Computer planned, image-guided combined resection and ablation for bilobar colorectal liver metastases

For patients with extensive bilobar colorectal liver metastases (CRLM), initial surgery may not be feasible and a multimodal approach including microwave ablation (MWA) provides the only chance for prolonged survival. Intraoperative navigation systems may improve the accuracy of ablation and surgical resection of so-called “vanishing lesions”, ultimately improving patient outcome. Clinical application of intraoperative navigated liver surgery is illustrated in a patient undergoing combined resection/MWA for multiple, synchronous, bilobar CRLM. Regular follow-up with computed tomography (CT) allowed for temporal development of the ablation zones. Of the ten lesions detected in a preoperative CT scan, the largest lesion was resected and the others were ablated using an intraoperative navigation system. Twelve months post-surgery a new lesion (Seg IVa) was detected and treated by trans-arterial embolization. Nineteen months post-surgery new liver and lung metastases were detected and a palliative chemotherapy started. The patient passed away four years after initial diagnosis. For patients with extensive CRLM not treatable by standard surgery, navigated MWA/resection may provide excellent tumor control, improving longer-term survival. Intraoperative navigation systems provide precise, real-time information to the surgeon, aiding the decision-making process and substantially improving the accuracy of both ablation and resection. Regular follow-ups including 3D modeling allow for early discrimination between ablation zones and recurrent tumor lesions.

Spinal cord biological safety of image-guided radiation therapy versus conventional radiation therapy

Tumor models were simulated in purebred Beagles at the T9-10 levels of the spinal cord and treated with spinal image-guided radiation therapy or conventional radiation therapy with 50 or 70 Gy total radiation. Three months after radiation, neuronal injury at the T9-10 levels was observed, including reversible injury induced by spinal image-guided radiation therapy and apoptosis induced by conventional radiation therapy. The number of apoptotic cells and expression of the proapoptotic protein Fas were significantly reduced, but expression of the anti-apoptotic protein heat shock protein 70 was significantly increased after image-guided radiation therapy compared with the conventional method of the same radiation dose. Moreover, the spinal cord cell apoptotic index positively correlated with the ratio of Fas/heat shock protein 70. These findings indicate that 3 months of radiation therapy can induce a late response in the spinal cord to radiation therapy; image-guided radiation therapy is safer and results in less neuronal injury compared with conventional radiation therapy.

Portal hypertension: Imaging of portosystemic collateral pathways and associated image-guided therapy

Portal hypertension is a common clinical syndrome, defined by a pathologic increase in the portal venous pressure. Increased resistance to portal blood flow, the primary factor in the pathophysiology of portal hypertension, is in part due to morphological changes occurring in chronic liver diseases. This results in rerouting of blood flow away from the liver through collateral pathways to low-pressure systemic veins. Through a variety of computed tomographic, sonographic, magnetic resonance imaging and angiographic examples, this article discusses the appearances and prevalence of both common and less common portosystemic collateral channels in the thorax and abdomen. A brief overview of established interventional radiologic techniques for treatment of portal hypertension will also be provided. Awareness of the various imaging manifestations of portal hypertension can be helpful for assessing overall prognosis and planning proper management.

Progress in image-guided radiotherapy for the treatment of non-small cell lung cancer

Lung cancer is one of the most common malignant tumors. It has the highest incidence and mortality rate of all cancers worldwide. Late diagnosis of nonsmall cell lung cancer(NSCLC) is very common in clinical practice, and most patients miss the chance for radical surgery. Thus, radiotherapy plays an indispensable role in the treatment of NSCLC. Radiotherapy technology has evolved from the classic two-dimensional approach to three-dimensional conformal and intensity-modulated radiotherapy. However, how to ensure delivery of an accurate dose to the tumor while minimizing the irradiation of normal tissues remains a huge challenge for radiation oncologists, especially due to the positioning error between fractions and the autonomous movement of organs. In recent years, image-guided radiotherapy(IGRT) has greatly increased the accuracy of tumor irradiation while reducing the irradiation dose delivered to healthy tissues and organs. This paper presents a brief review of the definition of IGRT and the various technologies and applications of IGRT. IGRT can help ensure accurate dosing of the target area and reduce radiation damage to the surrounding normal tissue. IGRT may increase the local control rate of tumors and reduce the incidence of radio-therapeutic complications.

