In radiography, the process to produce an image is quite different. The camera is actually a radiation source and it operates quite differently than a photographic camera. The film is not placed inside the camera but instead is placed on the opposite site of the object being imaged. The radiation is not reflected to the film, but rather passes through the object and then strikes the film. The image on the film is dependent upon how much of the radiation makes it through the object and to the film. Some materials like bone and metal stop more of the radiation from passing through than do materials like flesh and plastic. The amount of material that the X-rays must travel through also affects how many X-rays reach the film. Differences in the type of material and the amount of material that the X-rays must penetrate are responsible for the details in the image.
We use Either an X-ray machine or a radioactive source (Ir-192, Co-60, or in rare cases Cs-137) can be used as a source. Iridium-192 (symbol Ir192) is an isotope of iridium. Its half-life is 73.83 days. It decays by emitting beta particles and gamma radiation. Iridium-192 is used as a gamma ray source in industrial radiography to locate flaws in metal components. It is also used in radiotherapy as a radiation source. Cobalt-60 (60Co) is a radioactive isotope of cobalt. Due to its short half life of 5.27 years 60Co is not found in nature. It is produced artificially.