Tin Colloid Research Articles

Formulation and In-vivo Characterization of 177Lu-tin-colloid as a Radiosynovectomy Agent.

Arthritis is an inflammatory disorder that affects one or more joints of the body for various reasons, including autoimmune disorders, trauma, or infection. In many cases, traditional long-term treatment with various drug combinations (NSAIDs, diseasemodifying antirheumatic drugs, systemic corticosteroids, etc.) can provide relief, but many joints require additional local treatment. Radiosynovectomy (RSV) is an alternative method to current treatment options. Both the global supply shortage of 90Y in recent years and the increasing use of 177Lu-labeled radiopharmaceuticals in the field of nuclear medicine have made it possible to develop 177Lu-labeled microparticles and test them in small groups as RSV agents. This study aimed to develop the 177Lu labeled tin colloid formulation and demonstrate its invivo characterization. Particle size, shape, and labelling efficiency of the four formulations developed were determined. The formula with the highest labelling efficiency was selected for further studies. The quality of the formulation was evaluated based on radionuclidic, radiochemical, and microbial purity. In-vitro stability was evaluated by determining the labelling efficiency. In-vitro stability was tested in PBS and synovial fluid. The biological characterization was assessed using SPECT/CT after injecting the formulation into the normal knee joints of the rabbits. Aggregated colloidal particles were spherical with a particle size of <5 μm. Labelling efficiency and radiochemical purity were >95 and 97.65% (Rf=0.2), respectively. The formulation was stable in vitro for up to 72 hours, both in PBS and synovial fluid. The formulation was homogeneously distributed in the joint at 0 and 1 hour after injection, and radioactivity- related involvement and inguinal lymph node involvement due to possible leakage were not detected in the late period. No pyrogenic/allergic side effects were observed during this period. 177Lu-tin-colloid was successfully prepared under optimized reaction conditions with high binding efficiency and radiochemical purity. The radiolabeled colloid was found to be stable in-vitro both in PBS and synovial fluid at room temperature. Serial PCET/CT images revealed that the activity was completely retained within the synovial cavity, with no activity leakage out of the joint until 48 hours after the injection. With the support of the results from further clinical studies, it may be possible for the formulation to enter clinical use.

Synthesis and Stability Studies of &amp;lt;sup&amp;gt;225&amp;lt;/sup&amp;gt;Actinium Tin Colloid Radiopharmaceutical

Synthesis of novel 225Ac-Sn particles was described for the first time. Detailed experimental and stability studies were successfully exhibited. Treatment of excess amount of SnCl2 with 0.2 mCi 225Ac furnished highly stable 225Ac tin colloid with 90% of radiochemical yield (RCY) at optimized reaction condition. R-TLC analyses indicated 95% of radiochemical purity (RCP). Stability studies showed that colloidal structure also retained free daughter radionuclides formed by the 225Ac decay chain. 225Ac tin colloids could be ideal nanocarriers for localized cell killing due to high linear energy transfer and prevention of free radioisotope daughters.

Obesity due to melanocortin 4 receptor (MC4R) deficiency is associated with delayed gastric emptying.

People who are severely obese due to melanocortin-4 receptor (MC4R) deficiency experience hyperphagia and impaired fullness after a meal (satiety). Meal-induced satiety is influenced by hormones, such as peptide-YY (PYY), which are released by enteroendocrine cells upon nutrient delivery to the small intestine. We investigated whether gastric emptying and PYY levels are altered in MC4R deficiency. Gastric emptying was measured with a gastric scintigraphy protocol using technetium-99m (99 Tcm )-Tin Colloid for 3.5 h in individuals with loss of function MC4R variants and a control group of similar age and weight. In a separate study, we measured plasma PYY levels before and at multiple time points after three standardised meals given to individuals with MC4R deficiency and controls. Fasting PYY (basal secretion) and postprandial PYY levels were measured and the area under the curve and inter-meal peak were calculated. We found that gastric emptying time was significantly delayed and percentage meal retention increased in individuals with MC4R deficiency compared to obese controls. In addition, fasting and mean PYY secretion throughout the day were decreased in MC4R deficiency, whereas postprandial PYY secretion was unaltered. Delayed gastric emptying and reduced basal PYY secretion may contribute to impaired satiety in people with obesity due to MC4R deficiency.

