99mTc-antimony Sulfide Colloid Research Articles

68Ga-NOTA-Evans Blue PET/CT findings in lymphangioleiomyomatosis compared with 99mTC-ASC lymphoscintigraphy: a prospective study

BackgroundLymphangioleiomyomatosis (LAM) is a rare multisystem disease characterized by cystic lung disease and extrapulmonary manifestations, including lymphatic system disorder. The objective of this study was to investigate the findings of 68Ga-NOTA-Evans Blue (NEB) PET/CT in LAM and compare it with that of 99mTc-ASC lymphoscintigraphy.MethodsTen patients diagnosed with LAM according to the American Thoracic Society/Japanese Respiratory Society guidelines for LAM were recruited in this study. PET/CT acquisition was performed at 20 to 40 min after subcutaneous injection of 68Ga-NEB into the first interdigital spaces of both feet (0.3 ml, 37 MBq/foot). All subjects also underwent 99mTc-antimony sulfide colloid (ASC) lymphoscintigraphy within a week for comparison.Results68Ga-NEB PET/CT displayed various lymphatic system abnormalities in 10 (100%) of 10 patients. These included pulmonary lymphatic abnormalities in 10 (100%) of 10 patients, enlarged lymph nodes in 5 (50%), lymphangioleiomyomas in 2 (20%), dilation of the lumbar trunk and/or iliac lymph vessels in 5 (50%), thoracic duct dilation in 2 (20%), chylous effusion in 1 (10%). For pulmonary lymphatic abnormalities, the positive rates of 68Ga-NEB PET/CT and 99mTc-ASC lymphoscintigraphy were 100% (10/10) and 10% (1/10), respectively (P < 0.001). As for the 7 patients with extrapulmonary lymphatic manifestations, 68Ga-NEB PET/CT also presented more information than 99mTc-ASC lymphoscintigraphy.Conclusion68Ga-NEB PET/CT visualized pulmonary lymphatic abnormality and displayed extrapulmonary lymphatic system disorders of LAM, and might play a role in the diagnosis and evaluation of the disease. 68Ga-NEB PET/CT is advantageous over conventional 99mTc-ASC lymphoscintigraphy in LAM by providing more detailed information of lymphatic dysfunction.

Usefulness of 99mTc-ASC lymphoscintigraphy and SPECT/CT in the evaluation of rare lymphatic disorders: Gorham-Stout disease, lymphangioma, and lymphangioleiomyomatosis.

The purpose of this study was to investigate the role of 99mTc-antimony sulfide colloid (ASC) lymphoscintigraphy and single photon emission computed tomography/computed tomography (SPECT/CT) in the evaluation of rare lymphatic disorders, including Gorham--Stout disease (GSD), lymphangioma, and lymphangioleiomyomatosis (LAM).Nine patients suspected to have rare lymphatic disorders were included in this retrospective study. All patients underwent 99mTc-ASC lymphoscintigraphy and SPECT/CT to evaluate the lesions. The lymphoscintigraphy results were compared with the clinical and immunopathological findings.99mTc-ASC lymphoscintigraphy and SPECT/CT could provide lymphatic draining and anatomical information for rare lymphatic disorders. Among the 9 patients, 3 were diagnosed with GSD (1 female, 2 males; aged 15–34 years, range 27.0 ± 10.4 years), 3 with lymphangioma (1 female, 2 males; aged 17–42 years, range 32.0 ± 13.2 years), and 3 patients were diagnosed with LAM (3 females; aged 33–50 years, range 43.7 ± 9.3 years]. GSD is characterized by multiple bone destruction, including spine, ribs, ilium, pubis, ischium, and femur. The tracer uptake of involved bones and soft tissue around bone is increased, accompanied by chylothorax, chylopericardium, and chylous leakage in abdominal and pelvic cavity. Lymphangiomas present as multiple cystic lesions with increased tracer uptake in the peripancreatic, retroperitoneal, and iliac areas, and in the abdominopelvic cavity. LAM presents as multiple thin-walled cysts in the bilateral lungs and multiple retroperitoneal enlarged lymph nodes with increased tracer uptake.99mTc-ASC lymphoscintigraphy and SPECT/CT could comprehensively and specifically detect some rare lymphatic disorders, namely, GSD, lymphangioma, and LAM. This technique is useful for the evaluation of GSD, lymphangioma, and LAM.

