The best of both worlds: a hybrid approach for optimal pre- and intraoperative identification of sentinel lymph nodes.

PURPOSE: Hybrid image-guided surgery technologies such as combined radio- and fluorescence-guidance are increasingly gaining interest, but their added value still needs to be proven. In order to evaluate if and how fluorescence-guidance can help realize improvements beyond the current state-of-the-art in sentinel node (SN) biopsy procedures, use of the hybrid tracer indocyanine green (ICG)-99mTc-nancolloid was evaluated in a large cohort of patients. PATIENTS AND METHODS: A prospective trial was conducted (n = 501 procedures) in a heterogeneous cohort of 495 patients with different malignancies (skin malignancies, oral cavity cancer, penile cancer, prostate cancer and vulva cancer). After injection of ICG-99mTc-nanocolloid, SNs were preoperatively identified based on lymphoscintigraphy and SPECT/CT. Intraoperatively, SNs were pursued via gamma tracing, visual identification (blue dye) and/or near-infrared fluorescence imaging during either open surgical procedures (head and neck, penile, vulvar cancer and melanoma) or robot assisted laparoscopic surgery (prostate cancer). As the patients acted as their own control, use of hybrid guidance could be compared to conventional radioguidance and the use of blue dye (n = 300). This was based on reported surgical complications, overall survival, LN recurrence free survival, and false negative rates (FNR). RESULTS: A total of 1,327 SN-related hotspots were identified on 501 preoperative SPECT/CT scans. Intraoperatively, a total number of 1,643 SNs were identified based on the combination of gamma-tracing (>98%) and fluorescence-guidance (>95%). In patients wherein blue dye was used (n = 300) fluorescence-based SN detection was superior over visual blue dye-based detection (22-78%). No adverse effects related to the use of the hybrid tracer or the fluorescence-guidance procedure were found and outcome values were not negatively influenced. CONCLUSION: With ICG-99mTc-nanocolloid, the SN biopsy procedure has become more accurate and independent of the use of blue dye. With that, the procedure has evolved to be universal for different malignancies and anatomical locations.

Hybrid radioguided occult lesion localization (hybrid ROLL) of (18)F-FDG-avid lesions using the hybrid tracer indocyanine green-(99m)Tc-nanocolloid.

PURPOSE: To assess if combined fluorescence- and radio-guided occult lesion localization (hybrid ROLL) is feasible in patients scheduled for surgical resection of non-palpable (18)F-FDG-avid lesions on PET/CT. METHODS: Four patients with (18)F-FDG-avid lesions on follow-up PET/CT that were not palpable during physical examination but were suspected to harbor metastasis were enrolled. Guided by ultrasound, the hybrid tracer indocyanine green (ICG)-(99m)Tc-nanocolloid was injected centrally in the target lesion. SPECT/CT imaging was used to confirm tracer deposition. Intraoperatively, lesions were localized using a hand-held gamma ray detection probe, a portable gamma camera, and a fluorescence camera. After excision, the gamma camera was used to check the wound bed for residual activity. RESULTS: A total of six (18)F-FDG-avid lymph nodes were identified and scheduled for hybrid ROLL. Comparison of the PET/CT images with the acquired SPECT/CT after hybrid tracer injection confirmed accurate tracer deposition. No side effects were observed. Combined radio- and fluorescence-guidance enabled localization and excision of the target lesion in all patients. Five of the six excised lesions proved tumor-positive at histopathology. CONCLUSION: The hybrid ROLL approach appears to be feasible and can facilitate the intraoperative localization and excision of non-palpable lesions suspected to harbor tumor metastases. In addition to the initial radioguided detection, the fluorescence component of the hybrid tracer enables high-resolution intraoperative visualization of the target lesion. The procedure needs further evaluation in a larger cohort and wider range of malignancies to substantiate these preliminary findings.

