Whole-body positron emission tomography/computed tomography scans may help physicians identify malignant cancerous tumors

May 29 2005

A team of researchers at Johns Hopkins Medical Institutions in Baltimore, Md., reports that whole-body positron emission tomography/computed tomography (PET/CT) scans may help physicians identify new, unexpected malignant cancerous tumors in patients, according to an article in the May issue of the Society of Nuclear Medicine’s Journal of Nuclear Medicine.

"PET/CT can help find additional lesions in patients known to have cancer," said SNM member Richard L. Wahl, M.D., director of nuclear medicine/PET at the Russell H. Morgan Department of Radiology and Radiological Science. PET/CT scans from nearly 2,000 cancer patients over a two-year period were evaluated retrospectively, explained Wahl, who was one of the first in the world and the first in this country to prove that PET could accurately diagnose breast cancer, melanoma and ovarian cancer and that it was superior to CT in staging lung cancer.

Wahl explained that in patients with known cancer, work-ups focus on a patient’s primary disease and incidental coexistence of another primary malignant lesion can be missed. "Such newly identified lesions are often of early stage and have a better likelihood of being cured if treated promptly and aggressively," indicated Wahl, the senior author who co-wrote the JNM article, "Detection of Unexpected Additional Primary Malignancies With PET/CT,” with SNM members Takayoshi Ishimori, M.D., Ph.D. (lead author), and Pavni V. Patel, M.D. Results of modern techniques such as PET/CT can be “potentially medically significant and relevant," said Wahl.

PET is a powerful medical imaging modality that noninvasively traces molecular and physiologic processes in the body. Currently, the most common use of PET is for whole-body oncologic imaging for diagnosis, staging, restaging and measuring early therapy responses. CT is an X-ray test that generates a detailed view of the anatomy or structure of organs and tissues in the body. Combining PET with CT provides images showing function (PET) and anatomy (CT) and a merged or “fused” picture of the body’s metabolism and structure.