Fusion lymphoscintigraphy with a 24-hour Tc-99m MDP bone scan for sentinel lymph node detection and imaging

A 62-year-old woman with right breast carcinoma who had a breast biopsy 3 weeks earlier was referred for a whole-body Tc-99m MDP bone scan to identify possible osseous metastases. Twenty-four hours later, she underwent lymphoscintigraphy using four peritumoral injections of 250 microCi filtered Tc-99m sulfur colloid of 0.22 microm each. The lymphoscintigraphic images showed good delineation of three right axillary lymph nodes in relation to the rib cage. Performing a bone scan just before lymphoscintigraphy for sentinel node detection may help the surgeon to identify sentinel lymph nodes. This is more anatomically precise than using a flood source to delineate body contour. A Tc-99m MDP bone scan followed by lymphoscintigraphy should be considered in patients with breast carcinoma who will have both bone imaging and lymphoscintigraphy.     

Lymphoscintigraphic studies of lymphatic drainage from the testes

Two colloidal radiopharmaceuticals, Au-198 and Tc-99m antimony, were used to evaluate the lymphatic drainage of the testis in experimental animals and humans. One to 24 hours after direct intratesticular injection of Au-198 colloid in dogs and 4-6 hours after injection of Tc-99m antimony colloid in men, distribution within retroperitoneal lymph nodes was demonstrated. Uptake within the para-aortic lymph nodes primarily draining the testis was decreased following proximal ligation of the spermatic vessels in dogs. Testicular lymphoscintigraphy successfully demonstrated an intact spermatic cord lymphatic communication to the para-aortic nodes in five of six patients with chronic lower-extremity lymphedema. When the intact testicle and spermatic cord were transposed to the thigh in a patient with chronic lymphedema of the lower extremity, percutaneous pedal lymphoscintigraphy successfully demonstrated uptake within the para-aortic lymph nodes draining the ipsilateral testis.     

Use of lymphoscintigraphy with SPECT/CT for sentinel node localization in a case of vaginal melanoma

A 45-year-old woman with vaginal melanoma underwent Tc-99m sulfur colloid (filtered) lymphoscintigraphy with the acquisition of planar and SPECT/CT images for localization of a sentinel node before surgery. The study identified both inguinal and perirectal sentinel nodes, which proved beneficial in mapping potential anatomic spread of disease for staging and therapy planning. These results provide evidence for the use of routine SPECT/CT imaging for pelvic lymphoscintigraphic studies or as an adjunct tool for localizing sentinel nodes in cases that would not be demonstrated with planar imaging alone.     

Direct lymphatic drainage from a melanoma on the back to paravertebral lymph nodes in the thorax.

Preoperative lymphoscintigraphy with Tc-99m antimony sulfide colloid was performed in a patient with cutaneous melanoma on the lower back just to the right of the midline. There was direct lymphatic drainage to paravertebral nodes in the chest on the right side at the level of the sixth and seventh thoracic vertebrae. There was also drainage directly to the right groin and via a series of interval nodes to the right axilla. Knowledge of the presence of such drainage may influence the surgical management of patients.     

Lymphoscintigraphy using larger colloid particles may enhance visualization of the sentinel node in breast cancer: a case report

Lymphoscintigraphy along with a gamma-detecting probe has been applied successfully to breast cancer patients to localize the sentinel node during surgery, with a 5% false-negative rate. The authors report a case of stage II breast cancer. The sentinel node was not visualized on the initial lymphoscintigraphy with peritumoral injection of 37 MBq (1 mCi) 10 ml Tc-99m colloidal rhenium sulfide (Tc-99m ReS colloid; average particle size, 100 nm). However, the sentinel node was visualized in the left lateral view of the second lymphoscintigraphy with peritumoral injection of 37 MBq (1 mCi) 10 ml Tc-99m ReS colloid (average particle size, 500 nm). Lymphoscintigraphy using the larger colloid particles may enhance visualization of a sentinel node in breast cancer.     

