Abstract: Focus steering technique plays a crucial role in various high-intensity focused ultrasound (HIFU) treatment scenarios. However, due to current technological limitations, the focus quality degrades rapidly and prefocal grating lobes arise with increasing focus-shifting distance, which may adversely affect the safety of the treatment. To enlarge the focal steering range of a phased array, a novel method for array element arrangement is proposed in this study, which can increase both the safety and the efficient steering range of the focus. Additionally, a “near-field focusing” strategy for ablation using an HIFU phased array is introduced. Experimental results demonstrate that this strategy not only effectively reduces the average acoustic intensity at the medium’s surface but also inhibits temperature elevation in the prefocal region. Thus, this approach could mitigate the risks of skin burn and abdominal edema during clinical HIFU therapy.

使用球面斐波那契网格排布的聚焦超声阵列结合近场聚焦策略减轻焦域前场过热风险

[1]AgrawalM, GargK, SamalaR, et al., 2021. Outcome and complications of MR guided focused ultrasound for essential tremor: a systematic review and meta-analysis. Frontiers in Neurology, 12:654711.

[2]BachuVS, KeddaJ, SukI, et al., 2021. High-intensity focused ultrasound: a review of mechanisms and clinical applications. Annals of Biomedical Engineering, 49(9):1975-1991.

[3]BrauchartJS, GrabnerPJ, 2015. Distributing many points on spheres: minimal energy and designs. Journal of Complexity, 31(3):293-326.

[4]ChaussyCG, ThüroffS, 2017. High-intensity focused ultrasound for the treatment of prostate cancer: a review. Journal of Endourology, 31(S1):S-30-S-37.

[5]ChukkapalliG, KarpikSR, EthierCR, 1999. A scheme for generating unstructured grids on spheres with application to parallel computation. Journal of Computational Physics, 149(1):114-127.

[6]DamianouC, HynynenK, 1993. Focal spacing and near-field heating during pulsed high temperature ultrasound therapy. Ultrasound in Medicine & Biology, 19(9):777-787.

[7]DaumDR, HynynenK, 1998. Thermal dose optimization via temporal switching in ultrasound surgery. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 45(1):208-215.

[8]DiederichCJ, HynynenK, 1999. Ultrasound technology for hyperthermia. Ultrasound in Medicine & Biology, 25(6):871-887.

[9]EllensN, PulkkinenA, SongJ, et al., 2011. The utility of sparse 2D fully electronically steerable focused ultrasound phased arrays for thermal surgery: a simulation study. Physics in Medicine and Biology, 56(15):4913-4932.

[10]Garcia-GutierrezCM, Becerra-HerrejonH, Garcia-BecerraCA, et al., 2022. High intensity focused ultrasound (HIFU) in prostate diseases (benign prostatic hyperplasia (BPH) and prostate cancer). In: Arnouk H (Ed.), Advances in Soft Tissue Tumors. IntechOpen, London, UK.

[11]GavrilovLR, HandJW, 2000. A theoretical assessment of the relative performance of spherical phased arrays for ultrasound surgery. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 47(1):125-139.

[12]GonzálezÁ, 2010. Measurement of areas on a sphere using Fibonacci and latitude–longitude lattices. Mathematical Geosciences, 42(1):49-64.

[13]GossSA, FrizzellLA, KouzmanoffJT, et al., 1996. Sparse random ultrasound phased array for focal surgery. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 43(6):1111-1121.

[14]HaarGT, CoussiosC, 2007. High intensity focused ultrasound: physical principles and devices. International Journal of Hyperthermia, 23(2):89-104.

[15]HüttigC, StemmerK, 2008. The spiral grid: a new approach to discretize the sphere and its application to mantle convection. Geochemistry, Geophysics, Geosystems, 9(2):Q02018.

[16]JiYS, ZhuJQ, ZhuLL, et al., 2020. High-intensity focused ultrasound ablation for unresectable primary and metastatic liver cancer: real-world research in a Chinese tertiary center with 275 cases. Frontiers in Oncology, 10:519164.

[17]KennedyJE, Ter HaarGR, CranstonD, 2003. High intensity focused ultrasound: surgery of the future? The British Journal of Radiology, 76(909):590-599.