Image-guided lens extraction surgery: a systematic review

A systematic review of the recent literature regarding the current image-guided systems used for cataract surgery or refractive lens exchange was performed based on the PubMed and Google Scholar databases in March 2018. Literature review returned 21 eligible studies. These studies compared image-guided systems with other keratometric devices regarding their accuracy, repeatability and reproducibility in measurement of keratometric values, astigmatism magnitude and axis, as well as in IOL power calculation. Additionally, the image-guided systems were compared with conventional manual ink-marking techniques for the alignment of toric IOLs. In conclusion, image-guided systems seem to be an accurate and reliable technology with measurements of high repeatability and reproducibility regarding the keratometry and IOL power calculation, but not yet interchangeable with the current established and validated keratometric devices. However, they are superior over the conventional manual inkmarking techniques for toric IOL alignment.

Real-time fluorescence image-guided gastrointestinal oncologic surgery:Towards a new era

Technological improvements are crucial in the evolution of surgery.Real-time fluorescence-guided surgery(FGS)has spread worldwide,mainly because of its usefulness during the intraoperative decision-making processes.The success of any gastrointestinal oncologic resection is based on the anatomical identification of the primary tumor and its regional lymph nodes.FGS allows also to evaluate the blood perfusion at the gastrointestinal stumps after colorectal or esophageal resections.Therefore,a reduction on the anastomotic leak rates has been postulated as one of the foreseeable benefits provided by the use of FGS in these procedures.Although the use of fluorescence in lymph node detection was initially described in breast cancer surgery,the technique is currently applied in gastric or splenic flexure cancers,as they both present complex and variable lymphatic drainages.FGS allows also to perform intraoperative lymphograms or sentinel lymph node biopsies.New applications of FGS are being developed to assist in the detection of peritoneal metastases or in the evaluation of the tumor resection margins.The present review aims to provide a general overview of the current status of real-time FGS in gastrointestinal oncologic surgery.We put a special focus on the different applications of FGS,discussing the main findings and limitations found in the contemporary literature and also the promising near future applications.

Biological effects of human lung cells MRC-5 in CBCT positioning for image-guided radiotherapy

Image-guided radiotherapy(IGRT) provides precise positioning for the tumor target, but it may bring extra irradiation dose in the target positioning with a cone beam CT(CBCT) which has been increasingly used in IGRT. In this work, we focused on biological effects of the low-dose irradiation in IGRT, which have not been considered so far. Primary human fibroblasts cells from the lung and MRC-5 were irradiated by a CBCT. DNA doublestrand breaks(c-H2 AX foci) and micronucleus frequency of the irradiated samples were analyzed. Compared to the control, the c-H2 AX foci yields of the samples irradiated to 16 m Gy increased significantly, and the micronuclei rate of the samples irradiated for 3 days increased notably. The dose by imaging guidance device can be genotoxic to normal tissue cells, suggesting a potential risk of a secondary cancer. The effects, if confirmed by clinical studies,should be considered prudentially in designing IGRT treatment plans for the radiosensitive population, especially for children.

