How has the development of the two-photon imaging
microscope improved our ability to locate and analyze rare
types of cancerous cells?
More than 85% of all cancers begin as precancerous lesions that are confined to the surface epithelium,
which can be as thick as 500 μm deep in human tissue. Two-photon imaging (TPI) is a powerful
technique for the early diagnosis of epithelial cancers because it permits non-invasive imaging of sub-
cellular features potentially hundreds of micrometers deep into tissue. TPI can be used to distinguish
cancerous and precancerous tissue from normal tissue down to 40 μm deep. By attaching a fluorescent
contrast agent to a non-fluorescent target of interest, TPI also has the ability to monitor a variety of
additional bio-molecular signatures that are more strongly indicative of cancer.
–microscope allows to study the dynamics of the immune system's response to
cancer and infectious diseases.
–reduced photodynamic tissue damage and fluorophore photobleaching
fluorescence differs from single photon excited fluorescence with regard to stage one of the three-stage
fluorescence process. In two-photon excitation a fluorophore accomplishes the transition from its ground
state to an excited state by the near-simul-1s) absorption of two photons. One photon
excites the fluorophore to a ‘virtual’intermediate state while the second photon further excites the
fluorophore to the excited state(2). The two photons have approximately half the energy and double the
wavelength of the photon required for a single photon excitation quantum event to occur.
The two-photon microscope allows scientists to study the dynamics of the immune
system's response to cancer and infectious diseases. The multi-photon microscope’s
unique features allow dynamic processes in living tissue to be viewed. Longer wavelengths of light than
those used in the traditional microscope enable researchers to potentially look deeper into living tissue
than ever before.The microscope is an outstanding tool to study how our bodies fight cancer both in early
and advanced stages. If we can learn more about how our immune system attacks cancer cells directly in
the context of intact tissues, we can develop improved immune-therapies. How are nanotechnologies being used in non-invasive
Exploratory surgery is a surgery performed solely for diagnostic purposes, without
the intent of treating a disease. Rather, it is used to look for things which do not
show up with other diagnostic techniques, such as suspected cancers which cannot
be identified in medical imaging studies. Exploratory surgeries are also used with
patients who are unable to communicate about their symptoms, such as animals. It
can also be used with patients who are unable to communicate about their
symptoms, such as with animals.
In an exploratory surgery, the goal is to open the body up to get a look inside and
to use the information to arrive at a diagnosis. In some cases, biopsies may be
taken to sample areas of interest, but excisions, repairs, and other surgical
procedures which are all designed to treat disease, are not a part of exploratory
surgery. A surgical procedure can also turn into an exploratory surgery when the
surgeon opens the patient up and realizes that the situation is much more
complicated than originally anticipated, requiring a new evaluation and approach to
A medical procedure is defined as non-invasive when no break in the skin is created
and there is no contact with the internal body cavity, the only contact is on the
exterior surface of the body. Examples include pulse-taking, listening to heart and
lung sounds via a stethoscope, temperature examination using thermometers, X-
rays, etc. One of the biggest trends within surgery is the recognition and move
towards minimally invasive methods. This is driven by shorter patient recovery
times since the pain of a minimal invasive surgery is much less and recovery is
faster. One of the ways to achieve exploratory surgery with non-invasive methods is
through the use of nanotechnologies.
Many types of nanotechnologies are in different stages of development but their
meaningful contribution to minimal invasive surgery is well recognized. The
following are different nanotechnologies available to the field of minimal invasive
Femtosecond Lasers (also known as ultra-fast lasers) emit optical pulses at fixed
durations measured in femtoseconds (which are one-quadrillionth of a second).
These lasers are useful in targeting and destroying specific organisms within a
single cell. For example, cancerous cells can be targeted with such precision that
the surrounding 'good' cells remain unaffected.
Nanoshell particles have a ‘tunable optical resonance’. This means that they can be
tuned to absorb or scatter light at particular wavelengths. This quality makes them successful in treating cancer. These particles are silica rounds coated with a metal
shell (mostly gold); the size of them can be varied to interact with different wave