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10.1245/ASO.2006.04.025
Annals of Surgical Oncology 13:386-396 (2006)
© 2006 Society of Surgical Oncology
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Original Article

Sentinel Lymph Node Mapping of the Gastrointestinal Tract by Using Invisible Light

Edward G. Soltesz, MD, MPH1, Sungjee Kim, PhD2, Sang-Wook Kim, PhD2, Rita G. Laurence, BS1, Alec M. De Grand, BS3, Cherie P. Parungo, MD1, Lawrence H. Cohn, MD1, Moungi G. Bawendi, PhD4 and John V. Frangioni, MD, PhD3,4

1 Department of Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, Massachusetts 02115
2 Department of Chemistry, Massachusetts Institute of Technology, Building 6-221,77 Massachusetts Avenue, Cambridge, Massachusetts 02139
3 Department of Medicine, Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Room SL-B05, Boston, Massachusetts 02215
4 Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Room SL-B05, Boston, Massachusetts 02215

Correspondence: Address correspondence and reprint requests to: John V. Frangioni, MD, PhD; E-mail: jfrangio{at}bidmc.harvard.edu.


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Background: Because many gastrointestinal (GI) tumors spread by way of lymphatics, histological assessment of the first draining lymph nodes has both prognostic and therapeutic significance. However, sentinel lymph node mapping of the GI tract by using available techniques is limited by unpredictable drainage patterns, high background signal, and the inability to image lymphatic tracers relative to surgical anatomy in real time. Our goal was to develop a method for patient-specific intraoperative sentinel lymph node mapping of the GI tract by using invisible near-infrared light.

Methods: We developed an intraoperative near-infrared fluorescence imaging system that simultaneously displays surgical anatomy and otherwise invisible near-infrared fluorescence images of the surgical field. Near-infrared fluorescent quantum dots were injected intraparenchymally into the stomach, small bowel, and colon, and draining lymphatic channels and sentinel lymph nodes were visualized. Dissection was performed under real-time image guidance.

Results: In 10 adult pigs, we demonstrated that 200 pmol of quantum dots quickly and accurately map lymphatic drainage and sentinel lymph nodes. Injection into the mid jejunum and colon results in fluorescence of a single lymph node at the root of the bowel mesentery. Injection into the stomach resulted in identification of a retrogastric node. Histological analysis in all cases confirmed the presence of nodal tissue.

Conclusions: We report the use of invisible near-infrared light for intraoperative sentinel lymph node mapping of the GI tract. This technology overcomes the limitations of currently available methods, permits patient-specific imaging of lymphatic flow and sentinel nodes, and provides highly sensitive, real-time image-guided dissection.

Key Words: Sentinel lymph node mapping • GI tumors • Near-infrared light • Quantum dots


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Metastatic disease in gastrointestinal (GI) cancers directly correlates with patient survival.1 Because many GI tumors spread by way of lymphatics, assessment of the regional lymph nodes near a primary malignancy for the presence of malignant cells permits more accurate staging and therapeutic planning.

The introduction of sentinel lymph node (SLN) mapping and biopsy by Morton et al.2 in the early 1990s revolutionized the assessment of nodal status for the spread of neoplasms, particularly for melanoma and breast cancer. The underlying hypothesis of SLN mapping is that the first lymph node to receive lymphatic drainage from a tumor site will contain tumor cells if there has been direct lymphatic spread.3 Current techniques of SLN mapping in breast cancer and melanoma involve preoperative injection of a radioactive colloid tracer (e.g., 99mTc sulfur colloid) followed by intraoperative injection of a visible blue dye (e.g., isosulfan blue). The dye allows limited visualization of afferent lymphatic vessels and the SLN, and the radioactive colloid tracer improves detection rate and confirms complete collection of the SLN with the use of an intraoperative handheld gamma probe.4

