Radyofrekans Ablasyonun Temel Prensipleri
Özet
Bu çalışma, genitoüriner kanserlerin tedavisinde son yirmi yılda yaygınlaşan minimal invaziv bir yöntem olan radyofrekans (RF) ablasyonun temel prensiplerini ve doku üzerindeki etkilerini incelemektedir. Cerrahiye alternatif veya cerrahinin bir bileşeni olarak kullanılan RFA, elektromanyetik dalgalar yerine 375-500 kHz aralığındaki alternatif elektrik akımının oluşturduğu iyonik hareketlilik ve sürtünme yoluyla dokuda koagülasyon nekrozu oluşturmayı hedefler. Dokuda ani hücresel ölüm ve geri dönüşümsüz hasar ideal olarak 50 °C üzerindeki sıcaklıklarda gerçekleşirken, 100 °C’nin üzerindeki sıcaklıklar buharlaşma ve kömürleşmeye neden olarak elektrik iletimini ve ablasyon alanını olumsuz etkiler. Tedavinin başarısı; büyük damarların neden olduğu ısı kaybı (heat sink etkisi), dokunun lokal elektrik ve termal iletim özellikleri gibi faktörlere doğrudan bağlıdır. Klinik uygulamalarda monopolar ve bipolar sistemler kullanılmakta olup; koagülasyon nekrozu hacmini artırmak ve doku direncini (empedansını) azaltmak amacıyla salin instilasyonu, içerden soğutmalı elektrotlar, pulse (kesintili) RF ablasyon, çoklu, çengelli (umbrella) veya kombine prob teknikleri gibi çeşitli teknolojik yöntemler geliştirilmiştir. Bu yöntemler sayesinde morbidite ve maliyetler azaltılmakta, cerrahi şansı olmayan hastalar için de etkin bir tedavi seçeneği sunulmaktadır.
This study examines the basic principles and tissue effects of radiofrequency (RF) ablation, a minimal invasive method that has become widespread in the treatment of genitourinary cancers over the last two decades. Used as an alternative to or a component of surgery, RFA aims to induce coagulation necrosis in tissue through ionic mobility and friction generated by alternating electrical current in the 375-500 kHz range rather than electromagnetic waves. While immediate cellular death and irreversible damage ideally occur at temperatures above 50 °C, temperatures exceeding 100 °C cause vaporization and charring, which adversely affect electrical conduction and reduce the ablation area. The success of the treatment directly depends on factors such as heat loss caused by large vessels (the heat sink effect), and the local electrical and thermal conduction properties of the tissue. Monopolar and bipolar systems are utilized in clinical practice, and various technological methods—including saline instillation, internally cooled electrodes, pulsed RF ablation, and multiple, hooked (umbrella), or combined probe techniques—have been developed to increase the volume of coagulation necrosis and decrease tissue impedance. These methods reduce morbidity and costs, providing an effective treatment option for patients who cannot undergo surgery.
Referanslar
Gazelle GS, Goldberg SN, Solbiati L, Livraghi T. Tumor ablation with radio-frequency energy. Radiology. 2000; 217(3): 633-46.
Nelson K, Jutric Z, Georgiades C. Physics and physiology of thermal ablations. Image-Guided Interventions in Oncology, Editor: Georgiades C, Kim HS. Switzerland, 2020; 2-5.
Esparaz AM, Goldberg SN, Ahmed M. Principles of image-guided therapies. Interventional Oncology: Principles and practice of image-guided cancer therapy, 2nd Edition, Editor: Geschwind JFH, Soulen MC. United Kingdom, Cambridge, 2016; 3-4.
Seegenschmiedt M, Brady L, Sauer R. Interstitial thermoradiotherapy: review on technical and clinical aspects. Am J Clin Oncol. 1990; 13: 352-63.
Larson T, Bostwick D, Corcia A. Temperature-correlated histopathologic changes following microwave thermoablation of obstructive tissues in patients with benign prostatic hyperplasia. Urology. 1996; 47: 463-69.
