTV optimization versus 19.8 Gy for sector optimization.
• Median F-PTV V150 was 77.2% for F-PTV optimization versus 75.6% for sector optimization.
• F-PTV optimization resulted in higher D90 and V150 values, indicating potentially better dose coverage.

Conclusions:

• Optimizing radiation dose delivery to the F-PTV in HDR prostate brachytherapy leads to superior dosimetric coverage compared to sector-based optimization.
• These findings suggest that F-PTV based planning may improve treatment efficacy for prostate cancer patients receiving HDR brachytherapy with a focal boost.