Lymphoscintigraphy in early-stage non-small cell lung cancer with technetium-99m nanocolloids and hybrid SPECT/CT: a pilot project

The goal of our study was to determine if lymph node activity could be visualized using a hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) scanner with two commonly used colloidal lymphatic radiotracers--99mTc-antimony sulfide colloid (ASC) and 99mTc-filtered sulfur colloid (FSC) in the setting of low-stage non-small cell lung cancer (NSCLC). Patients undergoing CT-guided percutaneous lung biopsies for clinically suspected early-stage lung cancer were randomized to peri-lesional injection of 37 MBq (0.5 mL) of either ASC or FSC. SPECT/CT of the thorax was performed at either 1, 2, or 3 h post-injection. The images were reviewed to determine if lymph node activity separate from the injection site could be identified. 24 patients were included. Lymph node activity was identified in 50% of patients. A total of 15 lymph nodes with activity were visualized including 5 ipsilateral hilar, 6 ipsilateral mediastinal, and 4 distant locations. No contralateral mediastinal or hilar activity was visualized. There was a tendency to improved visualization with ASC and the longer 3 h wait time. Most patients also demonstrated significant pleural, tracheobronchial, and/or systemic activity. SPECT/CT imaging can demonstrate lymph node activity separate from the injection site in at least some low-stage NSCLC patients with a perilesional injection of 99mTc nanocolloid tracers. Further investigation into the role of pre-operative lymphoscintigraphy with SPECT/CT in patients with lung cancer is warranted.

Concordance Between Peri-Areolar Blue Dye and Peri-Incisional Radiotracer Injections for Sentinel Node Mapping in Patients with a History of Primary Breast Cancer Excisonal Biopsy

Background: We evaluated the concordance between peri-areolar blue dye and peri-incisional radiotracer injections for axillary sentinel node mapping of patients with the history of previous breast lesion excisional biopsy. Methods: 80 patients with the history of previous excisional biopsy of the breast lesions were included. All patients received two injections of 99mTc-antimony sulfide colloid in both ends of incision line in an intradermal fashion. 2 mL patient blue V dye was injection to all patients in the peri-areolar area of the index quadrant after induction of anesthesia. All blue or hot nodes were harvested as sentinel lymph nodes.Results: At least one sentinel node could be detected during surgery in 79 patients. In total 94 sentinel nodes were detected. All detected sentinel nodes were hot. In three patients sentinel nodes were detected by gamma probe but not blue dye. The tumor location in all of these patients was in the upper lateral quadrant and the incision line was extended into the axillary tail of the breast in all of them. 91 out of 94 sentinel nodes were stained blue, which amounts to 95.8% concordance between blue dye and radiotracer on a per node analysis.Conclusions: Single peri-areolar injection in the index quadrant would suffice for sentinel node mapping of patients with history of excisional biopsy. Care should be taken in patients with large excisional biopsy in the extreme proximity to axilla.

High discordance rates between sub-areolar and peri-tumoural breast lymphoscintigraphy

To test the hypothesis that sub-areolar (SA) lymphoscintigraphy (LSG) identifies the same sentinel node as peri-tumoural (PT) injections. It is commonly believed that all LSG techniques will identify the same sentinel lymph nodes (SLN) draining the breast. Hybrid imaging technology (SPECT/CT) allows accurate identification of the exact location of SLNs. Using SPECT/CT SA and PT LSG techniques were compared. In a multi-centre trial 39 patients sequentially underwent LSG (SA followed by PT) separated by 2-7 days. Patients were referred by 4 surgeons to 3 LSG centres, with standardization of isotope (99mTc-antimony sulfide colloid), LSG and SPECT/CT evaluation techniques. LSG were evaluated for SLN concordance and degree of discordance in the axilla and internal mammary nodes (IMN). 39 eligible patients, median age 62 years, were recruited. Successful axillary SLN mapping for SA and PT injection techniques was 87% and 95% respectively. Successful internal mammary SLN mapping occurred with SA and PT LSG in 5% and 36% respectively. Discordance was identified in the IMN (39%) and axilla (21%), with an overall rate of discordance between SA and PT LSG of 56%. There is a high level of discordance in the localization of SLN by these commonly used LSG injection techniques. This discordance has implications for accuracy of axillary and extra-axillary staging and could impact on patient outcome.

