When septa are removed and data are recorded between detectors in any combination, the data are acquired in which mode?

When septa are removed and data are recorded between detectors in any combination, the data acquisition takes place in 3D mode. In this mode, the system is able to capture a three-dimensional representation of the radiopharmaceutical distribution within the patient's body. Without the septa, the detectors can capture more scattering events and interactions, allowing for more comprehensive data collection that includes information from multiple angles and positions. This results in improved image quality and more accurate localization of radioactivity.

3D mode enhances the capabilities of imaging compared to 2D mode, where data is typically limited to two-dimensional counts without the depth information that 3D imaging provides. Hybrid mode typically refers to systems that combine different imaging modalities rather than focusing on the dimensionality of the data acquisition. The term "40 mode" is not commonly recognized in the context of nuclear medicine imaging and does not correspond to standard imaging terminology. Thus, the acquisition in this scenario is characterized distinctly by its three-dimensional approach, which is why it is accurately identified as 3D mode.