Biomedical Engineering Reference
In-Depth Information
90
10
-3
-1
1
3
X (mm)
(g)
90
10
-3
-1
1
3
X (mm)
(h)
90
10
-3
-1
1
3
X (mm)
(i)
60
10
-3
-1
1
3
X (mm)
(j)
FIGURE 2.9
(
Continued
) Laser beam heating axisymmetric FDM numerical model result. A CO
2
laser (λ = 10.6 μm) at total power of 0.5 W with
Gaussian beam profile, 2σ diameter = 7 mm for 20 s on tissue 2 mm thick with 50% mass fraction water. The effective laser absorption coefficient
was μ
a
= 492 (cm
−1
); and the beam center surface fluence rate 2.59 (W cm
−2
). (a) Beam center surface temperature history; 100°C reached at
t
= 18 s.
(b) Spatial distribution of temperature at the end of heating, 20 s. (c) Apoptosis/necrosis 10% and 90% damage contours. (d) Chinese hamster ovary
cell 10-90% contours. (e) BhK cell 10-90% contours. (f) Microvascular damage 10-90% contours. (g) Cardiac muscle whitening 10-90% contours.
(h) Skin burn coefficient (Diller
(27)
) 10-90% contours. (i) Collagen birefringence loss 10-90% contours. (j) Collagen shrinkage 10-60% contours.
time lesion, since the 10% and 90% boundaries fall well inside
the boundaries of all of the other damage processes, extend-
ing only to a depth of 1 mm and radius of 1.5 mm, in keeping
with its slowly evolving nature. In contrast, it is highly likely
that Chinese hamster ovary and BhK cells will be killed out to
a radius of about 2.5 mm over the full thickness. Similarly, car-
diac muscle whitening, gross microvascular damage, and skin
burns are equally likely to be observed over about the same