A novel technique for sacropelvic fixation using image-guided sacroiliac screws:a case series and biomechanical study

In this study, we sought to assess the safety and accuracy of sacropelvic fixation performed with image-guided sacroiliac screw placement using postoperative computed tomography and X-rays. The sacroiliac screws were placed with navigation in five patients. Intact specimens were mounted onto a six-degrees-of-freedom spine motion simulator. Long lumbosacral constructs using bilateral sacroiliac screws and bilateral S1 pedicle and iliac screws were tested in seven cadaveric spines. Nine sacroiliac screws were well-placed under an image guidance system(IGS);one was placed poorly without IGS with no symptoms. Both fixation techniques significantly reduced range of motion(P<0.05) at L5-S1. The research concluded that rigid lumbosacral fixation can be achieved with sacroiliac screws,and image guidance improves its safety and accuracy. This new technique of image-guided sacroiliac screw insertion should prove useful in many types of fusion to the sacrum, particularly for patients with poor bone quality,complicated anatomy, infection, previous failed fusion and iliac harvesting.

Long-term clinical outcomes of lipiodol marking using standard gastroscopy for image-guided radiotherapy of upper gastrointestinal cancers

BACKGROUND Image-guided radiotherapy(IGRT)has significantly improved the precision in which radiotherapy is delivered in cancer treatment.Typically,IGRT uses bony landmarks and key anatomical structures to locate the tumor.Recent studies have demonstrated the feasibility of peri-tumor fiducials in enabling even more accurate delineation of target and normal tissue.The use of gold coils as fiducials in gastrointestinal tumors has been extensively studied.However,placement requires expertise and specialized endoscopic ultrasound equipment.This article reports the long-term outcomes of using a standard gastroscopy to inject liquid fiducials for the treatment of oesophageal and gastric tumors with IGRT.AIM To assess the long-term outcomes of liquid fiducial-guided IGRT in a cohort of oesophageal and gastric cancer patients.METHODS A retrospective cohort study of consecutive adults with Oesophagogastric cancers referred for liquid fiducial placement before definitive/neo-adjuvant or palliative IGRT between 2013 and 2021 at a tertiary hospital in Melbourne,Australia was conducted.Up to four liquid fiducials were inserted per patient,each injection consisting of 0.2-0.5mL of a 1:1 mixture of iodized oil(Lipiodol;Aspen Pharmacare)and n-butyl 2-cyanoacrylate(Histoacryl®;B.Braun).A 23-gauge injector(Cook Medical)was used for the injection.All procedures were performed by or under the supervision of a gastroenterologist.Liquid fiducial-based IGRT(LF-IGRT)consisted of computer-assisted direct matching of the fiducial region on cone-beam computerised tomography at the time of radiotherapy.Patients received standard-IGRT(S-IGRT)if fiducial visibility was insufficient,consisting of bone match as a surrogate for tumor position.Radiotherapy was delivered to 54Gy in 30 fractions for curative patients and up to 45Gy in 15 fractions for palliative treatments.RESULTS 52 patients were referred for liquid fiducial placement within the study period.A total of 51 patients underwent liquid fiducial implantation.Of these a total of 31 patients received radiotherapy.Among these,the median age was 77.4 years with a range between 57.5 and 88.8,and 64.5%were male.Twenty-seven out of the 31 patients were able to have LF-IGRT while four had S-IGRT.There were no complications after endoscopic implantation of liquid fiducials in our cohort.The cohort overall survival(OS)post-radiotherapy was 19 mo(range 0 to 87 mo).Whilst the progression-free survival(PFS)post-radiotherapy was 13 mo(range 0 to 74 mo).For those treated with curative intent,the median OS was 22.0 mo(range 0 to 87 mo)with a PFS median of 14.0 mo(range 0 to 74 mo).Grade 3 complication rate post-radiotherapy was 29%.CONCLUSION LF-IGRT is feasible in 87.1%of patients undergoing liquid fiducial placement through standard gastroscopy injection technique.Our cohort has an overall survival of 19 mo and PFS of 13 mo.Further studies are warranted to determine the long-term outcomes of liquid-fiducial based IGRT.

