Nuclear medicine has become fundamentally life-saving as a diagnostic tool in today’s medicine, however exposure to radioisotopes has risks. Understanding these risks and making an educated decision is crucial in personal choices regarding medical treatment. This overview of recent and relevant research provides an insight and support to the benefits of radioisotope usage, whilst presenting the associated risks. ? INTRODUCTION: With the discovery of radioisotopes in 1934, and the production of radionuclides in 1946, the world has witnessed a major growth and evolution in the field of Nuclear Medicine.
(Mandal, 2012) This specialty field utilises radionuclides for the diagnosis and subsequent treatment of disease. The process involves administering radioactive materials to the patient, with the ability to localize this material to a specific organ. (Department of Nuclear Medicine - Austin Hospital, 2007) This then allows the specialists to map an organ’s cellular function, instead of the physical changes in it’s tissue which more traditional imaging techniques such as X-ray reveal. (DNM, 2007) prepare a presentation on an issue of public concern related to the careprofession.
Although being highly effective in its application, the use of radioactive substances poses an inherent risk to both the patient, health professionals, and on a broader scale, the environment. This article discusses the implications of nuclear medicine and evaluates the dangers associated with it. ISOTOPES: WHAT ARE THEY? Many of the known chemical elements have a number of isotopes. (Gothard, 2004) Isotopes can be referred to as a ‘species’ of the base element, however, unlike elements, they feature a differing mass number, meaning the amount of protons and neutrons is imbalanced. (Gothard, 2004)/
Sometimes, an isotope exists with an unstable nucleus, spontaneously emitting excess energy through radiation known as alpha (? ) particles, beta (? ) particles or gamma (?? ) rays. (Figure 1) (Mandal, 2012) This is known as a radioactive isotope, or radioisotopes. As radioisotopes emit certain particles over time, its nucleus will begin to decay until it becomes stable again. RADIOISOTOPES IN NUCLEAR MEDICINE:
Following the discovery of radioisotopes, doctors were able to learn how to combine them with existing pharmaceuticals, which were already known, to concentrate in certain parts of the body. By utilising the radioactivity of the resulting compound, specialist equipment was able to be designed to trace the distribution of these compounds through the patients body. Two major imaging systems currently in use are PET and SPECT scanners. (Mandal, 2012) POSITRON EMISSION TOMOGRAPHY (PET): This method of nuclear scanning involves injecting a radioactive glucose combination into a patient.
As a result of the high metabolism of cancerous cells, the radioactive glucose will be rapidly consumed by a cancerous cell. (National Cancer Institute, N/A) Subsequent rotational scanning of the patients body will allow an image to be developed through the detection of gamma rays emitted from the radioactive glucose mix. This shows the location of these cancerous cells due to their radioactivity. (NCI, N/A) The digital image is then converted into two and three dimensional images of the targeted organ.
From the images, further analysis could determine if a previously identified cancer cell is dying, as the cancer would require a smaller amount of the glucose mix. (PET PROS, 2009) SINGLE POSITRON EMISSION TOMOGRAPHY (SPECT): SPECT scans differ from PET scans by the medium they use to transport the radioisotope. (Mayfield Clinic, 2014) It involves radioactive material known as tracers, which, when injected into a patient, mix with the blood and are transported around the body. As with PET scanning, the makeup of the radioactive tracer can be controlled to give the ability to target a specific part of the body.
(NCI, N/A) The gamma sensors are then able to record an image of the blood flow through the tissue. The image resolution provided by SPECT scanning isn’t as high as a PET scan due to the internal processes and the way the radiation is measured. (NCI, N/A) However, SPECT scans are considerably cheaper due to requiring easily obtained radioisotopes. This allows a wider cross section of the community to take advantage of the technology. The SPECT scan opposite can be used to effectively identify abnormalities regarding the function of the patient’s brain.
The two images on the top show decreased blood flow to the left side of the brain, confirming for surgeons the nonfunctioning area of the brain, causing seizures. (Mayfield Clinic, 2014) ? RADIATION THERAPY: Radiation can be classified as either ionizing or non-ionizing. The difference lies in the radiation’s frequency. (American Cancer Society, 2010) Ionizing radiation has a very high frequency, and contains enough energy to alter the structure or DNA of the cell when it collides with it.
It is this property that radiation therapy uses to kill off damaged cancer cells when high doses are directly targeted at the known cancer cells. (ACS, 2010) RISKS AND ISSUES: Radiation, despite the negative public image, is an everyday fact of life. The light coming from the sun, and the heat that our bodies emit are all forms of radiation. (Radiation Protection, 2012) As was highlighted earlier, the radioisotopes used in nuclear medicine are all forms of ionization radiation.
Following the discovery of radioisotopes, doctors were able to learn how to combine them with existing pharmaceuticals, which were already known, to concentrate in certain parts of the body. By utilising the radioactivity of the resulting compound, specialist equipment was able to be designed to trace the distribution of these compounds through the patients body. Two major imaging systems currently in use are PET and SPECT scanners. (Mandal, 2012) POSITRON EMISSION TOMOGRAPHY (PET): This method of nuclear scanning involves injecting a radioactive glucose combination into a patient.
As a result of the high metabolism of cancerous cells, the radioactive glucose will be rapidly consumed by a cancerous cell. (National Cancer Institute, N/A) Subsequent rotational scanning of the patients body will allow an image to be developed through the detection of gamma rays emitted from the radioactive glucose mix. This shows the location of these cancerous cells due to their radioactivity. (NCI, N/A) The digital image is then converted into two and three dimensional images of the targeted organ.
From the images, further analysis could determine if a previously identified cancer cell is dying, as the cancer would require a smaller amount of the glucose mix. (PET PROS, 2009) SINGLE POSITRON EMISSION TOMOGRAPHY (SPECT): SPECT scans differ from PET scans by the medium they use to transport the radioisotope. (Mayfield Clinic, 2014) It involves radioactive material known as tracers, which, when injected into a patient, mix with the blood and are transported around the body. As with PET scanning, the makeup of the radioactive tracer can be controlled to give the ability to target a specific part of the body.
(NCI, N/A) The gamma sensors are then able to record an image of the blood flow through the tissue. The image resolution provided by SPECT scanning isn’t as high as a PET scan due to the internal processes and the way the radiation is measured. (NCI, N/A) However, SPECT scans are considerably cheaper due to requiring easily obtained radioisotopes. This allows a wider cross section of the community to take advantage of the technology. The SPECT scan opposite can be used to effectively identify abnormalities regarding the function of the patient’s brain.
The two images on the top show decreased blood flow to the left side of the brain, confirming for surgeons the nonfunctioning area of the brain, causing seizures. (Mayfield Clinic, 2014) ? RADIATION THERAPY: Radiation can be classified as either ionizing or non-ionizing. The difference lies in the radiation’s frequency. (American Cancer Society, 2010) Ionizing radiation has a very high frequency, and contains enough energy to alter the structure or DNA of the cell when it collides with it.
It is this property that radiation therapy uses to kill off damaged cancer cells when high doses are directly targeted at the known cancer cells. (ACS, 2010) RISKS AND ISSUES: Radiation, despite the negative public image, is an everyday fact of life. The light coming from the sun, and the heat that our bodies emit are all forms of radiation. (Radiation Protection, 2012) As was highlighted earlier, the radioisotopes used in nuclear medicine are all forms of ionization radiation.
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