Novel Imaging for Cancer: Dr Sarah Bohndiek – by Raheela Rehman
Held at Schlumberger’s Gould Research Center, a suitable venue as the backdrop, that brought together the Institute of Physics, CamAWiSE, and Schlumberger to play host to Dr Sarah Bohndiek. Dr Bohndiek, whose research cross-cuts both physical and biological sciences, introduced her comprehensive, rigorous and exciting research in the techniques to detect and understand cancerous cell growth. The research into novel cancer discovery methods is used by Sarah for developing new detection devices as well as augmenting existing ones.
Cancer is a disease of cells. Most cells in the body are able to divide to produce more copies of themselves, but they have a tightly controlled Stop-Go signalling mechanism, which restricts growth to on-a-need basis. Dr Bohndiek gave the example of how a wound requires cell growth for repair, with an essential stop signal when fully healed. When this stop signal is faulty, the number of cells will continue to increase, ballooning out of control into what is termed as a tumour.
Sarah covered four areas of her research:
- Molecular Imaging
The importance of O2 in cancer, and its detection
- Optoacoustic Imaging
Improving cancer staging with blood vessel maps
- Hyperspectral Imaging
Improving early cancer detection with molecular endoscopy
- Future Challenges
Prospectives on clinical translation
1. Molecular Imaging
Dr Bohndiek explained oxygen (O2) plays a role in cancer cell growth and how molecular imaging uses this role in detecting cancer. Tumours consume a lot of O2, but due to the lack of blood vessels to supply this need, the tumour has to develop its own blood supply. A high intrinsic contrast is available by optically imaging the O2 metabolism of cancer. However, the depth of light penetration in tissue is limited and we normally lack the ability to detect more than one signal at a time. There are several approaches Dr Bohndiek’s group is studying to overcome this limitation: Hyperspectral Fluorescence Imaging, Light Scattering, and Optoacoustic imaging.
2. Optoacoustic Imaging
Cancerous tissue requires O2 and depending on the amount present, light is absorbed to varying degrees. Detecting this light absorption can provide a map of the blood supply to the tumour, and thus may indicate the cancer stage. Optoacoustic imaging uses a near infrared light source, which elevates the tissue temperature by 0.1oC and generates a thermoelastic expansion in the soft matter. The result is a thermo-acoustic wave at the ultrasonic level (16 kHz – 1 GHz). As sound energy is far less scattered than light in tissue, detecting these ultrasound waves enables deeper tissue imaging.
3. Hyperspectral Imaging
Detecting early oesophageal cancer through traditional endoscopy techniques, uses visible light and requires a biopsy taken every 1cm. Early detection, followed by therapy allows 80% survival rate for the next 10 years. In collaboration with Prof. Rebecca Fitzgerald from the MRC Cancer Cell Unit, Dr Bohndiek’s research intends to augment the traditional endoscopy procedure to increase the detection quality. Two methods being investigated are a) incorporating fluorescence and b) spectral and spatial light resolution.
The first process involves using a sugar dye applied to the oesophageal lining of the patient. The sugar binds to non-cancerous cells, which when viewed by fluorescence imaging shows as bright normal healthy tissue. However, cancerous tissue appears dark, hence providing a contrast in tissue type.
The second process makes better use of the available spectral and spatial light distributions. This ‘hyperspectral imaging’ concept is used routinely in remote sensing for detection of military vehicles by drones, but can also be applied in medicine. Normally poor image contrast arises due to the limited colour resolution of a typical camera (red, green and blue). Dr Bohndiek is working with Imec (Belgium) to increase the number of available colour filters. By replacing the standard red-green-blue camera sensor with over 100 colours on the camera sensor chip, the contrast in endoscopy could be improved.
4. Future Challenges
Technical maturity of medical devices being brought into the market often have timelines similar to that of pharmaceutical drugs. The rate at which new tools are brought into the field can be increased by progressing test, acceptance and finally spread of the devices. Dr Bohndiek works closely with small companies, with niche technologies, to provide direct feedback. The next step in this practice is to have the devices in multiple centres for trial.
Discussions with attendees after the presentation revealed that Dr Bohndiek’s research sparked interest in possible application in the oil and gas sector, and the welding sector. The possibility of science and technology being applied across different fields I believe is true innovation!