Development of 68Ga-labeled tin colloids for evaluating phagocytic function of Kupffer cells using preclinical PET imaging.

This study aimed to investigate the optimal conditions for producing 68Ga-labeled tin colloid and the feasibility of 68Ga-tin colloid positron emission tomography (PET) for visualization and evaluation of the phagocytic function of Kupffer cells (KCs) in vivo. 68Ga-tin colloid was prepared by adding tin solution (1mM, 0.2mL) to 68Ga solution (1.0mL), followed by pH adjustment with sodium acetate (1M, 0.2mL). Various labeling times were tested to find the optimal one. Colloid size was measured by filtering the solution through three-ply membrane filters (with pore sizes of 200, 3000, and 5000nm), and radioactivity was measured in the whole filtrate and the filters using a gamma counter. The in vitro stability of the colloid was evaluated by the size measurement after incubation under ambient conditions for up to 60min. PET scanning was performed for 30min after intravenous administration of 68Ga-tin colloid solution (4MBq) to healthy rats. Time-activity-curves for the liver, spleen, and blood pool were generated. Finally, liver uptake was compared before and after the establishment of KC-depletion and non-alcoholic steatohepatitis (NASH) rat models. Colloid size increased with increasing labeling time. After pH adjustment, the colloid sizes remained nearly unchanged. The optimal labeling time was determined as 30min. PET imaging of healthy rats revealed that liver uptake of the 68Ga-tin colloid increased with increasing colloid size. In KC-depleted rats, liver uptake significantly decreased (n = 4, p < 0.01). NASH model rats showed significantly decreased uptake of 68Ga-tin colloid in the livers (n = 5, p < 0.01). 68Ga-tin colloid, prepared by a simple radiolabeling method, enabled in vivo PET imaging to evaluate the phagocytic function of KCs.

Evaluation of technetium-99m metastable nanocolloid as an imaging agent for performing milk scans.

ObjectiveThe aim of this study was to determine whether technetium-99m (99mTc) nanocolloid was a suitable alternative tracer for carrying out milk scan studies in pediatric patients.Participants and methodsTwenty-seven milk scans performed with 99mTc nanocolloid were retrospectively assessed for identification of significant esophageal hold-up, gastroesophageal reflux, pulmonary aspiration, and gastric emptying (GE). Scans were also assessed for liver, spleen, and bone marrow uptake. GE results were compared with those of 27 randomly selected normal GE studies carried out using 99mTc tin colloid.ResultsNone of the studies had liver, spleen, or bone marrow uptake, and all studies were interpretable. Significant esophageal hold-up and gastroesophageal reflux was observed in 11 and 48% of the patients, respectively. Only one patient had evidence of pulmonary aspiration, and all patients had normal GE at 2 h after radiolabeled milk ingestion. The average rate of GE at 2 h was faster in the 99mTc nanocolloid group compared with the 99mTc tin colloid group (8.85% retained±8.96% vs. 15.48% retained±10.52%, P=0.016).ConclusionOur findings show that 99mTc nanocolloid is technically a suitable alternative to 99mTc sulfur colloid for performing milk scans. However, we could not conclude with certainty on the comparison of the GE rates of 99mTc nanocolloid and 99mTc tin colloid. This was because of the variability in the two population groups as well as the fact that the milk that was used in each patient was individualized to the patient and was not standardized.

Update on the indications and results of sentinel node mapping in upper GI cancer.