Diffusion-weighted imaging and variable flip angle T1 mapping: a supplement for image-guided biopsy in follow-up analysis of liver fibrosis

Purpose To evaluate the performance of diffusion-weighted imaging(DWI) and variable flip angle(VFA) T1 mapping as a supplement to image-guided biopsy in follow-up analysis of liver fibrosis. Materials and Methods This prospective study was approved by the institution's committee on human research, and written informed consent was provided from the enrolled patients. We investigated five MRI parameters of DWI and VFA T1 mapping, collected from 11 patients who underwent serial ultrasound image-guided biopsy with follow-up MRI within 1.5 years after treatment for liver fibrosis/cirrhosis. For each patient, four consecutive MRI examinations were conducted, including baseline MRI before treatment and three follow-up MRI examinations after treatment at each 0.5-year interval. ADC values at four b values and T1 relaxation times were correlated to pathology-confirmed liver fibrosis stages, which were subsequently divided into two groups, stages F2–3 and F4. The receiver operating characteristic(ROC) analysis and repeated measurement analysis of variance were used for statistical analysis. Results Among these ADC parameters, ADC value(b = 500 s/mm^2) was the most consistent in differentiating between stage F2–3 and F4 liver fibrosis. Repeated measurement analysis showed that the intra-group and inter-group differences were 0.447 and 0.024, respectively. T1 relaxation time could not consistently differentiate between the F2–3 and F4 groups; however, it was repeatable, and the intra-group and inter-group differences were 0.410 and 0.042, respectively. Conclusion MRI-ADC value at a b value of 500 s/mm^2 can be a promising biomarker for differentiating stages F2–3 and F4 liver fibrosis. A combination of this biomarker with repeatable T1 relaxation time may function as a non-invasive tool for follow-up liver fibrosis in patients who reject repeated image-guided biopsy.

The Associations for Vaginal Point Doses of Vaginal Stenosis in Image-Guided Brachytherapy

Purpose: To evaluate the associations for vaginal dose points of vaginal stricture in image-guided brachytherapy. Materials and Methods: Twenty-six patients of locally advanced cervical cancer were treated with Image-Guided Brachytherapy (IGBT) with the dose at least 7 Gy per fraction to the D90 of High-Risk Clinical Target Volume (HR-CTV). The vaginal dose points of recommendations of the American Brachytherapy Society (ABS) were added into the plan and cumulative dose to these points was evaluated in Equivalent Dose of 2 Gy (EQD2) concepts. Results: The mean doses to right vaginal dose point (VR), left vaginal dose point (VL) and average dose of VR/VL ((VR + VL)/2) were 101.5 Gy, 98.2 Gy and 99.8 Gy in EQD2 concepts, respectively. Volume-based planning significantly reduced the cumulative dose in EQD2 concepts at vaginal points. At the median follow-up time of 22 months, grade-2 vaginal stricture was observed in two patients. The incidences of vaginal stricture were not differed between the cumulative dose to vaginal dose points in EQD2 concepts of ≤90 Gy versus >90 Gy (P = 1.000) and ≤100 Gy versus >100 Gy (P = 0.815). Conclusion: No association for cumulative vaginal doses and events of vaginal stricture was found.

