nuclear medicine technologist

Nuclear Medicine Technologist – PET/SPECT/CT imaging

Nuclear Medicine Technologist is a specialised healthcare professional affiliated with a Nuclear Medicine Department or Radiopharmacy. Nuclear medicine encompasses several disciplines including medical physics, imaging algorithms, radiochemistry and medical sciences to help and create a treatment plan for each patient.  The role of the Nuclear Medicine Technologist is to prepare and formulate a radiopharmaceutical imaging or radiotherapeutic agent and organise the administration of the individual dose to the patient.  The aim is to help form a patient treatment plan for the diagnosis of a range of disease states.  These disease states include stages of cancers, neurological disorders, heart disease, endocrine and gastrointestinal conditions amongst others.

The radiopharmaceutical contains a radionuclide which spontaneously emits radiation via alpha particles, beta particles or gamma rays.  The Nuclear Medicine Technologists – in association with the medical physicist – operate SPECT (single photon emission tomography) and PET (positron emission tomography) gamma camera systems to detect the radiation from the radiopharmaceuticals emitting from inside the human body.  This set-up enables the generation of images which are analysed to show the regions of the radiopharmaceuticals localised within the organs of the human body.  The abnormal areas will retain a level of radioactivity compared to the healthy surrounding tissues.  The nuclear medicine technologist and physicians analyse the generated images to diagnose molecular and metabolic processes: Also useful in the evaluation of physiological, anatomical and various pathological conditions.  The duties of the Nuclear Medicine Technologist extend to the operation of computed tomography (SPECT) and magnetic resonance imaging (MRI) scanners. Both these systems can be hybrids of SPECT and PET scanners.

Nuclear Medicine Technologist

Nuclear medicine imaging generates non-invasive images except when a radiopharmaceutical is given intravenously, and in most cases, the procedure is pain-free to help in the diagnosis and evaluation of the disease state of the patient. These SPECT and PET  imaging scans utilise radioactive materials called radiopharmaceuticals or radiotracers.  The radiotracer can be injected, swallowed or inhaled as a gas.  The tracer will then accumulate in the human body during the examination.  The radioactive emissions from the radiotracer are detected by a gamma camera or another imaging device which is capable of producing the images from inside the human body to generate the molecular information.  The advantages of these systems are that the nuclear medicine images can be combined with computed tomography (CT) or magnetic resonance imaging (MRI) to generate image fusion.  This approach enables two scans to be done in one patient sitting and the information can be correlated with one image combine to produce an accurate diagnosis.  These hybrid scanners extend to single photon emission computed tomography (SPECT)/computed tomography (CT) systems including positron emission tomography (PET)/computed tomography (CT) machines.  Another technology platform being developed uses a combination of the PET/MRI hybrid scanner.

Nuclear medicine technologist also offers radiotherapeutic procedures which include radioactive iodine (I-131) therapy using SPECT imaging.  In this procedure, a tiny amount of radioactive material is used to treat cancer and other medical conditions affecting the thyroid gland.  Also, Non-Hodgkin’s lymphoma patients who do not respond to chemotherapy may undergo radioimmunotherapy (RIT).  The radioimmunotherapy (RIT) is a personalised cancer treatment that combines radiation therapy with the targeting ability of immunotherapy and is designed to imitate cellular activity in the immune system of the human body.

Radiation Therapeutic Physics

Radiation therapeutic physics (radiotherapy physics or radiation oncology physics) is concerned mostly with linear accelerator (Linac) systems and kilovoltage X-ray treatment units.  In addition to more advanced modalities such as tomotherapy, gamma knife, cyberknife, proton therapy, and brachytherapy.

Therapeutic physics may include boron neutron capture therapy, sealed source radiotherapy and terahertz radiation systems. Therapeutic physics also involves high-intensity focused ultrasound, optical radiation lasers, ultraviolet and amongst others. Furthermore, extending to photodynamic therapy including nuclear medicine using unsealed source radiotherapy and photomedicine.

Nuclear Medicine is a discipline that uses radiation to gain information about the functioning of the human body’s organs to diagnose disease and to apply appropriate therapy treatments.  The information generated helps the physicians to make a reasonable and accurate diagnosis of the patient’s disease state.

The organs of the human body which can easily undergo imaging include thyroid, bones, heart, liver amongst others. Another use of radiation is its ability to treat diseased organs and/or tumours. Radiotracers in medicine are widely used throughout the World healthcare organisations and this extends to mobile facilities. About 10,000+ hospitals worldwide use radioisotopes in medicine for diagnosis and therapy procedures.  The most diverse radioisotope used in diagnosis is technetium-99m.  This radionuclide accounts for over 30 million procedures per annum and accounts for 80% of all nuclear medicine procedures.  In context, the USA produces some 18 million nuclear medicine procedures per year. In Europe, there is about 10 million procedure from a population of 500 million people. Marketing suggests that the use of radiopharmaceuticals in diagnosis is growing at a rate of 10% per annum.

Nuclear medicine which began in the 1950s by physicians investigating the endocrine system using iodine-131 to diagnose and treat thyroid disease. The medical physicist liaises with a radiologist due to the hybrid PET-CT systems including SPECT scanners.  CT scanning and nuclear medicine contribute to over a third of the total radiation exposure.  The average total yearly radiation exposure in the USA per person is 6 mSv per year.

The responsibility of the Health Physicist (Radiation Safety or Radiation Protection Officer) is with the evaluation and control of health hazards associated with the safe handling of radiation sources. Therefore, the supervision and monitoring of radionuclides or ionising radiation in the clinical setting is of paramount importance to regulatory requirements.

The application of more advanced computer systems is to enable processes to analysis complex driven by the generation of computer algorithms for the delineation of anatomical structures for the next generation of PET and SPECT scanners.  For example, image segmentation plays a central role in various biomedical imaging applications.  These include quantification of tissue volumes, diagnosis and localization of pathology.

In addition, to the study of anatomical structure, treatment planning and computer-integrated surgery, the application of a 3-D volume extraction algorithm was suggested for the segmentation of cerebrovascular structure for the brain.  Previous knowledge of the cerebrovascular structure and multiple seed voxels are identified on the initial image.

In light of the preserved voxel connectivity, the seed voxels were grown within the cerebrovascular structure area throughout the 3-D volume extraction procedure.  This algorithm improved the segmentation results compared to other methods such as the histogram approach.  Furthermore, this 3-D volume extraction algorithm is also applicable to segment tree-like organ structures. For example, the renal artery and coronary artery can be derived from these medical imaging modalities.

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