A device (1) for use in imaging a subject using both light and gamma rays emanating from the subject, the device including: a first sensor means (2) responsive to light received thereby from the subject to generate first signals (6) for use in forming a first image (10) of the subject a second sensor means (3) responsive to gamma rays received thereby from the subject to generate second signals (7) for use in forming a second image (11) of the subject and arranged to receive gamma rays from the subject which have passed from the subject through the first sensor means before reaching the second sensor means.
