3D numerical investigation of a frequency-domain model-based method for fast transcranial photoacoustic imaging.

Objective. Transcranial photoacoustic computed tomography (PACT) is challenged by skull-induced aberrations. Although the time-reversal (TR) method can compensate for these effects, it requires full-wave simulations for every frame, making it impractical for time-sensitive applications. To address this limitation, we propose a frequency-domain model-based (FDMB) method for fast and accurate transcranial PACT.Approach. The FDMB method is numerically validated against the TR method by evaluating performance under varying numbers of sensor elements, data sampling rates, and perturbations in both the speed-of-sound maps and sensor locations.Main results. The FDMB method achieves up to a 1265.75-fold speedup over the TR method, while consistently delivering better image quality. These results demonstrate the strong potential of the proposed method for efficient and accurate three-dimensional transcranial PACT, offering a promising route toward near real-time transcranial imaging.Significance. Skull-induced aberrations remain a fundamental obstacle in transcranial PACT. The proposed method overcomes this challenge by using a precomputed model matrix (MM) in the frequency-domain. Since the high frequencies are strongly attenuated by the skull, only low frequencies contribute meaningfully to the reconstruction, allowing the MM to be reduced in size. Furthermore, since the MM is independent of the imaging objects, it can be reused for fast transcranial PACT.