One of the disadvantage of x ray radiography is superposition of images. Computed tomography technique developed in 1972. this a very sensitive technique to make the images of internal structures ,without any super positions . This method of imaging first invented by godfry housefield . he awarded nobel prize for this invention. The theoretical basis for this invention was gave by an Indian scientist gopalsamudram n ramachandran. In this technique a low dose x ray beam rotated around the body of the patient. The coming out rays are to be noted, by a sensitive detectors .in this method same body part examined in different angles .with the help of a computer the images are processed and analyzed. It can also give three dimensional views of organs. Doctors get a complete series of pictures .

Angiography

Angiography is a technique used to image the blood vessels. This technique gives the positions of block in blood vessels. The image in known as angiograph. The angiograph is taken of the organ ,and stored in a computer . a second angiograph is taken after contrast containing iodine , which is used to opaque x rays , the first image is subtracted from the second , give a clear picture of blood vessels.