Effect of radiotracer injection volume on the success of sentinel node biopsy in early-stage breast cancer patients

The volume of radiotracer to be injected for sentinel node mapping is a controversial issue in breast cancer patients. In the current study, we evaluated the effect of radiotracer injection volume on the success rate of sentinel node mapping in early-stage breast cancer patients. A total of 383 patients with early-stage breast cancer (cN0) were included in the study. The patients received an intradermal injection of Tc-antimony sulfide colloid for sentinel node mapping. The volume of injection was 0.1 ml for 102 patients, 0.2 ml for 221 patients, 0.5 ml for 30 patients, and 1 ml for 30 patients. The detection rate of the sentinel nodes during surgery was compared between the different injection volume groups. The overall detection rate was 93.9%. Detection rates were 95.1, 95, 90, and 86.7% for 0.1, 0.2, 0.5, and 1 ml volumes, respectively, which did not show a statistically significant difference despite minimal decrease in detection at higher volumes (P=0.214). The time of sentinel node visualization was not statistically different between the studied groups either (P=0.65). Increasing the volume of radiotracer in intradermal injections does not have a statistically significant effect on the sentinel node detection rate (despite minimal decrease in detection at higher volumes), nor on the time of sentinel node visualization. A low volume (0.1 ml) of radiotracer for intradermal injections can be as successful as higher volumes for sentinel node mapping with the added benefit of reduced pain from injections.

Efficacy of high-energy collimator for sentinel node lymphoscintigraphy of early breast cancer patients

IntroductionLymphoscintigraphy is an important part of sentinel node mapping in breast cancer patients. Sometimes star shaped artefacts due to septal penetration can be problematic during imaging. In the current study, we evaluated the possibility of high energy (HE) collimators use for lymphoscintigraphy.Patients and methodsTwenty patients with early breast carcinoma were included. Thirty minutes after radiotracer injection (99mTc-antimony sulphide colloid), anterior and lateral images were acquired using a dual head gamma camera equipped with a parallel hole low energy high resolution (LEHR) collimator on one head and HE collimator on another head. All images were reviewed by two nuclear medicine specialists regarding detectability and number of axillary sentinel nodes and presence of star artefact.ResultsAll images taken by LEHR collimators showed star artefact of the injection site. No image taken by HE collimator showed this effect. In two patients the sentinel node was visible only by HE collimator. Tumour location in both of these patients was in the upper lateral quadrant and both had history of excisional biopsy. In two patients additional sentinel node was visible adjacent to the first one only on the LEHR images.ConclusionsHE collimators can be used for sentinel lymph node mapping and lymphoscintigraphy of the breast cancer patients. This collimator can almost eliminate star-shaped artefacts due to septal penetration which can be advantageous in some cases. However, to separate two adjacent sentinel nodes from each other LEHR collimators perform better.

P3-07-15: Sequential Peri-Areolar and Peri-Tumoural SPECT/CT Lymphoscintigraphy Has Identified High Rates of Discordance in Both Axillary and Internal Mammary Sentinel Lymph Node Mapping.

