Often xenografts or subcutaneous tumors in mice are used in oncology research. Traditionally their volume growth has been monitored by using a mechanical caliper. Recently technological evolution and the increase in computing power have facilitated the development of new devices. The Peira TM900 is such an innovative device for tumor volume measurement and monitoring. It is a lightweight handheld instrument that makes a direct optical 3D measurement of the tumor volume. It does so by acquiring a stereoscopic image and reconstructing the 3D shape of the tumor. Therefor it allows a direct 3D capture of the volume. A tumor image, its 3D shape and all geometrical data are automatically calculated and stored. The system includes database, data management and processing software and can be complemented with a weight scale. The more recent version of the instrument is the Budetec TM900v2, www.budetec.be . (Click for more information TM900v2).