Some recent studies (discussed in detail below) of SLN mapping have also suggested its feasibility in many GI cancers.5–7 The SLN has been shown to accurately reflect the tumor status of regional GI nodes with 95% accuracy.5 However, methods developed for SLN mapping of other organs are not readily amenable to use with GI tumors. The ideal method should be sensitive, accurate, rapid, noninvasive, nonradioactive, and potentially usable in a laparoscopic setting. None of the current methods fulfills all of these criteria. Lymphatic mapping with blue dye results in a high rate of false-positive nodes because the small dye particles can readily diffuse through the true SLN and traverse multiple nodes.8 Additionally, blue dye has poor tissue contrast and is difficult to detect in deep, dark anatomical regions such as the abdomen. Although the use of radioisotope tracers has improved the detection rate and accuracy of GI SLN mapping, the high radioactivity of the primary injection site can interfere with intraoperative in vivo detection of nearby nodes. Additionally, if radioisotopes are injected during surgery, the time period required for the tracer to migrate to the SLN may delay the operative procedure. Conversely, preoperative injection of the radiocolloid tracer often necessitates endoscopy anywhere from 2 to 16 hours before surgery.9 This is difficult, if not impossible, to accomplish and is applicable only in endoscopically accessible regions of the colon and stomach. Finally, laparoscopic GI lymphatic mapping using radiolabeled colloid is technically limited by relatively inflexible laparoscopic gamma probes.10

We recently developed a near-infrared (NIR) fluorescence imaging system that permits real-time intraoperative SLN mapping by using optimized quantum dots (QDs).11,12 QDs are bright fluorescent semiconductor nanocrystals that contain an inorganic core and shell of metal and an outer solubilizing organic coating. These fluorescent biological labels are excellent probes for SLN mapping because they are highly fluorescent, nonradioactive, and visible deep within tissue.13 NIR light, otherwise invisible to the human eye, provides extremely high signal-to-background ratios without changing the look of the surgical field.

In this study, we investigated the feasibility of using NIR fluorescent QDs for intraoperative mapping of the lymphatic drainage of various GI organs, and for guiding excision of the primary draining node, in a patient-specific manner.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
NIR Fluorescent Lymphatic Tracer and Imaging System
The complete synthesis of QDs used in this study has been previously described.12 Briefly, type II NIR fluorescent semiconductor nanocrystals (QDs) were engineered with a hydrodynamic diameter of 15 to 20 nm, a maximal absorption cross section, an 840- to 860-nm fluorescence emission, an aqueous quantum yield of ≥13%, and a stable oligomeric phosphine coating. The large-animal intraoperative NIR fluorescence imaging system used in this study has also been described previously in detail.11

Surgical Preparation
Adult Yorkshire pigs (n = 10; mean weight, 35 kg) of either sex were obtained from EM Parsons (Hadley, MA) and used in compliance with approved institutional protocols. General anesthesia was induced with 5 mg of intramuscular tamsulosin and 5% isoflurane/6 L of oxygen. Animals were intubated with a size 7 endotracheal tube, and anesthesia was maintained with 1.5% to 2% isoflurane. Maintenance intravenous fluid was infused, a vertical midline laparotomy was created, and the peritoneal cavity was entered for lymphatic mapping.

Lymphatic Mapping and SLN Identification
GI lymphatic mapping was performed by injecting 100 µL of either 2 µM of NIR QDs in phosphate-buffered saline (pH 7.4) or 1% (17.6 mM) isosulfan blue (Lymphazurin; BenVenue Laboratories Inc., Bedford, OH) subserosally by using a 27-gauge tuberculin syringe. Gastric injections (n = 3) were made into the body, approximately 5 cm from the lesser curvature, and colonic (n = 6) and jejunal (n = 6) injections were made near the mesenteric border. Completely reproducible subserosal injections were made by one surgeon after refinement of the technique. Lymphatic flow was visualized in real time by using the NIR imaging system. The first lymph node encountered on the path delineated by the tracer(s) was defined as the SLN. The time from injection to first appearance in the SLN was recorded.

NIR Fluorescence-Guided Nodal Dissection
After identification of lymphatic channels and the SLN, real-time imaging was used to guide dissection. Adjacent nodes that did not exhibit fluorescence were also excised as negative controls. Postresection NIR fluorescence imaging of the surgical field was performed to confirm that all nodal tissue had been excised. In a subset of injections, the identified SLN was not immediately dissected but was allowed to remain in situ for 4 hours to determine whether QDs migrated beyond the SLN.