The clinical utilization of sentinel node (SN) mapping for early esophageal cancer or gastric cancer has been unclear for a long time. However, previous investigations regarding SN mapping of these cancers have shown relatively good results with regard to the detection rate and diagnostic accuracy for determining the lymph node status. SN mapping helps obtain information about individual metastatic status and allows the modification of the operation in early-stage upper gastrointestinal (GI) disease. Radio-guided methods for identifying SNs in early esophageal cancer have been established via endoscopic injection of technetium-99m tin colloid. Previous studies have reported that the SN concept seems valid, and radio-guided SN mapping can be feasible in cT1N0 esophageal cancer. SN navigation surgery are believed to have potential as strategies for minimally invasive modified surgery for early esophageal cancer. A Japanese study group conducted a prospective multicenter trial of SN mapping for early gastric cancer using a dual tracer method with radioactive colloid and blue dyes; they demonstrated a high detection rate and accuracy for determining the metastatic status based on SN mapping. Subsequently, minimized gastrectomy, including partial gastrectomy and segmental gastrectomy with individualized selective and modified lymphadenectomy for early gastric cancer with a negative SN has been performed to evaluate the long-term survival and postoperative quality of life (QOL) in a multicenter prospective trial. This study verified the SN concept in early-stage upper GI disease with cN0 and found that function-preserving esophagectomy or gastrectomy may help maintain patients' post-surgical QOL.

Clinical significance of lymphatic flows around pylorus identified by sentinel node mapping in patients with gastric cancer.

12 Background: The sentinel node (SN) concept is safely applied and validated in early gastric cancer. Gastric lymph nodes are divided into five basins with the main gastric arteries. The suprapyloric lymph nodes (No. 5) and the anterosuperior lymph nodes with the common hepatic artery (No. 8a) are classified in the right gastric artery (r-GA) basin, and the subpyloric lymph nodes (No. 6) are classified in the right gastroepiploic artery (r-GEA) basin. The aim of this study is to analyze the lymphatic flows between these lymph nodes and basins. Methods: Five hundred and fourty-nine patients with cT1N0 or cT2N0 gastric cancer underwent SN mapping. We used technetium-99 tin colloid solution and blue dye as a tracer. Results: We detected SN No. 5 in 36 (6.6 %) patients. In these patients, we detected SN No. 5 with SNs that belonged to the left gastric artery (l-GA) basin (69 %), r-GA basin (14 %), and r-GEA basin (44 %). No. 6 was detected as SN significantly more frequently with SN No. 5. We detected SN No. 6 in 100 (18.2 %) patients. In these patients, we detected SN No. 6 with SNs that belonged to the l-GA basin (42 %), left gastroepiploic artery (l-GEA) basin (4 %), r-GA basin (28 %), and r-GEA basin (41 %). No. 4d, No. 5 and No. 8a were detected as SNs significantly more frequently with SN No. 6. We detected SN No. 8a in 43 (7.8 %) patients. In these patients, we detected SN No. 8a with SNs that belonged to the l-GA basin (65 %), l-GEA basin (7 %), r-GA basin (21 %), r-GEA basin (58 %), and posterior gastric artery (p-GA) basin (7 %). No. 6 and No. 9 were detected as SNs significantly more frequently with SN No. 8a. SN No. 5 and No. 8a were tend to be detected with not SNs that belonged to the r-GA basin but No. 6, and SN No. 6 was detected significantly more frequently with No. 4d, No. 5 and No. 8a. Conclusions: Our findings show that lymphatic flows exist not only between lymph nodes which are belonged to the same basin, but also between No. 5 and No.6, and No.6 and No. 8a. On the other hand, the lymphatic flows between No. 5 and No. 8a seem to be limited. Our results suggest that the lymph node dissection of No. 6 given lymphatic flows from lesser curvature side and retroperitoneal side is important for surgery of gastric cancer.

Sentinel lymph node biopsy in breast cancer: review on various methodological approaches.

