What statement is true regarding the modified in vivo method for labeling red blood cells?

The modified in vivo method for labeling red blood cells primarily involves incubating a sample of the patient's blood with a reconstituted stannous pyrophosphate. This chemical agent facilitates the incorporation of technetium-99m into the red blood cells. The process ensures that when the stannous pyrophosphate is added to the blood sample, it allows for the technetium-99m to be effectively reduced and subsequently taken up by the red blood cells, resulting in a successful labeling.

This method is advantageous because it simplifies the process of in vivo imaging by preparing the cells for effective labeling before they are reintroduced into the patient's circulation. It focuses on ensuring that the stannous agent is present in the blood sample to promote the labeling effectively, setting it apart from other methods that may not emphasize this crucial step.

In contrast, other options outline aspects that are either not characteristic of the modified in vivo technique or misrepresent the process overall. For instance, while excess 99mTc-pertechnetate may be present initially, it is not the primary focus of removing it once the labeling occurs; rather, the effective incorporation during incubation with stannous pyrophosphate is what matters most. Additionally, stating that red cell labeling