[18]KimYS, KeserciB, PartanenA, et al., 2012. Volumetric MR-HIFU ablation of uterine fibroids: role of treatment cell size in the improvement of energy efficiency. European Journal of Radiology, 81(11):3652-3659.

[19]KlímaK, PickM, ProsZ, 1981. On the problem of equal area block on a sphere. Studia Geophysica et Geodaetica, 25(1):24-35.

[20]KociubaJ, ŁozińskiT, ZgliczyńskaM, et al., 2023. Adverse events and complications after magnetic resonance-guided focused ultrasound (MRgFUS) therapy in uterine fibroids–a systematic review and future perspectives. International Journal of Hyperthermia, 40(1):2174274.

[21]KöhlerMO, MougenotC, QuessonB, et al., 2009. Volumetric HIFU ablation under 3D guidance of rapid MRI thermometry. Medical Physics, 36(8):3521-3535.

[22]LamMK, HuismanM, NijenhuisRJ, et al., 2015. Quality of MR thermometry during palliative MR-guided high-intensity focused ultrasound (MR-HIFU) treatment of bone metastases. Journal of Therapeutic Ultrasound, 3(1):5.

[23]MarinovaM, GhaeiS, ReckerF, et al., 2021. Efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for uterine fibroids: an observational single-center study. International Journal of Hyperthermia, 38(2):30-38.

[24]MougenotC, KöhlerMO, EnholmJ, et al., 2011. Quantification of near-field heating during volumetric MR-HIFU ablation. Medical Physics, 38(1):272-282.

[25]MullerME, 1959. A note on a method for generating points uniformly on n-dimensional spheres. Communications of the ACM, 2(4):19-20.

[26]QuadriSA, WaqasM, KhanI, et al., 2018. High-intensity focused ultrasound: past, present, and future in neurosurgery. Neurosurgical Focus, 44(2):E16.

[27]RakhmanovEA, SaffEB, ZhouYM, 1994. Minimal discrete energy on the sphere. Mathematical Research Letters, 1(6):647-662.

[28]RamaekersP, de GreefM, BerrietR, et al., 2017a. Evaluation of a novel therapeutic focused ultrasound transducer based on Fermat’s spiral. Physics in Medicine and Biology, 62(12):5021-5045.

[29]RamaekersP, RiesM, MoonenCTW, et al., 2017b. Improved intercostal HIFU ablation using a phased array transducer based on Fermat’s spiral and Voronoi tessellation: a numerical evaluation. Medical Physics, 44(3):1071-1088.

[30]RosnitskiyPB, VysokanovBA, GavrilovLR, et al., 2018. Method for designing multielement fully populated random phased arrays for ultrasound surgery applications. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 65(4):630-637.

[31]RosnitskiyPB, SapozhnikovOA, GavrilovLR, et al., 2020. Designing fully populated phased arrays for noninvasive ultrasound surgery with controlled degree of irregularity in the arrangement of elements. Acoustical Physics, 66(4):352-361.

[32]SwinbankR, James PurserR, 2006. Fibonacci grids: a novel approach to global modelling. Quarterly Journal of the Royal Meteorological Society, 132(619):1769-1793.

[33]Ter HaarGR, 2001. High intensity focused ultrasound for the treatment of tumors. Echocardiography, 18(4):317-322.

[34]UchidaT, NakanoM, HongoS, et al., 2012. High-intensity focused ultrasound therapy for prostate cancer. International Journal of Urology, 19(3):187-201.

[35]VyasU, ChristensenD, 2012. Ultrasound beam simulations in inhomogeneous tissue geometries using the hybrid angular spectrum method. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 59(6):1093-1100.

[36]ZhaoH, YangGW, WangDY, et al., 2010. Concurrent gemcitabine and high-intensity focused ultrasound therapy in patients with locally advanced pancreatic cancer. Anti-Cancer Drugs, 21(4):447-452.

[37]ZhouYF, 2011. High intensity focused ultrasound in clinical tumor ablation. World Journal of Clinical Oncology, 2(1):8-27.

[38]ZiglioliF, BaciarelloM, MasperoG, et al., 2020. Oncologic outcome, side effects and comorbidity of high-intensity focused ultrasound (HIFU) for localized prostate cancer. A review. Annals of Medicine and Surgery, 56:110-115.