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The Bebig Co0.A86 source was modeled using two different shapes: a detailed, GD, and a simplified, GS, geometries. The source was considered as a cylindrical active core of Co-60 with a diameter of 0.5 mm and a length of 3.5 mm, surrounded by an air shell 0.1 mm thick. A cylindrical stainless-steel capsule 0.15 mm thick, with an internal diameter of 0.7 mm, an external diameter of 1.0 mm and a lenght of 5 mm. A rounded tip closed the structure for the GD source geometry and a flat tip closed the structure for the GS source geometry. A 5 mm length source cable, with a diameter of 0.9 mm, made with a interlaced stainless-steel was also included in the back end.
| Cobalt | AISI 316L | AISI 316L (cable) | Water | Air | ||
|---|---|---|---|---|---|---|
| H | --- | --- | --- | 11.1 | 0.073 | |
| C | --- | 0.03 | 0.03 | --- | 0.012 | |
| N | --- | 0.1 | 0.1 | --- | 75.032 | |
| O | --- | --- | --- | 88.9 | 23.608 | |
| Si | --- | 0.75 | 0.75 | --- | --- | |
| P | --- | 0.045 | 0.045 | --- | --- | |
| S | --- | 0.03 | 0.03 | --- | --- | |
| Ar | --- | --- | --- | --- | 1.274 | |
| Cr | --- | 17 | 17 | --- | --- | |
| Mn | --- | 2 | 2 | --- | --- | |
| Fe | --- | 65.545 | 65.545 | --- | --- | |
| Ni | --- | 12 | 12 | --- | --- | |
| Mo | --- | 2.5 | 2.5 | --- | --- | |
| Co | 100 | --- | --- | --- | --- | |
| 8.9 | 8.03 | 4.81 | 0.998 | 1.20x10-3 | Density (g/cm3) |
| GD | GS |
| Sk = (3.046 ± 0.007) x 10-7 U/Bq | Sk = (3.046 ± 0.007) x 10-7 U/Bq |
Angular variation of Air Kerma Strength for the source geometry GD. Table of values (14.3 KiB): Download
Angular variation of Air Kerma Strength for the source geometry GS. Table of values (14.3 KiB): Download
Figure: Air kerma strength per unit of activity at the reference distance, r0 = 1 m, as a function of θ, for the detailed GD (dots) and the simplified GS (thick solid line) source geometries. The thin solid line indicates the relative differences between both results (right y axis).
Radial dose function for the source geometry GD. Table of values (40.1 KiB): Download
Radial dose function for the source geometry GS. Table of values (40.1 KiB): Download
| r(cm) | GD | GS |
|---|---|---|
| 0.1 | 0.8240(5) | 0.8237(5) |
| 0.15 | 0.9582(6) | 0.9576(6) |
| 0.20 | 1.0353(7) | 1.0341(7) |
| 0.25 | 1.0707(7) | 1.0693(7) |
| 0.30 | 1.0767(7) | 1.0759(7) |
| 0.35 | 1.0669(7) | 1.0664(7) |
| 0.40 | 1.0516(8) | 1.0508(8) |
| 0.45 | 1.0392(8) | 1.0383(8) |
| 0.5 | 1.0291(8) | 1.0286(8) |
| 0.6 | 1.0185(8) | 1.0177(8) |
| 0.75 | 1.0102(8) | 1.0081(8) |
| 1 | 1.0000(9) | 1.0000(9) |
| 1.5 | 0.9894(9) | 0.9890(9) |
| 2 | 0.9794(10) | 0.9783(10) |
| 2.5 | 0.9712(11) | 0.9713(11) |
| 3 | 0.9638(12) | 0.9618(12) |
| 4 | 0.9471(13) | 0.9472(13) |
| 5 | 0.9335(14) | 0.9313(14) |
| 6 | 0.9150(15) | 0.9153(15) |
| 7 | 0.898(2) | 0.897(2) |
| 8 | 0.883(2) | 0.883(2) |
| 10 | 0.847(2) | 0.846(2) |
| 12 | 0.813(2) | 0.807(2) |
| 14 | 0.774(2) | 0.775(2) |
| 15 | 0.756(2) | 0.758(2) |
| 20 | 0.661(2) | 0.658(2) |
[1] Granero D, Pérez-Calatayud J, Ballester F. Technical note: Dosimetric study of a new Co-60 source used in brachytherapy. Med Phys 2007;34:3485-8
[2] Selvam TP, Bhola S. Technical note: EGSnrc-based dosimetric study of the
BEBIG 60Co HDR brachytherapy sources. Med Phys 2010;37:1365-70.
[3] Anwarul IM, Akramuzzaman MM, Zakaria GA. EGSnrc Monte Carlo-aided
dosimetric studies of the new BEBIG 60 Co HDR brachytherapy source. J
Contemp Brachytherapy 2013;5:148-56
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1 As general rule, the values between parentheses indicate the uncertainty with coverage factor k=1, e.g 73.831(8) means 73.831 ± 0.008.
2 For the calculations of TG-43 parameters and functions the linear source approximation was assumed (L = 3.5 mm)
Bebig Co0.A86
