Intraoperative Gamma Probe Research Articles

Topography and Lateralization of Nodal Metastases in Muscle-Invasive Bladder Cancer Using Super-Extended Pelvic Lymph Node Dissection with the Sentinel Lymph Node Technique.

Background: This study assessed the topography and lateralization of lymph node (LN) metastases in muscle-invasive bladder cancer (MIBC) patients using super-extended pelvic lymph node dissection (sePLND) with sentinel lymph node dissection (SLND). Methods: We analyzed 54 MIBC patients who underwent cystectomy with sePLND and SLND. Tumor location was classified using cystoscopy. Nanocolloid-Tc-99m was injected peritumorally. Preoperative SPECT/CT lymphoscintigraphy and an intraoperative gamma probe were used for SLN detection. Results: A total of 1414 LNs, including 192 SLNs, were resected from 54 patients. Metastases were found in 72 LNs from 22 patients (41%). The obturator fossa was the primary site for LN metastases (37.5%). SLNs were most common in the external iliac region (34.4%). In 36% of the patients with positive LNs, metastases were identified only through sePLND. In 9% of the patients, metastases were found solely in the pararectal region, identified through SLND. Tumor lateralization correlated with ipsilateral positive LNs, but 20% of the patients had contralateral metastases. Conclusions: The pararectal region may be the exclusive site for positive LNs in MIBC. The obturator fossa is the most prevalent region for LN metastases. Unilateral PLND should be avoided due to the risk of contralateral metastases. Combining sePLND with SLND improves staging.

Defining the optimal target-to-background ratio to identify positive lymph nodes in prostate cancer patients undergoing robot-assisted [99mTc]Tc-PSMA radioguided surgery: updated results and ad interim analyses of a prospective phase II study

IntroductionProstate-specific membrane antigen radioguided surgery (PSMA-RGS) might identify lymph node invasion (LNI) in prostate cancer (PCa) patients undergoing extended pelvic lymph node dissection (ePLND). The optimal target-to-background (TtB) ratio to define RGS positivity is still unknown.Materials & methodsAd interim analyses which focused on 30 patients with available pathological information were conducted. All patients underwent preoperative PSMA positron emission tomography (PET). 99m-Technetium-PSMA imaging and surgery ([99mTc]Tc-PSMA-I&S) was administered the day before surgery. In vivo measurements were conducted using an intraoperative gamma probe. Performance characteristics and implications associated with different TtB ratios were assessed.ResultsOverall, 9 (30%) patients had LNI, with 22 (13%) and 80 (11%) positive regions and lymph nodes, respectively. PSMA-RGS showed uptakes in 12 (40%) vs. 7 (23%) vs. 6 (20%) patients for a TtB ratio ≥ 2 vs. ≥ 3 vs. ≥ 4. At a per-region level, sensitivity, specificity and accuracy for a TtB ratio ≥ 2 vs. ≥ 3 vs. ≥ 4 were 72%, 88% and 87% vs. 54%, 98% and 92% vs. 36%, 99% and 91%. Performing ePLND only in patients with suspicious spots at PSMA PET (n = 7) would have spared 77% ePLNDs at the cost of missing 13% (n = 3) pN1 patients. A TtB ratio ≥ 2 at RGS identified 8 (24%) suspicious areas not detected by PSMA PET, of these 5 (63%) harbored LNI, with one pN1 patient (11%) that would have been missed by PSMA PET. Adoption of a TtB ratio ≥ 2 vs. ≥ 3 vs. ≥ 4, would have allowed to spare 18 (60%) vs. 23 (77%) vs. 24 (80%) ePLNDs missing 2 (11%) vs. 3 (13%) vs. 4 (17%) pN1 patients.ConclusionsPSMA-RGS using a TtB ratio ≥ 2 to identify suspicious nodes, could allow to spare > 50% ePLNDs and would identify additional pN1 patients compared to PSMA PET and higher TtB ratios.

The GEM-handle as convenient labeling strategy for bimodal single-domain antibody-based tracers carrying 99mTc and a near-infrared fluorescent dye for intra-operative decision-making.