Abstract Introduction: The release of the MA20 intergroup trial results has confirmed the importance of locoregional radiation on local and distant disease control and survival. Sentinel lymph node (SLN) evaluation is the gold standard for regional lymph node evaluation and radiation oncologists continue to utilize the nodal staging to plan adjuvant locoregional therapy. Despite over a decade of experience in SLN evaluation there persists a common belief that the lymphatic drainage of the whole breast is to anteropectoral axillary lymph nodes. Several different lymphoscintigraphy injection techniques are in use with claims that they all identify the same axillary sentinel nodes. However this is not based on a high level of evidence. The evolution of SPECT/CT has led to the accurate anatomic identification of SLN, hence the different lymphoscintigraphy techniques can now be directly compared. Method: 38 patients underwent double sequential lymphoscintigraphy (peri-areolar followed by peri-tumoural) separated by 1–7 days. Patients were referred by 4 surgeons to 3 separate lymphoscintigraphy centres with standardisation of tracer substance (99mTc-antimony sulfide colloid), lymphoscintigraphy and SPECT/CT evaluation techniques. The degree of discordance in sentinel node evaluation was defined as: Type 1 - One study demonstrates SLN(s) in a nodal basin [axilla or internal mammary chain (IMC)] and the other study demonstrates none. Type 2 - Both studies identified SLN(s) in a nodal basin however the SLN(s) are all different. Type 3 - Both studies identified SLNs in a nodal basin, however some SLN(s) are identical and others not. Results: Notably 21 patients (55%) had either axilla or IMC lymphoscintigraphy discordance. Two patients had both axilla and IMC lymphoscintigraphy discordance. The majority of discordance was identified in the IMC. In the concordant IMC lymphoscintigraphies neither study demonstrated IMC SLN. There were no studies that identified identical IMC nodes in both PA and PT lymphoscintigraphy. Discordant axillary drainage was more evident in patients with lateral sector tumours compared to IM discordance with medial sector tumours. Conclusions: Accurate lymphoscintigraphy is the road map to assist a surgeon identify lymph node metastases. In turn accurate staging will determine appropriate adjuvant therapy decisions particularly regional node irradiation. This study demonstrates a high degree of discordance between PA and PT lymphoscintigraphy techniques in 55% of patients. Inadequate lymphoscintigraphy can result in unrealized false negative results, which could impact patient outcomes and clinical trial results. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-15.

Factors influencing the time of sentinel node visualization in breast cancer patients using intradermal injection of the radiotracer

BackgroundThe objective of our study was to determine the important factors that have influence on the time of sentinel node visualization using intradermal injection of 99mTc-antimony sulfide colloid. MethodsTwo hundred fifty consecutive patients with the diagnosis of early-stage breast cancer were evaluated. Anterior and lateral views were acquired in various intervals after intradermal injection of the tracer until 180 minutes or visualization of the sentinel node. The effect of several variables on the time of sentinel node visualization was evaluated by univariate and multivariate analyses. ResultsThe time of sentinel node visualization was significantly correlated with age, body mass index (BMI), and interval between biopsy and sentinel node mapping. Standardized beta values for these variables were .1, .3, -.55 respectively. ConclusionsOlder age and higher BMI can result in slow sentinel node visualization. Longer interval between biopsy and sentinel node mapping can be associated with rapid sentinel node detection.

The Effect of Excisional Biopsy on the Accuracy of Sentinel Lymph Node Mapping in Early Stage Breast Cancer: Comparison with Core Needle Biopsy

Despite the successful application of sentinel node mapping in breast cancer patients, its use in patients with a history of previous excisional biopsy of the breast tumors is a matter of controversy. In the present study we evaluated the accuracy of sentinel node biopsy in this group of patients and compared the results with those in whom the diagnosis of breast cancer was established by core needle biopsy. Eighty patients with early stage breast carcinoma were included into our study. Forty patients had a history of previous excisional biopsy and the remainder 40 had undergone core needle biopsy. Intradermal injections of 99mTc-antimony sulfide colloid as well as patent blue were both used for sentinel node mapping. Sentinel nodes were harvested during surgery with the aid of surgical gamma probe. All patients underwent standard axillary lymph node dissection subsequently. Detection rate was 97.5 per cent for both groups of the study. Number of detected sentinel node during surgery was not significantly different between groups. False negative rate was 0 per cent for both groups of the study. In conclusion sentinel node biopsy is reliable in patients with previous history of excisional biopsy of the breast tumors and has a low false negative rate.