Identification of sentinel lymph node in stage I-II breast cancer with lymphoscintigraphy and surgical gamma probe: comparison of Tc-99m MIBI and Tc-99m sulfur colloid

AIM: To evaluate the efficacy of the surgical gamma probe (SGP) after peritumoral injection of Tc-99m MIBI and filtered Tc-99m sulfur colloid (SC) in sentinel lymph node (SLN) detection in stage I and II breast cancer for deciding on the need for axillary dissection. MATERIALS AND METHODS: Thirty patients with stage I-II breast cancer had peritumoral injection of Tc-99m MIBI (74 MBq/0.2 mL [2 mCi/0.2 mL] at 4 different locations) and 42 different patients had peritumoral injection of filtered Tc-99m sulfur colloid (50 MBq/0.2 mL [1.3 mCi/0.2 mL] at 4 different locations). Anterior, lateral, and anterolateral spot images were acquired at 10, 30, 45, 60, and 120 minutes and 24 hours are injection in 5 patients. During surgery, counts were obtained from the injection site, affected breast tissue, internal mammary, axillary, and supraclavicular regions and the contralateral side using the gamma probe. Peritumoral blue dye was also injected during surgery. The first lymph nodes with counts at least twice the background tissue and/or with blue dye uptake were surgically isolated. Modified radical mastectomy and axillary dissection were performed. RESULTS: Histopathologic evaluation was made on SLN and other excised tissues. In the Tc-99m sulfur colloid group, lymphatic drainage and lymph nodes were demonstrated with lymphoscintigraphy in 31 of 42 patients. SLN was detected by SGP in 35 of 42 patients. In the Tc-99m MIBI group, lymphatic drainage and lymph nodes were visualized with lymphoscintigraphy in 23 of 30 patients. SLN was detected in 25 of 30 patients with SGP in this group. CONCLUSION: In patients with stage I-II breast cancer, SLN could be successfully demonstrated with lymphoscintigraphy and SGP by the peritumoral injection of filtered Tc-99m sulfur colloid and Tc-99m MIBI.     

Successful internal mammary visualization with periareolar injections of Tc-99m antimony sulfur colloid in sentinel node breast lymphoscintigraphy

PURPOSE: The subareolar and periareolar injection techniques result in higher detection rates and do not require tumor localization in impalpable lesions when compared with the peritumoral technique. One of the main criticisms, however, is the widely reported inability to detect internal mammary nodes. This contrasts with our clinical experience using Tc-99m antimony sulfur colloid, in which internal mammary nodes are commonly seen. METHODS: A retrospective analysis of 241 patients over 38 months was performed to investigate the ability of our periareolar injection technique to detect internal mammary lymph node drainage in breast cancer sentinel node lymphoscintigraphy. Four injections of 5 to 10 MBq (0.14-0.27 mCi) Tc-99m antimony sulfur colloid were administered on the day of surgery followed by massage and imaging. The radioisotope was suspended in 0.1 mL with a 0.5-mL air lock. Each injection was performed over 2 seconds with a 25-gauge needle at a depth of 1.1 to 1.3 cm. Patients whose records could not be retrieved or who underwent an injection technique apart from periareolar or peritumoral were removed from the analysis. RESULTS: One hundred thirty-three patients underwent the periareolar technique, 72 patients underwent the peritumoral technique, and 36 patients were excluded from the analysis. Internal mammary drainage was seen in 24 of 133 (18.0%) patients, of which 12 (9%) were seen only in the internal mammary chain. This is much higher than previous studies quoting 0.0% to 4.3% and is similar to previously reported rates using the peritumoral technique. CONCLUSIONS: Our periareolar injection technique using Tc-99m antimony sulfur colloid is able to detect internal mammary lymph nodes in at least 18.0% of patients.     

The use of periareolar intradermal Tc-99m tin colloid and peritumoral intraparenchymal isosulfan blue dye injections for determination of the sentinel lymph node

PURPOSE: The purpose of the present study was to evaluate the use of lymphoscintigraphy, blue dye, and gamma probe detection methods for determination of the sentinel lymph node (SLN) using both periareolar intradermal injection of Tc-99m tin colloid and peritumoral intraparenchymal injection of isosulfan blue dye. METHODS: One hundred patients with T1-2 breast cancer and clinically negative nodes were enrolled in the present study. The study was composed of 2 groups. Backup axillary lymph node dissection (ALND) was mandatory in group 1 (20 patients) regardless of their lymph node status. In group 2 (80 patients), complete ALND was performed when intraoperative frozen section analysis of SLN revealed metastases. Otherwise, only SLN biopsy was performed without ALND. One day before surgery, Tc-99m tin colloid was injected at 4 periareolar sites intradermally. Lymphoscintigraphy was performed 1 to 2 hours after injection of the radiocolloid. Twenty minutes before surgery, isosulfan blue dye was injected into parenchyma surrounding the tumor or the biopsy cavity. RESULTS: The detection rates of SLN and false-negative rate of lymphoscintigraphy, blue dye, and gamma probe detection were 85%, 95% 100%, and 0% in group 1, 91%, 87%, and 95% in group 2, respectively. Detection rate by the combination of blue dye and radio tracer was 98%. CONCLUSIONS: According to the results of our study, we conclude that perioareolar intradermal injection of Tc-99m tin colloid combined with peritumoral intraparenchymal injection of blue dye is an accurate and easy method of locating the sentinel node with very high detection rates. It is recommended that the combination of all methods such as lymphoscintigraphy, blue dye, and gamma probe application will increase the success rate of SLN detection in patients with breast cancer.     

