Hybrid intraoperative imaging techniques in radioguided surgery: present clinical applications and future outlook

Abstract

PurposeThis review aims to summarise the hybrid modality radioguidance techniques currently in clinical use and development, and to discuss possible future avenues of research. Due to the novelty of these approaches, evidence of their clinical relevance does not yet exist. The purpose of this review is to inform nuclear medicine practitioners of current cutting edge research in radioguided surgery which may enter standard clinical practice within the next 5–10 years. Hybrid imaging is of growing importance to nuclear medicine diagnostics, but it is only with recent advances in technology that hybrid modalities are being investigated for use during radioguided surgery. These modalities aim to overcome some of the difficulties of surgical imaging while maintaining many benefits, or providing entirely new information unavailable to surgeons with traditional radioguidance.MethodsA literature review was carried out using online reference databases (Scopus, PubMed). Review articles obtained using this technique were citation mined to obtain further references.ResultsIn total, 2367 papers were returned, with 425 suitable for further assessment. 60 papers directly related to hybrid intraoperative imaging in radioguided surgery are reported on. Of these papers, 25 described the clinical use of hybrid imaging, 22 described the development of new hybrid probes and tracers, and 13 described the development of hybrid technologies for future clinical use. Hybrid gamma–NIR fluorescence was found to be the most common clinical technique, with 35 papers associated with these modalities. Other hybrid combinations include gamma–bright field imaging, gamma–ultrasound imaging, gamma–β imaging and β–OCT imaging. The combination of preoperative and intraoperative images is also discussed.ConclusionHybrid imaging offers new possibilities for assisting clinicians and surgeons in localising the site of uptake in procedures such as in sentinel node detection.

Recent advances in nuclear and hybrid detection modalities for image-guided surgery

“…To provide the surgeon with the best guidance as currently possible, many recent advances focus on the use of optical and nuclear detection modalities within a single surgical workflow [153,208,209]. Within the field of image-guided surgery, fluorescence imaging is rapidly gaining popularity, often providing detailed real-time visualization of targeted tissues within their anatomical context [210].…”

“…Furthermore, ex vivo analysis of surgical specimens within the OR has also been suggested for direct margin evaluation [224]. Although no research is reported on this format yet, one could imagine a hybrid application where γ rays are used for lesion localization and Cerenkov imaging is used for margin evaluation [208].…”

“…Integration of US and γ images are also shown via a surgical navigation setup [241]. In this setup, the 3D molecular imaging capabilities of fhSPECT are acquired and [208]). (b-c) fhSPECT-US fusion images for breast cancer SN localization (from [248]).…”

New intraoperative imaging technologies: Innovating the surgeon’s eye toward surgical precision

“…Hybrid intraoperative imaging solutions coupling the functional information provided by the radionuclides with anatomical details obtained with optical techniques, such as NIR fluorescence‐radio‐guided surgery, are currently under investigation to augment surgical precision …”

CdTe compact gamma camera for coded aperture imaging in radioguided surgery

“…Medipix2 photon counting readout chip. This imaging probealso adopted in an experimental CT/SPECT system dedicated to the breast [34], and for imaging at nuclear facilities [27,28] could be adopted for various tasks as preoperative or intraoperative SLN localization with 99m Tc radiotracer in breast cancer or melanoma patients [18,[35][36][37][38], breast imaging with 99m Tc-Sestamibi [39], thyroid imaging [40], breast RGS with 125 I and/or 99m Tc radiotracers [41], and in hybrid imaging systems [42]. The same detector unitdeveloped within the Medipix2 Fig.…”