Intra-operative fluorescence imaging has demonstrated its ability to improve tumor lesion identification. However, the limited tissue penetration of the fluorescent signals hinders the detection of deep-lying or occult lesions. Integrating fluorescence imaging with SPECT and/or intra-operative gamma-probing synergistically combines the deep tissue penetration of gamma rays for tumor localization with the precision of fluorescence imaging for precise tumor resection. In this study, we detail the use of a genetically encoded multifunctional handle, henceforth referred to as a GEM-handle, for the development of fluorescent/radioactive bimodal single-domain antibody (sdAb)-based tracers. A sdAb that targets the urokinase plasminogen activator receptor (uPAR) was engineered to carry a GEM-handle containing a carboxy-terminal hexahistidine-tag and cysteine-tag. A two-step labeling strategy was optimized and applied to site-specifically label IRDye800CW and 99mTc to the sdAb. Bimodal labeling of the sdAbs proved straightforward and successful. 99mTc activity was however restricted to 18.5 MBq per nmol fluorescently-labeled sdAb to prevent radiobleaching of IRDye800CW without impeding SPECT/CT imaging. Subsequently, the in vivo biodistribution and tumor-targeting capacity of the bimodal tracer were evaluated in uPAR-positive tumor-bearing mice using SPECT/CT and fluorescence imaging. The bimodal sdAb showed expected renal background signals due to tracer clearance, along with slightly elevated non-specific liver signals. Four hours post-injection, both SPECT/CT and fluorescent images achieved satisfactory tumor uptake and contrast, with significantly higher values observed for the anti-uPAR bimodal sdAb compared to a control non-targeting sdAb. In conclusion, the GEM-handle is a convenient method for designing and producing bimodal sdAb-based tracers with adequate in vivo characteristics.

Determination of Lesion Localization with Intraoperative Gamma Probe in the Presence of a Primary Parathyroid Lesion with Early Wash-Out in Radionuclide

Objective: In this research, we aimed to evaluate the success of the minimally invasive surgical method performed with intraoperative gamma-probe despite early wash-out in solitary primary parathyroid lesions and to contribute to the literature on this subject. Methods: This retrospective study included 48 adult patients diagnosed with hyperparathyroidism, with an average parathormone value of 105 pg/mL (range: 82-127 pg/mL). Radionuclide imaging was conducted using Tc-99m sestamibi and Tc-99m-pertechnetate. Minimally invasive surgery with an intraoperative gamma probe was planned for patients with primary parathyroid lesions and surgical indications. At the conclusion of the operation, count equalization was observed in all four quadrants. Results: Minimally invasive surgery was performed on 42 patients with the assistance of an intraoperative gamma probe. In 6 patients, the procedure was extended to conduct a four-gland exploration due to early wash-out. Each patient had one pathological lesion removed, all of which were histopathologically confirmed as parathyroid adenomas. Among the 6 patients with extended surgeries, 4 experienced early wash-out, and all 6 had been diagnosed with multinodular goiter. Conclusion: In cases with primary hyperparathyroidism, it is aimed to remove the pathological lesion with minimally invasive surgery and leave the glands that continue their normal function in place. Preoperative localization methods help the surgeon in this regard, but pathologies in the surrounding tissue can reduce the success of minimally invasive surgery.

The Comparison of Low and High-Dose Scintigraphy Findings in Patients with Primary Parathyroid Lesions in which Intraoperative Gamma-Probe was Applied.

We aimed to evaluate the effectiveness of high-dose and low-dose use of radioactive material in intraoperative gamma probe application methods in patients diagnosed with primary hyperparathyroidism and planned for surgery. 47 patients with primary hyperparathyroidism underwent minimally-invasive parathyroid surgery (MIS) after preoperative imaging studies consisting of ultrasonography (USG) and sestamibi parathyroid scintigraphy (SPS) showed a possible primary parathyroid lesion (PPL). All patients received Tc-99 sestamibi on day-of-surgery imaging (DOSI) to help with the localization of a primary parathyroid lesion (PPL) via both DOSI and intraoperative gamma probe (IGP). Patients in Group I were administered 20-25 mCi Tc-99m sestamibi (methoxy isobutyl isonitrile) and images were obtained at the 20th and 120th minutes. Patients in Group II were administered 8-10 mCi doses and images were obtained at the 20th and 40th minutes. Two nuclear medicine specialists independently evaluated the images. Lesions in the localizations determined by DOSI and IGP were compared with the histopathological results of these lesions. 47 patients, 35 females, and 12 males were included in the study. The mean age of 28 patients in the first group given the high dose was 54 (41-60), and the mean age was 48 (42-57) in the second group given the low dose (p=0.011). In the group given low-dose radioactive material during intraoperative gamma probe application, the observer's sensitivity, specificity, positive, and negative predictive values for finding pathology were 61.1, 100, 100, and 12.5, respectively. In the group given high-dose radioactive material, the same values were 90.9, 33.3, 50, and 83.3, respectively. While the success of MIS increases with the use of DOSI and IGP in large lesions, the success decreases with the prolongation of the accumulation time of the given dose. In the intraoperative gamma probe technique used in primary hyperparathyroidism patients, the method used with low-dose radioactive material has lower sensitivity but higher specificity in estimating the post-operative pathology compared to the high-dose technique.

