A molecular breast imaging system structured to be operable in first and second modes of operation, the first mode of operation being configured for combined MBI and ultrasound imaging and the second mode of operation being configured for combined MBI and image-guided biopsy, the system comprising: a support structure arranged proximate to an examination region; a first detector head coupled to the support structure to extend along a first portion of the examination region and including: a first gamma ray detector supported by the support structure and extending to define a first imaging plane proximate to the examination region; a first collimator extending substantially coplanar with the first imaging plane and arranged between examination region and the first gamma ray detector; a second detector head coupled to the support structure to extend along a second portion of the examination region and including: a second gamma ray detector supported by the support structure and extending to define a second imaging plane proximate to the examination region; a second collimator extending substantially coplanar with the second imaging plane and arranged between examination region and the second gamma ray detector; a compression plate including either an acoustic coupling plate for performing said ultrasound imaging or a biopsy grid plate through which a biopsy needle is delivered to the breast to carry out said image-guided biopsy, the compression plate being coupled to the first detector head; and an adjustable coupling (514, 508, 608) arranged between the first detector head and the support structure to permit movement of the first detector head between a first position of the first detector head and a second position of the first detector head such as to keep the compression plate fixed during a conversion of the system from the first mode of operation to the second mode of operation, wherein said conversion is enabled by said movement, wherein the first position of the first detector head is a position in which the first detector head is substantially directly opposed to the second detector head, and a second position of the first detector head is a position in which the first detector head is not substantially directly opposed to the second detector head. a support structure arranged proximate to an examination region; a first detector head coupled to the support structure to extend along a first portion of the examination region and including: a first gamma ray detector supported by the support structure and extending to define a first imaging plane proximate to the examination region; a first collimator extending substantially coplanar with the first imaging plane and arranged between examination region and the first gamma ray detector; a first gamma ray detector supported by the support structure and extending to define a first imaging plane proximate to the examination region; a first collimator extending substantially coplanar with the first imaging plane and arranged between examination region and the first gamma ray detector; a second detector head coupled to the support structure to extend along a second portion of the examination region and including: a second gamma ray detector supported by the support structure and extending to define a second imaging plane proximate to the examination region; a second collimator extending substantially coplanar with the second imaging plane and arranged between examination region and the second gamma ray detector; a compression plate including either an acoustic coupling plate for performing said ultrasound imaging or a biopsy grid plate through which a biopsy needle is delivered to the breast to carry out said image-guided biopsy, the compression plate being coupled to the first detector head; and a second gamma ray detector supported by the support structure and extending to define a second imaging plane proximate to the examination region; a second collimator extending substantially coplanar with the second imaging plane and arranged between examination region and the second gamma ray detector; a compression plate including either an acoustic coupling plate for performing said ultrasound imaging or a biopsy grid plate through which a biopsy needle is delivered to the breast to carry out said image-guided biopsy, the compression plate being coupled to the first detector head; and an adjustable coupling (514, 508, 608) arranged between the first detector head and the support structure to permit movement of the first detector head between a first position of the first detector head and a second position of the first detector head such as to keep the compression plate fixed during a conversion of the system from the first mode of operation to the second mode of operation, wherein said conversion is enabled by said movement, wherein the first position of the first detector head is a position in which the first detector head is substantially directly opposed to the second detector head, and a second position of the first detector head is a position in which the first detector head is not substantially directly opposed to the second detector head.