Lung cancer causes 30 percent of all cancer deaths per year making it the leading cause of cancer death in the United States on an annual basis.

It takes more lives annually than breast cancer, prostate cancer, colon cancer, liver cancer, kidney cancer, and melanoma combined. More than 50% of the time, new lung cancer cases are diagnosed at a very late stage, making them difficult to treat effectively. In fact, only 5 to 10 percent of those diagnosed with advanced lung cancer will reach the five year survival plateau.

Recent improvements in diagnostic technology, biopsy and treatment techniques have enhanced the clinician’s ability to accurately diagnose, stage and treat lung cancer. Perhaps no other improvement has been as important as the use of computed tomography, often called a CT or CAT scan, as a front line screening tool in detecting early stage lung cancer in asymptomatic patients.

A landmark study published in the October 2006 New England Journal of Medicine found that with CT Screening, lung cancer can be detected at the earliest stage (Stage I) in 85 percent of patients and can lead to an estimated 10 year survival rate of 88 percent. The estimated 10 year survival rate goes even higher, to 92 percent, for those whose early detected cancers are able to be removed completely with surgery.

The clinician’s ability to accurately stage a lung cancer patient, or assess the spread of disease, has vastly improved in recent years as well. Another important technological advancement in this area has been the development of a diagnostic imaging modality called PET, or Positron Emission Tomography.

PET technology is unique in the diagnostic imaging world because of its ability to image bodily function versus traditional diagnostic imaging’s ability to image anatomy. Often times, metabolic changes, or changes in how our cells behave, occur before anatomical changes take place. PET technology allows us to image those metabolic changes, thus allowing us to detect diseases, such as lung cancer, at an earlier stage.

In recent years, we have discovered a way to combine PET technology with CT technology into one simple, non-invasive exam. The combination of these two modalities together allows us to benefit from the superior anatomic detail of the CT exam with the metabolic detail of the PET exam.

When these two images are fused together, we create one of the most powerful and accurate cancer imaging tools available today. The PET/CT imaging test has become the most effective way to non-invasively detect the initial spread of breast cancer, how well a patient is responding to therapy, as well as the true extent of a recurrence. It has not only diagnostic value but also prognostic value.

So how does a PET/CT scan work? CT scanners send x-rays through the body, which are then measured by detectors in the CT scanner. A computer algorithm then processes those measurements to produce pictures of the body’s internal structures.

PET images begin with an injection of a solution of glucose (sugar) that has been “tagged” with a radioactive chemical isotope (generally fluorine 18, or FDG). Metabolically active organs or tumors consume sugar at high rates, and as the tagged sugar starts to decay, it emits positrons. These positrons then collide with electrons, giving off gamma rays, and a computer converts the gamma rays into images.

These images indicate metabolic “hot spots,” often indicating rapidly growing tumors (because cancerous cells generally consume more sugar/energy than other organs or tumors).

The entire examination usually takes less than 30 minutes, providing comprehensive diagnostic information to your health care team very quickly. The procedure is also non-invasive and is very comfortable for the patient.

In addition, if the patient requires radiotherapy for treatment, these images can be fused with the simulation images in order to pinpoint areas which may require higher does of radiation.

EDITOR’S NOTE — Dr. Ling is the radiation oncologist at the Foster J. Boyd, MD, Regional Cancer Center, an affiliate of CMH Regional Health System located at 31 Farquhar Ave., Wilmington. Healthy Outlook, a periodic offering of CMH medical staff and other staff, includes information from several resources including the writer’s professional experience.