Yüksek Yoğunlukta Odaklanmış Ultrason Yönteminin Temel Prensipleri
Özet
Yüksek Yoğunlukta Odaklanmış Ultrason (HIFU), geleneksel kanser tedavilerine alternatif olarak geliştirilen, iyonlaştırıcı olmayan ve minimal invazif bir termal ablasyon yöntemidir. Temel prensibi, ultrason ışınlarını üstteki dokulara zarar vermeden derinlerdeki hedef bölgeye odaklayarak koagülasyon nekrozu ve sitotoksik etki yaratmaktır. Dokularda hızlı sıcaklık artışıyla geri dönüşsüz hücre ölümüne yol açan termal etki ve kavitasyon gibi süreçleri içeren mekanik etki olmak üzere iki ana mekanizmayla çalışır. Sistem; terapötik ışını ileten piezoelektrik dönüştürücüler ile işlemi gerçek zamanlı izleyen ultrasonografi (USG) veya manyetik rezonans görüntüleme (MRG) bileşenlerinden oluşur. Organın erişilebilirliğine göre ekstrakorporeal, transrektal ve interstisyel prob çeşitleri bulunan HIFU, aşamalı dizi teknolojisindeki gelişmelerle homojen olmayan dokularda daha esnek odaklama yeteneği kazanmıştır. Klinik uygulamaları beyin cerrahisi, üroloji, jinekoloji ve onkolojide yaygın şekilde araştırılan bu yöntem; düşük işlem maliyeti, hızlı iyileşme süresi, kanamayı durdurma potansiyeli ve iyonizan radyasyon içermemesi nedeniyle sınırsız tekrarlanabilme gibi önemli avantajlar sunmaktadır.
High-Intensity Focused Ultrasound (HIFU) is a non-ionizing and minimally invasive thermal ablation method developed as an alternative to conventional cancer treatments. Its core principle is to focus ultrasound beams onto a deep target zone without damaging overlying tissues, thereby inducing coagulation necrosis and cytotoxic effects. It operates through two primary mechanisms: a thermal effect, which causes rapid temperature elevation leading to irreversible cell death, and a mechanical effect involving processes like cavitation. The system comprises two main components: piezoelectric transducers that deliver the therapeutic beam and real-time imaging modalities such as ultrasonography (USG) or magnetic resonance imaging (MRI) to monitor the procedure. Depending on organ accessibility, HIFU utilizes extracorporeal, transrectal, or interstitial probes, and advancements in phased-array technology have enabled more flexible focusing in non-homogeneous tissues. Extensively researched in neurosurgery, urology, gynecology, and oncology, this technology offers significant advantages, including lower procedural costs, faster recovery times, the potential to stop bleeding, and the absence of ionizing radiation, allowing for virtually infinite repeat treatments.
Referanslar
Lehmann J.F. The biophysical basis of biologic ultrasonic reactions with special reference to ultrasonic therapy. Arch Phys Med Rehabil. 1953;34: 139.
Lafon C., Melodelima, D., Salomir R., Chapelon J.Y. Interstitial devices for minimally invasive thermal ablation by high-intensity ultrasound. Int J Hyperth. 2007;23: 153–63.
Lynn J.G., Zwermer R.L., Chick A.J., Miller A.E. A new method for the generation and use of focused ultrasound in experimental biology. J Gen Physiol. 1942;26: 179–93.
Lynn J.G., Zwemer R.L., Chick A.J. The biological application of focused ultrasound waves. Science. 1942;96: 119–20.
Fry W.J., Barnard J.W., Fry F.J., Krumins R.F., Brennan J.F. Ultrasonically produced localized selective lesions in the central nervous system. Am J Phys Med. 1955;34: 413–23.
Izadifar Z, Chapman D, Babyn P. An Introduction to High Intensity Focused Ultrasound: Systematic Review on Principles, Devices, and Clinical Applications. J Clin Med. 2020;9: 460.
Zhou, Y.-F. High intensity focused ultrasound in clinical tumor ablation. World J Clin Oncol. 2011; 2- 8.
Dewey, W.C. Arrhenius relationships from the molecule and cell to the clinic. Int J Hyperth. 2009;25, 3–20.
Diederich CJ. Thermal ablation and high-temperature thermal therapy: overview of technology and clinical implementation. Int J Hyperthermia. 2005; 21: 745-53.
Mason TJ. A sound investment. Chem Ind. 1998; 21: 878-82.
Yagel S. High-intensity focused ultrasound: a revolution in non-invasive ultrasound treatment? Ultrasound Obstet Gynecol. 2004; 23: 216-7.
Makin I.R., Mast T.D., Faidi W., Runk M.M., Barthe P.G., Slayton M.H. Miniaturized ultrasound arrays for interstitial ablation and imaging. Ultrasound Med Biol. 2005; 31: 1539–50.
Salgaonkar V.A., Diederich C.J. Catheter-based ultrasound technology for image-guided thermal therapy. Current technology and applications. Int J Hyperth. 2015; 31: 203–15.
Gelet A, Chapelon JY, Bouvier R, Rouvière O, Lasne Y, Lyonnet D, Dubernard JM. Transrectal high-intensity focused ultrasound: minimally invasive therapy of localized prostate cancer. J Endourol. 2000; 14: 519-28.
Visioli AG, Rivens IH, ter Haar GR, Horwich A, Huddart RA, Moskovic E, Padhani A, Glees J. Preliminary results of a phase I dose escalation clinical trial using focused ultrasound in the treatment of localised tumours. Eur J Ultrasound. 1999; 9: 11-8.
Dubinsky TJ, Cuevas C, Dighe MK, Kolokythas O, Hwang JH. High-intensity focused ultrasound: current potential and oncologic applications. AJR Am J Roentgenol. 2008; 190: 191-9.
