There is substantial evidence regarding the positive influences of natural elements on patients' health outcomes. However, research has predominantly focused on natural green elements rather than natural blue elements. While sky and water are significant components of what humans perceive as "nature" and both offer considerable restorative effects in various built environments, research about their role in healthcare facilities has been limited. Therefore, this study investigated influences of exposure to natural blue elements on patients in medical imaging environments, specifically in Positron Emission Tomography/Computed Tomography (PET/CT) rooms. Virtual reality (VR) was employed to develop several scenarios with design strategies based on natural blue elements. These scenarios were presented to twenty participants who were former patients of medical imaging settings. The study employed a mixed methods research approach, collecting both subjective (questions on visual perception, positive and negative affects, self-reported stress) and physiological responses (mean heart rate and vagally-mediated heart rate variability). The study supports the idea that virtual reality serves as an effective tool for prototyping PET/CT scan environments. Furthermore, the results show that certain design strategies incorporating all aspects of natural blue elements, such as flowing water and its sound, water motion, water reflection, light in the sky, clouds, and the presence of birds in flight, have the potential to evoke specific positive subjective and physiological responses in participants. The findings also highlight the significant benefits of incorporating motion with natural blue elements, which makes them more realistic and, consequently, brings more life to medical imaging environments.