Histological Analysis
Nodal tissue was cryosectioned at 6 µm onto Superfrost Plus slides (Fisher Scientific, Hanover Park, IL), and consecutive sections were stained with hematoxylin and eosin or photographed on an NIR fluorescence microscope.14


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Real-Time NIR Fluorescence Imaging System
The NIR imaging system was able to unobtrusively provide real-time images to the surgeon during the entire procedure. Despite the shifting of abdominal contents and continued peristalsis, real-time images of lymphatic flow and the SLN were easily visualized. While operating, the surgeon can view color video, NIR fluorescent, and pseudocolored merged images of the operative field in real time. This last image is particularly useful to the surgeon because it permits visualization of lymphatic flow against a background of normal anatomy. By using a nonanatomical color such as lime green (i.e., a pseudocolor) for this overlay, lymphatic flow and the SLN can be clearly delineated. The imaging system’s variable field of view allows zooming capability for more precise dissection if needed. Finally, the invisible nature of the light does not disturb the operative field. The entire system resides on a portable cart with the camera and light apparatus suspended on an adjustable boom. The system is easily moved to various operating areas by one person.

Jejunal and Colonic Lymphatic Mapping
Tissue autofluorescence of the jejunum (Fig. 1AGo) and colon (Fig. 2AGo) was minimal. After subserosal injection of 200 pmol of QDs near the mesenteric border, lymphatic channels extending into the mesentery were immediately visible. Within 1 minute, a single lymph node deep within the mesentery was fluorescent (Figs. 1AGo and 2AGo). In all animals, the lymphatic channels between the injection site and the SLN were clearly visible. Peritoneal fluid, which was allowed to collect over the fluorescent SLN, did not affect visualization. There was no visible leak of QDs from lymphatic vessels or nodal tissue; minimal leakage of QDs at the injection site did not affect visualization of the lymphatic vessels or SLN. In all cases, fluorescent lymphatic channels terminated in one mesenteric SLN. Image guidance permitted all target SLNs to be easily removed with a high degree of precision. Adjacent nodal tissue was also resected and demonstrated no fluorescence (Fig. 1AGo). Postresection imaging of the surgical site confirmed no residual fluorescent nodal tissue (Fig. 2BGo). No noticeable inflammatory changes or edema was seen grossly or histologically in the injection site, mesentery, or nodal tissue. Both gross examination and fluorescence microscopy demonstrated that the QDs localize to the subcapsular and intermediate sinuses of the SLNs (Fig. 1B and CGo).


Figure 1
Figure 1
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  		FIG. 1. Near-infrared (NIR) fluorescent sentinel lymph node (SLN) mapping of the porcine jejunum. (A) A total of 200 pmol of NIR quantum dots (QDs) were injected into a midjejunal segment of the pig. From top to bottom are shown NIR fluorescence images of the surgical field before injection, during injection, 1 minute after injection, during image-guided SLN resection, and during postresection evaluation of the sentinel (S) and negative control (N) nodal groups. At each time point are shown color video (left), NIR fluorescence (middle), and pseudocolored merged images (right). The lymphatic channels between the injection site (arrowheads) and SLN (arrows) are clearly visible. Postresection evaluation of sentinel (S) and the immediately adjacent negative control (N) nodal groups demonstrates fluorescence in a portion of a single node. All NIR fluorescence images have identical exposure time and normalization. (B) The sentinel nodal group in A was further dissected of nonfluorescent tissue and then bisected to reveal QD retention in the subcapsular and intermediate sinuses of the SLN. (C) Frozen-section histological analysis of the SLN shown in B. Shown are 2 representative hematoxylin and eosin-stained sections and consecutive unstained sections photographed on a NIR fluorescence microscope at x10 and x40. Note the absence of trauma or edema in this nodal tissue. H + E, hematoxylin and eosin.

