Positron Emission Tomography (PET) is an imaging technique which utilizes positron emitting radiopharmaceuticals. The most popular PET agent is F-18 Deoxyglucose (FDG). Following intravenous administration, this radiopharmaceutical undergoes metabolism by various tissues and provides information regarding the physiological, biochemical, and metabolic functions of the tissues under study. Not surprisingly, malignant tumors tend to attract and concentrate the radiolabeled glucose due to their hyper-metabolic state. PET scans can distinguish malignant from benign processes, determine the extent of masses, accurately stage cancers, and measure treatment response (Figure 1).

PET imaging was introduced to the medical community before MRI, so why is it not as widely utilized? The answer is complex and has to do with reimbursement, availability of the radiopharmaceutical, and cost of the equipment.

In November of 1997, HCFA approved reimbursement for the first PET imaging indication in lung cancer (non-small cell lung carcinoma). Today, in addition to lung carcinoma, most third party payers reimburse for PET imaging in cases of lymphoma, melanoma, and recurrent colorectal carcinoma. Esophageal and head and neck carcinoma may be approved as early as July of 2001, pending final decision from Medicare. Furthermore, reimbursement for PET scans is anticipated for non-oncologic conditions, such as myocardial viability, refractory seizures, and Alzheimer’s disease.

FDG is a cyclotron-produced radiopharmaceutical with a half-life of 2.5 hours. PET imaging is dependent on the availability and prompt supply of this agent. Only in recent years, due to the increasing demand for PET, have commercial radiopharmacies established and increased production of this agent. Today, FDG is readily available throughout the US.

The average cost of a PET scanner is 1.5 million dollars. Many community hospitals cannot justify such an investment and may have difficulties obtaining a Certificate Of Need in the states requiring such documentation.

Mobile PET enterprises offer PET services without the risk of capital investment. The leading vendors are Alliance Imaging, Inc., Insight Health Services Corp., Mobile P.E.T. Systems, Inc., and RCOA Imaging Services, Inc. (in alphabetical order). For a fixed fee of $850-$1000 per scan (the price typically goes down when the number of scans per day exceeds six), these companies provide the imaging equipment. They leave the hospital’s billing service to deal with pre-certification, as well as the PET insurance claims (and denials). The hospital is also required to pay for the cost of FDG and, occasionally, to store it, if the Mobile PET machine is late to arrive. Additional details of a typical agreement with a mobile PET service include a minimum requirement of four scans per day after four months of service. The image studies are stored as a hard copy, or archived on a DAT tape. Interface with an individual hospital’s teleradiology or PACS system is user-dependent. Most vendors offer to pay for minimal physician training and provide an "over-read " program for the first few months of service.

Mobile PET helps to expose the medical community to this revolutionary technology. Many studies have demonstrated superiority of PET over CT in the staging and diagnosis of various tumors. PET is accurate in predicting myocardial viability and useful in the diagnosis of a variety of neurological disorders. PET is cost effective and helps eliminate unnecessary surgery, procedures, and tests. Finally, PET helps to improve patient care and patient satisfaction.