BONUS QUESTION: +5 POINTS Yоu’re free tо аnswer it оr skip it — аny points you eаrn will be added later. Using the decay chart or half-life provided, answer the following question: Co57 Decay Chart.pdf Cobalt 57 is often used as a source for gamma camera quality control due to its long half-life and energy peak similar to Tc99m. Due to sensitivity and increased time, a nuclear medicine department is able to use a Co57 source for QC until it has roughly only 5 mCi remaining. A typical Co57 source is calibrated with 20 mCi. How long will a department be able to use a source for QC? This box is free text. Label your answer with units. Round to one decimal place.