 

Figure 2
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  		FIG. 2. Near-infrared (NIR) fluorescent sentinel lymph node (SLN) mapping of the porcine colon. (A) A total of 200 pmol of NIR quantum dots (QDs) were injected into a segment of porcine colon. From top to bottom are shown NIR fluorescence images of the surgical field before injection, during injection, 5 seconds after injection, and 1 minute after injection. At each time point are shown color video (left), NIR fluorescence (middle), and pseudocolored merged images (right). The lymphatic channel between the injection site (arrowheads) and SLN (arrows) is clearly visible. (B) NIR fluorescent imaging of the surgical field after excision of the SLN in A reveals no QD fluorescence in the area of the excised SLN, thus indicating complete removal of that nodal tissue. Note the persistence of fluorescence at the injection site (arrowheads) and along the lymphatic channels leading to the excised SLN.

 
Gastric Lymphatic Mapping
Like the jejunum and colon, tissue autofluorescence of the stomach was minimal (Fig. 3AGo). After injection of 200 pmol of QDs subserosally into the cardia along the lesser curvature of the stomach, lymphatic channels could be seen extending posteriorly (Fig. 3AGo). Within 1 minute, a single fluorescent retrogastric lymph node could be identified (Fig. 3AGo). There was no visible leak of QDs from lymphatic vessels or nodal tissue. Histological analysis of the single retrogastric SLN confirmed nodal tissue with no associated inflammatory changes, whereas adjacent nodal tissue demonstrated no fluorescence (Fig. 3BGo).


Figure 3
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  		FIG. 3. Near-infrared (NIR) fluorescent sentinel lymph node (SLN) mapping of the porcine stomach. (A) A total of 200 pmol of NIR quantum dots (QDs) were injected into the anterior surface of the lesser curvature of the stomach in a pig. From top to bottom are shown NIR fluorescence images of the surgical field before injection, during injection, 30 seconds after injection, and 1 minute after injection. At each time point are shown color video (left), NIR fluorescence (middle), and pseudocolored merged images (right). Fluorescent lymphatic pathways are visible emanating from the injection site (arrowheads), extending around the lesser curvature of the stomach, and terminating in a single retrogastric lymph node (arrows). Note that the SLN (arrows) is visible only after the stomach is rotated superiorly on the axis of the lesser curvature. The injection site on the anterior surface of the stomach is no longer visible from this perspective. (B) Postresection evaluation of the SLN (S) and 2 immediately adjacent negative control nodes (N) demonstrates fluorescence in a single node (arrow).

 
Isosulfan Blue Colocalization
Because isosulfan blue is considered the gold-standard visible lymphatic tracer, coinjection of QDs and isosulfan blue was performed in the stomach, colon, and jejunum to document migration to the same SLN as the QDs. After subserosal injection of 200 pmol of QDs and identification of the afferent lymphatic channels and SLN, an equal volume of 1% isosulfan blue (100 µL) was injected into the same site. In all injections, QDs identified the SLN within 1 minute, whereas isosulfan blue could be visualized in the same node within 2 to 5 minutes of injection (Fig. 4Go). Injection sites for each organ were similar to those described previously. Some quenching of the QD fluorescence by isosulfan blue was expected and observed. In all cases, isosulfan blue identified the same SLN as did the fluorescent QDs. In contrast to QDs, isosulfan blue was poorly visualized through the mesentery, and dye extravasation reduced clarity (Fig. 4AGo). Once isosulfan was visualized in a mesenteric or retrogastric node, the node was immediately resected and sectioned. No adjacent nodes were blue or fluorescent.