Sentinel lymph node biopsy has been accepted as a standard procedure for early stage breast cancer. In this retrospective analysis, the results obtained with different methodological approaches using radiocolloid with or without blue dye were examined. A total of 158 sentinel lymph node biopsies were performed in 152 patients. Group A (85 patients) underwent lymphatic mapping using a combination of periareolar intradermal radiocolloid and subareolar blue dye injections. Group B (73 patients) underwent only periareolar intradermal radiocolloid injection. One large tin colloid and two small radiocolloids (nanocolloid of serum albumin -NC- and colloidal rhenium sulphide -CS-) were used. Successful lymphatic mapping was attained in 157 of 158 procedures (99.4%). Radiocolloids localized sentinel lymph nodes in 99.4% and blue dye in 75.3% of the cases. The number of sentinel lymph nodes removed was greater in nanocolloid and colloidal rhenium sulphide groups (P ≤0.05). Among 60 metastatic sentinel lymph nodes, frozen section analysis using hematoxylin and eosin staining failed to detect 1 macro- and 10 micrometastasis. Radiocolloid uptake was higher in sentinel lymph nodes accumulating blue dye (1643 ± 3216 counts/10 sec vs 526 ± 1284 counts/10 sec, P <0.001). Higher count rates were obtained by using larger sized colloids (median and interquartile range: tin colloid, 2050 and 4548; nanocolloid, 835 and 1799; colloidal rhenium sulphide, 996 and 2079; P = 0.01). Only 2 extra-axillary sentinel lymph nodes were visualized using periareolar intradermal injection modality. Radiocolloids were more successful than blue dye in sentinel lymph node detection. More sentinel lymph nodes were harvested with small colloids, but different sized radiocolloids were similarly successful. Sentinel lymph nodes having higher radiocolloid uptake tended to accumulate blue dye more frequently. Sentinel lymph nodes manifested higher count rates when a larger colloid was used. Frozen section was very successful in detecting macrometastatic disease in sentinel lymph nodes, but the technique failed in most of the micrometastates.

Radiation Dose to the Occupational Worker during the Synthesis of 188Re-labeled Radiopharmaceuticals in the Nuclear Medicine Department.

Aim:The aim of this study is to estimate whole-body radiation dose to the radiopharmacist involved in labeling of three different 188Re-labeled compounds, namely, 188Re-Lipiodol, 188Re-tin colloid, and 188Re-hydroxyl-ethylidene-diphosphonate (HEDP) and to compare the occupational burden with the dose limits recommended by Atomic Energy Regulatory Board, India.Materials and Methods:The Department of Nuclear Medicine at Fortis Memorial Research Institute currently synthesizes three different Rhenium-188 labeled compounds, namely, 188Re-Lipiodol, 188Re-HEDP, and 188Re-tin colloid. To estimate the radiation exposure to the radiopharmacist involved in the synthesis, a survey meter was used to measure radiation level before the start of labeling procedure in the radiopharmacy by keeping it at the location where the radiopharmacist normally stands during preparation. Data were collected for 6 syntheses of each 188Re-Lipiodol, 4 for 188Re-HEDP, and 3 for 188Re-tin colloid followed by the quality control. The pocket dosimeter was used by the radiopharmacistat chest level, performing the labeling of 188Re-labeled compounds. All radiopharmaceuticals were synthesized by a single radiopharmacist.Results:1850 MBq (50 mCi) 188W-188Re generator was eluted before the preparation of each radiopharmaceutical. The amount of 188ReO4- used for labeling with lipiodol/4-hexadecyl-1,2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol, HEDP, and Tin colloid was in the range of 3182–4440 MBq (86–120 mCi), 2812–3774 MBq (76–102 mCi), and 962–1295 MBq (26–35 mCi), respectively. Meantime required to complete the synthesis was 95, 40, and 131.5 min, respectively. Mean whole-body effective dose received was 0.052, 0.009, and 0.004 mSv, respectively, as measured by using the pocket dosimeter.Conclusion:From this small study, we observed that the whole-body radiation dose to the radiopharmacist in radiolabeling and quality control of 188Re-labeled radiopharmaceuticals is within prescribed limits at the current synthesis frequency.