Hi'CT:a pixel sensor-based device for ion tomography

Carbon ions,commonly referred to as particle therapy,have become increasingly popular in the last decade.Accurately predicting the range of ions in tissues is important for the precise delivery of doses in heavy-ion radiotherapy.Range uncertainty is currently the largest contributor to dose uncertainty in normal tissues,leading to the use of safety margins in treatment planning.One potential method is the direct relative stopping measurement(RSP)with ions.Heavy-ion CT(Hi′CT),a compact segmented full digital tomography detector using monolithic active pixel sensors,was designed and evaluated using a 430 MeV/u high-energy carbon ion pencil beam in Geant4.The precise position of the individual carbon ion track can be recorded and reconstructed using a 30μm×30μm small pixel pitch size.Two types of customized image reconstruction algorithms were developed,and their performances were evaluated using three different modules of CAT-PHAN 600-series phantoms.The RSP measurement accuracy of the tracking algorithm for different types of materials in the CTP404 module was less than 1%.In terms of spatial resolution,the tracking algorithm could achieve a 20%modulation transfer function normalization value of CTP528 imaging results at 5 lp/cm,which is significantly better than that of the fast imaging algorithm(3 lp/cm).The density resolution obtained using the tracking algorithm of the customized CTP515 was approximately 10.5%.In conclusion,a compact digital Hi'CT system was designed,and its nominal performance was evaluated in a simulation.The RSP resolution and image quality provide potential feasibility for scanning most parts of an adult body or pediatric patient,particularly for head and neck tumor treatment.

Irreversible electroporation for the management of pancreatic cancer: Current data and future directions

Pancreatic cancer is currently the seventh leading cause of cancer death(4.5%of all cancer deaths)while 80%-90%of the patients suffer from unresectable disease at the time of diagnosis.Prognosis remains poor,with a mean survival up to 15 mo following systemic chemotherapy.Loco-regional thermal ablative techniques are rarely implemented due to the increased risk of thermal injury to the adjacent structures,which can lead to severe adverse events.Irreversible electroporation,a promising novel non-thermal ablative modality,has been recently introduced in clinical practice for the management of inoperable pancreatic cancer as a safer and more effective loco-regional treatment option.Experimental and initial clinical data are optimistic.This review will focus on the basic principles of IRE technology,currently available data,and future directions.

Static superconducting gantry‑based proton CT combined with X‑ray CT as prior image for FLASH proton therapy

Proton FLASH therapy with an ultra-high dose rate is in urgent need of more accurate treatment plan system(TPS)to promote the development of proton computed tomography(CT)without intrinsic error compared with the transformation from X-ray CT.This paper presents an imaging mode of proton CT based on static superconducting gantry different from the conventional rotational gantry.The beam energy for proton CT is fixed at 350 MeV,which is boosted by a compact proton linac from 230 MeV,and then delivered by the gantry to scan the patient’s body for proton imaging.This study demonstrates that the static superconducting gantry-based proton CT is effective in clinical applications.In particular,the imaging mode,which combines the relative stopping power(RSP)map from X-ray CT as prior knowledge,can produce much a higher accuracy RSP map for TPSs and positioning and achieve ultra-fast image for real-time image-guided radiotherapy.This paper presents the conceptual design of a boosting linac,static superconducting gantry and proton CT imaging equipment.The feasibility of energy enhancement is verified by simulation,and results from Geant4 simulations and reconstruction algorithms are presented,including the simulation verification of the advantage of the imaging mode.

Thermal ablation of metastatic disease to the musculoskeletal system

A variety of indications have been published regarding the use of percutaneous thermal ablation for treating tumors of the musculoskeletal system,including bone and soft tissue lesions,benign and malignant lesions,and primary and metastatic tumors.In the appropriately selected patient,the advantages of percutaneous thermal ablation include decreased morbidity,decreased cost,and shorter hospitalization stays compared to surgery.The number of different thermal ablation modalities is increasing,and each modality has its advantages and disadvantages.Studies directly comparing the effectiveness of the various thermal ablation modalities are sparse,however,so the choice of ablation modality often depends on availability,user preference,and local expertise.Although the list of uses for percutaneous thermal ablation is ever-expanding,in this article,we will discuss the two most well-established indications,which are palliation of pain attributed to bone and soft tissue metastases and local control of oligometastatic disease.Numerous clinical trials have shown percutaneous thermal ablation to be an effective method of palliating pain due to bone and soft tissue metastases and of achieving local control in the setting of oligometastatic disease with low rates of complication.

