Validation of a commercial software dose calculation for Y-90 microspheres

Area of Science:

• Medical Physics
• Radiotherapy
• Nuclear Medicine

Background:

• New commercial software aids in calculating radiation dose distributions for Yttrium-90 (Y-90) microsphere treatments of liver lesions.
• Accurate dose calculation is crucial for effective treatment and minimizing normal tissue toxicity.

Purpose of the Study:

• To validate the MIM SurePlan Liver Y90 software by comparing its dose calculations against a Monte Carlo-derived dose kernel method.
• To assess the accuracy of MIM SurePlan Liver Y90's Local Deposition Method (LDM) and Voxel S Value (VSV) algorithms.

Main Methods:

• Dose calculations were performed on 10 patients treated with Y-90 microspheres for metastatic liver cancer.
• Three methods were used: MIM SurePlan Liver Y90 (LDM and VSV algorithms) and a Fluka Monte Carlo-derived dose kernel (MCK) as ground truth.
• Analysis included 3D Gamma passing rates and various dosimetric parameters.

Main Results:

• The VSV algorithm achieved high 3D Gamma passing rates (99.3%) compared to LDM (78.9%) when compared to MCK.
• Differences in combined target GTV V70Gy and normal liver mean doses were small between VSV and MCK.
• Larger differences were observed in GTV mean doses and D95, attributed to dose gradients and calculation method variations.

Conclusions:

• The MIM SurePlan Liver Y90 VSV algorithm demonstrates good agreement with MCK calculations for Y-90 microsphere liver treatments.
• Dosimetric metrics like lesion mean dose and D95 may be less robust to variations in calculation parameters for small lesions.