Digital image matrix sizes

Fig. 1. Schematic overview of the tumor spheroid-based migration assay. Tumor spheroids (TS) are transferred from their cuiture vessei or piate into a 96-weii fiat-bottomed migration piate pre-coated with an extraceiiuiar matrix (ECM) protein of choice (in this case, geiatin). Digital images of the spheroids are then captured at t=0 and once every 24 h for a period of up to 72 h, exemplified here by CAL spheroids. Image analysis software is used to calculate the spheroid size and extent of migration. Scale bar=100 p.m.

Reconstructed digital PET images are stored in the computer in the format of a matrix. The images are characterized by two quantities matrix size and pixel depth. In PET studies, the computer memory approximates the FOV as a square matrix of a definite size that can range from 64 x 64 to 512 x 512 with a total of 1,026 (1K) to 262,144 (262 K) picture elements, called pixels, respectively. The matrix size depends on the type of study and is chosen by the operator. Since the FOV is approximated to the matrix size, the pixel size is calculated by dividing the length of FOV by the number of pixels across the matrix. For example, if an image of 250 x 250 mm FOV is stored in a... 

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