Which type of phantom is typically used for evaluating SPECT systems?

The choice of a SPECT phantom designed specifically for evaluating SPECT systems is the most relevant because it is tailored to accurately mimic the characteristics of human tissues and organs as they would be visualized in a SPECT imaging scenario. These phantoms incorporate features such as specific geometries, contours, and enhanced capabilities that allow for the simulation of radiotracer uptake and distribution, which are essential for assessing the performance of the SPECT system.

Using a specialized SPECT phantom provides a controlled environment to test the system's spatial resolution, sensitivity, and energy response among other parameters. Such targeted phantoms help in the calibration and quality control of SPECT imaging systems, ensuring that the imaging devices perform optimally and produce reliable images that can be used for clinical diagnosis.

In contrast, while water phantoms and solid water phantoms are useful in many radiation therapy and nuclear medicine applications, they do not possess the anatomical complexity and radiopharmaceutical characteristics needed for comprehensive SPECT evaluation. A human body phantom, though it may provide useful insights into human body responses, can be complex to use and may not be as readily available or feasible as specifically designed SPECT phantoms for straightforward evaluation purposes.