Automatic specific absorption rate (SAR) prediction for hyperthermia treatment planning using deep learning method.

Abstract

<h4>Objective</h4>To develop a deep learning method for fast and accurate prediction of Specific Absorption Rate (SAR) distributions in the human head to support real-time hyperthermia treatment planning (HTP) of brain cancer patients.<h4>Approach</h4>We propose an encoder-decoder neural network with cross-attention blocks to predict SAR maps from brain electrical properties, tumor 3D isocenter coordinates and microwave antenna phase settings. A dataset of 201 simulations was generated using finite-element modeling by varying tissue properties, tumor positions, and antenna phases within a human head model equipped with a three-ring phased-array applicator. The model was trained and evaluated on this dataset using standard error metrics and structural similarity analysis.<h4>Main results</h4>On a held-out test set of 20 samples, the model achieved a mean root-mean-squared error (RMSE) of 3.3 W/kg and a mean absolute error (MAE) of 1.6 W/kg across the whole brain. In target regions, RMSE and MAE were 4.8 and 2.5 W/kg, respectively. The structural similarity index (SSIM) reached a mean value of 0.90, and the computation time was reduced from 10 min (simulation-based) to 4 s using our deep learning approach. The proposed method enables accurate, efficient SAR prediction for HTP in the brain, potentially supporting real-time HTP to optimize tumor temperature and improve clinical outcomes.<h4>Significance</h4>This work introduces a novel deep learning-based approach that significantly accelerates SAR calculation in HTP, enabling adaptive therapy strategies to improve treatment outcomes in hyperthermia.