The detection of sentinel lymph nodes in laparoscopic surgery can eliminate systemic lymphadenectomy for patients with early stage endometrial cancer

BackgroundThe examination of a sentinel lymph node (SLN), where lymph node metastasis first occurs, may be advocated as an alternative staging technique. The aim of this study was to evaluate the feasibility and detection rates of an SLN biopsy in patients with endometrial cancer.Study designTwo hundred and eleven patients with endometrial cancer underwent an SLN biopsy at hysterectomy using three kinds of tracers including 99m-technetium-labeled tin colloid (99mTc), indigo carmine and indocyanine green. Factors related to the side-specific detection rate, sensitivity and false negative rate were analyzed.ResultsThe detection rates of the SLN biopsy using 99mTc, indigo carmine and indocyanine green were 77.9, 17.0 and 73.4%, respectively. The detection rate was lower in elderly patients (≥60 years) (67.9 vs 89.2%, p < 0.01), patients with >50% myometrial invasion (68.3 vs 85.2%, p < 0.01), patients with high-grade tumors (69.5 vs 84.9%, p < 0.01) and patients who underwent laparotomy (71.2 vs 84.9%, p < 0.01). There were no significant differences in body mass index. The sensitivity was not significantly different in any factor. However, the false negative rate was higher in patients with > 50% myometrial invasion (11.5 vs 1.2%, p < 0.01), high-grade tumors (13.3 vs 0.8%, p < 0.01) and who underwent laparotomy (12.2 vs 0.4%, p < 0.01).ConclusionPatients who underwent laparoscopy with < 50% myometrial invasion and low-grade tumors not only have higher detection rates, but also have lower false negative rates. These patients may avoid systemic lymphadenectomy according to the status of the SLN biopsy.

Formulation and characterization of lutetium-177-labeled stannous (tin) colloid for radiosynovectomy.

Easy large-scale production, easy availability, cost-effectiveness, long half-life, and favorable radiation characteristics have made lutetium-177 (Lu) a preferred radionuclide for use in therapy. Lutetium-177-labeled stannous (Lu-Sn) colloid particles were formulated for application in radiosynovectomy, followed by in-vitro and in-vivo characterization. Stannous chloride (SnCl2) solution and Lu were heated together, the pH was adjusted, and the particles were recovered by centrifugation. The heating time and amount of SnCl2 were varied to optimize the labeling protocol. The labeling efficiency (LE) and radiochemical purity (RCP) of the product were determined. The size and shape of the particles were determined by means of electron microscopy. In-vitro stability was tested in PBS and synovial fluid, and in-vivo stability was tested in humans. LE and RCP were greater than 95% and ∼99% (Rf=0-0.1), respectively. Aggregated colloidal particles were spherical (mean size: 241±47 nm). The product was stable in vitro for up to 7 days in PBS as well as in synovial fluid. Injection of the product into the infected knee joint of a patient resulted in its homogenous distribution in the intra-articular space, as seen on the scan. No leakage of activity was seen outside the knee joint even 7 days after injection, indicating good tracer binding and in-vivo stability. Lu-Sn colloid was successfully prepared with a high LE (>95%) and high RCP (99%) under optimized reaction conditions. Because of the numerous benefits of Lu and the ease of preparation of tin colloid particles, Lu-Sn colloid particles are significantly superior to its currently available counterparts for use in radiosynovectomy.

The detection of sentinel lymph nodes in laparoscopic surgery for uterine cervical cancer using 99m-technetium-tin colloid, indocyanine green, and blue dye.

