Diagnosing Lung Cancer - Lung Cancer Diagnosis

Physical Examination
Patients who are suspected of having lung cancer should undergo a thorough physical examination. In addition, the physician may ask the patient to provide a sample of sputum (matter from the throat and ungs, which is spit out through the mouth). The sputum sample will be sent for testing to see if it contains bacteria, other infectious organisms, or cancer cells; cancer cells may be present in the sputum in certain types of lung cancer. If sputum analysis does not provide a definite diagnosis, more tests will be needed. The physician may want to perform one or more of the following tests.

Chest radiograph (x-ray) is used to detect enlarged lymph nodes in the chest or a localized mass in the lungs.
Computed tomography (CT or "CAT" scan) is a computer-assisted technique that produces cross-sectional images of the body.
Magnetic resonance imaging (MRI scan) is a diagnostic method in which hydrogen ions within the body (and/or specific body parts) are excited by exposure to a magnetic field. The resulting signals are processed by a computer to create an image of the chest to define the location and extent of lung involvement.
Bronchoscopy is a visual examination of the windpipe and lung branches performed by a pulmonologist (respiratory disease specialist) using a flexible scope. Bronchoscopy may involve brushings (using a small, brush-like device to gather cells from the tissue lining the respiratory system), washings of the respiratory tissues for cell analysis, and biopsy (removal and examination of small amounts of tissue). If the bronchoscopy is still unrevealing, or "negative," a needle biopsy may be performed.
Needle biopsy, with CT-guidance, may be performed on suspicious areas in the lungs or pleura. Fine needle aspiration (FNA) uses a slim, hollow needle that is attached to a syringe. The needle is inserted into the suspicious mass and it is pushed back and forth to free some cells, which are aspirated (drawn up) into the syringe and are smeared on a glass slide for analysis. Large needle, or core biopsy, uses a large-bore needle to obtain a tissue sample for analysis.
Bone scan may also be performed to rule out suspicions of metastasis to the bones. Metastasis is the process wherein cancerous cells break away from the original tumor, travel, and grow within other body parts.

A newer imaging test, called CT/PET fusion imaging, combines the technology of CT scan with the technology of PET (positive emission tomography) scan. PET scans involve injecting a sugar-based radiopharmaceutical, which travels through the body and collects in organs and tissues. The PET scan is used to detect cancer cells in the body and the CT scan provides detailed images that can determine the location and size of the cancer. When the results of these tests are "fused" (brought together), the images provide more complete diagnostic information. CT/PET fusion imaging may be used to help diagnose some forms of lung cancer.