Real-time cardiovascular magnetic resonance-guided radiofrequency ablation:A comprehensive review

Cardiac magnetic resonance(CMR)imaging could enable major advantages when guiding in real-time cardiac electrophysiology procedures offering high-resolu-tion anatomy,arrhythmia substrate,and ablation lesion visualization in the absence of ionizing radiation.Over the last decade,technologies and platforms for performing electrophysiology procedures in a CMR environment have been developed.However,performing procedures outside the conventional fluoro-scopic laboratory posed technical,practical and safety concerns.The development of magnetic resonance imaging compatible ablation systems,the recording of high-quality electrograms despite significant electromagnetic interference and reliable methods for catheter visualization and lesion assessment are the main limiting factors.The first human reports,in order to establish a procedural workflow,have rationally focused on the relatively simple typical atrial flutter ablation and have shown that CMR-guided cavotricuspid isthmus ablation represents a valid alternative to conventional ablation.Potential expansion to other more complex arrhythmias,especially ventricular tachycardia and atrial fibrillation,would be of essential impact,taking into consideration the widespread use of substrate-based strategies.Importantly,all limitations need to be solved before application of CMR-guided ablation in a broad clinical setting.

High intensity focused ultrasound in clinical tumor ablation

Recent advances in high intensity focused ultrasound(HIFU),which was developed in the 1940s as a viable thermal tissue ablation approach,have increased its popularity.In clinics,HIFU has been applied to treat a variety of solid malignant tumors in a well-defined volume,including the pancreas,liver,prostate,breast,uterine fibroids,and soft-tissue sarcomas.In comparison to conventional tumor/cancer treatment modalities,such as open surgery,radio-and chemo-therapy,HIFU has the advantages of non-invasion,non-ionization,and fewer complications after treatment.Over 100 000 cases have been treated throughout the world with great success.The fundamental principles of HIFU ablation are coagulative thermal necrosis due to the absorption of ultrasound energy during transmission in tissue and the induced cavitation damage.This paper reviews the clinical outcomes of HIFU ablation for applicable cancers,and then summarizes the recommendations for a satisfactory HIFU treatment according to clinical experience.In addition,the current challenges in HIFU for engineers and physicians are also included.More recent horizons have broadened the application of HIFU in tumor treatment,such as HIFU-mediated drug delivery,vessel occlusion,and soft tissue erosion(“histotripsy”).In summary,HIFU is likely to play a significant role in the future oncology practice.

Computed tomography-guided percutaneous core needle biopsy in pancreatic tumor diagnosis

AIM: To evaluate the techniques, results, and complications related to computed tomography(CT)-guided percutaneous core needle biopsies of solid pancreatic lesions.METHODS: CT-guided percutaneous biopsies of solid pancreatic lesions performed at a cancer reference center between January 2012 and September 2013 were retrospectively analyzed. Biopsy material was collected with a 16-20 G Tru-Core needle(10-15 cm; Angiotech, Vancouver, CA) using a coaxial system and automatic biopsy gun. When direct access to the lesion was not possible, indirect(transgastric or transhepatic) access or hydrodissection and/or pneumodissection maneuvers were used. Characteristics of the patients, lesions, procedures, and histologic results were recorded using a standardized form. RESULTS: A total of 103 procedures included in the study were performed on patients with a mean age of 64.8 year(range: 39-94 year). The mean size of the pancreatic lesions was 45.5 mm(range: 15-195 mm). Most(75/103, 72.8%) procedures were performed via direct access, though hydrodissection and/or pneumodissection were used in 22.2%(23/103) of cases and indirect transhepatic or transgastric access was used in 4.8%(5/103) of cases. Histologic analysis was performed on all biopsies, and diagnoses were conclusive in 98.1%(101/103) of cases, confirming3.9%(4/103) of tumors were benign and 94.2%(97/103) were malignant; results were atypical in 1.9%(2/103) of cases, requiring a repeat biopsy to diagnose a neuroendocrine tumor, and surgical resection to confirm a primary adenocarcinoma. Only mild/moderate complications were observed in 9/103 patients(8.7%),and they were more commonly associated with biopsies of lesions located in the head/uncinate process(n =8), than of those located in the body/tail(n = 1) of the pancreas, but this difference was not significant.CONCLUSION: CT-guided biopsy of a pancreatic lesion is a safe procedure with a high success rate, and is an excellent option for minimally invasive diagnosis.