[Utility of SPECT/CT scan for anatomical localization of pararectal and presacral sentinel nodes in prostate cancer]. / Utilidad de la SPECT-TC para la localización anatómica de los ganglios centinelas presacrales y pararrectales en el cáncer de próstata.

AIM: This study has aimed to evaluate the added value of SPECT-CT scan in the preoperative assessment of sentinel nodes of the presacral and pararectal regions localized outside the standard area of extended pelvic lymphadenectomy for the staging of the pelvis in prostate cancer. SPECT-CT scan can serve as a guide for the excision of these nodes by lymphadenectomy by open surgery or laparoscopy. MATERIAL AND METHODS: We evaluated 4 patients with prostate cancer presenting sentinel nodes in the pararectal and presacral regions on SPECT-CT scan performed in addition to lymphoscintigraphy. These patients underwent lymphadenectomy with robot-assisted laparoscopy together with prostatectomy. All of the excised lymph nodes were sent for histopathology study. RESULTS: An average of 6 sentinel nodes per patient were found on SPECT-CT scan with a mean of 2 sentinel nodes in presacral/pararectal región. Lymphadenectomy including these areas was performed. Pararectal/presacral sentinel nodes of all patients depicted by SPECT-CT scan were tumor free on histopathology study. Sentinel nodes (no pararectal/presacral) were positive for malignancy in only one patient. CONCLUSION: Preoperative SPECT-CT scan is a useful tool to localize the sentinel nodes in pararectal/presacral regions. It can be an anatomic guide for new modalities of laparoscopic surgery such as robot-assisted procedures that can access the pelvic areas visualized with SPECT-CT scan, making excision of these nodes possible.

Hybrid tracers for sentinel node biopsy.

Conventional sentinel node (SN) mapping is performed by injection of a radiocolloid followed by lymphoscintigraphy to identify the number and location of the primary tumor draining lymph node(s), the so-called SN(s). Over the last decade research has focused on the introduction of new imaging agents that can further aid (surgical) SN identification. Different tracers for SN mapping, with varying sizes and isotopes have been reported, most of which have proven their value in a clinical setting. A major challenge lies in transferring this diagnostic information obtained at the nuclear medicine department to the operating theatre thereby providing the surgeon with (image) guidance. Conventionally, an intraoperative injection of vital blue dye or a fluorescence dye is given to allow intraoperative optical SN identification. However, for some indications, the radiotracer-based approach remains crucial. More recently, hybrid tracers, that contain both a radioactive and fluorescent label, were introduced to allow for direct integration of pre- and intraoperative guidance technologies. Their potential is especially high when they are used in combination with new surgical imaging modalities and navigation tools. Next to a description of the known tracers for SN mapping, this review discusses the application of hybrid tracers during SN biopsy and how the introduction of these new techniques can further aid in translation of nuclear medicine information into the operating theatre.

An innovative multimodality approach for sentinel node mapping and biopsy in head and neck malignancies.

PURPOSE: Recent innovations such as preoperative SPECT/CT, intraoperative imaging using portable devices and a hybrid tracer were evaluated in a multimodality approach for sentinel node (SN) mapping and biopsy in head and neck malignancies. MATERIAL AND METHODS: The evaluation included 25 consecutive patients with head and neck malignancies (16 melanomas and 9 oral cavity squamous cell carcinomas). Patients were peritumorally injected with the hybrid tracer ICG-(99m)Tc-nanocolloid. SNs were initially identified with lymphoscintigraphy followed by single photon emission computed tomography (SPECT/CT) 2 hours after tracer administration. During surgery a portable gamma camera in combination with a near-infrared fluorescence camera was used in addition to a handheld gamma ray detection probe to locate the SNs. RESULTS: In all patients the use of conventional lymphoscintigraphy, SPECT/CT and the additional help of the portable gamma camera in one case were able to depict a total of 67 SNs (55 of them visualized on planar images, 11 additional on SPECT/CT and 1 additional with the portable gamma camera). A total of 67 of the preoperatively defined SNs together with 22 additional SNs were removed intraoperatively; 12 out of the 22 additional SNs found during operation were located in the vicinity of the injection site in anatomical areas such as the periauricular or submental regions. The other 10 additional SNs were found by radioguided post-resection control of the excision SN site. CONCLUSION: In the present series 26% additional SNs were found using the multimodal approach, that incorporates SPECT/CT and intraoperative imaging to the conventional procedure. This approach appears to be useful in malignancies located close to the area of lymphatic drainage such as the periauricular area and the oral cavity.