Evaluation of Surgical Aid of Methylene Blue in Addition to Intraoperative Gamma Probe for Sentinel Lymph Node Extirpation in 116 Canine Mast Cell Tumors (2017-2022).

Methylene Blue (MB) is combined with radiopharmaceutical for intraoperative sentinel lymph node (SLN) mapping, but its role during SLN extirpation has not been investigated yet in veterinary medicine. The aim of this study was to assess whether MB increased surgical detection of SLN beyond the use of intraoperative gamma-probe (IGP) alone in clinically node-negative dogs with mast cell tumors (MCTs) following the detection of sentinel lymphocentrums (SLCs) via preoperative planar lymphoscintigraphy. Dogs enrolled underwent MCT excision and SLC exploration guided by both MB and IGP. Data recorded for each SLN were staining (blue/non-blue), radioactivity (hot/non-hot), and histopathological status (HN0-1 vs. HN2-3). A total of 103 dogs bearing 80 cutaneous, 35 subcutaneous, and 1 mucocutaneous MCTs were included; 140 SLCs were explored, for a total of 196 SLNs removed. Associating MB with IGP raised the SLNs detection rate from 90% to 95%. A total of 44% of SLNs were metastatic: 86% were blue/hot, 7% were only blue, 5% were only hot, and 2% were non-blue/non-hot. All HN3 SLNs were hot. Combining MB with IGP can increase the rate of SLN detection in dogs with MCTs; nonetheless, all lymph nodes identified during dissection should be removed, as they might be unstained but metastatic.

Does the sonography-scintigraphy correlation affect the success of minimally invasive parathyroid Surgery? Results from a single center

In patients with primary hyperparathyroidism, complete surgical resection of all hyperfunctioning parathyroid tissue is essential. The aim of this study was to evaluate the success rates of minimally invasive parathyroidectomies for primary hyperparathyroidism performed after localization studies with 99mTc-sestamibi (MIBI) scintigraphy and neck ultrasonography (USG). And also, we aimed to determine the factors affecting the success rate in surgery. Retrospective analysis of 58 consecutive patients with a diagnosis of primary hyperparathyroidism who underwent parathyroidectomy between January 2018 and December 2021 in our institution. The patients were evaluated according to Miami criteria and divided into two groups as successful or unsuccessful surgery. Demographic and clinical characteristics of the patients were obtained from hospital records. Surgical success was achieved in 50 (86.2%) of the 58 patients included in the study. In both groups, neck USG and MIBI scintigraphy showed the same localization for the lesion in a correlated manner. The clinical complaints of the patients, preoperative PTH, Ca and 24-hour urinary Ca levels were similar in both groups. In 10 (17.2%) patients, inconsistency in localization was found between USG and MIBI scintigraphy, and surgical failure was found in 4 (40%) of these patients. Surgical failure was statistically significant in patients with inconsistency in localization between USG and MIBI scintigraphy. The sono-scintigraphic scan concordance increases surgical success rates in cases where minimally invasive parathyroid surgery is planned. If there is an inconsistency between USG and MIBI, preoperative four dimentional computed tomography, intraoperative rapid PTH, gamma probe or frozen method can be used. It should be kept in mind that multiple gland pathologies may be more common in addition to solitary adenoma in lesions smaller than 1 cm in USG. In addition, in these cases, as the diagnostic value of scintigraphy is low, surgical success will also decrease.

Diagnostic Value of Radio-Guided Sentinel Node Detection in Patients with Prostate Cancer Undergoing Radical Prostatectomy with Modified-Extended Lymphadenectomy.

