Biomedical Engineering Reference
In-Depth Information
cles can induce new chemical effects or cause mechanical damage. But there is still
no empirical evidence.
8.3
Combination with Imaging Monitor
Another important usage of nanoparticle is to enhance medical imaging as contrast
agents. There are already many studies in this aspect (Kohler et al.
2006
; Sun et al.
2008
; Sharma and Chen
2009
). Some nanoparticles can be used as contrast agents
because of their dependences on temperature. Therefore, in hyperthermia, maybe
one can detect the temperature distribution information of interest domain with the
help of these thermo sensitive particles which can help reveal the tissue destruction
details. By all appearances, an idealistic case lies in that the chosen nanoparticles
should possess both excellent heating and image enhancing functions. Thus, when
nanoparticles finish raising temperature of the tissue, they can also serve as mediums
to diagnose state of disease and therapeutic effect, thereby providing planning
guidance for clinicians.
8.4
Combination with Chemotherapy and Radiotherapy
Hyperthermia can be combined with chemotherapy or radiotherapy to achieve
better therapeutic effect, since heating makes tumor cells more sensitive to the
chemotherapy or radiotherapy (Saniei
2009
; Horsman and Overgaard
2007
; Issels
2008
; Ben-Yosef et al.
2004
; Hurwitz et al.
2007
). Combining them with nano
hyperthermia can help satisfy the required selective destruction of malignant cells
without causing damages to healthy cells.
Nanoparticles can serve as carriers to deliver drug to tumor tissue, which provides
a new way to combine drug therapy with hyperthermia. As reported in existing
researches, nanoparticles integrated with chemotherapeutics and thermal seeds
can realize enhanced drug release in tumor cells and selective heat deposition
simultaneously. This is a particularly attractive feature, which meets the demands
for homogenous heating within targeted tissue and effective drug release at the same
time. Now there are many experiments on thermochemotherapy using nanoparticles
integrated with some drugs, such as carboplatin-Fe@C-loaded chitosan nanoparticles
(Li et al.
2009
), nanosized As
2
O
3
/Fe
3
O
4
complex (Du et al.
2009
), etc.
Hypoxia is a key intrinsic resistance to radiation therapy. Therefore, any strategy
that mitigates tissue hypoxia could potentially overcome radio resistance and
promote the effects of radiation therapy. For example, gold nanoshell-mediated
hyperthermia can cause an increase in tumor perfusion that reduces the radio resis-
tant hypoxic fraction. Then a subsequent radiation will induce vascular disruption
with extensive tumor necrosis (Diagaradjane et al.
2008
).
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