Multimodal surgical guidance towards the sentinel node in vulvar cancer.

INTRODUCTION: Conventional sentinel node (SN) mapping is performed by injecting a radiocolloid followed by lymphoscintigraphy (and SPECT/CT imaging). An extra intraoperative injection with blue dye can then allow for optical identification of the SN. In order to improve the current clinical standard, the hybrid tracer indocyanine green (ICG)-(99m)Tc-nanocolloid was introduced, a tracer that is both radioactive and fluorescent. This feasibility study aimed to evaluate the value of a multimodal-based SN biopsy in vulvar cancer. MATERIALS AND METHODS: Fifteen patients with vulvar cancer (29 groins) scheduled for SN biopsy were peritumorally injected with ICG-(99m)Tc-nanocolloid followed by lymphoscintigraphy and SPECT/CT imaging to identify the SNs. In thirteen patients, shortly before the start of the operation, blue dye was intradermally injected around the lesion. SNs were harvested using a combination of radiotracing, fluorescence imaging, and optical blue dye detection. A portable gamma camera was used before and after SN excision to confirm excision of the preoperatively defined SNs. RESULTS: Preoperative lymphoscintigraphy and SPECT/CT imaging visualized drainage to 39 SNs in 28 groins. During the operation, 98% (ex vivo 100%) of the SNs were radioactive. With fluorescence imaging 96% of the SNs (ex vivo 100%) could be visualized. Only 65% of the SNs had stained blue at the time of excision. CONCLUSION: ICG-(99m)Tc-nanocolloid can be used for preoperative SN identification and enables multimodal (radioactive and fluorescent) surgical guidance in patients with vulvar cancer. The addition of fluorescence-based optical guidance offers more effective SN visualization compared to blue dye.

Added value of the hybrid tracer indocyanine green-99mTc-nanocolloid for sentinel node biopsy in a series of patients with different lymphatic drainage patterns.

INTRODUCTION: Indocyanine green (ICG)-(99m)Tc-nanocolloid is a novel hybrid fluorescent radioactive tracer for sentinel node (SN) biopsy. This study has aimed to evaluate the added value of this novel versatile tracer in a series of patients with different malignancies. MATERIAL AND METHODS: Twenty patients (with penile carcinoma, oral cavity tumors, melanoma) were consecutively included between March-May 2012. Planar lymphoscintigraphy was performed 15 min and 2h after injection of ICG-(99m)Tc-nanocolloid followed by SPECT/CT. Blue dye (1 ml) was injected in 14 patients in surgery room. Intraoperatively, SNs were localized using a gamma probe and visualized by optical SN-detection using blue dye and fluorescence imaging. Finally, a portable gamma camera was used to confirm complete SN removal. RESULTS: At least one SN was identified by SPECT/CT in all patients. All SNs (total 68, 100%) were excised using a combination of radio- and fluorescence guidance: 89.7% were intraoperatively localized with the gamma probe. The remaining SNs, located near the injection site, were localized using fluorescence imaging. During the surgery, 97% of the SNs were fluorescent while only 39.2% were stained blue. Ex vivo, all SNs were both radioactive and fluorescent. The SN was positive in 5 patients. CONCLUSION: Synchronous radio- and fluorescence guided SN biopsy is feasible using ICG-(99m)Tc-nanocolloid. This hybrid approach combines the beneficial properties of both modalities. Adding fluorescence imaging improves optical SN detection compared to blue dye. It has been shown to be especially useful in the localization of SNs near the injection site.