Background. In many malignancies, sentinel lymph node dissection (SLND) is being used as a nodal staging tool. We prospectively evaluated the diagnostic value of radio-guided sentinel lymph node (SLN) detection in patients with prostate cancer (PCa). This study aimed to investigate the reliability of the radio-guided SLN detection technique for perioperative localization of LNs metastases as well as to map lymphatic drainage patterns of the prostate. Methods. Forty-three patients with intermediate- or high-risk cN0cM0 PCa at conventional imaging underwent radical prostatectomy with modified-extended pelvic lymph node dissection (mePLND). A day before the planned surgery, a Tc-99m nanocolloid was injected into the prostate under the control of transrectal ultrasonography (TRUS). Preoperative single-photon emission computed tomography (SPECT-CT) imaging and intraoperative gamma-probe were used to identify SLNs. All positive lesions were excised, followed by mePLND. The excised lymph nodes (LNs) were then submitted for histopathological examination, which was used as a reference for the calculation of diagnostic parameters of the SLN technique for SPECT-CT and the intraoperative gamma-probe. Results. In total, 119 SLNs were detected preoperatively (SPECT-CT) and 118 intraoperatively (gamma-probe). The study revealed that both SLN detection techniques showed a sensitivity of 90% and a specificity of 6.06%. The negative predictive value (NPV) was 66.67%. SLN technique would have correctly staged nine of 10 patients, which is the same result as in the case of limited LND. However, it allowed the removal of all metastatic nodes only in four of them. SLND would have comprised 69.7% of preoperatively detected LNs, and removed 13 out of 19 positive LNs (68.42%), respectively. Conclusions. Radio-guided SLND has a low diagnostic rate and is a poor staging tool. ePLND remains the gold standard in nodal metastases assessment in PCa. Our study indicates that lymphatic drainage of the prostate and actual metastasis routes may vary significantly.

Single-Photon Emission Computed Tomographic Reverse Lymphatic Mapping for Groin Vascularized Lymph Node Transplant Planning.

Superficial inguinal (groin) vascularized lymph node transplantation is the most common option for the treatment of lymphedema, particularly in combination with free abdominal flap breast reconstruction. This study examines the utility of single-photon emission computed tomographic (SPECT/CT) lymphoscintigraphy for lower extremity reverse lymphatic mapping in presurgical planning for groin vascularized lymph node transplantation and appraises the physiologic lymphatic drainage to the superficial inguinal lymph nodes. All patients who underwent bilateral lower extremity SPECT/CT reverse lymphatic mapping over a 5-year period were included. Retrospective case note analysis was performed to collect demographic, surgical, and outcomes data. The study included 84 patients; 56 of these subsequently underwent groin vascularized lymph node transplantation (58 flaps). Fifty-four of these flaps were combined with free abdominal flaps for breast reconstruction (55 flaps). Using SPECT/CT reverse lymphatic mapping investigation of 168 inguinal regions, drainage to at least one superficial inguinal region was visualized in 38.1 percent of patients; in 13.1 percent, drainage was visualized to both superficial inguinal regions. Using this information for presurgical planning, groin vascularized lymph node flap harvest was performed from the contralateral side in 57 of 58 cases (98.3 percent) using intraoperative gamma probe guidance, and no patient developed donor lower extremity lymphedema during follow-up (mean ± SD, 34.5 ± 15.4 months). The authors' use of presurgical SPECT/CT reverse lymphatic mapping together with limited flap dissection and intraoperative gamma probe guidance resulted in no clinical cases of iatrogenic donor lower extremity lymphedema. The high incidence of drainage from the lower extremity to the superficial inguinal region mandates the use of reverse lymphatic mapping when performing groin vascularized lymph node transplantation. Therapeutic, IV.

Diagnostic value of nuclear medicine modaities for the detection of sentinel lymph nodes in patients with breast cancer

