Medical imaging involves several scanning techniques to visualise the human body for diagnostic and treatment purposes. Also, medical imaging is very useful for patient follow-up, with regards to the progress of the disease state, which has already been diagnosed, and/or is undergoing a treatment plan. The vast majority of medical imaging is based on the application of X-rays and ultrasound (US). These medical imaging modalities are involved in all levels of hospital care. In addition, they are instrumental in the public health and preventive medicine settings as well as in the curative and further extending to palliative care. The main objective is to establish the correct diagnoses.
Medical imaging through a clinical setting is a vital contribution to the overall diagnosis of the patient and helps in the decision of an overall treatment plan. The utilisation of imaging techniques in nuclear medicine is increasing with new technological advances in medical imaging. Therefore, in the spectrum of a broad range of medical imaging modalities are the specialities of nuclear medicine, positron emission tomography (PET), magnetic resonance imaging (MRI) and ultrasound.
Overall, imaging for medical purposes involves a team of radiologists, radiographers, sonographers and medical physicists. Medical imaging involves a multidisciplinary approach to obtain a correct diagnosis for the individual patient with an aim of providing a personalised approach to patient care. These medical imaging techniques can be applied as non-invasive methods to view inside the human body, without any surgical intervention. They can be used to assist diagnosis or treat a variety of medical conditions. Medical imaging techniques utilise radiation that is part of the electromagnetic spectrum.
These include imaging X-rays which are the conventional X-ray, computed tomography (CT) and mammography. To improve X-ray image quality, a contrast agent can be used, for example, in angiography examinations.
Furthermore, medical imaging utilised in nuclear medicine can be attributed to several techniques to visualise biological processes. The radiopharmaceuticals used are usually small amounts of radioactive markers: these are used in molecular imaging. Other non-radioactive types of medical imaging include magnetic resonance imaging (MRI) and ultrasound (US) imaging. MRI uses strong magnetic fields, which do not produce any known irreversible biological effects in humans. Diagnostic ultrasound (US) systems use high-frequency sound waves to produce images of internal body organs and soft tissue. X-ray imaging uses X-ray beams that are projected onto the body. When these X-ray beams pass through the human body some are absorbed, and the resultant image is detected on the other side of the body.
Some types of medical imaging function without using ionising radiation; for example, magnetic resonance imaging (MRI) and ultrasound imaging and these have significant applications in the diagnosis of disease.
Medical imaging modalities include positron emission tomography (PET), single photon emission computed tomography (SPECT) and hybrid imaging systems. Alternatively, other systems use the application of radio-guided surgery (RGS) and this extends to positron emission mammography (PEM).
In addition, there is the application of short and long-lived radioisotopes for research and development of new imaging agents and associated targeted therapies. Other techniques include magnetic resonance imaging (MRI), computed tomography (CT), ultrasound (US) imaging and planar X-ray (digital, analogue, portable) systems.