Radiology & Lung Cancer Detection

Most lung cancer is detected through X-rays.

Lung cancer is a terminal disease that primarily affects the lungs. However, lung cancer can spread to other tissues and organs through the lymph nodes or the blood stream if not detected early and treated. There are several diagnostic methods of imaging technology that are used by radiologists in the detection of lung cancer, and most lung cancer is detected by routine chest X-rays for other issues before any signs or symptoms of lung cancer arise.

Causes, Signs and Symptoms

Smoking is the No. 1 cause of lung cancer. Other causes include: second-hand smoke, asbestos exposure, lung diseases like tuberculosis (TB) and chronic obtrusive pulmonary disease (COPD), radon exposure and certain occupations.

Most patients with lung cancer do not experience any signs or symptoms until the much later stages of the disease. In some cases, patients will experience one or more of the signs and symptoms of lung cancer, including a cough that is either new or has gotten worse over time; coughing up any amount of blood; chest pain that is dull, achy and persistent; shortness of breath; wheezing or hoarseness; or repeating respiratory infections such as bronchitis or pneumonia. If you have any of these signs or symptoms, seek medical attention immediately.

Chest Radiology (X-ray)

Chest X-rays are one of the most readily available diagnostic tools. Chest X-rays are the first step taken in the diagnosis of lung cancer. This type of imaging exposes the patient to small doses of radiation. These X-rays take images of the lungs from side, frontal and back views, revealing the presence of any abnormal masses. However, X-rays cannot determine if the mass found is cancerous; further testing is needed. This additional testing will also determine the extent of any damage.

Computerized Tomatography (CT)

CT scans are enhanced 3-D X-rays producing cross-section images of the area being scanned, including the abdomen, chest and head. With this enhanced 3-D ability, a CT scan is much more accurate than the typical chest X-ray in the detection of lung cancer. The imaging of a CT scan is so precise that it can detect specific features on tumors found in patients with lung cancer, enabling doctors to better detect any damage and spreading caused by this terminal disease. CT images also can pinpoint the location and size of tumors in lung cancer patients. Radiation exposure is minimal with a CT scan.

Magnetic Resonance Imaging (MRI)

This type of imaging is produced by radio waves, magnetism and computers to give very detailed images of the areas that are scanned. CT imaging is not as accurate as MRI imaging in the detection of lung cancer tumor types, and there is no exposure to radiation. MRI scans are becoming more available, but tend to be a much slower process than the CT scan. MRIs are also significantly more expensive than a CT scan. In addition, special resolution is poorer on MRI imaging and respiratory movement can blur images.

Patients who have undergone any procedure involving the implantation of a heart valve, pacemaker or any other metal implant of any kind, cannot have an MRI scan. Doctors fear that the magnetism of the machine would displace or interfere with these implanted devises.

Positrom Emission Tomography (PET)

Measuring metabolic activities and tissue functions, PET imaging can detect where glucose is being used in the body. This allows doctors to differentiate between benign (non-cancerous) tumors and malignant (cancerous) tumors. PET imaging is done using intravenous (IV) radioactive drugs that move through the blood stream and attach to various cells in the body producing a colored 3-D image for doctors to examine metabolism in tissue cells. PET imaging can determine whether or not a tumor is actively growing and spreading. In addition, PET scans help determine the particular type of cells within a particular tumor to provide extensive information on the growth of such tumors. This method provides detailed information on lung cancer, and goes a long way in properly diagnosing and treating the disease.

References

• European Respiratory Journal: Diagnostic Imaging of Lung Cancer
• EMedicineHealth: Lung Cancer Overview
• MedicineNet.com: Lung Cancer