Why 99mTc is the preferred radioisotope for diagnostic studies?
99mTc is preferred because it has many favorable properties required for use in nuclear medicine, which are as follows: • 140 keV gamma energy of 99mTc is ideally suited for efficient detection and giving high- resolution pictures with the gamma-camera. The loss due to attenuation by the body tissue is also low at this energy. • The decay of 99mTc (T1/2 6 hrs) is associated with insignificant particulate emission and hence99mTc radiopharmaceuticals typically containing even upto 30 -40 mCi can be injected safely into patients. Such large dose helps in getting better quality images and thereby more reliable information. • The 6-hr half -life of 99mTc is well suited for most of the nuclear medicine studies. • The versatile chemistry of Tc allows the chemical formulation of a variety of labeled compounds for multifarious applications. • 99mTc can be conveniently obtained from a generator system of 99Mo-99mTc • The parent 99Mo is available at low cost and hence the cost of the final radiop
