KW seminar: Molecular imaging Flashcards
(38 cards)
What is molecular imaging?
Molecular imaging encompasses a variety of imaging techniques that rely on the use of exogenously added specific probes (tracers/contrast agents) to target and detect desired cellular and molecular processes in a living organism.
Very roughly, what different techniques are there?
- Ultrasound
- Photo acoustic microscopy
- Optical coherence tomography
- Magnetic force microscopy
What is nuclear imaging?
Nuclear imaging is a method of producing images by detecting radiation from different parts of the body after a radioactive probe is given to the patient. The images are digitally generated on a computer and transferred to a nuclear medicine physician, who interprets the images to make a diagnosis
Also called “endoradiology”: because (it records radiation emitting from within the body rather than radiation that is generated by external sources like X-rays. In addition, nuclear medicine scans differ from radiology, as the emphasis is not on imaging anatomy, but on the function.
What are the two most common forms of nuclear imaging?
Single photon emission computed tomography (SPECT) and positron emission tomography (PET)
What is optical imaging?
Medical optical imaging is the use of light as an investigational imaging technique for medical applications. The probe that could be used for this is fluorescent dye
What are some examples of optical imaging?
Optical microscopy, spectroscopy, endoscopy, scanning laser ophthalmoscopy, laser Doppler imaging, and optical coherence tomography.
The lecturer doesn’t name this, but I think he means microscopy when referring to optical imaging. All the other forms you do not have to study
Explain what the sensitivity, resolution and depth is of nuclear imaging (probe: radionuclide)
Sensitivity: high
Resolution: moderate
Depth: whole body
Explain what the sensitivity, resolution and depth is of optical imaging (probe: fluorescent dye)
Sensitivity: high
Resolutation: high
Depth: superficial
Explain what the sensitivity, resolution and depth is of MRI imaging (probe: paramagnetic agent)
Sensitivity: poor
Resolution: high
Depth: whole body
For an overview and comparison of the different molecular imaging, see this figure
Okay
What two molecular imaging are the best options for molecular imaging, due to picomolar sensitivity?
Nuclear and optical imaging (MRI has a poor sensitivity)
What two forms of molecular imaging are best for examining the whole body?
Nuclear and MRI imaging (optical imaging is very superficial, and you need a thin slice of tissue to study under the microscope)
What probe is used in a PET-scan?
A sugar, called F-18 FDG
What shift is seen in the clinic regarding imaging?
That, as we learn more about diseases, we are becoming more aware that this happens on cellular, and even genetic level. Therefore we are using molecular imaging nowadays more than e.g. X-rays
Molecular imaging fills the gap between molecular ___, molecular ___ and molecular ___ ___
Molecular imaging fills the gap between molecular biology, molecular diagnosis and molecular targeted therapy
Molecular imaging of targets and drugs. To keep the health care system affordable
Fill in:
In biology, ___ of disease as well as ___ drugs have to be understood better.
Drug design and development should become more efficient and cheaper: selection of ___ drugs at an early stage, with less patients in trials, showing the distinguished properties of the drug.
(Drug) treatment should become more ____.
In biology, targets of disease as well as targeted drugs have to be understood better.
Drug design and development should become more efficient and cheaper: selection of high potential drugs at an early stage, with less patients in trials, showing the distinguished properties of the drug.
(Drug) treatment should become more “personalized/precise”.
True/false: Drug development is too expensive
True
Development costs of drug to market: > 1 billion dollar
Drug development is not efficient enough. About 65% of the trials fail at a certain phase. Which phase is this?
Phase II of clinical trials
Drug development is not efficient enough. How many % of drugs in clinical devleopment reach the market?
About 10% of drugs in clinical development reaches the market
We’ve seen that 10% of the drugs in clinical trials reach the market. However these drugs are not effective enough. Why?
Because often only 40% of the patients benefit from the drug. Imagine that a drug sales worldwide yearly ~1000 billion euro’s. This means that 600 billion is spent in vain because the patients do not benefit
There has been a change in the categories of drugs (size). What is this change?
From small chemical molecules to a diversity of biologicals.
Why is there a change from small chemical molecules to a diversity of biologicals?
Becuase biologicals have a much longer half-time (e.g. peptides hav a half-life of 2 hours before they are destroyed by the liver, monoclonal antibodies 120+ hours)
What are the characteristics of next generation targeted biologicals?
More potent, multiple specificities and (immune) functions
What are some examples of next generation targeted biologicals?
For illustration
- Antibody drug conjugates (ADCs)
- Immune checkpoint inhibiting antibodies (ICIs)
- Fusion antibodies, e.g. immunocytokines
- Bi- and multispecific antibodies
- Antibody fragments, antibody-like scaffolds
- Polynucleotides
- Nanoparticles
- Cells
