Lack of accrual

In this particular study the physicians want to use a new technique of how they obtain the PET/CT pictures. It is called breath-hold (BH) PET/CT". As the name suggests, they will ask the patient to hold their breath for about 20-30 seconds, and only during that time will they obtain pictures. This is repeated several times. In contrast to the standard PET/CT scan, they expect less "blurring" of the pictures, so that they can see the tumor better and measure the uptake of radioactive sugar in the tumor better and more reliably. Basically, this is the difference between taking pictures of a runner as compared to taking pictures of a person standing still. Since PET images need to be obtained over several minutes and people can not hold their breath for this extended time, we break the procedure into several cycles of 20-30 seconds (or longer, if possible) and then add all the "frozen" pictures in the end into one. They want to know if BH PET/CT scan measure changes in the cancer during therapy (i.e., from the baseline scan before therapy to the follow up scan at within 4 weeks later).

Inclusion Criteria:

• Age ≥ 18 years old
• Patients with early stage biopsy-proven lung cancer or patients with lung or liver metastases from any primary cancer (metastatic disease proven by biopsy, or clearly established clinically and by imaging studies who are being treated with stereotactic body radiotherapy (SBRT)or an ablation will be eligible.
• Patient has at least one lesion ≥ 1cm in size.
• Signed informed consent

Exclusion Criteria:

• Pregnant women are ineligible.
• Patients who are unable to follow breathing instructions either due to language difficulties or hearing impairment This will be determined either by one of the consenting individuals when they approach the patient to ask for informed consent or prior to acquisition of the clinical PET/CT.
• Patients who are too ill to hold their breath.