Multicellular Dosimetry Tools


Cross-Dose S Values for Multicellular Dosimetry (click for tabulations)

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 R N . 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 R C . 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 diameters of the cell (RC) and cell nucleus (RN).  As denoted in Table 1, eight folders of files have been created, one for each combination of cell sizes.  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 their centers 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 2 for 125I shows the S value data for 125I that is taken from file i125.53.

 

  Table 1.  Cell Dimensions and Name of Corresponding Data Folder
 

RC (µm)

RN (µm)

Folder

 

5

3

rc5rn3

 

5

4

rc5rn4

 

6

5

rc6rn5

 

6

4

rc6rn4

 

6

3

rc6rn3

 

7

6

rc7rn6

 

7

5

rc7rn5

 

7

4

rc7rn4

   

 

Table 2. 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