Quantitative Margin Assessment Using High-resolution Positron Emission Tomography - Computed Tomograhy

The ideal outcome in oncological surgery is resection of all tumor tissue with a margin of healthy tissue. However, positive surgical margins (PSMs) occur in up to 35% of the cases, depending on tumor type. The final margin status is only available five to seven days after surgery so that in case of a PSM, intensive adjuvant radiotherapy or chemotherapy is necessary. Despite adjuvant treatment, patients still have a significantly reduced overall survival. Therefore, the intraoperative identification of PSMs is paramount to enable surgical corrections and obtain a complete resection.

The investigators propose a dedicated intraoperative high-resolution PET-CT (positron emission tomography - computed tomography) imaging system for margin assessment of the excised specimen. The proposed specimen imaging system would combine the proven functional imaging capabilities of PET with the anatomical imaging info of CT, providing multi-modal information to determine whether tumor cells are present at the excision edges of the specimen. The tomographic images obtained can precisely demonstrate tumor extension along the x, y, and z axis, and the PET signal is not distorted by bone tissue. PET is the most sensitive medical imaging modality capable of detecting the picomolar concentrations of radiotracer, allowing to assess the presence of tumor cells within the specimen margins with high precision. Current standard PET-CT scanners have a spatial resolution between 3mm and 6mm, which is insufficient to accurately assess the excision margins of tumors. A specimen imaging system ideally should have a sub-millimeter resolution. The specimen PET system which will be used in this study is capable of this. The potential of intraoperative PET-CT has been shown in several tumor types, enabling the intraoperative identification of PSMs in prostatectomy and lumpectomy specimens.

Inclusion criteria

• Age ≥18 years.
• Patient is confirmed with oral squamous cell carcinoma, soft tissue sarcoma or osteosarcoma.
• Patient is indicated to undergo curative surgery of the primary tumor.
• Patient is estimated compliant for study participation by the investigator.
• Written informed consent.

Exclusion criteria

• Medical or psychiatric conditions that compromise the patient's ability to give informed consent;
• Patient has previously received radiotherapy of the primary tumor region;
• Patient has participated in other clinical studies with radiation exposure of more than 1 mSv in the past 12 months;
• A blood glucose level over 200 mg/dL on the day of surgery.
• Pregnancy or lactation.