Intraoperative
tumor-specific real-time fluorescence imaging
This is exactly I
decided not to do, blogging about science or in general anything serious such
as to educate readers. Please don’t be skeptic here, im more comfortable
writing hardcore-rubbish (with a downright tendency, I was told) stuff you seen
in my last few post.
So why a clear
deviation from my normal course? You see love surgeons; they are bright
meritocrats with a great eye and a skillful fingertip. They often take bad decisions; leave out tumorous
tissue (during surgery) and the tumor tissue left behind after surgery can cause
all the bad you can imagine.
Removal of brain tumor by
surgery is the common preliminary treatment and is usually followed by
radiation and chemotherapy. Surgeon aims to remove the maximum amount of the
tumor mass without sacrificing the patients’ neurological function and importantly
without an aggressive surgery on brain. The great-naked eye can’t always
distinguish between a tumor and normal brain tissue, making it difficult to
completely remove a tumor and sometimes more brain tissue is removed than
necessary as I said earlier.
Fluorescence imaging
is an optical technique where chemical compounds that absorb in the
near-infrared (NIR) region, 700–1000 nm, can be used to visualize and investigate
in vivo molecular targets because
most tissues generate little NIR fluorescence. Fluorescence imaging offers
superior resolution, sensitivity and convenient for visual inspection and palpation
during surgery. The combination of accurate real-time imaging with
tumor-specific fluorescent agents has the
potential to revolutionize surgical procedures. Real-time imaging can shift the
paradigm of surgical inspection by enabling localization of lesions that are
difficult or impossible to detect by visual observation or palpation.
Healthy tissue should not show any fluorescence signal
either in vivo, ex vivo or on histopathological validation, in other words the
probe should be highly tumour specific. Image
processing speeds should be much faster than real-time, otherwise making this
application unfeasible for use in surgical applications. The mean duration
for capturing in vivo intraoperative fluorescence images and video is 10
min (range: 4–36 min). Images need to be presented in an
interactive and 3D format to the surgeons and they also should be able to
integrate and manipulate these images during the surgical procedure.
Radiological modalities
like PET (Positron Emission Tomography) is impractical for use in the operating
room due to their size, cost, operating complexity, and performance. Recently, an advanced
intra-operative magnetic resonance imaging (MRI) scanner and an image guided
surgical system were developed. Although it does provide surgeons with real
time images during surgery, it has several disadvantages. The first is its
cost, at $9.2M it is impractical for many hospitals to acquire. Further,
several challenges arise when working in close proximity to a magnetic field
including surgical objects.
Wait, how about
specific binding, washout time, image to background ratio, toxicity, binding
affinity, blocking experiments? I am not
an expert in this fascinating area of research, please refer to reliable
journals.
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