Medical Physics and Biomedical Engineering


World Cancer Day 2023: New research into mapping oxygenation levels in tumours

4 February 2023

medical image of a human prostate showing a cancerous tumour

Solid tumours in the body are often treated with surgery and/or radiotherapy, but often this treatment is not effective, or the cancer recurs after treatment. Hypoxia (lack of oxygen supply) in the tumour is often an indicator that a tumour will be resistant to radiotherapy and other treatments. Knowing whether a tumour is hypoxic can help doctors to make treatment decisions that may improve patient survival. Currently, hypoxia is measured using histological methods, in which a sample of tumour tissue is removed by biopsy and prepared for microscopic examination in a laboratory. This is invasive and time-consuming, and does not provide an indication of oxygen levels throughout the entire tumour. As hypoxia-specific treatments become available, there is a need for ways to measure oxygen levels and detect areas of hypoxia non-invasively and across a larger region.

Quantitative susceptibility mapping (QSM) is an emerging MRI technique that uses the usually-discarded phase component of the complex MRI signal to calculate the magnetic properties of tissues. It has been used extensively in the human brain, including for measurements of oxygenation in blood vessels, but it has not yet been fully extended to other parts of the body, nor has it been used for measuring oxygenation in tissue outside blood vessels.

medical images showing a human head with a tumour growing in the neck
Our project, funded by a Cancer Research UK multidisciplinary project award and led by Professor Karin Shmueli and Professor Shonit Punwani, aims to develop a new technology for susceptibility-based cancer oxygenation mapping (SBCOM), which will use QSM to create maps showing levels of oxygenation throughout tumours, focusing specifically on prostate cancer (PCa) and head and neck squamous cell carcinoma (HNSCC). We have already shown that QSM can be performed reliably in the head and neck in healthy volunteers and in the lower abdomen, and have improved the technique to account for the added complexities of these parts of the body.

As part of a multi-disciplinary team involving UCL Medical Physics and Biomedical Engineering, the UCL Cancer Institute, UCLH, and Guy’s and St Thomas’ Hospital, we will collect MR images from HNSCC patients (see the example QSM image here) and use SBCOM to make maps of oxygenation throughout the head and neck region. To develop the technique to study prostate cancer, we have teamed up with an ongoing histology-MRI mapping study (UCL Centre for Medical Imaging, UCLH Department of Pathology and UCL Centre for Medical Image Computing) to collect MR images from PCa patients as well as the resected prostate specimen after prostatectomy. An example of susceptibility maps we have calculated from MRI scans in two patients and corresponding maps of the resected prostate specimens are shown here.

medical images of prostate specimens
We plan to compare our non-invasive susceptibility-based oxygenation maps acquired in vivo with histological measures of oxygenation from resected prostate specimens. If successful, SBCOM will provide a method for non-invasively identifying hypoxia in tumours and lymph nodes, which will assist with treatment planning and monitoring, and allow more personalised treatment in HNSCC, PCa and other solid cancers.


Susceptibility-Based Cancer Oxygenation Mapping - by Dr Matt Cherukara and Dr Laxmi Muralidharan

Meet the experts

Dr Matt Cherukara and Dr Laxmi Muralidharan are postdoctoral research fellows in Professor Karin Shmueli’s MRI group at UCL Medical Physics and Biomedical Engineering.

Dr Matt Cherukara, Research Fellow

a profile picture of Dr Matt Cherukara

“When I decided to change careers and come back to academic research, it was important to me to be working on a project that had the potential for real benefit to patients. I’m excited to be working in cancer research, as the field uses cutting edge imaging science to meet an urgent clinical need.”

Dr Laxmi Muralidharan, Research Fellow in MRI Susceptibility Mapping of Prostate Cancer 

A profile picture of Dr Laxmi Muralidharan

“It’s always exciting to work on a research project that has the potential for clinical translation, as it can lead to real world impact and patient benefit.”

Prof Karin Shmueli, Professor of Magnetic Resonance Imaging Physics

Prof Karin Shmueli standing outside her office door

Karin’s research focuses on optimising MRI techniques to reveal clinically useful information by exploiting new contrast mechanisms. She uses the phase of the MRI signal (rather than the magnitude used in most conventional MRI) to calculate maps of tissue electromagnetic properties like its magnetic susceptibility or electrical conductivity.

Karin is a pioneer of methods to calculate magnetic susceptibility maps from MRI phase images. The susceptibility of living tissues depends on their composition so these quantitative susceptibility mapping (QSM) techniques can provide clinically useful information on disease-related changes in tissue iron or myelin content.

Together with her research group and collaborators, Karin aims to use these QSM and other phase-based MRI methods to generate clinical MRI biomarkers to improve diagnosis and monitoring of therapies in a range of diseases from Alzheimer’s to head-and-neck cancer.

With a long history of major breakthroughs, UCL is home to one of the largest concentrations of cancer specialists to be found anywhere in the world. On World Cancer Day 2023, find out more about UCL’s world-leading research on cancer at the UCL Cancer Institute