Figure 4
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  		FIG. 4. Near-infrared (NIR) fluorescent sentinel lymph node (SLN) mapping of the porcine jejunum with isosulfan blue colocalization. (A) A total of 200 pmol of NIR quantum dots (QDs) were injected (arrowheads) into a midjejunal segment of the pig. From top to bottom are shown NIR fluorescence images of the surgical field during QD injection, during isosulfan blue injection 1 minute after the QD injection, at 5 minutes after isosulfan injection (arrowheads), and after deep mesenteric dissection. At each time point are shown color video (left), NIR fluorescence (middle), and pseudocolored merged images (right). QDs rapidly localize to the SLN (arrow). Coinjection of isosulfan blue quenches the QD fluorescence, as evidenced by the loss of QD fluorescence at 5 minutes after isosulfan injection (see arrowheads at 5 minutes). Blue nodal tissue becomes visible only after deep dissection of the jejunal mesentery. (B) Bisected SLN from A shows localization of isosulfan blue dye to the same node (arrows) as the QDs.

 
Nodal Migration
After standard QD injection into small bowel and colon in three separate animals, as described previously, a single mesenteric SLN was fluorescent within 60 seconds. There was no observed migration of QDs beyond the identified SLN at 4 hours after initial injection (data not shown). Furthermore, QDs remained localized to the subcapsular and intermediate sinuses of the SLNs and did not travel further. Thus, our rapid resection of the first fluorescent lymph node in the previous studies did not prevent assessment of further positive nodes.


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
We demonstrated the use of NIR fluorescent QDs for SLN mapping of the GI tract in a large-animal model approaching the size of humans. This technique permits precise, rapid, real-time, intraoperative SLN imaging and therefore overcomes many of the limitations of current lymphatic mapping techniques. Injection of just 200 pmol of NIR fluorescent QDs into various intra-abdominal organs identified, in <1 minute, the afferent lymphatics and the SLN in 100% of cases. Additionally, this technique permitted visualization of the lymphatic channels between the injection site and the first lymph node: an essential relationship that defines the SLN. Image-guided dissection was easily and accurately accomplished given the brilliant fluorescence of the QDs. It is important to note that the current gold-standard mapping agent, isosulfan blue, colocalized to the nodes identified by QDs. These findings suggest that NIR fluorescent QDs are optimal lymphotropic optical probes and can be used to provide highly sensitive and specific real-time intraoperative SLN mapping in the GI tract where current mapping techniques are inadequate or technically limited.

SLN mapping has gained acceptance as a technique to assess the tumor status of the lymph nodes in breast cancer and melanoma. A decade of experience, together with large, multicenter clinical trials, has convincingly validated the SLN hypothesis, and the prediction of nodal status in these cancers now exceeds 95% in recent studies.15,16 Although numerous groups have demonstrated the feasibility of SLN mapping in GI cancers,5–7 reports have differed in their rate of prediction of nodal status by SLN mapping. In contrast to previous multi-institutional studies, Bertagnolli et al.17 found that the SLN procedure is not as accurate for colon cancer as it is for breast cancer or malignant melanoma. Significant limitations of that study, including low patient number, lack of standardization of injection technique, and technical complexity, highlight the inadequacies of the current SLN mapping technology. NIR light-guided SLN mapping provides unequivocal, real-time identification of the SLN, thus eliminating technical errors that lead to false-negative results.

GI SLN mapping also remains controversial because the results often do not affect the extent of the resection. The aberrant drainage patterns of the GI lymphatics have been cited as an obstacle to intra-abdominal SLN mapping.18,19 The complexity of the GI lymphatics, as evidenced by the high incidence of skip metastases, necessitates intraoperative patient-specific SLN mapping. Indeed, the results of such mapping may alter the planned boundaries of a radical lymphadenectomy if aberrant drainage is found. Additionally, because several reports have confirmed that current staging methods for GI tumors often underestimate micrometastases in regional lymph nodes, SLN mapping can direct the pathologist to critical regional lymph nodes for histopathologic analysis.20–22 By allowing the pathologist to focus on one node, or even one area of one node, for analysis, SLN biopsy can potentially un-cover more micrometastatic disease, although the prognostic value of micrometastases in GI cancer remains the subject of much debate. Finally, if randomized trials someday demonstrate equivalency of limited versus radical lymphadenectomy in situations of negative SLN analysis, NIR fluorescent SLN mapping may obviate the need for aggressive, non-therapeutic lymphadenectomies in node-negative patients. This, in turn, might permit more resections to be performed laparoscopically. Thus, NIR fluorescent light-guided SLN mapping in GI cancers could potentially affect the clinical course by providing unequivocal identification of the SLN and by decreasing the morbidity associated with nontherapeutic radical lymph node resections.

