Surgical Tech Flashcards
What is a tumour margin?
Healthy area of tissue around a tumour that may have tumour cells within - There is not a standard definition of how wide a “clear margin” has to be. In some hospitals, doctors want 2 millimeters (mm) or more of normal tissue between the edge of the cancer and the outer edge of the removed tissue. In other hospitals, though, doctors consider a 1-mm rim of healthy tissue — and sometimes even smaller than that — to be a clear margin.
What are the basic ways of detecting tumour margin?
Sight and Feel - May result in too much healthy tissue removed or not enough tumour tissue removed
What are the current intra-operative tumour assessment techniques?
Cryostat Freezing - Tumour tissue removed and frozen (30-40 mins) and -20 degrees. Cut with microtome and then stained under microscope. Problem is loss of definition with freezing (frozen artefacts), bloating of cells, difficulty in cutting thin slices, difficulty of frozen cells taking up stains. Can overcome artefacts by freezing tissue so quickly that water doesnt have time to form crystals.
Fluorescence guided - Use flourophores to stain tissue - not tumour specific
What is the iKnife?
Uses Rapid Evaporation Ionization Mass Spec (REIMS) to detect vapour produced by diathermy knife (used normally in surgery to cauterise blood vessels) - detects specific glycophospholipids to determine tumour type
Tested on 81 in vivo samples, and matched post operation histological results for them all!
Slow, not all surgeries use diathermy knife, expensive
What is the Dune Margin Probe?
Uses electromagnetic waves to characterise tissue - used in lumpectomy (breast tissue removal)
Rapid, reagent free, prevent need for secondary op
Not RT, retrospective - not used to directly guide surgery
What is FLARE?
Fluorescence Assisted Resection and Exploration
Uses NIR flourophore injected into patient near site of tumour - detected by swing NIR on general site
Not tumour specific - low signal strength due to wide area illuminated by NIR
What is uPAR?
Urokinase Type Plasminogen receptor - increased in tumour cells (colon, breast , skin) - binds uPA and activates - converts plasminogen to plasmin - activated MMP (degrades ECM to aid metastasis) and activates TGF-B1 (aids tumour cell growth)
What is the antibody for uPAR?
ATN658
What is the flourophore used to bind the uPAR antibody?
ZW800-1 (NIR)
What were the experiments performed using uPAR NIR?
Xenograft model - showed fluorescence
Human HT29 Human colon cancer cells - no fluorescence
What is a CPN?
Conjugated Polymer Nanoparticle
What are the benefits of CPNs over flourophores?
No Bleaching
1400x florescence
4 year stability
