What activity of l-123, relative to Tc-99m, would be required to provide the the same dose to the patient from both tracers?

l. A growing alternative to Tc-99m based tracers is I-123, which has a gamma ray energy of 149 keY almost identical to the Tc-99m gamma ray energy of 140 keV, but I-123 has a longer halflife. Assume we have two tacers that are labelled with Tc-99m and I-123 respectively, and that both have identical biodistributions within the body. a. What activity of l-123, relative to Tc-99m, would be required to provide the the same dose to the patient from both tracers? Neglect biological half-life effects. (3 marks) b. What effect would the use of the above activities have on the SNR of the images? (2 marks) 2. A vial containing Tc-99m is labelled “2 mCi/ml @8 a.m.”. a. What is the activity of the sample at 4 p.m. On the same day? (2 marks) b. What volume should be withdrawn at 4 p.m. On the same day to prepare an injuection of 1.5 mCi for apatient? (2 marks)