Doctors hail benefits of nuclear medicine

Nuclear medicine is painless, safe and very cost-effective. The best aspect of nuclear medicine is that it is easy to find the structure and function of sick organs. The field is becoming more familiar as its clinical use increases, as positron emission tomography is used to diagnose cancers and radioisotopes are used in cancer treatment.
Beginning tomorrow until Friday, the World Congress of Nuclear Medicine and Biology will be held at the COEX conference center, in southern Seoul.
But still there are many people who are afraid of nuclear medicine primarily because it uses radioactive materials.
“The amount of radiation exposure depends on the amount of usage, the exposure time and the distance from the source. The amount of radiation used on patients is the absolute minimum of a few picograms [one trillionth of a gram] and the exposure length is very short,” said Lee Gyeong-han, a doctor of nuclear medicine at Samsung Medical Center. “It’s not dangerous at all to the human body,” he added.
“About 85 percent of the radiation exposure amount we receive every day comes from the environment, such as the air, soil and rocks. Television sets, luminous watches and smoke detectors also emit radioactive materials,” Dr. Lee said. The radiation exposure amount for medical uses is very small, he added.
Finding the disease at an early stage is very important in treating many serious ailments. For that positron emission tomography is popular. By injecting isotopes that introduce a fluorine, whose atomic weight is 18, to the body and recording the radiation distribution, tomography allows doctors to identify abnormal molecular conditions.
Cancer cells can be easily found this way because their glucose metabolism is more active than normal cells. Tomography also aids in differentiating cancers. The glucose metabolism of a fast-growing malignant cancer is more active than that of a slow-growing cancer.
In order to check for cancer, full body positron emission tomography is used.

“A stomach endoscope is used to check for stomach cancer and a brain magnetic resonance imager is more accurate to detect and monitor brain cancer, but when it’s hard to know whether a patient has cancer in a specific organ, full body positron emission tomography helps in finding hidden cancers,” said Lee Myeong-cheol, a doctor of nuclear medicine at Seoul National University Hospital. He added that tomography finds cancers in 1 percent of the total number of people tested.
When checking if cancer treatment is being effective or if the cancer has recurred, nuclear medicine is also used. After getting radiation treatment, a nuclear medical examination is the most effective way to check for the possibility of a relapse.
Nuclear medical examinations are also used to find brain disorders at an early stage. “It is possible to diagnose brain disorders when changes are taking place in the molecular biology, such as the neutrotransmitters, even before atomic changes take place in the brain,” said Seoul National Hospital’s Dr. Lee.
For example, in early stages of Alzheimer’s disease, glucose metabolism drops in the frontal lobe. If nuclear medicine is used, the disease can be found at an early stage, while a magnetic resonance imager can only find it after the disease has progressed for some time.
Patients with ischemic heart diseases such as angina pectoris or myocardial infarction sometimes receive nuclear medical examinations in order to check the state of their heart muscles before deciding whether to have an operation.
Nuclear medical examinations using gamma cameras have been used for decades in order to thoroughly test for thyroid disease.
Nuclear medicine is also used in treatment, particularly for thyroid cancer or hyperthyroidism. By injecting radioactive iodine (131I), the diseased thyroid cells can be destroyed.

by Dr. Hwang Se-hee