Zevas N, Kuwayama A. Pathologic analysis of experimental thermal lesions: comparison of induction heating and radiofrequency electrocoagulation. J Neurosurg. 1972; 37: 418-22.
Mertyna P, Dewhirst MW, Halpern E, Goldberg W, Goldberg SN. Radiofrequency ablation: the effect of distance and baseline temperature on thermal dose required for coagulation. Int J Hyperthermia. 2008; 24: 550-59.
Coldwell DM. Interventional radiology in the treatment of the cancer patient. Manuel of Interventional Oncology, Editor: Coldwell DM. New York, Thieme, 2018; 33-87.
Hansler JM, Solbiati L, Hager ED, Ierace T, Cova L, Baronzio GF. Tumor ablation using radiofrequency energy: technical methods and application on liver tumors. Hyperthermia in Cancer Treatment: A Primer, Editor: Baronzio GF, Hager ED. New York, Springer, 2006; 190-98.
Hansler J, Neureiter D, Wasserburger M, Janka R, Bernatik T, Schneider T, Müller W, Frieser M, Schaber S, Becker D, Hahn EG, Strobel D. Percutaneous US-guided radiofrequency ablation with perfused needle applicators: improved survival with the VX2 tumor model in rabbits. Radiology. 2004; 230 (1): 169-74.
Hansler J, Neureiter D, Strobel D, Müller W, Mutter D, Bernatik T, Hahn EG, Becker D. Cellular and vascular reactions in the liver to radio-frequency thermo-ablation with wet needle applicators. Study on juvenile domestic pigs. Eur Surg Res. 2002; 34: 357-63.
Livraghi T, Goldberg SN, Monti F, Bizzini A, Lazzaroni S, Meloni F, Pellicano S, Solbiati L, Gazelle GS. Saline-enhanced radiofrequency tissue ablation in the treatment of liver metastases. Radiology. 1997; 202: 205-10.
Hansler J, Frieser M, Schaber S, Kutschall C, Bernatik T, Müller W, Becker D, Hahn EG, Strobel D. Radiofrequency ablation (RFA) of hepatocellular carcinoma with a saline perfused device: a pilot study. J Vasc Interv Radiol. 2003; 14: 575-80.
Hansler J, Witte A, Strobel D, Wein A, Bernatik T, Pavel M, Müller W, Hahn EG, Becker D. Radio-frequency-ablation (RFA) with wet electrodes in the treatment of primary and secondary tumors of the liver. Ultraschall Med. 2003; 24: 27-33.
Goldberg SN, Gazelle GS, Solbiati L, Rittman WJ, Mueller PR. Radiofrequency tissue ablation: increased lesion diameter with a perfusion electrode. Acad Radiol. 1996; 3: 636-44.
Solbiati L, Goldberg SN, Ierace T, Livraghi T, Meloni F, Dellanoce M, Sironi S, Gazelle GS. Hepatic metastases: percutaneous radio-frequency ablation with cooled-tip electrodes. Radiology. 1997; 205: 367-73.
Goldberg SN, Gazelle GS. Radiofrequency tissue ablation: physical principles and techniques for increasing coagulation necrosis. Hepatogastroenterology. 2001; 48(38): 359-67.
Goldberg SN, Gazelle GS, Dawson SL, Rittman WJ, Mueller PR, Rosenthal DI. Tissue ablation with radiofrequency using multi-probe arrays. Acad Radiol. 1995; 2: 670-74.
Leveen RF. Laser hyperthermia and radiofrequency ablation of hepatic lesions. Semin Interv Radiol. 1997; 14: 313-24.
Siperstein AE, Rogers SJ, Hansen PD, Gitomirsky A. Laparoscopic thermal ablation of hepatic neuroendocrine tumor metastases. Surgery. 1997; 122(6): 1147-55.
Goldberg SN, Solbiati L, Hahn PF, Cosman E, Conrad JE, Fogle R, Gazelle GS. Radiofrequency tumor ablation using a clustered electrode technique: results in animals and patients with liver metastases. Radiology. 1998; 209: 371-79.
