Last month we shared with you the marvellous free physics lectures that take place at the University of Birmingham. Cian in Year 9 went to one of these and was kind enough to write us some notes on the lecture to share with the rest of the school. He truly embodies being self-motivated to achieve, providing valuable contributions to us all by sharing his experiences. Thank you Cian!
“‘Colour beyond human vision’. Colour can be used beyond the visible range. Colour can be measured in many more than 3 channels. Colour is used in imaging.
Histology is when a small sample of tissue is taken and dyed with colour to determine whether a tumor is removed. Colour in the human body is already able to tell us information. Colour of blood can tell us about health. Sadly, humans are not transparent, but they are also not fully opaque. Light scatters through our cells, so it is unable to be used for medical imaging. But we can combine light and sound to get medical imaging. We can use the photoacoustic effect. Light absortion = impulsive heating = increased pressure. The lecturer used a camera on an empty can, and when the flash activated it made A small ping. The haemoglobin in blood absorbs light. We can play sound waves back in time, and it can show us images of when the light was absorbed. This is an imaging technique and can show us the absorption rates of different materials. It is safe and non-ionising, and the lasers are low powered, so they are not harming to human tissue. Imaging can measure blood vessels in the human hand. The amount of research across the years is increasing, to the point where it may be able to be used in marketing very soon. We can detect sound with light. A simple system doesn’t always make the best images. Photoacoustic signals can be weak. The deeper the ultrasound source, the worse the imaging is, as the sound gets weaker as it goes through.
We want a sensitive detector that can detect high and low frequencies of ultrasound. If we lose the high frequency, we lose the higher resolution. We need a detector that is small and scalable. Optical ultrasound detectors are transparent and meet the requirements for a good thing. We detect sound by pointing a laser beam at the sensor and it bounces around the sensor.
We add more laser beams to make imaging scans faster. We can see very detailed images like the valves to stop blood flowing in wrong direction. Larger blood vessels at bottom branch into smaller ones. Dynamic imaging. We can look at below the surface burns and injuries. We can also see for arthritis.
We can also see how things like cancer and tumors react to different drugs. We can give drugs over time and do a scan every day, then compare the images. Since the scans are non-ionising, they are safe to do numerous times without any bad health effects.