Lymphatic drainage patterns on early versus delayed breast lymphoscintigraphy performed after injection of filtered Tc-99m sulfur colloid in breast cancer patients undergoing sentinel lymph node biopsy

The axillary lymph node status is the most important predictor of prognosis and aids in breast cancer treatment planning. Patients with breast cancer now frequently undergo sentinel lymph node (SLN) biopsy rather than axillary lymph node dissection to determine the status of the regional lymph nodes. However, the optimal timing of radionuclide injection relative to the timing of SLN biopsy remains controversial. The objective of this study was to compare the lymphatic drainage patterns on lymphoscintigraphy performed at 15 minutes to 4 hours and at 18 to 24 hours after injection of filtered Tc-99m sulfur colloid, and to determine whether, over time, radiocolloid migrates to second-echelon nodes that are not the SLNs. Fifteen women with breast cancer (mean age, 55 years; range, 38-78 years) were scheduled to undergo SLN biopsy after each received an injection of 18.5 MBq (0.5 mCi) filtered Tc-99m sulfur colloid into the breast parenchyma surrounding the tumor or biopsy cavity. Both early (15 minutes to 4 hours after radionuclide injection) and delayed (18-24 hours after radionuclide injection) lymphoscintigraphy was performed in each patient. SLN biopsy was performed, followed by completion axillary lymph node dissection and planned breast surgery. In each patient the patterns of distribution of the radionuclide in the lymph nodes were the same on early and delayed lymphoscintigrams. These findings, that the distributions of radionuclide in lymph nodes are identical on early and delayed images obtained after injection of filtered Tc-99m sulfur colloid, suggest that performing SLN biopsy on the day after injection does not diminish the accuracy of the technique in predicting the potential site of metastasis in the regional lymph nodes in patients undergoing this procedure for breast cancer.     

A comparison of two technetium-99m-labeled radiopharmaceuticals for lymphoscintigraphy: concise communication

A comparison of stannous phytate and antimony sulfide colloid, both labeled with Tc-99m, was conducted during the performance of internal mammary lymphoscintigraphy in 46 patients. Thirteen of these patients were randomized to receive both radiotracers in two consecutive studies. The results indicated a statistical difference between agents; Tc-99m antimony sulfide allowed visualization of a greater number of more intense nodes, better delineation of the total length of the internal mammary lymph-node chain, and a more consistent visualization of supraclavicular nodes. Although previously published animal data suggest utility of Tc-99m stannous phytate for lymph-node imaging, Tc-99m antimony sulfide was shown in this clinical comparison to provide a more reliable representation of lymph-node anatomy.     

Timing of sentinel lymphadenectomy in cutaneous melanoma

PURPOSE: The conduct of sentinel lymphadenectomy for cutaneous melanoma varies substantially among the medical disciplines. The authors sought to characterize the number of hot spots identified during preoperative lymphoscintigraphy for cutaneous melanoma and to determine its relation to the harvesting of sentinel lymph nodes. METHODS: Sixty-nine patients with cutaneous melanoma underwent lymphoscintigraphy with filtered Tc-99m sulfur colloid before sentinel lymphadenectomy. The lymphoscintigrams were reviewed and the number of hot spots visualized over time and the number of sentinel nodes harvested were determined. RESULTS: Lymphoscintigraphy identified 79 patients with 87 lymphatic basins at risk for metastatic disease. Lymphoscintigraphy was performed in a mean time of 30 minutes (range, 15 to 40 minutes). The mean number of hot spots increased from 0.2 to 2.0 hot spots 40 minutes after the initial static image, but the number of hot spots stabilized between 20 and 40 minutes. The same number of sentinel nodes as hot spots visualized were harvested in 58% of patients. Fewer sentinel nodes were identified at the time of surgery than were visualized by lymphoscintigrams in 39% of patients. CONCLUSIONS: More hot spots were identified up to 40 minutes after the initiation of lymphoscintigraphy. Sentinel lymphadenectomy can be performed as near to 40 minutes after the initiation of lymphoscintigraphy as is logistically reasonable. However, there may be substantial latitude in delayed performance of sentinel lymphadenectomy.     

