Changing paradigms in radioguided surgery and intraoperative imaging: the GOSTT concept

Abstract

Ever since the first descriptions as an aid for sentinel lymph node biopsy in the early 1990s [1, 2], interest in radioguided surgery has been rising sharply and continues to do so with respect to both the number of articles published in the medical literature and the amount of procedures performed. In Europe, lymphoscintigraphic imaging procedures for sentinel lymph node biopsy have markedly increased, by about 17.5%, between the years 2005 and 2008 (source: European Association of Nuclear Medicine), a period during which single photon imaging procedures in general were expected to remain substantially stable or actually show some decline attributed to competition by the growing number of positron emission tomography (PET) studies. Several reasons can be envisaged to explain the popularity of radioguided surgery. In particular, prior to the introduction of intraoperative radioguidance, professional skills and dexterity of surgeons had to build on the a priori knowledge of anatomy and while in the operation theatre primarily rely on two senses, sight and palpation. Introducing intraoperative gamma probe counting has forced surgeons to integrate a third sense, hearing, in addition to the prior two. In fact, this “upgrade” proved to be very convenient; the increasing intensity and pitch of the sound as a function of increasing count rates was adopted as a primary guide for the surgeon, in order not to distract him/her from focusing on the surgical field while performing gamma probe exploration, as a solution more superior than observing the numerical display of the count rates [3]. Another important reason for the wide acceptance of the radioguided surgery concept can be attributed to alignment and synergy with current trends of oncological surgery adopting less aggressive and invasive approaches; in this regard, the possibility of identifying with highest accuracy those patients who can be spared unnecessary lymph node dissection (a procedure fraught with a high incidence of morbidity and long-term complications) is certainly a crucial asset that radioguided sentinel node biopsy has brought about in clinical practice, concerning especially early breast cancer and cutaneous melanoma [4, 5]. The success of radioguided sentinel lymph node biopsy in patients with breast cancer or with cutaneous melanoma, where this technique has now become an integral part of the standard of care [6], has driven countless clinical trials aimed at validating the same approach in the management of other solid tumours [7]. J. J. Zaknun (*) Section of Nuclear Medicine, Division of Human Health, International Atomic Energy Agency (IAEA), 5 Wagramerstrasse, PO Box 200, Room A-2278, 1400 Vienna, Austria e-mail: J.Zaknun@iaea.org