Final answer:
The lungs would be the first organ system to perfuse following an IV injection of Tc DTPA, as the tracer would enter the right atrium, then the right ventricle, and would be sent to the lungs in the pulmonary circuit.
Step-by-step explanation:
The question pertains to the sequence of organ perfusion following an intravenous (IV) injection of Tc DTPA (Technetium-99m diethylenetriaminepentaacetic acid), which is a radioactive tracer used in medical imaging. After an IV injection, the tracer would first enter the right atrium of the heart, then the right ventricle, and from there it would be pumped into the pulmonary circuit. Therefore, the lungs would be the first organ system to perfuse the tracer.
For reference, the right atrium initially receives blood from the systemic circuit (Answer to question: a. left atrium b. left ventricle c. right atrium d. right ventricle), and the right ventricle sends blood specifically to the lungs (Answer to question: a. the head b. the upper body c. the lungs d. the lower body).