Disposable medical devices E-beam sterilization can be processed in different ways. It has been processed in carton boxes for many years. In this case it is often irradiated at an energy level of 10 MeV, although irradiation facilities work at lower energies.
Medical devices can also be treated piece by piece. This second case has the advantage to require lower energy level (cheaper accelerators and cheaper shielding). By the same token it requires one electron accelerator per product type.
1. Disposable medical devices in carton boxes |
What is the power requirement of a 10 MeV electron accelerator |
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that must sterilize (dose 25 kGy) the following boxes in |
2000 |
hours |
Considering that |
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Scanning Horn width is variable |
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Scanning Horn width is |
80 |
cm |
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Width (cm) |
Length (cm) |
Height (cm) |
Weight (kg) |
m3 |
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Box 1 |
40 |
50 |
22 |
6 |
12.800 |
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Box 2 |
40 |
60 |
40 |
17 |
14.800 |
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Box 3 |
60 |
75 |
45 |
15 |
6.400 |
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Box 4 |
60 |
70 |
25 |
11 |
17.300 |
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Box 5 |
60 |
80 |
30 |
20 |
9.500 |
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60.800 |
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Number of boxes (# boxes) is equal to the number of cubic meters / volume of each box |
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# boxes |
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Box 1 |
290.909 |
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Box 2 |
154.167 |
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Box 3 |
31.605 |
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Box 4 |
164.762 |
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Box 5 |
65.972 |
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The Ratio (g/cm2) is Weight / (Width x Length) for each type of box
If the Ratio is > 3,6, the box requires double side irradiation.
The total surface to irradiate - practically - if the scan width is fixed is
(width of scan x # boxes x Length)
multiplied by 2 if this box requires double side irradiation
The total surface to irradiate - practically - if the scan width is variable
if we consider 5cm over-scanning on each side
((5 + width of box + 5) x # boxes x Length)
multiplied by 2 if this box requires double side irradiation |
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Tot Surf at |
Tot Surf at |
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80 |
+ 5 / + 5 |
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Ratio (g/cm2) |
Irradiation |
(m2) |
(m2) |
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Box 1 |
3,00 |
S. Side Ir. |
116.364 |
72.727 |
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Box 2 |
7,08 |
Double S. Ir. |
148.000 |
92.500 |
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Box 3 |
3,33 |
S. Side Ir. |
18.963 |
16.593 |
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Box 4 |
2,62 |
S. Side Ir. |
92.267 |
80.733 |
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Box 5 |
4,17 |
Double S. Ir. |
84.444 |
73.889 |
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460.038 |
336.442 |
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Formula |
A / T = K F I / D |
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1. Scan Width Variable (+5 cm on each side) |
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336.442 |
linear m at |
variable |
scan width in |
2000,00 |
hours |
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This translates into |
2,80 |
m2/min |
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A / T |
2,80 |
m2/min |
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D |
2,5 |
Mrad |
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I = A D / T K F |
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K |
1,17 |
(Mrad m2/mA min) |
I : Current = |
7,49 |
mA |
F |
0,8 |
% efficiency |
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Power |
74,88 |
kW |
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2. Scan Width = 80 cm |
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460.038 |
linear m at |
80 |
scan width in |
2000 |
hours |
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This translates into |
3,83 |
m2/min |
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A / T |
3,83 |
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D |
2,5 |
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I = A D / T K F |
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K |
1,17 |
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I : Current = |
10,24 |
mA |
F |
0,8 |
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Power |
102,3944334 |
kW |
2. Disposable medical devices conveyed piece by piece under the beam |
Irradiation :
Key Concept