Augmented reality technology for preoperative planning and intraoperative navigation during hepatobiliary surgery: A review of current methods

Background: Augmented reality(AR) technology is used to reconstruct three-dimensional(3D) images of hepatic and biliary structures from computed tomography and magnetic resonance imaging data, and to superimpose the virtual images onto a view of the surgical field. In liver surgery, these superimposed virtual images help the surgeon to visualize intrahepatic structures and therefore, to operate precisely and to improve clinical outcomes.Data Sources: The keywords "augmented reality", "liver", "laparoscopic" and "hepatectomy" were used for searching publications in the Pub Med database. The primary source of literatures was from peer-reviewed journals up to December 2016. Additional articles were identified by manual search of references found in the key articles.Results: In general, AR technology mainly includes 3D reconstruction, display, registration as well as tracking techniques and has recently been adopted gradually for liver surgeries including laparoscopy and laparotomy with video-based AR assisted laparoscopic resection as the main technical application. By applying AR technology, blood vessels and tumor structures in the liver can be displayed during surgery,which permits precise navigation during complex surgical procedures. Liver transformation and registration errors during surgery were the main factors that limit the application of AR technology.Conclusions: With recent advances, AR technologies have the potential to improve hepatobiliary surgical procedures. However, additional clinical studies will be required to evaluate AR as a tool for reducing postoperative morbidity and mortality and for the improvement of long-term clinical outcomes. Future research is needed in the fusion of multiple imaging modalities, improving biomechanical liver modeling,and enhancing image data processing and tracking technologies to increase the accuracy of current AR methods.

Near-infrared fluorescence sentinel lymph node detection in gastric cancer: A pilot study

AIM: To investigate feasibility and accuracy of near-infrared fluorescence imaging using indocyanine green: nanocolloid for sentinel lymph node (SLN) detection in gastric cancer.METHODS: A prospective, single-institution, phase I feasibility trial was conducted. Patients suffering from gastric cancer and planned for gastrectomy were included. During surgery, a subserosal injection of 1.6 mL ICG:Nanocoll was administered around the tumor. NIR fluorescence imaging of the abdominal cavity was performed using the Mini-FLARE&#x02122; NIR fluorescence imaging system. Lymphatic pathways and SLNs were visualized. Of every detected SLN, the corresponding lymph node station, signal-to-background ratio and histopathological diagnosis was determined. Patients underwent standard-of-care gastrectomy. Detected SLNs outside the standard dissection planes were also resected and evaluated.RESULTS: Twenty-six patients were enrolled. Four patients were excluded because distant metastases were found during surgery or due to technical failure of the injection. In 21 of the remaining 22 patients, at least 1 SLN was detected by NIR Fluorescence imaging (mean 3.1 SLNs; range 1-6). In 8 of the 21 patients, tumor-positive LNs were found. Overall accuracy of the technique was 90% (70%-99%; 95%CI), which decreased by higher pT-stage (100%, 100%, 100%, 90%, 0% for respectively Tx, T1, T2, T3, T4 tumors). All NIR-negative SLNs were completely effaced by tumor. Mean fluorescence signal-to-background ratio of SLNs was 4.4 (range 1.4-19.8). In 8 of the 21 patients, SLNs outside the standard resection plane were identified, that contained malignant cells in 2 patients.CONCLUSION: This study shows successful use of ICG:Nanocoll as lymphatic tracer for SLN detection in gastric cancer. Moreover, tumor-containing LNs outside the standard dissection planes were identified.