Table 5. Fits of experimental data with Eq. (7): estimated parameter values and goodness-of-fit statistics. Columns 1–3 are self-explanatory, column 4 is the chi-square per degree-of-freedom in the fit. While the values of λ are restricted to a rather narrow range, which is in line with the expectation of biological variability between different cell lines, the values of A cover a very wide range. This large variability is justified by the different geometries of the tumours in the list: while spheroids have shapes that never depart too much from the sphere – even when they have very irregular edges – real, vascularized tumours have complex geometries and the total area in contact with blood vessels is very large, hence the large average A value reported for human tumours.
| Dataset | λ (μm) | A | χ2/DF |
|---|---|---|---|
| 9L spheroids | 93.93 ± 0.08 | 2.75 ± 0.87 | 1.11 |
| Rat-T1 spheroids | 123.56 ± 1.14 | 20.74 ± 2.27 | 1.54 |
| MR1 spheroids | 90.95 ± 0.001 | 0.76 ± 0.04 | 1.20 |
| Human tumors | 99.40 ± 5.46 | 9648.2 ± 0.02 | 1.02 |