Comparison of early and delayed lymphoscintigraphy images of early breast cancer patients undergoing sentinel node mapping

We compared early and delayed lymphoscintigraphy images using intradermal injection of (99m)Tc-antimony sulfide colloid, which has small particles. Eighty patients with early-stage breast cancer were included into the study. Intradermal injection of (99m)Tc-antimony sulfide colloid was used for sentinel node mapping. After radiotracer injection, 30 min and 20 h later, lymphoscitigraphy images were obtained in lateral and anterior views. After the completion of each image sets, the location of the visible nodes in the axilla was marked on the skin. Two nuclear medicine specialists reviewed the images independently and the number and location of detected nodes were recorded. At least one hotspot was detected in the axillary region in 78 (97.5%) and 79 (98.75%) patients on the early and delayed images, respectively. No extra-axillary drainage was noted in the patients. The number and location of detected hot spots were the same in 77 patients on both image sets. In one patient the early image did not show any axillary hot spot despite its visualization on the delayed image set and in one patient no hot spot was noted on either images. In one patient an additional axillary hot spot was noted on the delayed image, which was not apparent on the early image. Our study showed that a delay of up to 20 h in sentinel lymph node biopsy using intradermal injection of (99m)Tc-antimony sulfide colloid does not result in washout of the tracer from the true sentinel node or migration of the radiotracer into second-echelon nodes.

Factors affecting sentinel lymph node detection failure in breast cancer patients using intradermal injection of the tracer

Objective The standard method for axillary lymph node staging in early breast cancer is sentinel lymph node biopsy. In some patients the sentinel lymph node can not be localized during surgery and these patients have to undergo standard axillary lymph node dissection. In this study we have evaluated the predictors of sentinel lymph node localization failure using 99mTc-antimony sulfide colloid and intradermal injection combined with blue dye technique. Material and methods 202 consecutive patients with early stage breast cancer (clinically stage I or II) were retrospectively evaluated. Patients whose sentinel lymph node was localized during surgery were compared to those with localization failure considering several variables. Results Sentinel lymph node was successfully located on the pre-operative lymphoscintigraphy images in 180 patients (89%). Both univariate and multivariate analyses showed that only sentinel lymph node non-visualization by pre-operative lymphoscintigraphy, experience of the surgeon, and axillary lymph node involvement are associated with sentinel node localization failure during surgery. Conclusions This study shows the importance of pre-operative lymphoscintigraphy in order to identify the group of patients with possible localization failure during surgery and warning the surgeon beforehand. We also recommend that all surgeons pass the learning curve of sentinel lymph node biopsy before routinely performing this procedure.

How long the lymphoscintigraphy imaging should be continued for sentinel lymph node mapping?

We assessed the need for delayed lymphoscintigraphy imaging for sentinel lymph node (SLN) biopsy in stage I and II breast cancer patients using intradermal injection of (99m)Tc-antimony sulfide colloid. Seventy-five patients with early-stage breast cancer were included in our study. Periareolar intradermal injections of 0.5 mCi/0.2 mL (99m)Tc-antimony sulfide colloid was used for the patients without previous excisional biopsy (45 patients). Two intradermal injection of 0.5 mCi/0.2 mL (99m)Tc-antimony sulfide colloid was used on each side of the dermal incision in patients with the history of excisional biopsy (30 patients). Anterior and lateral static images were taken at 2 min. If SLN was not visualized, delayed imaging at 5, 10, 30, 60, 90, 150, and 180 min was done (till the visualization of the SLN or 180 min). SLN was performed by the combination of gamma probe and blue dye during surgery. Sentinel lymph node detection rate was 96% (72/75). SLNs were detected on the immediate (2 min) images in 55 (73.33%) patients. In the remaining patients, the SLNs were detected first on the 5-, 10-, and 30-min images in 10 (13/33%), 5 (6.66%), and 2 (2.66%) patients, respectively. In three patients (4%), SLN was not detected by lymphoscintigraphy even on 180-min images. During surgery, SLN was not detected in these three patients either. Considering the rapid flow of (99m)Tc-antimony sulfide colloid in our study, lymphoscintigraphy imaging can be completed in the nuclear medicine department without any delay in sending the patient back to the surgery department. Thirty minutes after radiotracer injection seems to be the optimal time for lymphoscintigraphy and delayed imaging beyond 30 min would not be necessary.

