Abstract: Shaped RF field distributions from separate "surface" coils overlap to define a limited inner-volume deep within a human body or other object under examination. A spin echo MRI signal is effectively elicited only from such limited inner-volume so as to permit conventional MRI signal processing (e.g., utilizing Fourier Transformations) to derive and display magnetic resonance images of desired cross-sections of the limited inner-volume thus avoiding possible motion artifact and/or other potential noise sources located elsewhere in the object. A special receiver coil decoupling circuit is used to automatically increase its resonant frequency during RF transmit times.

Abstract: An electrical charge amplifier including a filter circuit is AC coupled to a semiconductor (CdTe) detector and generates a voltage pulse in response to an electrical charge generated in the detector by an incident pulse of radiation. The filter allows only frequencies within a predetermined range to contribute to the voltage pulse. The selected range of frequencies is determined in accordance with the duration of the incident radiation pulse such that the voltage pulse faithfully represents the magnitude of incident radiation in spite of undersirable detector characteristics which would otherwise introduce distortions. Exemplary charge amplifier and detector structures are also described.