For patients to benefit fully from the technology we describe in this study, sensitive analysis of the SLN at the time of operation will be required. Two recent advances suggest that this will soon be available. First, Ferris et al.23 have developed a fully automated quantitative reverse transcription-polymerase chain reaction instrument that provides SLN analysis in <30 minutes with 100% accuracy. Second, Bigio et al.24 have developed a fiberoptic, light-based method for analyzing resected SLNs that takes only seconds; in clinical studies, it provided a sensitivity of 75% and a specificity of 89%.25 As these technologies, and others, evolve, one can start to envision a seamless, real-time process for intraoperative SLN mapping, SLN resection, and SLN analysis.

Despite the worldwide validation of the SLN hypothesis and its growing use in many forms of cancer, the current technique has significant limitations, especially when used intra-abdominally. Blue dye cannot always adequately identify the SLN in abdominal malignancies as a result of poor tissue contrast and visualization in deep anatomical spaces. For this reason, some groups have used a radioisotope lymphatic mapping agent. Because of their slower transit time, however, most radiocolloids require preoperative endoscopic injection, thus severely limiting their clinical use. In contrast to lymphatic mapping with the blue dye method, in which success is defined as the identification of a blue lymphatic channel leading to a node, radiocolloid lymphatic mapping has no standard definition of success. Criteria defining a positive SLN have been largely arbitrary and empiric, usually based on ratios of background to SLN radioactivity. Detection of a true SLN with the radioisotope method can also be confounded by varying amounts of shine-through radioactivity from the primary injection site, essentially causing increased background radioactivity and decreasing ratio results. Overall, the learning curve for the current method of SLN mapping is anywhere between 30 and 60 cases.26 The technology we describe in this study virtually eliminates the learning curve because the entire procedure can now be performed under direct visual guidance and because the results are immediately visible.

Tracer particle size has an important effect on migration time in SLN mapping. Particles <5 nm partition into blood, those between 5 to 10 nm can migrate through nodal tissue and result in false-positive results, and those >1000 nm largely remain at the injection site.8 Blue dye contains particles <5 nm and thus can pass through the SLN and traverse multiple nodes in addition to becoming intravascular. Thus, SLN mapping with the blue dye method can lead to false-positive results. Various preparations of 99mTc have also been used in GI SLN mapping. Kitagawa et al.27 preoperatively injected 99mTc tin colloid into patients with gastric cancer and used a handheld gamma probe to identify highly radioactive nodes. At operation, the radioisotope was endoscopically injected either 2 or 16 hours before surgery. Radioactivity ratio analysis identified an average of 3.6 SLNs (range, 1–8) in 95% of patients. The need for endoscopically guided tracer injection before surgery, however, severely limits the utility of this agent. Finally, the ability to perform laparoscopic SLN mapping is limited by the relative inflexibility of present laparoscopic gamma probes.

GI SLN mapping using NIR QDs overcomes these limitations. Because QDs can be engineered to precise sizes, the potential for detecting multiple SLNs is less because the QDs will be retained in the first nodal tissue. Additionally, these optical biological probes are bright and can be seen at tissue depths of 1 cm, thus allowing visualization of a mesenteric SLN beneath often thick, adipose-rich mesentery. The intraoperative use of NIR QDs to visually map lymphatic flow and identify SLNs obviates the need for preoperative radiocolloid injections and the use of blue dye. Instead, surgeons can track lymphatic flow in real time and guide their nodal dissection with the aid of online video feed-back after one simple intraoperative injection. Preoperative endoscopic injection of QDs can also be used, both to intraoperatively localize tumor and to map the SLN. Unlike other tracers, QDs rapidly localize to and remain trapped in the SLN. During surgery, NIR fluorescence from the injection site does not interfere with visualization of the SLN on the video monitor, and the actual surgical field remains unchanged because NIR QDs are invisible to the human eye. Finally, the entire NIR-imaging system is portable and can be adapted to a laparoscopic platform.