An evaluation of pelvic lymphoscintigraphy in the staging of colorectal carcinoma

Lymphoscintigraphy was used to delineate the lymphatic drainage of the rectum and distal colon in 18 patients with carcinoma of the rectum or sigmoid colon, in four with inflammatory disease of the large bowel and in 20 controls without colorectal pathology. Abdominal imaging was performed after submucosal injection of either 4 mCi 99mTc-antimony sulphide colloid or 0.5 mCi 99mTc-dextran into the rectum through a proctoscope. In nine patients with colorectal carcinoma, abdominal imaging was performed immediately pre-operatively and the excised specimen of large bowel was also imaged in vitro immediately postoperatively. The presence or absence of nodal uptake of radionuclide on abdominal scanning did not discriminate between normal and diseased large bowel, and the extent of nodal uptake demonstrated either by abdominal scans or by in vitro scans of excised specimens bore no relationship to the presence or absence of nodal metastases demonstrated histologically in the cancer patients. Pelvic lymphoscintigraphy as performed in this study has no demonstrable value in the diagnosis or staging of colorectal cancer.

Lymphatic drainage from the skin of the back to retroperitoneal and paravertebral lymph nodes in melanoma patients.

Preoperative lymphoscintigraphy (LS) with 99mTc antimony sulphide colloid is now part of the routine management of patients with intermediate thickness melanoma at the Sydney Melanoma Unit. Over a 13-year period, 1375 patients have been examined using LS, and we have observed many unusual lymphatic drainage pathways, including direct drainage through the body wall to retroperitoneal and paravertebral lymph nodes from the skin of the back. The aim of this study was to determine the incidence of such drainage in the 542 patients who had primary melanoma sites on the posterior trunk. The lymphoscintigrams performed on these patients were examined for the presence of direct lymphatic drainage through the posterior body wall to sentinel nodes in the retroperitoneal and paravertebral regions. Lymphatic drainage directly through the body wall to such lymph nodes occurred in 14 of these 542 patients. Preoperative knowledge of the presence of this lymph drainage pattern may influence surgical management, and follow-up investigations in these patients can be tailored to ensure that the relevant areas are examined with anatomic imaging or F18-FDG PET scans.

Investigation of the swollen limb with isotope lymphography

The usefulness of isotope lymphography was evaluated in patients with chronic lower leg swelling. Forty patients (15 male, 25 female, age range 5 months-67 years) were assigned one of six clinical diagnoses based on clinical assessments, venography and lymphography. All the patients and seven normal controls were examined with bilateral isotope lymphography involving subcutaneous injection of 0.15 ml 99mTc-antimony sulphide colloid into the first web space of each foot. The percentage uptake of isotope-colloid in the inguinal lymph nodes at 1 and 2 h was equated with lymphatic function. Highly significant (P = 0.0001) differences existed between the different clinical groups and isotope lymphography discriminated well between oedema of lymphatic and non-lymphatic origin. Isotope lymphography appears to be a safe and useful test of lymphatic function.

Comparison of three RE agents—99mTc-phytate, 99mTc-sulfur colloid and 99mTc-Sb2S3 colloid in the rodent species

99mTc-phytate, 99mTc-sulfur colloid and 99mTc-antimony sulfide colloid are recognised as RE agents in clinical nuclear medicine. Since these three agents exist in vitro in different forms of particulate aggregation it was of interest to compare their properties and to evaluate the merits and limitations of each of these agents. A comparison was carried out in rats and rabbits as a prelude to a systematic study in human subjects. Quality tested radiopharmaceuticals were prepared and their pharmacokinetics studied in rats. The blood clearance, tissue distribution and scinti-imaging patterns of the RE system were also compared in rabbits. All the agents have excellent localizing properties in the liver but differ in varying extents in their disposition in other tissues. 99mTc-sulfur colloid has some predisposition for the lungs while 99mTc-phytate has a little propensity for the kidney and gut at late time periods. 99mTc-Sb2S3 colloid shows a more pronounced concentration in the bone-marrow, and displays intermediate properties between 99mTc-phytate and 99mTc-sulfur colloid, besides being the most stable (in vitro) radiopharmaceutical in this series of RE agents.

