The PET CT imaging method has come into prominence with detailed physiological and morphologic data provided by a single acquisition between oncological imaging methods in recent years. In new and high-tech PET CT systems, the total shooting time is 15 minutes or even shorter. Imaging includes areas between the head and upper thigh. In some special cases the entire body is imaged.

How does Pet Ct Do?
4-6 hours of fasting is required before shooting. Imaging is done after waiting for 45 minutes-1 hour in a private room after intravenous injection of a special radiopharmaceutical for cancer screening.  The images are obtained from photons captured by the system detector while passing over a surface moving from a circle-shaped area 70 cm in diameter. Total shooting time lasts about 15 minutes on average. Raw images are rendered in 3D with advanced technology reconstruction techniques. Both PET and CT images taken from the same regions of a single seance are brought upside down to obtain detailed morphological and physiological information about cancer disease. New and advanced PET CT systems can now be diagnosed even in cancer chambers smaller than 1 cm in size.

To Which Patients is Done?
PET CT is used for diagnostic purposes in cancer-suspected lesions as well as in pathologically diagnosed cancer patients to provide information on the progression of the disease (staging).Apart from this, it is also used in the evaluation of the response to treatment in patients receiving cancer treatment. It is mostly used in lung, breast, colon, stomach, esophagus, head and neck cancers and skin and soft tissue tumors. 
Apart from these, it can be used for early diagnosis in Alzheimer's and dementia and also in determining the cause of the disease in epilepsy.
It can also be used to determine the extent to which blocked coronary vessels damage the heart muscle and how well it will benefit from PTCA / stenting after heart attack. With the advancement of the technology, specific radiopharmaceuticals have been developed in PET CT systems to more organs and diseases and nowadays, besides FDG which is the standard oncological agent, agents such as Ga-68 DOTATATE and Ga68 PSMA are also successful imaging in neuroendocrine and prostate cancers respectively.

Pet Ct and Radiation
In advanced PET systems, high resolution diagnostic images can be obtained with much lower dose radiation in both CT and PET. After shots, patients should stay away from babies and pregnant women for only 4-6 hours due to the short half-life of the given radioactive substance. It is recommended to stop breastfeeding for 24 hours for the reason that breastfeeding women will receive a PET CT scan.