How is radiation useful in medical science?



In health and medicine, genomic research, medical imaging and functional exploration, radiotherapy, targeted irradiation, sterilization of surgical tools, parasitic illnesses are based on nuclear and irradiation techniques.



Nuclear and radiation techniques are often the sole means of diagnosis and treatment in a large number of health problems, or complement non-nuclear techniques. Nuclear medicine procedures with unsealed radioactive sources are used in-vitro and in-vivo for the diagnosis and management of diseases. Molecular biology based on nuclear techniques plays an effective role in the fight against communicable diseases like tuberculosis, malaria and HIV/AIDS. Radiotherapy, one of the earliest applications of radiation, remains a major cost-effective modality available for cancer treatment, often in conjunction with diagnostic radiology and nuclear medicine procedures for tumour localization. Fostering and maintaining a quality assurance culture, leading to accurate dosimetry, dose delivery and patient protection, are of paramount importance in the success of the application of these techniques. In addition to these areas of Radiation Medicine, public health measures are also supported by activities in nutritional and health environment areas.

Nuclear medicine can be broadly divided into two branches "in vitro" and "in vivo" procedures. (Isotopes are different species of atoms of the same chemical element with the same atomic number and position in the periodic table with identical chemical behavior but with different atomic masses and physical properties. They can be radioactive or stable). There are numerous radio-isotopic "in vitro" procedures for genotyping and molecular profiling applicable to clinical molecular biology. These procedures are becoming increasingly important in several clinical and pre-clinical conditions, from determining changes in cancer cells to drug resistance in malaria parasites. These techniques proved to be increasingly valuable in preventing catastrophic consequence of ineffective treatment.

The majority of nuclear medicine procedures are "in vivo" non-invasive procedures. After administration of the radiopharmaceutical typically by intravenous route (sometimes locally) to a patient, its distribution and localization provides functional or metabolic information. This helps doctors to make critical decisions based on objective information about the status and function of a particular organ or disease .The data is depicted with the aide of imaging systems called gamma-cameras (be they planar or SPECT systems) and transformed into images which allow visual determination and staging of the disease. One of the fastest growing techniques is positron emission tomography (PET) that requires special instrumentations called PET tomography. This technique allows clinicians to track organ function at a molecular level, therefore revealing intricate health changes earlier in individual patients than other diagnostic modalities.

The accurate measurement of radiation dose (dosimetry) is important in various applications such as radiation oncology, diagnostic radiology, nuclear medicine and radiation protection to prevent undue irradiations.

Reference: IAEA Web site, NEA Web site