Lung Scanning

A Lung scanning is a nuclear medicine test that produces a picture of blood flow to the lungs. A lung ventilation scan measures the ability of the lungs to take in air and uses radiopharmaceuticals to produce a picture of how air is distributed in the lungs. Lung perfusion scans and lung ventilation scans are usually performed in the same session. They are done to detect pulmonary embolisms, determine how much blood is flowing to lungs, determine which areas of the lungs are capable of ventilation, and assess how well the lungs are functioning after surgery. These tests are called by different names, including perfusion lung scan, aerosol lung scan, radionucleotide ventilation lung scan, ventilation lung scan, xenon lung scan, ventilation/perfusion scanning (VPS), pulmonary scintiphotography, or, most commonly, V/Q scan. The amount of radioactivity a person is exposed to during these tests is very low and is not harmful. However, if the patient has had other recent radionuclear tests, it may be necessary to wait until other radiopharmaceuticals have been cleared from the body so that they do not interfere with these tests. In Lung Scanning, a small amount of the protein labeled with a radioisotope is injected into the patient's hand or arm vein. The patient is positioned under a special camera that can detect radioactive material, and a series of photographs are made of the chest. When these images are projected onto a screen (oscilloscope), they show how the radioactive protein has been distributed by the blood vessels running through the lungs. In Lung Scanning, an absence of radioactive marker material suggest's decreased blood flow to that part of the lung, and possibly a pulmonary embolism. However, pneumonia, emphysema, or lung tumors can create readings on the lung perfusion scan that falsely suggest a pulmonary embolism is present.In the lung ventilation scan, absence of marker material when the lung perfusion scan for the area is normal suggests lung disease.Certain combinations of abnormalities in lung perfusion and ventilation scans suggest pulmonary embolism.

Lung Scans

A controversial study suggests that computed tomography (CT) scans catch lung cancer early in smokers and other high-risk people, enabling doctors to intervene when they still can improve a patient's chances of survival. However, some scientists criticize the study's design for leaving many questions unanswered.By the time lung cancer is typically discovered, it has spread to lymph nodes or other organs. As a result, only 15 percent of people with lung cancer survive 5 years after their diagnosis. Lung scans have been proposed as a tool to find early lung cancers.
In the two screenings, or in the interim, 484 participants were diagnosed with lung cancer. Of these, 412 had early-stage cancer confined to the lung. Most underwent surgery promptly after diagnosis. As of May 2006, 92 percent of these early-stage patients who had surgery were still alive, says study coauthor Claudia I. Henschke, a physician at the Weill Medical College of Cornell University in New York City. Typically, only 50 to 70 percent of early-stage patients survive 5 years.Although the study is a welcome foray into lung cancer screening, it doesn't establish CT scanning as an effective test, says pulmonologist Michael Unger of the Fox Chase Cancer Center in Philadelphia.The study lacked a separate group whose outcomes the researchers could compare with those of people getting CT screening. Such a population could have gotten chest X rays or no screening at all.Moreover, the biological nature of the cancers wasn't elucidated, Unger says. That means that the scientists didn't know whether they were catching aggressive cancers or just removing very slow-growing tumors that wouldn't have spread and ultimately killed the patient, says Denise Aberle, a radiologist at the University of California, Los Angeles School of Medicine.Attacking a suspected tumor with an array of invasive medical procedures can lead to "emotional, economic, and medical risks" for the patient, Aberle says. "Intuitively, we think that screening offers a better chance of survival. But we don't know [in this case] whether the potential benefit will outweigh the potential harm." The Lung scans in this study resulted in lung biopsies of 43 people who turned out to have no malignancies.For now, Unger says, asking a doctor for a CT scan as a test for lung cancer is like "opening a Pandora's box."The screening debate probably won't be settled until 2009. That's when the first results will emerge from a large U.S. trial by Aberle and others comparing mortality from lung cancer in people screened with either Lung scans or chest X rays. A similar trial is under way in Europe.

Lung Scans

A controversial study suggests that computed tomography (CT) scans catch lung cancer early in smokers and other high-risk people, enabling doctors to intervene when they still can improve a patient's chances of survival. However, some scientists criticize the study's design for leaving many questions unanswered.By the time lung cancer is typically discovered, it has spread to lymph nodes or other organs. As a result, only 15 percent of people with lung cancer survive 5 years after their diagnosis. Lung scans have been proposed as a tool to find early lung cancers.
In the two screenings, or in the interim, 484 participants were diagnosed with lung cancer. Of these, 412 had early-stage cancer confined to the lung. Most underwent surgery promptly after diagnosis. As of May 2006, 92 percent of these early-stage patients who had surgery were still alive, says study coauthor Claudia I. Henschke, a physician at the Weill Medical College of Cornell University in New York City. Typically, only 50 to 70 percent of early-stage patients survive 5 years.Although the study is a welcome foray into lung cancer screening, it doesn't establish CT scanning as an effective test, says pulmonologist Michael Unger of the Fox Chase Cancer Center in Philadelphia.The study lacked a separate group whose outcomes the researchers could compare with those of people getting CT screening. Such a population could have gotten chest X rays or no screening at all.Moreover, the biological nature of the cancers wasn't elucidated, Unger says. That means that the scientists didn't know whether they were catching aggressive cancers or just removing very slow-growing tumors that wouldn't have spread and ultimately killed the patient, says Denise Aberle, a radiologist at the University of California, Los Angeles School of Medicine.Attacking a suspected tumor with an array of invasive medical procedures can lead to "emotional, economic, and medical risks" for the patient, Aberle says. "Intuitively, we think that screening offers a better chance of survival. But we don't know [in this case] whether the potential benefit will outweigh the potential harm." The Lung scans in this study resulted in lung biopsies of 43 people who turned out to have no malignancies.For now, Unger says, asking a doctor for a CT scan as a test for lung cancer is like "opening a Pandora's box."The screening debate probably won't be settled until 2009. That's when the first results will emerge from a large U.S. trial by Aberle and others comparing mortality from lung cancer in people screened with either Lung scans or chest X rays. A similar trial is under way in Europe.