Spheroid volume determination

Written by Patrick C.H. Lo

A newly developed software program provides accurate and precise measurements of the volume of cellular spheroids.

Researchers prefer 3-D multicellular cancer spheroids over 2-D cell cultures for cancer drug screening since they better reflect the in vivo physiology of tumors. A direct indicator of the anticancer effect of a candidate drug is a reduction in the size of the cancer spheroid. Given that most spheroids are not perfectly spherical, size is best measured using a spheroid’s volume rather than its diameter.

For volume determination, confocal and light sheet fluorescence microscopes can be used to image the cancer spheroids and produce a z-stack of optical sections. ReViMS, a new software tool described in the November issue of BioTechniques by Filippo Piccinini and his colleagues, uses this z-stack to estimate the volume of the spheroid. Unlike other existing programs with similar functionality, ReViMS is user-friendly and freely available. Written in MATLAB, the program segments each fluorescent image in the z-stack and then reconstructs the volume of the spheroid. The method demonstrated high accuracy and precision when tested on cancer spheroids that had each been imaged from three different angles.