Which of the following characteristics is essential for maintaining the stability of radiopharmaceuticals?

Maintaining an inert atmosphere is essential for the stability of radiopharmaceuticals because it helps prevent chemical reactions that can degrade the compounds. Many radiopharmaceuticals are sensitive to moisture and oxygen, which can lead to hydrolysis or oxidation, resulting in loss of potency or the formation of harmful byproducts. An inert atmosphere, typically achieved using nitrogen or argon gas, ensures that these reactive species are minimized, thus preserving the integrity and effectiveness of the radiopharmaceuticals.

In contrast, high temperature storage can accelerate degradation processes, constant exposure to light can lead to photodegradation, and vibrational mixing is not a standard practice or requirement in maintaining the stability of these compounds.