Cross-dose S values
Cross-Dose S Values for Multicellular Dosimetry
Definitions
Target cell |
Cell for which the radiation dose is calculated. The target cell is represented by two concentric spheres. The cell nucleus is represented by the inner sphere with radius RN. The region between the inner and outer sphere represents the cytoplasm. The surface of the outer sphere represents the cell surface. The radius of the cell is RC. The target within the cell is either the entire cell or the cell nucleus. |
Source cell |
Cell that contains radioactivity. The radioactivity is assumed to be uniformly distributed in the cell (C), cytoplasm (Cy), or nucleus (N). Or the radioactivity is assumed to be uniformly distributed on the cell surface (CS). |
S value |
Mean absorbed dose to the target per unit cumulated activity in the source cell. S values are calculated according to the methods in Goddu et al. (1). |
Units for S value |
Gy/(Bq s) in the source cell. |
Radiation data |
As in our published article on multicellular dosimetry (1), the radiation data for each radionuclide are taken from Eckerman et al. (2). In view, of their very small absorbed fractions, photon radiations are not included in the calculations (1). |
Instructions for Use
Cross-dose S values have been calculated for eight different combinations of sizes of the cell and cell nucleus. They are RC = 5 µm and RN = 3 µm, RC = 5 µm and RN = 4 µm, RC = 6 µm and RN = 5 µm, RC = 6 µm and RN = 4 µm, RC = 6 µm and RN = 3 µm, RC = 7 µm and RN = 6 µm, RC = 7 µm and RN = 5 µm, and RC = 7 µm and RN = 4 µm. Eight folders have been created, one for each combination: rc5rn3, rc5rn4, rc6rn5, rc6rn4, rc6rn3, rc7rn6, rc7rn5, rc7rn4. Within each folder are cross-dose S values for 70 different radionuclides. If photons are emitted by the radionuclide, the beginning lines indicate the photons that were ignored in the calculations. The first line that follows this information describes the file that the radiation data was taken from. This is followed by the number of lines of S value data in the file. Five columns of S value data then follow. Columns 1, 2, 3, 4, and 5 are the S values for the following target ← source configurations: C ← C, C ← CS, N ← N, N ← Cy, and N ← CS, respectively. The first row is the self-dose to the target cell. The rows with zeros should be ignored. The first row after the zeros is the S value for when the target and source cells are touching so that the distance d between theiRCenters is one cell diameter. The next row of the S values is for when the centers of the target and source cells are spaced by one cell diameter + 1 µm. In the S value rows that follow, the distance between the centers of the cells is incremented by 1 µm. In the rows that follow the S Value data are details regarding the input parameters, including the actual radiation data used in the calculations. The example in Table 1 for 125I shows the S value data for 125I that is taken from file i125.53.
Table 1. Cross-Dose S Values RC = 5 µm, RN = 3 µm
Gy/(Bq s)
d (μm) |
C ← C |
C ← CS |
N ← N |
N ← Cy |
N ← CS |
10 |
7.59E-05 |
8.61E-05 |
7.77E-05 |
7.38E-05 |
7.32E-05 |
11 |
6.06E-05 |
6.11E-05 |
6.24E-05 |
6.00E-05 |
5.95E-05 |
12 |
4.89E-05 |
4.93E-05 |
4.81E-05 |
4.88E-05 |
4.89E-05 |
13 |
3.93E-05 |
3.99E-05 |
3.65E-05 |
3.93E-05 |
4.01E-05 |
14 |
3.14E-05 |
3.22E-05 |
2.79E-05 |
3.12E-05 |
3.23E-05 |
15 |
2.49E-05 |
2.58E-05 |
2.22E-05 |
2.45E-05 |
2.54E-05 |
16 |
1.97E-05 |
2.04E-05 |
1.83E-05 |
1.90E-05 |
1.96E-05 |
17 |
1.54E-05 |
1.60E-05 |
1.52E-05 |
1.48E-05 |
1.50E-05 |
18 |
1.20E-05 |
1.24E-05 |
1.21E-05 |
1.15E-05 |
1.15E-05 |
19 |
9.15E-06 |
9.47E-06 |
8.95E-06 |
8.93E-06 |
9.01E-06 |
20 |
6.86E-06 |
7.17E-06 |
6.09E-06 |
6.76E-06 |
6.99E-06 |
21 |
5.00E-06 |
5.38E-06 |
3.85E-06 |
4.87E-06 |
5.23E-06 |
22 |
3.51E-06 |
3.92E-06 |
2.34E-06 |
3.27E-06 |
3.69E-06 |
23 |
2.37E-06 |
2.77E-06 |
1.45E-06 |
2.04E-06 |
2.44E-06 |
24 |
1.53E-06 |
1.88E-06 |
9.13E-07 |
1.20E-06 |
1.50E-06 |
25 |
9.30E-07 |
1.21E-06 |
5.29E-07 |
7.11E-07 |
8.67E-07 |
26 |
5.38E-07 |
7.32E-07 |
2.45E-07 |
4.34E-07 |
5.12E-07 |
27 |
3.02E-07 |
4.14E-07 |
7.99E-08 |
2.47E-07 |
3.23E-07 |
28 |
1.66E-07 |
2.34E-07 |
1.42E-08 |
1.14E-07 |
1.79E-07 |
29 |
8.45E-08 |
1.37E-07 |
9.20E-10 |
3.69E-08 |
7.69E-08 |
30 |
3.54E-08 |
7.12E-08 |
6.08E-15 |
6.44E-09 |
2.01E-08 |
31 |
1.07E-08 |
2.90E-08 |
0.00E+00 |
4.10E-10 |
1.93E-09 |
32 |
1.80E-09 |
7.25E-09 |
0.00E+00 |
2.47E-15 |
3.11E-13 |
33 |
1.12E-10 |
6.77E-10 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
34 |
6.03E-16 |
9.92E-14 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
35 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
36 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
37 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
0.00E+00 |
List of references
1. S. M. Goddu, D. V. Rao, and R. W. Howell, Multicellular dosimetry for micrometastases: dependence of self-dose versus cross-dose to cell nuclei on type and energy of radiation and subcellular distribution of radionuclides. J. Nucl. Med. 35, 521-530 (1994).
2. K. F. Eckerman, R. J. Westfall, J. C. Ryman, and M. Cristy, Nuclear decay data files of the dosimetry research group, ORNL/TM-12350. Oak Ridge National Laboratory, 1993.
