18F-FLT more accurate than 18F-FDG for differentiating unclear lung lesions

Lung cancer is the leading cause of cancer death in both men and women. To successfully fight the disease, doctors use a variety of techniques to diagnose the cancer and determine the extent of its spread throughout the body. When using positron emission tomography (PET) as a diagnostic tool, 18F-FDG has proven to be a reliable and accurate tracer, but false positives have been noted in areas of inflammation. Recently, German researchers conducted a study comparing the results of 18F-FDG PET and 18F-FLT PET and found the latter to be a more precise indicator for diagnosing unclear lung lesions.

The study, published in the September 2003 issue of The Journal of Nuclear Medicine, included examinations of 26 patients with pulmonary nodules revealed on chest CT. Subsequent biopsies confirmed that eighteen of the patients involved had malignant tumors, and eight had benign tumors. Using standardized uptake value (SUV), tumoral uptake was calculated for both 18F-FDG PET and 18F-FLT PET.

Results revealed 18F-FLT SUV correlated better than18F-FDG SUV with the proliferation index. This confirms the theory that 18F-FLT, a tracer specifically designed to reveal the presence of malignant tumors, is better at differentiating cancerous growths from other lesions. While the results show promise for the use of 18F-FLT, they do not indicate 18F-FLT can replace 18F-FDG, which is quite accurate in staging tumors.

In his invited commentary, Anthony F. Shields, MD, PhD of Karmanos Cancer Institute, Wayne State University School of Medicine, indicates more clinical trials are needed to further evaluate 18F-FLT, as well as other tracers that can supplement the information provided by 18F-FDG.

“Imaging Proliferation in Lung Tumors with PET: 18F-FLT vs. 18F-FDG” was written by Andreas K. Buck, MD, Holger Schirrmeister, MD, Jörg Kotzerke, MD, Gerhard Glatting, PhD, Bernd Neumaier, PhD, and Sven N. Reske, MD from the Department of Nuclear Medicine; Gisela Halter, MD and Imke Wurziger, of the Department of Thoracic Surgery; Torsten Mattfeldt, MD, of the Department of Pathology; and Martin Hetzel, MD, of the Department of Internal Medicine II, all from the University of Ulm in Ulm, Germany.

Copies of the article and images related to the study are available to media upon request to Kimberly A. Bennett. Current and past issues of The Journal of Nuclear Medicine can be found online at jnm.snmjournals.org. Print copies can be obtained at $15 per copy by contacting the SNM Service Center, Society of Nuclear Medicine, 1850 Samuel Morse Drive, Reston, VA 20190-5315; phone: (703) 326-1186; fax: (703) 708-9015; email: servicecenter@snm.org. A yearly subscription to the journal is $210 for individuals and $318 for institutions. A subscription is a Society of Nuclear Medicine member benefit.

The Society of Nuclear Medicine is an international scientific and professional organization of more than 14,000 members dedicated to promoting the science, technology, and practical applications of nuclear medicine. The SNM is based in Reston, VA.