Embodiments of the present invention provide phantoms, and associated methodsofcalibration which are suitable for use in both medical resonance imaging andradiographic imaging systems. A phantom for calibration of a medical imagingsystem, comprises a first component having a first outer shape, a portion ofwhichdefines part of at least one pocket； and a second component coupled to thefirstcomponent and having a second outer shape, a portion of which defines anotherpartof the at least one pocket. At least one of the first and second componentscomprises areservoir, the reservoir having a shape at least a portion of which locates acentre ofthe at least one pocket.
