Comparison of 3D conformal breast radiation treatment plans using the anisotropic analytical algorithm and pencil...

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Accurate dose calculation is crucial for effective radiotherapy.
• Anisotropic analytical algorithm (AAA) and pencil beam convolution (PBC) are two common algorithms used in treatment planning.
• Understanding their dosimetric differences and clinical implications is essential for optimizing patient care.

Purpose of the Study:

• To compare dosimetric differences between AAA and PBC algorithms in breast cancer treatment planning.
• To evaluate the plan quality achieved by AAA versus PBC using dosimetric parameters.
• To assess discrepancies between AAA/PBC plans and independent monitor unit (MU) verification calculations.

Main Methods:

• Ten lumpectomy (Group I) and ten mastectomy (Group II) cases were included.
• Treatment plans were initially calculated using PBC and then recalculated using AAA with identical monitor units.
• Plan quality was assessed using dose-volume histograms (DVHs) and independent MU verification.

Main Results:

• PBC plans overestimated target dose compared to AAA plans.
• AAA plans achieved similar target coverage but resulted in larger high-dose volumes (V105%) in mastectomy cases.
• AAA plans significantly increased ipsilateral lung low-dose (5 Gy) exposure and showed superior area undercoverage compared to PBC.

Conclusions:

• While AAA can achieve comparable target coverage to PBC, it leads to increased low-dose lung exposure and potential skin dose.
• AAA plans exhibited greater discrepancies during MU verification, suggesting a need for adjusted tolerance levels.
• The findings highlight the importance of careful evaluation of dose distribution and verification for AAA-based treatment plans.