A limitation to the clinical use of NIR QDs for SLN mapping is their potential toxicity. These biological probes presently contain heavy metals at their cores and an amphiphilic organic coating. Alone, cadmium, telluride, selenide, and alkyl phosphines have known acute and chronic toxicity, but their toxicities as precomplexed nanocrystals are unknown. In our nonsurvival animal studies, we found no evidence for acute toxicity; heart rate and rhythm, blood pressure, and oxygen saturation remained stable through prolonged operative procedures. As we reported elsewhere, extra polating known dose-effect relationships for inhalation and oral exposures of these heavy metals indicates that our dose of 200 pmol of NIR QDs corresponds to a dose 50 times lower than that defined as causing respiratory symptoms and 300 times lower than that required to produce renal insufficiency.12 Because most of the injected dose is removed by resecting the injection site and nodal tissue, toxicity may be negligible.

In summary, we report highly sensitive, real-time intraoperative SLN mapping of the GI tract by using invisible NIR light and fluorescent QDs. This novel technology overcomes many of the formidable limitations of current techniques and lays the foundation for future studies.


   ACKNOWLEDGMENTS
 
This work was supported in part by National Institutes of Health (NIH) National Research Service Award F32-HL-071464-02 (E.G.S), the National Science Foundation-Materials Research Science and Engineering Center Program under grant DMR-9808941 (M.G.B.), the Office of Naval Research (M.G.B.), the Department of Energy (Office of Biological and Environmental Research) grant DEFG02-01ER63188 (J.V.F.), an Application Development Award (J.V.F.) from the Center for Integration of Medicine and Innovative Technology, and NIH grant R33-EB-000673 (J.V.F. and M.G.B.).

