The evolution of nuclear medicine has resulted in a number of effective procedures in diagnosis and treatment. Based on the rapid development of MRI, CT, and Ultrasound, there is no doubt about the future of nuclear medicine, but not to forget that it is a diagnostic tool for continuous improvement.

History of Nuclear Medicine

The beginning of nuclear medicine started with an invention by Ernest Orlando Lawrence between 1901 and 1958, he invented the cyclotron. He worked as a nuclear physicist at the University of California and centered his research on raiding atoms at high speed to generate new particles. To achieve this immensity of raiding accelerators were used but it was almost impossible to create a machine that would withstand the amount of electrical potential needed. Ernest was able to counter that obstacle by building the first cyclotron, and he kept on improving it, till it went over the potential of one million volts.

What is Nuclear Medicine?

This indeed is a branch of medicine that uses radioactive tracers in the diagnosis and treatment of diseases, also to assess body functions. The scans performed are usually carried out by radiographers. Moreover, because the detection of the radiation emitted is from inside the body, its specialty is call endo-radiology. An example is an x-ray procedure. 

Comparisons

The significant difference between nuclear medicine diagnostic tests and other traditional imaging types is that nuclear imaging technique shows the physiological function of the tissue or organ under investigation. On the other hand, traditional imaging systems like computed tomography (CT) and magnetic resonance imaging (MRI) shows only the anatomy or the structure. They are also organ and tissue-specific. While a CT or MRI scan can be used to visualize the whole of the chest or abdominal cavity, an example being that nuclear imaging techniques are used to view particular organs like the lungs, the heart or brain. Studies of nuclear medicine can also be whole-body based if the agent being used targets specific cell functions or receptors. Examples include the whole-body PET scan or PET/CT scan.

What are Radioactive Tracers?

They are made up of carrier molecules that are in tight bonds to an atom. These carrier molecules differ greatly depending on what the scan is to be used for. Some tracers bind to molecules that interact with a particular protein or sugar in the body and can even interact with the patient’s own cells. For instance, let us say a doctor wants to know the exact source of an intestinal bleeding, they may add radioactive atoms to a sample of red blood cells taken from the patient. They will then reinject the blood and use a SPECT scan to see how the blood will travel in the patient. Any accumulation of radioactivity in the patient tells the doctor where the problem lies.

For most diagnostic purposes, the radioactive tracer is given to the patient by intravenous (IV) injection. However, a radioactive tracer may also be given by inhalation, oral ingestion, or direct injection to an organ. The mode of administration will depend on the process of the disease that is under study.

Types of Imaging Used in Nuclear Medicine

Molecular imaging is related to the process by which a very small amount of radioactive materials (radiopharmaceuticals) are used to diagnose and treat diseases. In this type of medical imaging, the radioactive materials are detected using special cameras. These cameras work with computers to provide very distinctive pictures of the part of the body being imaged.

X-ray imaging makes use of an x-ray beam that’s projected onto the body. While passing through the body, parts of this beam are absorbed. The x-rays are detected on the opposite side of the body resulting in the formation of an image.

Other types of medical imaging work without making use of ionizing radiation, an example being the magnetic resonance imaging (MRI) and ultrasound imaging, but they do have particular uses in diagnosing a disease.

What is Nuclear Medicine Scans used for?

Single-photon emission computerized tomography (SPECT) scans are mainly used in the diagnosing and tracking of the progression of heart diseases, like blockage of the coronary arteries. They also have radiotracers to help in the detection of bone disorders, diseases of the gallbladder and intestinal bleeding. Agents of SPECT have recently become available for diagnosing Parkinson’s disease and differentiating them from other anatomically-related disorders of movement and dementias.

The primary purpose of PET scans is to detect cancer and monitor its growth, how it responds to treatment, and to trace metastases. In a rapidly dividing cancer cell, one can notice the increase of glucose due to its utilization. As a matter of fact, the degree of aggressiveness for most cancers is almost paralleled to the rate of glucose utilization. In the past 15 years, slightly modified radiolabeled glucose molecules (F-18 labeled deoxyglucose / FDG) have been proven to be the best available tracer in the detection of cancer and its metastatic spread.

An instrument that produces both PET and CT scans of the same body regions in one examination (PET/CT scanner) has become the much-required imaging tool in the staging of most cancers worldwide.

Recently, a PET probe was approved by the FDA to help in the diagnosing of Alzheimer’s disease, whose previous diagnoses would have only been accurate after the death of the individual. In the absence of this imaging test, Alzheimer’s disease can be mistaken for vascular dementia or other forms of dementia prone to the elderly.

Risks of using Nuclear Medicine and Recent Advancement

The total radiation dose granted to patients by the radiopharmaceuticals used in diagnostic nuclear medicine is no more than what is granted during routine chest x-rays or CT exams. There are legitimate concerns about possible cancer induction even by low doses of radiation exposure from total medical imaging examinations, but this risk is accepted to be quite minimal in comparison to the expected benefit gotten from a needed diagnostic imaging test. Just like radiologists, nuclear medicine physicians are very committed to keeping radiation exposure of patients to the barest minimum, giving the least amount of radiotracer needed to provide a useful examination diagnostically. Researchers of nuclear medicine are bent on developing new radiotracers and technologies that will help physicians in producing clearer pictures.

Nuclear medicine will continue to be an essential diagnostic tool.There are some advancements already made and more seems to be close. The field of nuclear medicine continues to attract people of interest and engage the public. This involvement of the society will also guarantee that hospital management will provide the accurate funds for necessary investments.

 

 

References

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