Purpose of the study. To determine and compare the diagnostic efficacy of planar scintigraphy, SPECT (including SPECT/CT) and intraoperative gamma probe radiometry in the detection of sentinel lymph nodes (SLN) in patients with breast cancer.Material and methods. The study included 200 patients with diagnosed breast cancer who underwent SLN biopsy in the period 2020–2021. To identify SLN s, all patients underwent lymphoscintigraphy with a 99mtc-labeled colloidal radiopharmaceutical one day before surgery. Planar lymphoscintigraphy was performed on 200 patients included into the study, 181 underwent examination in the volume of SPECT or SPECT/CT (147 and 34 studies, respectively). The SLN was detected intraoperatively using a portable gamma probe (n=200). Subsequent histological examination determined the presence of lymphoid tissue and the status of the removed SLN.Results. SLN were detected in a comprehensive study (planar and tomographic studies) in all 200 patients studied (100 %), while planar scintigraphy did not visualize any SLN in 6 (3 %) cases, but they were determined during examination in tomographic mode. Also, in some cases, additional SLN were determined during tomography, which were not considered in the planar study. In 95 % of cases, SLN were localized in the axillary region. All non-axillary slns were identified on tomograms. The sensitivity of SPECT for SLN detection was 100 % (ci 98.0–100 %), which was higher than the sensitivity of planar scintigraphy and gamma probe (97.0 %, ci 96.5–97.4 % and 97.0 %, ci 96.1–97.4 %, respectively). The PPV values were also high (99.5 %, ci 99.0–100 % for planar scintigraphy, 99.5 %, ci 98.6–100 % for gamma probe and 98.3 %, ci 95.2–99.7 % for SPECT.Conclusion. Nuclear medicine imaging of sln with lymphotropic radiopharmaceuticals in patients with breast cancer is an effective and reliable method of navigation during surgery to perform a biopsy. SPECT and SPECT/CT can identify more lymph nodes than planar scintigraphy, improving their anatomical localization, and reducing the false negative rate. The diagnostic performance of SPECT/CT and SPECT is believed to be superior to that of planar lymphoscintigraphy and intraoperative navigation in detecting SLN.

Limited-angle TOF-PET for intraoperative surgical applications: proof of concept and first experimental data

The intraoperative gamma probe (IPG) based on single gamma-ray detection remains the current gold standard modality for sentinel lymph node identification and tumor removal in cancer patients. However, IPGs do not meet the <5% false negative rate (FNR) requirement, a key metric suggested by the American Society of Clinical Oncology (ASCO). We aim to reduce FNR by using time of flight (TOF) PET detector technology in limited angle geometry system by using only two detector panels in coincidence. For proof of concept, we used two Hamamatsu TOF PET detector modules (C13500-4075YC-12) featuring 12× 12 arrays of 4.14× 4.14× 20 mm3 LFS crystal pixels with 4.2 mm pitch and coupled one-one to silicon photomultiplier (SiPM) pixels. The measured detector coincidence timing resolution (CTR) was 271 ps FWHM for the whole detector. We 3D printed lesion phantom containing spheres 2–10 mm in diameter, representing lymph nodes, and placed it inside a 10-liter warm background water phantom. Experimental results showed that with subminute data acquisition, 6 mm diameter spheres could be identified in the image when a lesion phantom with a 10:1 activity ratio to background was used. The simulation results were in good agreement with the experimental data by resolving 6 mm diameter spherical lesions with a 60 second acquisition time in a 25 cm deep background water phantom with a 10:1 activity ratio. As expected, the image quality improved as the CTR improved in the simulation and with decreasing background water phantom depth or increasing lesion-to-background activity ratio in the experiment. With the results presented here, we concluded that using a limited angle TOF PET detector system is a major step forward for intraoperative applications in that lesion detectability is beyond what conventional gamma- and NIR-based probes could achieve.

IS CONFIRMATION OF PARATHYROID TISSUE BY FROZEN SECTION SUPERIOR TO LOCALIZATION OF SOLITARY PARATHYROID ADENOMA USING INTRAOPERATIVE GAMMA PROBE SURVEY? A RETROSPECTIVE COHORT STUDY.

In the surgical treatment of primary hyperparathyroidism, intraoperative localization of the diseased glands is an essential issue. We aimed to evaluate the impact of the intraoperative frozen section during radio-guided focused parathyroidectomy and compare its efficiency with intraoperative gamma probe survey and measurement of intraoperative quick parathyroid hormone. All consecutive patients underwent radio-guided focused parathyroidectomy for primary hyperparathyroidism due to solitary parathyroid adenoma. The outcomes of parathyroidectomy were evaluated by serum levels of calcium and parathyroid hormone. The primary outcome was the surgical cure diagnosed by normal serum calcium levels in the sixth postoperative month. A total of 55 patients with a mean age of 54.3±12.2 years were evaluated. The diagnostic accuracy of the preoperative localization tests was calculated as 92.7%. The intraoperative gamma probe survey impacted the operative plans of four patients (7.3%) by localizing the diseased gland in other positions. The accuracy of intraoperative quick parathyroid hormone and frozen section analysis was 100% for both. In all patients, serum calcium and PTH levels dropped to normal in the sixth postoperative month. There were no cases of the persistent or recurrent disease during the follow-up period. The results of the intraoperative gamma probe survey, intraoperative quick parathyroid hormone, and frozen section were concordant with the final pathology in all cases. In four patients (7.3%), intraoperative gamma probe survey impacted the operative plans. The intraoperative gamma probe survey may be used as the sole intraoperative method to locate the correct position of the solitary parathyroid adenoma.

