SignificanceShortwave-infrared (SWIR) imaging is reported to yield better contrast in fluorescence-guided surgery than near-infrared (NIR) imaging, due to a reduction in scattering. This benefit of SWIR was shown in animal studies, however not yet in clinical studies with patient samples.AimWe investigate the potential benefit of SWIR to NIR imaging in clinical samples containing cetuximab-IRDye800CW in fluorescence-guided surgery.ApproachThe potential of the epidermal growth factor-targeted NIR dye cetuximab-IRDye800CW in the shortwave range was examined by recording the absorption and emission spectrum. An ex vivo comparison of NIR and SWIR images using clinical tumor samples of patients with penile squamous cell carcinoma (PSCC) and head and neck squamous cell carcinoma (HNSCC) containing cetuximab-IRDye800CW was performed. The comparison was based on the tumor-to-background ratio and an adapted contrast-to-noise ratio (aCNR) using the standard of care pathology tissue assessment as the golden standard.ResultsBased on the emission spectrum, cetuximab-IRDye800CW can be detected in the SWIR range. In clinical PSCC samples, overall SWIR imaging was found to perform similarly to NIR imaging (NIR imaging is better than SWIR in the 2/7 criteria examined, and SWIR is better than NIR in the 3/7 criteria). However, when inspecting HNSCC data, NIR is better than SWIR in nearly all (5/7) examined criteria. This difference seems to originate from background autofluorescence overwhelming the off-peak SWIR fluorescence signal in HNSCC tissue.ConclusionSWIR imaging using the targeted tracer cetuximab-IRDye800CW currently does not provide additional benefit over NIR imaging in ex vivo clinical samples. Background fluorescence in the SWIR region, resulting in a higher background signal, limits SWIR imaging in HNSCC samples. However, SWIR shows potential in increasing the contrast of tumor borders in PSCC samples, as shown by a higher aCNR over a line.

Background: In this study, we assessed the ability of the EPOS system (Perimed AB, Järfälla, Stockholm, Sweden) to detect differences in tissue perfusion between healthy volunteers and patients with peripheral arterial disease (PAD) with different severity of disease. Methods: This single-center prospective pilot study included 10 healthy volunteers and 20 patients with PAD scheduled for endovascular therapy (EVT). EPOS measurements were performed at rest at 32 °C and 44 °C, followed by transcutaneous oxygen pressure (TcPo₂) measurements. The measurements were performed on the dorsal and medial side of the foot, as well as the lateral side of the calf. EPOS parameters included hemoglobin oxygen saturation (HbSo₂) and speed-resolved red blood cell (RBC) perfusion. Results: HbSo₂ at 44 °C was significantly different between the three groups for all measurement locations. The overall speed-resolved RBC perfusion at 44 °C was statistically significant between the groups on the dorsal and medial side of the foot but not on the calf. TcPo₂ values were not significantly different between the three groups. Conclusions: This study demonstrates that the EPOS system can depict differences in tissue perfusion between healthy volunteers, patients with Fontaine class IIb PAD, and those with Fontaine class III or IV PAD but only after heating to 44 °C.

Objective: To investigate the feasibility of fluorescence molecular imaging (FMI), using cetuximab‐800CW, as an intraoperative tool to determine surgical margins in penile squamous cell carcinoma (PSCC). Patients and methods: A total of 11 patients with PSCC received 75 mg cetuximab followed by 15 mg cetuximab‐800CW 2 days before surgery. FMI of the whole excision specimen and tissue slices was performed. Fluorescence visualisation was correlated to histopathology. Based on tumour and healthy tissue regions of interest, mean fluorescence intensity was calculated for each individual patient. Results: Significant differences between tumour and healthy mean fluorescence intensity were found with tumour‐to‐background ratios of a median (IQR) of 1.51 (0.99) and a mean (SD) of 1.51 (0.32) in the excision specimen and tissue slices, respectively. One patient showed a high relative fluorescence intensity with a signal‐to‐background ratio of 1.79, corresponding to a tumour‐positive margin on fresh frozen sectioning. Conclusion: In this Phase I study we showed that cetuximab‐800CW seems suitable to discriminate PSCC from background tissue. The tracer was well tolerated, and no false positive spots were seen.

