Radiation-Absorbed Dose Estimates to Cell Nucleus by 111In-NLS-Trastuzumab Localized in Compartments of MDA-MB-361 Human Breast Cancer Cell*
| Cell compartment | Æ (Bq × s) | S ([Gy/Bq × s] × 10−4) | Radiation dose to cell nucleus D‡ (Gy) |
|---|---|---|---|
| Membrane | 14,500 | 1.78 | 2.58 |
| Cytoplasm | 2,100 | 3.18 | 0.67 |
| Nucleus | 4,100 | 60.30 | 24.72 |
| Total | 27.97 |
↵* Cellular radiation dosimetry model of Goddu et al. (34) was used to estimate radiation-absorbed dose (D) to cell nucleus: D = Ã × S, where S is radiation-absorbed dose in nucleus (Gy) per unit of cumulated radioactivity in source compartment, Ã (Bq × s).
↵† Assumes rapid localization of 111In-NLS-trastuzumab in compartment and rate of elimination corresponding to radioactive decay of radionuclide, 111In. Ã = A0/λ, where A0 is amount of radioactivity localized in compartment at time 0 and λ is radioactive decay constant for 111In (2.83 × 10−6/s).
↵‡ Based on targeting a MDA-MB-361 human BC cell with diameter of 10 μm and nucleus with diameter of 6 μm to receptor saturation with 111In-NLS-trastuzumab. At concentrations of radioligand leading to receptor saturation, ∼60 mBq 111In-NLS-trastuzumab would be bound to each MDA-MB-361 cell at specific activity of 3.6 × 1010 MBq/mol.