Atoms of element which emit radiations in certain forms are called Isotopes. These are of 2 types (i) Stable isotopes which do not decay (ii) the radio-active isotopes emit radiations and decay with time. Artificial Radioisotopes can be produced by bombarding a stable isotope of an element with nuclear particles. Pakistan Atomic Energy Commission has set up a Radio isotope production group at PINSTECH in Islamabad. Swimming pool reactor is used for research purposes. Main operations involved in the production of radioisotopes include target preparation and irradiation. The sample is sealed off from any direct contact with reactor surfaces, other-wise irradiation of an unsealed target could cause contamination of the entire reactor by the radioactive products. Selected containers are used for the samples exposed in the reactor. Radioisotopes have many applications. Human body can be studied with the help of Radioisotopes and different diseases, diagnosis and treatments can be done. Volume of water and blood of the body can be measured by Radioisotopes which can also measure the amount of red blood corpuscles with chromium and iron. Different types of tumours in the human body can be studied with the radioisotopes of iodine, phosphorus and potassium. Radio-isotopes help in understanding the plant and animal metabolism, evaluation of improved varieties, fertilizer, water uptake and the elimination of insects and pests, studying plant, soil and animal nutrition. Radioisotopes are useful in recognizing the plant diseases, their prevention and cure. Carbon-14-isotopes are used to study metabolic changes in Tobacco plants induced by virus infection. Sulphur radioisotopes are used to find the Fungal diseases. They are used for the detection of leaks in water and petrol pipes in buildings and are used for inspecting damaged parts and poor electrical connections in the frames of aircrafts.