ObjectiveOur objective was to determine the feasibility and detection rates and clarify the most effective combination of injected tracer types for sentinel lymph node (SLN) mapping in uterine cervical cancer in patients who have undergone laparoscopic surgery or neoadjuvant chemotherapy (NAC).MethodsA total of 119 patients with cervical cancer underwent SLN biopsy at radical hysterectomy using three types of tracers. The various factors related to side-specific detection rate, sensitivity, and false negative (FN) rate were analyzed.ResultsThe SLN detection rates using 99m-technetium (99mTc)-tin colloid, indigo carmine, and indocyanine green (ICG) were 85.8%, 20.2%, and 61.6%, respectively. The patients with ≥2-cm-diameter tumors and those who received NAC had lower detection rates than those with <2-cm-diameter tumors (75.7% vs. 91.5%, p<0.01) and those who did not receive NAC (67.9% vs. 86.3%, p<0.01), respectively. Laparoscopic procedures had a higher detection rate than laparotomy (100.0% vs. 77.1%, p<0.01). No factors significantly affected the sensitivity; however, the patients with ≥2-cm-diameter tumors (86.0% vs. 1.4%, p<0.01), NAC (19.4% vs. 2.2%, p<0.01), and those who underwent laparotomy (7.4% vs. 0%, p<0.01) had an unfavorable FN rate.ConclusionAmong the examined tracers, 99mTc had the highest detection of SLN mapping in patients with uterine cervical cancer. Patients with local advanced cervical cancer with/without NAC treatment might be unsuited for SLN mapping. SLN mapping is feasible and results in an excellent detection rate in patients with <2-cm-diameter cervical cancer. Laparoscopic surgery is the best procedure for SLN detection in patients with early-stage disease.

Pylorus-Preserving Surgery Based on the Sentinel Node Concept in Early Gastric Cancer.

In patients with early stage gastric cancer in the middle third of the stomach, pylorus-preserving gastrectomy (PPG) can be an option as function-preserving surgery, although its oncologic safety is not definitively defined. This issues may be overcome using the sentinel node (SN) concept. The aim of this study was to investigate the effectiveness of the SN concept in early gastric cancer patients who are candidates for PPG. One hundred fifty-six patients with middle-third location of cT1N0 gastric cancer (single lesion, <4cm) underwent distal gastrectomy with SN mapping. As a tracer, technetium-99 tin colloid solution and blue dye were endoscopically injected into the submucosal layer surrounding the primary tumor. SN detection rate was 100% (156 of 156), and the accuracy of the nodal evaluation of metastasis was 99% (155 of 156). Suprapyloric lymph node (LN; LN No. 5) and infrapyloric LN (LN No. 6) were detected as SNs in 6 and 14% of the patients, respectively. We also found two cases with metastasis to LN No. 5 or LN No. 6. When performing PPG, the possibility of LN metastasis, especially to LN No. 5 and LN No. 6, cannot be underestimated. SN mapping can play an important role to predict the possibility of metastasis to LN No. 5 and LN No. 6.

Clinical significance of the anterosuperior lymph nodes along the common hepatic artery identified by sentinel node mapping in patients with gastric cancer.

The sentinel node (SN) concept is safely applied and validated in early gastric cancer. Gastric lymph nodes are divided into five basins with the main gastric arteries, and the anterosuperior lymph nodes with the common hepatic artery (No. 8a) are classified in the right gastric artery (r-GA) basin. Although No. 8a are considered to have lymphatic flow from the r-GA basin, there might be additional multiple lymphatic flows into No. 8a. The aim of this study is to analyze the lymphatic flows to No. 8a and to investigate the clinical significance of No. 8a as a sentinel node (SN No. 8a). Four hundred and twenty-nine patients with cT1N0 or cT2N0 gastric cancer underwent SN mapping. We used technetium-99 tin colloid solution and blue dye as a tracer. We detected SN No. 8a in 35 (8.2%) patients. In these patients, we detected SN No. 8a with SNs that belonged to the left gastric artery (l-GA) basin (66%), right gastroepiploic artery (r-GEA) basin (54%), and right gastric artery (r-GA) basin (46%). In addition, celiac artery lymph nodes were detected as SNs significantly more frequently. Function-preserving surgery was performed significantly less often in patients with SN No. 8a (p=0.018). We found that SN No. 8a seemed to have lymphatic flow not only from the r-GA basin, but also from the l-GA basin or r-GEA basin. When SN No. 8a are detected, we should be careful to perform function-preserving surgery, even in SN-negative cases.