Received for publication May 13, 2005. Accepted for publication August 26, 2005.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Daneker GW Jr, Ellis LM. Colon cancer nodal metastasis: biologic significance and therapeutic considerations. Surg Oncol Clin North Am 1996; 5:173–89.[Medline]
  2. Morton DL, Wen DR, Wong JH, et al. Technical details of intraoperative lymphatic mapping for early stage melanoma. Arch Surg 1992; 127:392–9.[Abstract]
  3. Cabanas RM.. An approach for the treatment of penile carcinoma. Cancer 1977; 39:456–66.[CrossRef][Medline]
  4. Cox CE, Pendas S, Cox JM, et al. Guidelines for sentinel node biopsy and lymphatic mapping of patients with breast cancer. Ann Surg 1998; 227:645–51; discussion 651–3.[CrossRef][Medline]
  5. Saha S, Bilchik A, Wiese D, et al. Ultrastaging of colorectal cancer by sentinel lymph node mapping technique—a multicenter trial. Ann Surg Oncol 2001; 8(9 Suppl):94S–98S.[Medline]
  6. Wood TF, Nora DT, Morton DL, et al. One hundred consecutive cases of sentinel lymph node mapping in early colorectal carcinoma: detection of missed micrometastases. J Gastrointest Surg 2002; 6:322–9; discussion 229–30.[CrossRef][Medline]
  7. Bilchik AJ, Giuliano A, Essner R, et al. Universal application of intraoperative lymphatic mapping and sentinel lymphadenectomy in solid neoplasms. Cancer J Sci Am 1998; 4:351–8.[Medline]
  8. Alazraki NP, Eshima D, Eshima LA, et al. Lymphoscintigraphy, the sentinel node concept, and the intraoperative gamma probe in melanoma, breast cancer, and other potential cancers. Semin Nucl Med 1997; 27:55–67.[CrossRef][Medline]
  9. Kitagawa Y, Ohgami M, Fujii H, et al. Laparoscopic detection of sentinel lymph nodes in gastrointestinal cancer: a novel and minimally invasive approach. Ann Surg Oncol 2001; 8(9 Suppl):86S–89S.[Medline]
  10. Kitagawa Y, Ohgami M, Fujii H, et al. Laparoscopic detection of sentinel lymph nodes in gastrointestinal cancer: a novel and minimally invasive approach. Ann Surg Oncol 2001; 8:86S–89S.[Medline]
  11. De Grand AM, Frangioni JV. An operational near-infrared fluorescence imaging system prototype for large animal surgery. Technol Cancer Res Treat 2003; 2:553–62.[Medline]
  12. Kim S, Lim YT, Soltesz EG, et al. Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping. Nat Biotechnol 2004; 22:93–7.[CrossRef][Medline]
  13. Lim YT, Kim S, Nakayama A, et al. Selection of quantum dot wavelengths for biomedical assays and imaging. Mol Imaging 2003; 2:50–64.[CrossRef][Medline]
  14. Zaheer A, Lenkinski RE, Mahmood A, et al. In vivo near-infrared fluorescence imaging of osteoblastic activity. Nat Biotechnol 2001; 19:1148–54.[CrossRef][Medline]
  15. Giuliano AE, Dale PS, Turner RR, et al. Improved axillary staging of breast cancer with sentinel lymphadenectomy. Ann Surg 1995; 222:394–9discussion 399–401.[Medline]
  16. Morton DL, Thompson JF, Essner R, et al. Validation of the accuracy of intraoperative lymphatic mapping and sentinel lymphadenectomy for early-stage melanoma: a multicenter trial. Multicenter Selective Lymphadenectomy Trial Group. Ann Surg 1999; 230:453–63; discussion 463–5.[CrossRef][Medline]
  17. Bertagnolli M, Miedema B, Redston M, et al. Sentinel node staging of resectable colon cancer: results of a multicenter study. Ann Surg 2004; 240:624–8; discussion 628–30.[Medline]
  18. Maruyama K, Sasako M, Kinoshita T, et al. Can sentinel node biopsy indicate rational extent of lymphadenectomy in gastric cancer surgery? Fundamental and new information on lymphnode dissection. Langenbecks Arch Surg 1999; 384:149–57.[CrossRef][Medline]
  19. Siewert JR, Sendler A. Potential and futility of sentinel node detection for gastric cancer. Recent Results Cancer Res 2000; 157:259–69.[Medline]
  20. Mori M, Mimori K, Inoue H, et al. Detection of cancer micrometastases in lymph nodes by reverse transcriptase-polymerase chain reaction. Cancer Res 1995; 55:3417–20.[Abstract/Free Full Text]
  21. Wood TF, Nora DT, Morton DL, et al. One hundred consecutive cases of sentinel lymph node mapping in early colorectal carcinoma: detection of missed micrometastases. J Gastrointest Surg 2002; 6:322–9; discussion 229–30.[CrossRef][Medline]
  22. Adell G, Boeryd B, Franlund B, et al. Occurrence and prognostic importance of micrometastases in regional lymph nodes in Dukes’ B colorectal carcinoma: an immunohistochemical study. Eur J Surg 1996; 162:637–42.[Medline]
  23. Ferris RL, Xi L, Raja S, et al. Molecular staging of cervical lymph nodes in squamous cell carcinoma of the head and neck. Cancer Res 2005; 65:2147–56.[Abstract/Free Full Text]
  24. Bigio IJ, Bown SG, Briggs G, et al. Diagnosis of breast cancer using elastic-scattering spectroscopy: preliminary clinical results. J Biomed Opt 2000; 5:221–8.[CrossRef][Medline]
  25. Johnson KS, Chicken DW, Pickard DC, et al. Elastic scattering spectroscopy for intraoperative determination of sentinel lymph node status in the breast. J Biomed Opt 2004; 9:1122–8.[CrossRef][Medline]
  26. Sanidas EE, Bree E, Tsiftsis DD. How many cases are enough for accreditation in sentinel lymph node biopsy in breast cancer? Am J Surg 2003; 185:202–10.[CrossRef][Medline]
  27. Kitagawa Y, Fujii H, Mukai M, et al. Radio-guided sentinel node detection for gastric cancer. Br J Surg 2002; 89:604–8.[CrossRef][Medline]



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