In this research study we want to learn more about the use of indocyanine green (ICG) during bone or soft tissue mass resections. Indocyanine green (ICG) is a type of dye that is used in medical diagnostics. We want to determine if ICG-guided tumor resection is more effective in obtaining negative margins. Lastly, we want to assess traditional oncologic outcomes of local recurrence, time to metastatic disease, and overall and disease specific survival.

If you are present for a preoperative clinic visit the day before your surgery, ICG may be administered via injection. Otherwise, ICG will be administered in the preoperative unit via IV injection at the time of presentation approximately 4 hours before your surgery. You will be monitored during and after ICG dosing.

During surgery ICG fluorescence using a near-infrared imager will be performed at the time of and immediately following primary tumor resection. The imager will evaluate the primary tumor to ensure appropriate tumor fluorescence. Once the primary resection is complete and the surgeon believes that he/she has achieved negative or planned positive margins, fluorescence measurements of the tumor bed will be performed. If areas of positive signal remain, these areas will be resected if possible and sent to pathology for histologic evaluation. It will be recorded if the surgeon perceived negative margins but the device detected positive margins.

Tumor specimens and residual fluorescence positive samples will be evaluated using fresh frozen and permanent histology. Permanent samples will be evaluated for tumor and local fluorescence using confocal microscopy with an ICG cube. Positive fluorescence signal and its correspondence with neoplasm will be noted, a will tumor that does not fluoresce.

Tissue being removed is 1-2 mm from non-structurally important tissue that either has or does not have signal positivity for additional pathologic assessment. It should have no impact on patient outcome, does not represent intervention on sensitive areas (such as neurovascular structures), and can further be used as potential margin around the tumor.

Inclusion Criteria:

• All patients 18 years of age or older who present to Massachusetts General Hospital Department of Orthopaedic Surgery with a benign or malignant bone or soft tissue mass that is consented for surgery during the study period.

Exclusion Criteria:

• Pregnant or nursing patients
• Patients with previously known anaphylaxis to IV contrast or iodine (other allergies may be considered on a case-by-case basis)
• Patients in renal failure who are not cleared for ICG administration by their primary physician or oncologist