Radioisotopes and Cancer Detection. A radioisotope

Chapter 5, Problem 2E

(choose chapter or problem)

Radioisotopes and Cancer Detection. A radioisotope commonly used in the detection of breast cancer is technetium-99m. This radionuclide is attached to a chemical that upon injection into a patient accumulates at cancer sites. The isotope’s radiation is then detected and the site located, using gamma cameras or other tomographic devices. Technetium-99m decays radioactively in accordance with the equation dy/dt = -ky, with k = 0.1155/h. The short half-life of technetium-99m has the advantage that its radioactivity does not endanger the patient. A disadvantage is that the isotope must be manufactured in a cyclotron. Since hospitals are not equipped with cyclotrons, doses of technetium-99m have to be ordered in advance from medical suppliers. Suppose a dosage of 5 millicuries (mCi) of technetium-99m is to be administered to a patient. Estimate the delivery time from production at the manufacturer to arrival at the hospital treatment room to be 24 h and calculate the amount of the radionuclide that the hospital must order, to be able to administer the proper dosage.