医学影像是指为了医疗或医学研究，对人体或人体某部份，以非侵入方式取得内部组织影像的技术与处理过程，是一种逆问题的推论演算，即成因（活体组织的特性）是经由结果（观测影像信号）反推而来。

作为一门科学，医学影像属于生物影像，并包含影像诊断学、放射学、内视镜、医疗用热影像技术、医学摄影和显微镜。另外，包括脑波图和脑磁造影等技术，虽然重点在于测量和记录，没有影像呈显，但因所产生的数据俱有定位特性（即含有位置信息），可被看作是另外一种形式的医学影像。

临床应用方面，又称为医学成像，或影像医学，有些医院会设有影像医学中心、影像医学部或影像医学科，设置相关的仪器设备，并编制有专门的护理师、放射技师以及医师，负责仪器设备的操作、影像的解释与诊断（在**须由医师负责），这与放射科负责放射治疗有所不同。

Medical imaging is the technique and process of creating visual representations of the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to reveal internal structures hidden by the skin and bones, as well as to diagnose and treat disease. Medical imaging also establishes a database of normal anatomy and physiology to make it possible to identify abnormalities. Although imaging of removed organs and tissues can be performed for medical reasons, such procedures are usually considered part of pathology instead of medical imaging.