Intraoperative tumor-specific real-time fluorescence imaging

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.

                                                                                           ≈