Assessment of sentinel lymph node detection by radioisotope scan and methylene blue alone in operable oral cavity cancer to assess its accuracy for metastasis

Background: Squamous cell carcinoma (SCC) is the most common malignancy affecting the oral cavity. It typically metastasizes into the regional cervical lymph nodes before spreading to distant organs.Methods: A prospective study on sentinel lymph node biopsy (SLNB) in early oral cancers using methylene blue dye and sentinel node localisation using pre-operative lymphoscintigraphy and intraoperative gamma probe in early oral cavity cancer.Results: Present study had a male to female ratio of 1.9:1, with (65.5%) male and (34.5%) female patients. Present study had a side distribution of disease more on left side with 138 patients (62.7%) and ratio of left to right was approximately 1.7:1. In present study most predominating gross morphological pattern of growth was ulcerative (35%) followed by ulcero-infilterative (25%). Buccal mucosa was the most common sub-site of origin of carcinoma in oral cavity, followed by tongue, with 83 (37.7%) and 64 (29.1%) patients. Identification rate of methylene blue dye was 91.7% (100 out of 109 patient). Identification rate of radionuclide tracer was 94.6% (105 out of 111 patient). In methylene blue dye group out of 103 metastatic sentinel lymph nodes, 9 metastatic sentinel lymph nodes were detected on IHC.Conclusions: With the above results it can be concluded the SLNB study is liable in detection of actual positive node and can avoid unnecessary neck dissections in patients with SCC with negative sentinel lymph node, as having very low risk of occult lymphatic metastases in the remaining lymphatic drainage.

Utility of intraoperative digital scintigraphy in radioguided parathyroidectomy.

Intraoperative scintigraphy (IoS) has been proposed as a tool for real-time intraoperative decision-making regarding parathyroid adenoma localization and confirmation of excision. Retrospective review of patients who underwent minimally invasive parathyroidectomies with scintigraphy performed intraoperatively. Preoperative neck ultrasound, 4D computed tomography, as well as intraoperative parathyroid hormone (IOPTH) and gamma probe measurements were conducted per standard practice. IoS images were obtained prior to and following parathyroid excision. Cases were reviewed to determine accuracy of IoS for localizing parathyroid pathology and confirming successful excision. Fifty-six cases met the inclusion criteria. Twenty-nine patients (51.8%) showed confirmation of excision of an abnormal gland on post-excision IoS. There were no significant differences in IOPTH reduction and postoperative laboratory values between patients with IoS-identified resolution and those without IoS-identified resolution. With low accuracy in correctly localizing abnormal glands and confirming their excision, there is no appreciable benefit of IoS at this time.

Feasibility of sentinel node navigated surgery in high-risk T1b esophageal adenocarcinoma patients using a hybrid tracer of technetium-99\xa0m and indocyanine green

BackgroundMinimally invasive esophagectomy with two-field lymphadenectomy is standard of care for T1b esophageal adenocarcinoma (EAC) with a high risk of lymph node metastasis. Sentinel node navigation surgery (SNNS) is a well-known concept to tailor the extent of lymphadenectomy. The aim of this study was to evaluate the feasibility and safety of SNNS with a hybrid tracer (technetium-99 m/indocyanine green/nanocolloid) for patients with high-risk T1b EAC.MethodsIn this prospective, multicenter pilot study, 5 patients with high-risk T1b EAC were included. The tracer was injected endoscopically around the endoscopic resection scar the day before surgery, followed by preoperative imaging (lymphoscintigraphy/SPECT-CT). During surgery, first the SNs were localized and resected based on preoperative imaging and intraoperative gammaprobe- and fluorescence-based detection, followed by esophagectomy. Primary endpoints were the percentage of patients with detectable SNs, concordance between preoperative and intraoperative SN detection, and the additive value of indocyanine green.ResultsSNs could be identified and resected in all patients (median 3 SNs per patient, range 2–7). There was a high concordance between preoperative and intraoperative SN detection. In 2 patients additional peritumoral SNs were identified with fluorescence-based detection. None of the resected lymph nodes showed signs of (micro)metastases and no nodal metastases were detected in the surgical resection specimen.ConclusionsSNNS using technetium-99 m/indocyanine green/nanocolloid seems feasible and safe in patients with high-risk T1b EAC. Indocyanine green fluorescence seems to be of additive value for detection of peritumoral SNs. Whether this approach can optimize selection for esophagectomy needs to be studied in future research.