Clinical Significance of Sentinel Node Positivity in Patients with Superficial Esophageal Cancer.

Sentinel node (SN) mapping in esophageal cancer has been reported to be technically feasible with an acceptable detection rate and accuracy. However, the clinical significance and survival analysis findings associated with the metastatic status of SNs in patients with early-stage esophageal cancer have not been clarified. In this study, we investigated the clinical significance and survival impact of SN mapping in early-stage esophageal cancer. Among patients who were diagnosed preoperatively with clinical T1N0M0 or T2N0M0 esophageal cancer and who underwent SN mapping, 70 consecutive patients who were diagnosed with pathological T1 primary thoracic esophageal cancer were enrolled in this study. Sixty-four (91 %) patients were diagnosed with squamous cell carcinoma while 5 (7 %) patients were with adenocarcinoma. Endoscopic injection of technetium-99m tin colloid was performed before surgery, and radioactive SNs were identified by preoperative lymphoscintigraphy and intraoperative gamma probing. Standard esophagectomy with lymphadenectomy was performed in all patients, and all resected nodes were evaluated by routine pathological examination. SNs were successfully detected in 65 (92.9 %) of 70 patients with pT1 esophageal cancer. The sensitivity to predict lymph node metastasis was 91.7 %, and the diagnostic accuracy based on SN status was 96.9 %. Although there was a wide distribution of SNs from cervical to abdominal areas, 84.5 % of the patients had no lymph node metastasis or had lymph node metastasis only in SN. The disease-specific survival of the patients with metastatic non-SNs was significantly worse relative to that of the patients with no lymph node metastasis or lymph node metastasis only in SN. This study demonstrated that radio-guided SN mapping is useful not only as an accurate diagnostic tool for detecting lymph node metastasis but also as a tool for prognostic stratification in patients with cN0 early esophageal cancer.

Double sentinel lymph node mapping with indocyanine green and 99m-technetium–tin colloid in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) frequently metastasizes to cervical lymph nodes, which is the most known prognostic factor. Screening methods to identify sentinel lymph nodes (SLNs) are therefore of great interest for the management of potential neck metastasis. The purpose of this study was to evaluate the clinical benefit of double SLN mapping with indocyanine green (ICG) and 99m-technetium–tin colloid (99mTc–tin colloid) for sentinel node navigation surgery (SNNS). Between 2007 and 2010, 16 patients diagnosed with OSCC were investigated by SLN biopsy using the double mapping method. 99mTc–tin colloid was injected into the peri-tumoural region on the preoperative day, and ICG was administered intraoperatively in the same position to assist in detecting nodes during surgery. Based on the gamma-ray signal and near-infrared (NIR) fluorescence of ICG, SLNs were identified and thereafter assessed pathologically and genetically for cancer involvement. Radio-guided detection was successful for all patients. ICG mapping identified a relatively larger number of nodes, suggesting that several non-SLNs were potentially involved. The double mapping method assisted surgeons to explore SLNs. Since the ICG fluorescence was shielded by the subcutaneous fatty tissue and the muscle layer including platysma and sternocleidomastoid, it was necessary to retract the tissue away from nodes.

