Question

Technetium (Tc) is a radioactive element widely used in modern medical imaging (radiology). Its existence was predicted in 1871 by D. Mendeleev, who noticed a gap between then known elements Molybdenum (42) and Ruthenium (44) in the periodic table he envisioned. Technetium used in radiology is a metastable isotope ⁹⁹Tc that emits gamma photons (half-life T_1/2 = 6 h). A solution containing trace amounts of ⁹⁹Tc (the tracer) is administered to a patient intravenously, and after the isotope uniformly spreads throughout the body with the bloodstream, gamma radiation is imaged with a special scintillator camera (g-ray camera) rotating around the patient’s body near the organ of interest. Assuming that once the medicine is injected, the initial rate of g-radiation emanating from the patient’s body is 1600 mSv/h (“Sv” stands for Sievert, a unit of radiation dose, equivalent to 1 Joule of energy dumped per 1 kg of body mass), estimate the time needed for the radioactivity of the patient to go down to the level comparable to the natural background. The typical natural radiation background at the surface of Earth measures to about 0.4 mSv/h.

Answer 1

in kinetice OVOLJ Tya 6hrs. Radio active decay a 1st order ho 1600 mswll Ignitial Rate) R 20.4msu/h (final Race of decay) R² K[A] Rok CA] in 2 z kt/ Ka una 00115 ho - 1600 m sv/h 0.115h [A] = 0.693 (Ao] - 1600 ms 6 has 1 00115 13, 913.04 mso 13.913 Su. Rf a Ocumsvine K[A]. A7 2 0. umsv 3.47 m sv. 0.115 time Required to go from [fo] (n). 0.115 ho 0.115hr en 13,9913.04 L x 8.296 3.47 272014 hrs. ... 7 2014 bours is needed for radioactivity of patient ty of the to go down to level comparable to nothione I background?