Clinically node-negative breast cancer, internal mammary lymph nodes, and sentinel lymph node biopsy

We report 2 cases demonstrating that localization of internal mammary (IM) sentinel lymph nodes with lymphoscintigraphy using peritumoral injection of Tc-99m antimony sulfide colloid, followed by resection using minimal access surgery, can reveal nodal metastatic disease in patients with clinically node-negative breast cancer when axillary sentinel nodes are not affected by metastatic disease. When this is found, it changes staging and can affect prognosis and treatment. These cases confirm that the technique used is sampling true sentinel IM nodes, that is nodes that receive direct lymph flow from the breast cancer, and confirm the importance of sampling IM sentinel lymph nodes. Unless techniques are used that are specifically designed to identify IM node drainage from the breast cancer site itself, with subsequent directed surgical removal of sentinel IM nodes, some patients with breast cancer will not be staged correctly.     

Sentinel node mapping in patients with malignant melanoma using melanoma Tc-99m colloidal rhenium sulfide

PURPOSE: The aim of the study was to localize the sentinel lymph node using lymphoscintigraphy aided by Tc-99m colloidal rhenium sulfide. MATERIALS AND METHODS: Thirty consecutive patients with histologically proved melanoma, but no clinical evidence of metastases, were examined before operation by injecting 20 to 40 MBq (0.5 to 1.1 mCi) Tc-99m colloidal rhenium sulfide with a mean particle size of 100 nm (range, 50 to 200 nm) intradermally around the lesion. Lymphoscintigraphy was performed immediately after injection. In addition, blue dye was injected before operation. A hand-held gamma probe guided the sentinel node biopsy. RESULTS: Lymphoscintigraphy revealed hot spots in all patients. During surgery, the sentinel node was identified in all 30 patients. The number of sentinel nodes per patient ranged from 1 to 4 (mean, 1.9). Histologic examination confirmed the metastatic involvement of the sentinel lymph node in 11 of 30 patients. The sentinel lymph node-positive rate was 22.4%, which was comparable to findings using Tc-99m-labeled nanocolloids. CONCLUSION: The findings indicate that Tc-99m-bound colloidal rhenium sulfide is suitable for sentinel node mapping.     

Lymphoscintigraphy of melanoma: Lymphatic channel activity guides localization of sentinel lymph nodes, and gamma camera imaging/counting confirms presence of radiotracer in excised nodes

Lymphoscintigraphy has become a standard preoperative procedure to map the cutaneous lymphatic channel for progression of nodal metastasis of melanoma of the skin. Lymphoscintigraphy was employed to visualize lymphatic channels as a guide to identify sentinel lymph nodes (SLNs). Excised tissue was imaged with a gamma camera to verify the findings of presurgical lymphoscintigraphy. Percent counts of SLN(s) among the total counts of the excised melanoma tumor or scar tissue and SLN(s) were calculated. METHODS: Eleven patients with cutaneous melanoma received four to ten intradermal injections of Tc-99m sulfur colloid at elual distances around the melanoma site. Images were made immediately after injection: 1 minute per image for 15 min; and then 5 minutes or 1,000,000 counts per image for 30 min. After surgery, the excised melanoma tumor or scar and SLN(s) were imaged/counted with a gamma camera. Percent counts of SLNs among the total counts of the excised melanoma tumor or scar tissue and SLNs were calculated. To validate the specimen count accuracy, an experimental phantom study was done. RESULTS: Linear lymphatic channels were identified between the injected sites and the SLNs in each patient. Gamma camera images demonstrated radioactivity in the SLNs of all patients, verifying the lymphoscintigraphy findings. Uptake in the SLNs of ten of the eleven patients ranged from 0.4 to 7.2% (mean 2.2%) of the total counts in excised tissue. We noted that a node with lower uptake should not be ignored because a lower percent of SLN activity does not necessarily rule out existing metastasis. In two of eleven patients, histopathologic showed metastases. One patient's melanoma on the middle back had lymphatic channel activity directed to both axillae. The results of the phantom study validated accuracy of our specimen counts. CONCLUSIONS: Because linear lymphatic channels existed between lymph nodes and the injected sites in all eleven patients, these lymphatic channels could be used as a guide for localizing SLNs. The SLNs indicated by presurgical lymphoscintigraphy were verified by postoperative gamma camera imaging, and radiotracer localization in the SLNs averaged 2.2%.     