Radiosynovectomy of ankle joint synovitis in juvenile rheumatoid arthritis treated with rhenium-188 tin colloid and imaging with SPECT/CT

Rheumatoid arthritis is a chronic disease that is mainly characterized by asymmetric erosive synovitis, particularly affecting peripheral joints. Radiation synovectomy, or radiosynovectomy, was first described in 1950s as an adjuvant treatment for rheumatoid arthritis. Radiosynovectomy is based on the irradiation of the synovial joint by means of intra-articular administration of various β-emitting radiopharmaceuticals. As a generator-produced beta-emitting radionuclide, the importance of rhenium-188 (Re-188) in radionuclide therapy is increasing rapidly. There are previous studies that used Re-188 tin colloid in knee joint synovitis, but its use in ankle joint has not yet been reported. We describe the use of Re-188 tin colloid in a 19-year-old male patient who presented with ankle joint synovitis.

Size Control of (99m)Tc-tin Colloid Using PVP and Buffer Solution for Sentinel Lymph Node Detection.

Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a (99m)Tc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with (99m)Tc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid ((99m)Tc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid ((99m)Tc-BPTC-50) were chosen for in vitro and in vivo studies. (99m)Tc-BPTC-50 (<20 nm) was primarily located in bone marrow and was then secreted through the kidneys, and (99m)Tc-PPTC-30 (>100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of (99m)Tc-PPTC-30 decreased over time, while (99m)Tc-BPTC-50 increased. Therefore, (99m)Tc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP.

Suitability of Sentinel Node Mapping as an Index of Metastasis in Early Gastric Cancer Following Endoscopic Resection

When pathological diagnosis following endoscopic resection (ER) for early gastric cancer (EGC) suggests probable lymph node metastasis, additional surgery with lymphadenectomy should be performed. The sentinel node (SN) concept has yet to be applied to tumors following ER. The aim of this study was to evaluate the feasibility of SN navigation surgery for such tumors. Forty patients diagnosed with EGC lesions <4 cm in diameter underwent gastrectomy with SN mapping following ER. A technetium-99 m tin colloid solution and a dye were injected into the submucosal layer around the post-ER scar in all four abdominal quadrants. We then compared the SN distribution and metastases among the patients who underwent ER and controls (n = 192). SNs were identifiable in all patients, and the mean number of SNs per case was 4.9. The location of the SN basin was similar in the patients who underwent ER and the controls. One patient (3 %) whose primary tumor had invaded the submucosal layer had a metastatic SN. The median time from ER to surgery was 73 days. No postoperative recurrence was observed in any patient over a median follow-up of 1,023 days. Our findings suggest that the SN basin is not greatly affected by ER. The SN concept could be suitable for tumors following ER, but conventional gastrectomy with lymphadenectomy involving the SN basin should be used at present.

In Vitro Evaluation of Tc-99m Radiopharmaceuticals for Gastric Emptying Studies

Objective: Gastrointestinal motility and functional motility disorders causing either delayed or accelerated gastric emptying (GE) may result in similar symptoms including nausea, vomiting, early satiety, fullness, bloating, and abdominal discomfort or pain. Hence, it is important to evaluate patients for both rapid and delayed GE in the same test. The gold standard technique to measure GE is scintigraphy by radiolabeled test meals. The aim of this study was to test alternative Tc-99m agents to label eggs as the solid meal and compare to Tc-99m sulfur colloid (SC) for gastric emptying studies.Methods: In search of alternative agents for gastric emptying studies, we mixed and fried eggs with four different particulate compounds (Tc-99m labeled SC, tin colloid, nanocolloid and MAA), as well as with free pertechnetate and Tc-99m DTPA. We then measured the stability of these compounds in simulated gastric juice.Results: Our experiments demonstrated that in addition to Tc-99m sulfur colloid;Tc-99m MAA, Tc-99m nanocolloid and Tc-99m tin colloid also appear to make stable complexes with eggs in acidic environment.Conclusion: Therefore, these agents may be used for gastric emptying studies which could be more practical in routine conditions.Conflict of interest:None declared.