To map or not to map the cN0 neck: Impact of sentinel lymph node biopsy in canine head and neck tumours.

Tumour stage is a prognostic indicator for canine malignant head and neck tumours (MHNT). However, consensus is lacking on nodal staging in the absence of clinically apparent nodal disease (cN0 neck). This prospective observational study aims to determine the diagnostic accuracy of radiopharmaceutical and blue dye for sentinel lymph node biopsy (SLNB), to assess the correspondence between sentinel lymph node (SLN) and clinically expected regional lymph node (RLN) and the impact on staging of the procedure in dogs with MHNT and cN0 neck. Twenty-three dogs with MHNT and cN0 neck underwent tumour excision and SLNB guided by preoperative lymphoscintigraphy and intraoperative gamma-probe and blue dye. Diagnostic performances and detection rate were calculated. Correspondence between SLN and RLN, number of nodes excised, histopathological status of the SLN and complications related to the procedure were recorded. The mapping technique identified at least one SLN in 19/23 dogs, with a detection rate of 83%. The SLN did not correspond to the RLN in 52% of dogs. Multiple nodes were removed in 61% of dogs. At histopathology, eight (42%) dogs had SLN+, of which four differed from the RLN. Only minor self-limiting complications occurred in five (22%) dogs. Radiopharmaceutical and blue dye guidance is accurate (sensitivity 88.9%; specificity 100%) for SLNB in dogs with MHNT and cN0 and allowed the extirpation of unpredictable and/or multiple SLN with minimal morbidity. Incorporation of SLNB in the management of MHNT is desirable to correctly stage the cN0 neck, owing the unpredictability of the lymphatic drainage.

Radioactive iodine-125 seed localization as an aid in reoperative neck surgery

BackgroundScarring and disrupted tissue planes add to already-complex neck anatomy and make localization of nonpalpable pathology difficult in cervical endocrine reoperations. We describe the use of radioactive iodine-125 seed localization (RSL) in 6 patients with metastatic papillary thyroid carcinoma (PTC) and 2 with recurrent hyperparathyroidism. MethodsEight patients had 2-D ultrasound-guided RSL of the target lesion, 0–3 days preoperatively. Intraoperative gamma probe (Neoprobe) was used to plan incision placement and localize the implanted seed. Recorded operative variables included: number of lymph nodes (LNs) harvested, estimated blood loss (EBL), operative time, length of stay (LOS) and RSL and operative complications. ResultsAll patients had successful resection of the targeted area and removal of the radioactive seed. There was no seed migration. Two complications occurred in the thyroid group. ConclusionRadioactive iodine 125 seeds facilitate successful localization of endocrine pathology during reoperative cervical procedures.

Is the retropharyngeal lymph node the first echelon node for carcinoma tonsil? Prospective evaluation and literature review.

