A mobile imaging system, comprising: a base having at least one caster; a first drive mechanism (70, 271) that moves the entire system in a transport mode and translates at least one imaging component relative to the base in a scan mode; and a second drive mechanism that extends the at least one caster relative to the base to raise the base off the ground in the transport mode, and retracts the at least one caster relative to the base to lower the base to the ground in the scan mode, characterized in that: the at least one imaging component is raised away from the ground in response to the second drive mechanism extending the at least one caster relative to the base and the at least one imaging component is lowered towards the ground in response to the second drive mechanism retracting the at least one caster relative to the base; and the base comprises at least one housing for the at least one caster, and the at least one caster retracts into the housing and extends out of the housing and the at least one caster comprises a wheel defining a wheel axis and a swivel joint defining a swivel axis and a pivot point defining a pivot axis, wherein the caster pivots on the pivot axis as the caster is retracted into the housing and extended out of the housing and the at least one caster has a first offset distance between the wheel axis and the swivel axis when the caster is extended and a second offset distance between the wheel axis and the swivel axis when the caster is retracted, and the second offset distance is less than the first offset distance. a base having at least one caster; a first drive mechanism (70, 271) that moves the entire system in a transport mode and translates at least one imaging component relative to the base in a scan mode; and a second drive mechanism that extends the at least one caster relative to the base to raise the base off the ground in the transport mode, and retracts the at least one caster relative to the base to lower the base to the ground in the scan mode, characterized in that: the at least one imaging component is raised away from the ground in response to the second drive mechanism extending the at least one caster relative to the base and the at least one imaging component is lowered towards the ground in response to the second drive mechanism retracting the at least one caster relative to the base; and the base comprises at least one housing for the at least one caster, and the at least one caster retracts into the housing and extends out of the housing and the at least one caster comprises a wheel defining a wheel axis and a swivel joint defining a swivel axis and a pivot point defining a pivot axis, wherein the caster pivots on the pivot axis as the caster is retracted into the housing and extended out of the housing and the at least one caster has a first offset distance between the wheel axis and the swivel axis when the caster is extended and a second offset distance between the wheel axis and the swivel axis when the caster is retracted, and the second offset distance is less than the first offset distance. the at least one imaging component is raised away from the ground in response to the second drive mechanism extending the at least one caster relative to the base and the at least one imaging component is lowered towards the ground in response to the second drive mechanism retracting the at least one caster relative to the base; and the base comprises at least one housing for the at least one caster, and the at least one caster retracts into the housing and extends out of the housing and the at least one caster comprises a wheel defining a wheel axis and a swivel joint defining a swivel axis and a pivot point defining a pivot axis, wherein the caster pivots on the pivot axis as the caster is retracted into the housing and extended out of the housing and the at least one caster has a first offset distance between the wheel axis and the swivel axis when the caster is extended and a second offset distance between the wheel axis and the swivel axis when the caster is retracted, and the second offset distance is less than the first offset distance.