Nuclear medicine is a branch of medicine involved in the diagnosis and treatment of various diseases using radioactive materials. The use of the words ‘nuclear’ and ‘radioactive’ can make the field sound a bit frightening. Yet developments in this field play a significant role in the early diagnosis of a number of conditions. Nuclear medicine also helps obtain satisfying treatment outcomes. As well as the field’s tests and anatomic imaging, it can also show tissue and organ function together with radiological tests using radioactive material.
We sat down with the Head of Yeditepe University Hospital Department of Nuclear Medicine, Assoc. Prof. Nalan Alan Selçuk who gave us a detailed explanation about radioactive materials, their effectiveness, and tests carried out at Yeditepe University Hospital using advanced nuclear medicine techniques and technology.
Assoc. Prof. Nalan Alan Selçuk briefs us, the radioactive materials used in nuclear medicine tests vary according to the organ to be examined. “People are naturally startled when they see the word radioactive. But the radioactive dosages we use are extremely low. For this reason the possibility of harming anyone’s health is recognized as zero. All our work is conducted at the level recommended by the International Atomic Energy Agency (IAEA).
Therefore the radiation dosages administered to our patients are not a level that could cause any damage to their health. For example, the amount of radioactive material used during a thyroid scintigraphy is equivalent to what a person might be exposed to during a two hour flight or a few hours sunbathing.”
USED FOR BOTH DIAGNOSIS AND TREATMENT
Nuclear medicine tests encapsulate tests directed at a specific organ or certain specific diseases. Procedures previously known under the general term scintigraphy now vary according to the organ and objective of the test
being carried out. One of these is PET – Positive Emission Tomography. This test facilitates imaging of normal or pathologic tissue accumulating intravenously injected metabolic radioactive material, allowing the measurement of important bodily functions such as blood oxygen, oxygen uptake and glucose metabolism. Since most PET screening is performed in conjunction with CT scanning, it is also known as PET CT. PET CT detects the exact location of abnormal metabolic activities in the body.
The radioactive material used in the PET screening depends on the organ being examined. For example, while fluorine marked glucose generally signifies a tumor, gallium 68 PSMA is specifically used in prostate cancer screening. DOA is a unique marker for neuro endocrine tumors. Radiocative materials are used for treatment as well as diagnosis. In cases where a prostate cancer lesion has been detected, molecules marked with a high energy radioactive material called lutetium 177 are re-injected into the patient to treat the condition.
THE METHOD OF CHOICE IN ONCOLOGY
PET CT has a particular usage in treating cancer patients. It can also be used in certain neurologic and heart diseases. 90% of usage is in the field of oncology, 5% neurology, and 5% cardiac cases. PET also plays a significant role in diagnosing coronary artery disease. In some myocardial infarction cases, it is thought that all the cells in the infarction area have been eradicated where as in some cases some of the tissue goes into hibernation, continuing to sustaining itself on a reduced supply of blood. When the blood is resupplied with the opening of the arteries, these tissues are revived. PET screening provides information about the concerned tissue as it relates to the heart, as well as on by-pass operations. Some centers decide on the efficacy of by-pass surgery only after determining whether or not hibernating tissue is present.
One nuclear test is densitometry, which determines the bone mineral intensity. Loss of bone minerals can lead to fractures; this test determines the patient’s response to treatment. Low dosage X rays can determine bone density in 10 minutes. These tests are generally applied in older aged patients.
Scintigraphy is the general term for imaging procedures conducted using radioactive materials with gamma camera equipment. It is used to diagnose problems in the thyroid gland, liver, spleen, stomach and intestines, kidneys, gall bladder, heart, lungs, veins and bones. Many patients have benefited from early diagnosis achieved using scintigraphy.
Used more and more frequently in recent years, gamma probe is a kind of nuclear medicine detector. The size of a pen, this handheld device is used under sterile conditions in the operating theater. Areas of the patient’s body that hold the radioactive material are located, enabling the gamma probe to pinpoint the location of the lesions. Targeted open surgical intervention is then carried out.
A POPULAR FIELD WITH A LONG HISTORY
Explaining that nuclear medicine is one of the most popular fields of specialization, Selçuk states “Doctors choose PET CT devices because of the advantages to the patient.
Assoc. Prof. Nalan Alan Selçuk went on to fill us in on the history of the procedure in Turkey. “The history of nuclear medicine is not as long as in other countries perhaps, but it has developed rapidly. A laboratory was first established by a specialist in endocrinology working in the area of thyroid function in the 1950’s in what is now Haseki Hospital. The story begins there. Nuclear medicine became a specialist field in 1974. Turkey was quick to adopt developments in other parts of the world; when compared to the rest of the world Turkey has kept well ahead in terms of routine patient diagnosis and treatment. “Whatever happens in the rest of the world happens in Turkey.”