An x-ray chopper wheel assembly, and corresponding method, include a chopper wheel having a solid area configured to block x-ray radiation received at a source side of the chopper wheel from an x-ray source. The chopper wheel defines one or more openings configured to pass x-ray radiation from the source side of the chopper wheel to an output side of the chopper wheel. The assembly further includes a source-side scatter plate arranged relative to the chopper wheel with a source-side gap in a range of approximately 0.2 mm to approximately 2.0 mm between the source-side scatter plate and the source side of the chopper wheel. The assembly and method can be used to limit leakage of scattered x-rays from the assembly, such as to safe levels for operation, while being significantly lighter than existing confinement enclosures.