Radionuclide lymphoscintigraphy with technetium 99m antimony sulfide colloid to identify lymphatic drainage of cutaneous melanoma at ambiguous sites in the head and neck and trunk.

Frequently the primary lesion of high-risk cutaneous melanoma (level III, greater than or equal to 1.5mm; greater than or equal to 1.0 mm with ulceration) is in an ambiguous lymphatic drainage site on the trunk, pelvic and shoulder girdles, and head and neck area. Lymphoscintigrams were performed by a circumferential intradermal injection of the biopsy site using technetium 99m (99mTc) antimony sulfide colloid in a total dose of 0.2 to 0.6 mCi in a volume of 0.1 to 0.5 ml. Imaging was done with a large-field gamma camera with high-resolution parallel hole collimator. Technetium 99m antimony sulfide colloid is an ideal agent for lymphoscintigrams because of small particle size (3-30 micron), which permits early migration into the interstitial space and lymphatics and rapid pickup by lymph nodes. Although it is a gamma emmitter with high activity, it has a short half-life and does not induce tissue necrosis. It does not localize the site of lymph node metastases, but indicates only the drainage pattern. Images were obtained at 1, 5, 10, 15, 30, and 60 minutes, respectively, and then three times every hour. Surgery was usually performed 24 hours later. The majority of patients had lesions with ambiguous drainage sites: head and neck (4 of 5 patients) and trunk (9 of 13 patients). The drainage by scan was to unpredictive sites in 72%, and resulted in a change of treatment planning by location and extent of ablation with node dissection in 9 of 18 patients. Ambiguous dissection sites included: (1) question of preauricular dissection with parotidectomy versus posterior auricular and cervical dissection for selected scalp lesions; (2) low-neck with or without axillary dissection for upper chest and shoulder lesions; and (3) axillary versus groin dissections for midflank lesions at zone of ambiguity between axilla and groin. It was concluded that preoperative 99mTc antimony sulfide lymphoscintigraphy is a highly useful planning technique in determining the appropriate lymphatic drainage basin for dissection in selected melanoma patients.

Radiation dose estimates for interstitialradiocolloid lymphoscintigraphy

The spatial distribution of radioactivity in the injection site, and its rate of clearance, have been measured in patients undergoing various types of interstitial radiocolloid lymphoscintigraphy using 99mTc-antimony sulfide colloid. The clearance of radioactivity from the injection site, and the expansion with time of the localized radioactivity vary considerably for different sites of injection. Maximum absorbed dose estimates of 45.6 rads to the center of the injection site (rectus sheath) and 21 rads to individual lymph nodes have been calculated for patients undergoing internal mammary lymphoscintigraphy with 450 mu Ci injected radioactivity. Absorbed dose estimates for finger web, toe web, and perianal injection sites are also presented.

Tumor immunity in rat lymph nodes following transplantation.

Inguinal lymph nodes in the Buffalo rat were autotransplanted to the popliteal fossa by an intact vascular pedicle or by microvascular anastomosis. These revascularized nodes had normal histology and made spontaneous afferent and efferent lymphatic reconnection with surrounding lymphatic vessels, as documented by ink and silicone rubber injection studies. Lymphoscintigraphy with 99mTc antimony sulfide colloid correctly predicted the 44 of 120 node transplants that had made afferent reconnection. To demonstrate immunologic activity of lymph nodes following transplantation, a cellular adherance assay was employed to detect cell-mediated cytotoxicity of lymph node cells isolated from rats sensitized to an allogeneic gliosarcoma. Cytotoxicity was detected in nontransplanted regional nodes sensitized to tumor (p less than 0.01) and in nodes transplanted by vascular pedicle and then sensitized to tumor (p less than 0.001). This study demonstrates that lymph nodes can be transplanted with restoration of functional lymphatic anatomy, and that following transplantation, lymph nodes retain the ability to mount an immune response against tumor.