The aims of this study were to assess changes in tissue perfusion up to 6 weeks after endovascular therapy (EVT), in hospital and at home, and to determine differences in tissue perfusion between patients with and without clinical improvement or good angiographic result. This single-center prospective cohort study included patients undergoing EVT for Rutherford stages two to six. Hyperspectral and thermal imaging were performed at the dorsal and plantar sides of the foot. These measurements consisted of a baseline measurement pre-EVT, and six follow-up measurements obtained at 1 and 4 h and 6 weeks in hospital, and 1 day, 7 days, and 14 days at home. Clinical improvement was defined as a decrease of one or more Rutherford class or decrease in the wound surface area and a good angiographic result was accomplished when a Transatlantic Inter-Society Consensus for the Management of PAD II C or D lesion was treated and uninterrupted flow continued in at least one below-the-knee artery in continuation with the inframalleolar arteries. The study included 34 patients with 41 treated limbs. Deoxyhemoglobin values were lower 1 h post-EVT compared with baseline and increased over time up to 6 weeks post-EVT. Significant differences in deoxyhemoglobin levels at 7 and 14 days post-EVT were determined between patients with and without clinical or angiographic success. This prospective pilot study shows the feasibility of hyperspectral imaging and thermal imaging post-EVT at home, which may decrease the need for hospital visits.

Complete tumor removal is crucial for successful surgical oncological outcomes. Targeted fluorescence imaging facilitates differentiation between healthy and cancerous tissue, enabling intraoperative margin assessment. However, its depth specificity is still limited. Three-dimensional fluorescence imaging could improve margin assessment, especially after tissue clearing. Conventional tissue clearing may take up to 24 h, limiting clinical applicability. This study developed and validated a fast tissue clearing protocol, achieving transparency within one hour. Ten patients from a fluorescence-guided surgery trial were included, from whom three tumor and three healthy tissue biopsies were acquired. These biopsies were used as control, cleared using a standard Benzyl Alcohol Benzyl Benzoate (BABB) clearing protocol, or cleared using the newly developed fast BABB clearing protocol. This protocol uses an orbital shaker, decreasing total process time to one hour. No significant difference in transparency was observed between normal and fast cleared biopsies. Fluorescence signals of all cleared biopsies increased directly after clearing and slowly decreased back to pre-cleared fluorescence signals over time. In non-cleared tumor biopsies, fluorescence intensity decreased substantially upon fixation, yet remained stable. Finally, clearing did not impact immunohistochemical staining. Therefore, fast tissue clearing is possible within one hour, enabling optical microscopy after tissue clearing for intraoperative pathology-assisted surgery.

Transoral Robotic Surgery (TORS) is utilized for treating various malignancies, such as early-stage oropharyngeal cancer and lymph node metastasis of an unknown primary tumor (CUP), and also benign conditions, like obstructive sleep apnea (OSA) and chronic lingual tonsillitis. However, the success and failure of TORS have not been analyzed to date. In this retrospective observational multicenter cohort study, we evaluated patients treated with TORS using the da Vinci surgical system. Success criteria were defined as identification of the primary tumor for CUP, >2 mm resection margin for malignant conditions, and improvement on respiratory polygraphy and tonsillitis complaints for benign conditions. A total of 220 interventions in 211 patients were included. We identified predictors of success, such as low comorbidity status ACE-27, positive P16 status, and lower age for CUP, and female gender and OSA severity for benign conditions. For other malignancies, no predictors for success were found. Predictors of failure based on postoperative complications included high comorbidity scores (ASA) and anticoagulant use, and for postoperative pain, younger age and female gender were identified. This study provides valuable insights into the outcomes and predictors of success and failure in TORS procedures across various conditions and may also help in patient selection and counseling.