Performance and Safety of Biology-Guided Radiotherapy Using the RefleXion Medical Radiotherapy System (BIOGUIDE-X)

1. Age greater than 21 years 2. A new or prior diagnosis of biopsy-proven cancer with a solid tumor (non-hematologic, non-lymphoma) 3. At least one active tumor in the bone or lung which is either the primary tumor or metastatic lesion determined either by biopsy or imaging suspicious of active disease 4. Target tumor size ≥2cm and ≤5cm 5. Target lesion in the bone or lung that is discrete and assessed by the investigator to be FDG-avid (i.e. SUVmax≥6 on third-party diagnostic PET/CT performed within 60 days with no intervening oncologic therapies) 6. ECOG Performance Status 0-3 7. Must have completed any other oncologic therapies at least 15 days prior to planned start of study procedures (preferably 30 days) and must have no plans to initiate systemic therapy until after study follow up is complete -OR- must be recorded by physician to have an active candidate lesion that is unresponsive to ongoing systemic therapy. 8. Females of childbearing potential should have negative urine or serum pregnancy test within 14 days prior to initiation of study scans. 9. Demonstrate adequate organ function: determined by ANC, platelets, hemoglobin, with no gross hematuria 10. For Cohort II only: Patient is dispositioned to undergo SBRT to a bone or lung tumor

1. Clinically significant blood glucose abnormalities that preclude a satisfactory FDG PET/CT scan. 2. Previous history of external radiotherapy where prior radiotherapy fields are anticipated to overlap with the radiotherapy fields required for the present study 3. Diffuse metastatic process (leptomeningeal disease, peritoneal carcinomatosis, diffuse bone marrow involvement, etc.) 4. PET-avid structures not intended for radiation are within 2cm from target on third-party diagnostic PET/CT as assessed by investigator 5. Known allergy to FDG 6. Known psychiatric or substance abuse disorder that would interfere with conduct of the study 7. Pregnant, breast-feeding or expecting to conceive during the study 8. Patient weight exceeding the weight limit outlined per IFU. 9. For Cohort II only: Patients with pacemakers and other implantable devices who are deemed to be at high risk by the treating physician for complications secondary to radiotherapy. 10. For Cohort II only: Patients with bone lesions who are determined to be high risk by the treating physician for pathologic fracture prior to beginning radiotherapy. 11. For Cohort II only: Active inflammatory bowel disease, scleroderma, or other disorder deemed to be a risk factor for excess toxicity in the area of treatment by the treating physician.