Tonsil cancer being predominantly treated by non-surgical means, there is a paucity of data on lymph nodal drainage pathways and histo-pathologically confirmed metastatic rates. This study assesses the retropharyngeal lymph node (RPLN) in N0 squamous cell carcinoma tonsil as a possible first echelon node and a site for occult metastasis. Prospective study involving treatment naïve N0 carcinoma tonsil treated by primary surgery and adjuvant treatment from June 2017 to March 2019. In-vivo lymph nodal drainage patterns were assessed by sentinel node mapping by preoperative SPECT-CT and intra-operative hand-held Gamma probe. All patients had a subsequent Level I-III/IV sampling neck dissection supplemented with RPLN dissection. Histological evaluation of sentinel nodes and RPLN involved step-serial sectioning and pan-cytokeratin immunohistochemistry. A comprehensive literature review was performed with keywords "retropharyngeal lymph node", "oropharynx", "tonsil", "squamous cell carcinoma" to determine the incidence of RPLN positivity in previously published series. Sentinel node was successfully identified by SPECT-CT in all 17 patients (ipsilateral level 2a-13/17, 2b-1/17, 3-1/17; bilateral 2a-1/17; isolated contralateral retropharyngeal node-1/17). 8/17 had occult neck metastasis. In no patient was an ipsilateral RPLN identified as the sentinel node. Histological sampling did not indicate metastatic tumor in the RPLN in any patient (0/17). A systematic literature review further confirmed that RPLN metastasis in oropharyngeal cancer is noted only in the presence of pN + disease at other neck levels, and isolated RPLN metastasis is extremely rare (1.2%). The ipsilateral RPLN is not identified either as the first echelon node or as a site of occult metastatic disease in N0 tonsil cancer. CTRI/2019/06/019551.

Role of Lymphoscintigraphy and SPECT-CT in Sentinel Lymph Node Detection in Early Stage Squamous Cell Carcinoma of Oral Cavity: Our Experience

Objective: A multidisciplinary team trial in a tertiary care centre in patients with early stage squamous cell carcinoma of oral cavity to review the established role of advanced imaging modalities like lymphoscintigraphy and SPECT-CT in sentinel lymph node identification and to layout our experience in performing this modality. Methods: A prospective, case control study of diagnosed cases of T1/T2 N0 squamous cell carcinoma of oral cavity undertaken from December 2016 to January 2018 at our institution of which the patients in study group underwent SLNB guided neck dissection and the patients in control group underwent Elective Neck Dissection. We compared both the groups in terms of the operating time, the post-operative histopathology, the diagnostic accuracy and the outcomes which were statistically analysed. Also we studied and analysed the efficacy of static and dynamic lymphoscintigraphy followed by SPECT-CT in identifying sentinel lymph node areas in neck and intra-operative gamma probe use to precisely locate the sentinel nodes. Results: Out of 40 patients, 20 each in study and control groups were included. The SLN identification rate was 100% with combined SPECT-CT and gamma probe use whereas it was 70% with imaging alone. The sensitivity, specificity, positive predictive value and negative predictive value of SLNB and END were 80% , 56.58%, 9.61%, 98% and 78.5 %, 73.48% ,10.67% , 98.8 % respectively. The operating time was less in the SLNB group with statistically significant difference between the two groups. Conclusion: High SLN identification rate with combined use of SPECT-CT and gamma probe and high NPV render SLNB as a reliable modality in the management of early stage oral cavity cancers in a centre with a multidisciplinary team set up and appropriate facilities.

Influence of 99m-Tc-Nanocolloid Activity Concentration on Sentinel Lymph Node Detection in Endometrial Cancer: A Quantitative SPECT/CT Study.

This study evaluates quantitative combined single photon emission tomography/computed x-ray tomography (SPECT/CT) to assess the influence of radiotracer concentration on detection of sentinel lymph nodes (SLN) in endometrial cancer (EC). Eighty EC patients underwent pericervical 99m-Tc-nanocolloid injection followed by SPECT/CT. The subgroup of patients with failed SLN detection in SPECT/CT (n = 20) was compared to match-paired patients showing at least two SLNs. Results of intraoperative gamma probe measurements and quantitative SPECT/CT were used for comparison. In patients with detection failure, the percentage of injected dose, absolute activity, and volume of the injection site were significantly lower (30 ± 24% vs. 55 ± 19%; p = 0.01, 43 ± 36 MBq vs. 73 ± 33 MBq; p = 0.04, and 183 ± 164 mL vs. 266 ± 164 mL; p = 0.03) while mean activity concentration in liver, spleen, and bone marrow was significantly higher (p = 0.02). Activity concentration (>33 KBq/mL) and absolute activity (>73 MBq) of injection areas correlated with successful intraoperative SLN detection. In a subgroup of 19 SLNs, a correlation between SPECT/CT-derived uptake and intraoperative count rate was found (R2 = 0.8; p < 0.001). SLN detection in EC patients depended on high radiotracer activity at the cervical injection site. Quantitative SPECT/CT could predict successful intraoperative SLN detection and may help to optimize injection technique.