PI Left Institution

Subjects with known or suspected primary soft tissue sarcoma of the extremities may be eligible for this study. Subjects may participate in this study if they are at least 18 years of age. Most participants will be receiving care at the clinical practices of the University of Pennsylvania Health System.

Positron emission tomography (PET/CT) imaging will be used to evaluate soft tissue sarcoma hypoxia using an investigational radiotracer, 18F-FMISO Subjects will also undergo an 18F-FDG PET/CT scan close to the time of their initial hypoxia PET/CT to compare in vivo measures of hypoxia to 18F-FDG uptake. The FDG PET/CT may be performed as part of standard clinical care or as a research scan. Both PET/CT scans will occur prior to starting new therapy.

Inclusion Criteria:

1. Known or suspected soft tissue sarcoma seen on at least one type of standard imaging (e.g. CT, ultrasound, MRI, or 18F-FDG PET/CT)
2. At least 18 years of age
3. Subjects with local disease or advanced/metastatic disease will be eligible
4. Willing to consent to use of tissue from biopsy or surgery for the purposes of this study
5. Participants must be informed of the investigational nature of this study and be willing and able to provide written informed consent and participate in this study in accordance with institutional and federal guidelines prior to study-specific procedures.

Exclusion Criteria:

1. Females who are pregnant at the time of screening will not be eligible for this study; a urine pregnancy test will be performed at screening in women of child-bearing potential
2. Inability to tolerate imaging procedures in the opinion of an investigator or treating physician
3. Serious or unstable medical or psychological conditions that, in the opinion of the investigator, would compromise the subject's safety or successful participation in the study