Preoperative evaluation of sentinel lymph node status in melanoma by means of (99m)Tc-MIBI and lymphoscintigraphy: a case report

Previous reports have shown that (99m)Tc-sestamibi (MIBI) could detect clinically occult metastatic melanoma lesions. This article reports on a patient with invasive melanoma of the right heel in whom the sentinel node status was preoperatively evaluated with this tracer. Although regional lymph nodes were clinically negative, (99m)Tc-MIBI scintigraphy showed focal increased tracer uptake in the right groin that corresponded to the location of 2 sentinel nodes visualized by lymphoscintigraphy with (99m)Tc-colloidal rhenium sulfide performed the same day. A gamma-probe was used intraoperatively to guide the excision of the sentinel nodes that were further classified as metastatic by histopathology. This double-technique approach is technically feasible and has the potential of selecting a group of patients who might benefit from a selective complete lymphadenectomy.     

Sentinel nodes of malignancies originating in the alimentary tract

The feasibility of the sentinel node concept for malignancies originating in the alimentary tract is attracting much interest among researchers in the field of gastrointestinal oncology. We have tested more than 350 such cases and obtained favorable and promising initial results. The detectability of sentinel nodes using endoscopically injected Tc-99m tin colloid for these tumors exceeded 90%. Although the false negative ratio was not so low (approximately 10%), most of these cases had an inaccurate preoperative evaluation of mural invasion and/or a technically unfavorable injection. When the indication is restricted to patients with early-stage disease, and when the radioactive colloid is properly administered, sentinel node navigation therapy would be applicable for gastrointestinal malignancies. To achieve successful sentinel node navigation surgery it is essential to accurately identify sentinel nodes, and lymphoscintigraphy is a very useful test to confirm the location of sentinel nodes preoperatively. However, image processing is required for lymphoscintigrams because the original image depicts only high activity at the injection site and faint radioactivity in the sentinel nodes. We have clearly imaged the silhouette of the body using Compton scattered photons, and have also proposed several methods to improve the contrast between the injection sites and sentinel nodes. Many sentinel nodes can be clearly visualized by subtraction of the background activity with heterogeneous distribution. The development of the portable gamma camera, enabling intraoperative imaging, also contributes to less invasive biopsy of sentinel nodes. We have obtained promising initial results using a portable imaging device with semiconductor detectors. These promising results suggest that sentinel node navigation therapy including radiotherapy will be a new therapy for early-stage gastrointestinal malignancies in the near future, with nuclear medicine contributing to the establishment of new, less invasive therapies for gastrointestinal cancer.     

Quantitative lymphoscintigraphy I: Basic concepts for optimal uptake of radiocolloids in the parasternal lymph nodes of rabbits.

The activity-size distribution of radiocolloids has been studied using gel-chromatography scanning (GCS) of columns filled with Sepharose 4B gel. Rabbits were injected subcutaneously with the colloid of interest, laid supine beneath a gamma camera, and imaged every 15 sec for 2 to 4 hr. From the stored data, the uptakes in the parasternal lymph nodes were analyzed in terms of two-compartment model, and the rate constants measured. The substances tested were Au- 198 colloid, Tc-99m antimony sulfide colloid, Tc-99m tin colloid, Tc-99m phytate, and Tc-99m sulfur colloid. It was shown that the optimal particle size for the colloid in the range 1-10 nm. The large and most rapid uptake was found for Au- 198 colloid, with a particle size of 5 nm, which appeared as a single peak in the GCS spectrum. The percentage uptake after 2 hr for Au- 198 colloid 8%, while it was 5% for antimony-sulfide colloid, which was the best of the Tc-99m-labeled colloids. The GCS spectrum for the antimony product showed a single-peaked size distribution with a somewhat broader range: 5-15 nm. The particles of the other colloids were either too large to pass into the lymphatic system, or too small to be trapped.     

Intratumoral versus intraparenchymal injection technique for lymphoscintigraphy in breast cancer

A 1.5-cm nonpalpable mass was detected in the upper outer quadrant of the left breast by screening mammography in a 55-year-old woman. The patient was scheduled for a sentinel node procedure, and lymphoscintigraphy was performed the day before surgery. Unintentionally, she received an intraparenchymal tracer injection 3 cm away from the malignant lesion instead of the intended intratumoral injection. Lymphoscintigraphy revealed two sentinel nodes in the axilla. A second dose of Tc-99m nanocolloid was injected the next day into the primary tumor through a catheter that had been inserted under ultrasound guidance the previous day. Once more, a lymphoscintigraphic image was obtained that showed additional sentinel nodes in two different regions outside the axilla. This observation supports the authors' contention that lymphatic watersheds exist in the breast and highlights the importance of tracer administration into or close to the tumor.     

Radioguided sentinel lymph node biopsy in malignant cutaneous melanoma.

The procedure of sentinel lymph node biopsy in patients with malignant cutaneous melanoma has evolved from the notion that the tumor drains in a logical way through the lymphatic system, from the first to subsequent levels. As a consequence, the first lymph node encountered (the sentinel node) will most likely be the first affected by metastasis; therefore, a negative sentinel node makes it highly unlikely that other nodes in the same lymphatic basin are affected. Although the long-term therapeutic benefit of the sentinel lymph node biopsy per se has not yet been ascertained, this procedure distinguishes patients without nodal metastases, who can avoid nodal basin dissection with its associated risk of lymphedema, from those with metastatic involvement, who may benefit from additional therapy. Sentinel lymph node biopsy would represent a significant advantage as a minimally invasive procedure, considering that an average of only 20% of melanoma patients with a Breslow thickness between 1.5 and 4 mm harbor metastasis in their sentinel node and are therefore candidates for elective lymph node dissection. Furthermore, histologic sampling errors (amounting to approximately 12% of lymph nodes in the conventional routine) can be reduced if one assesses a single (sentinel) node extensively rather than assessing the standard few histologic sections in a high number of lymph nodes per patient. The cells from which cutaneous melanomas originate are located between the dermis and the epidermis, a zone that drains to the inner lymphatic network in the reticular dermis and, in turn, to larger collecting lymphatics in the subcutis. Therefore, the optimal route for interstitial administration of radiocolloids for lymphoscintigraphy and subsequent radioguided sentinel lymph node biopsy is intradermal or subdermal injection. (99m)Tc-Labeled colloids in various size ranges are equally adequate for radioguided sentinel lymph node biopsy in patients with cutaneous melanoma, depending on local experience and availability. For melanomas along the midline of the head, neck, and trunk, particular consideration should be given to ambiguous lymphatic drainage, which frequently requires interstitial administration virtually all around the tumor or surgical scar from prior excision of the melanoma. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy because images are used to direct the surgeon to the sites of the nodes. The sentinel lymph node should have a significantly higher count than that of the background (at least 10:1 intraoperatively). After removal of the sentinel node, the surgical bed must be reexamined to ensure that all radioactive sites are identified and removed for analysis. Virtually the entire sentinel lymph node should be processed for histopathology, including both conventional hematoxylin-eosin staining and immune staining with antibodies to the S-100 and HMB-45 antigens. The success rate of radioguidance in localizing the sentinel lymph node in melanoma patients is approximately 98% in institutions that perform a high number of procedures and approaches 99% when combined with the vital blue-dye technique. Growing evidence of the high correlation between a sentinel lymph node biopsy negative for cancer and a negative status for the lymphatic basin-evidence, therefore, of the high prognostic value of sentinel node biopsy-has led to the procedure's being included in the most recent version of the TNM staging system and starting to become the standard of care for patients with cutaneous melanoma.     

Pearls and pitfalls of radionuclide imaging of the lymphatic system. Part 1: sentinel node lymphoscintigraphy in malignant melanoma

Radionuclide imaging of the lymphatic system has a major role in the management of two main patient groups. First, pre-operative lymphoscintigraphy is a highly accurate method of sentinel node localization and can help guide minimally invasive surgery in a variety of tumour groups. Second, lymphoscintigraphy can play a pivotal role in assessing the cause of extremity swelling. This is the first of two pictorial essays on radionuclide imaging of the lymphatic system and will focus on sentinel node imaging in malignant melanoma. Regional nodal sampling is routinely performed in an increasing number of tumour groups and is well established in malignant melanoma and breast carcinoma. Careful attention to technical performance and image interpretation is essential to maximize the clinical utility of the test. This article provides a pictorial review of the interpretative pearls and pitfalls of sentinel node lymphoscintigraphy in malignant melanoma patients.