Dr Emma Harris, Imaging for Radiotherapy Adaptation team
Dr. Emma Harris and her team are developing imaging techniques to increase the effectiveness of radiation oncology to treat a number of different cancer sites. Her main focus is the development of various novel ultrasonic imaging techniques to locate the radiotherapy target volume, to guide the delivery of radiotherapy and to help predict, and monitor, treatment response.
Radiation-induced fibrosis is a chronic side effect of radiotherapy given to patients with cancer and may limit the dose that is given. Fibrosis is a genetically regulated response to tissue injury and drugs may be given to reduce its severity. Reliable measures of fibrosis are required to support research in three specific areas: i) radiotherapy dose scheduling, ii) identification of patients’ genetic susceptibility to fibrosis, and iii) clinical evaluation of anti-fibrotic therapies. Quantitative in vivo measures of treatment response are needed to support the investigation of genetic and physiological susceptibility to radiation toxicity and clinical trials evaluating anti-fibrotic, anti-angiogenic and anti-hypoxia therapies.
This research project investigates the potential of new ultrasound based tools in vivo for assessment of radiation induced fibrosis in women following radiotherapy for breast cancer.
Dr Tuathan O’Shea is researching novel ways to use imaging techniques to improve radiation therapy delivery. It is well known that for many anatomical sites the tumour remains mobile during radiation therapy (RT) requiring margins around the target to account for motion (known as intra-fraction motion). With the application of imaging and improved information on tumour position, margins can be decreased, reducing radiation to surrounding healthy tissue and potentially allowing increased tumour dosage.
Highly conformal radiotherapy planning techniques such as IMRT and VMAT are only possible if the precise positions of the target volume and organs at risk are known. However, the motile and deformable characteristics of soft tissue organs make it extremely difficult to ascertain their position (despite daily x-ray imaging and careful patient set up) prior to and during radiation delivery. Therefore, large treatment margins are required to ensure adequate coverage of the target area at the expense of including healthy tissues in the treatment field. Daily soft-tissue imaging using ultrasound is a promising solution for determining the precise location of the target organ and surrounding tissues for radiotherapy, which could ultimately allow a more widespread use of highly conformal delivery plans.
Radiotherapy is an important treatment for cancer with around 50% of cancer patients receiving radiotherapy. Unfortunately, not all tumours respond in the same way. Some tumours may be radiation resistant resulting in treatment failure. It is important that we find accurate and cost effective methods to monitor the response of tumours to radiotherapy at multiple times throughout treatment. That way, the clinician can know if the treatment is failing and this allows them to change the patient’s treatment accordingly and quickly. Functional ultrasound imaging techniques such as contrast enhanced ultrasound, molecular ultrasound and elastography, show great promise for the evaluation of tumour response to therapy. They are also affordable and quick to perform making. This project will develop 3D ultrasound imaging which can measure multiple ultrasound characteristics of tumours which may be used to evaluate tumour response to therapy.
Ultrasound contrast imaging is an effective method for monitoring the response of the tumour vascular system to cancer therapies such as targeted drug therapies which target the tumour blood supply, radiotherapy and chemotherapy. One limitation of the techniques is that it is a 2D imaging technique, typically allowing only a small portion of the tumour to be evaluated. We are developing 3D ultrasound contrast imaging which will allow us to evaluate the response of the entire tumour and to look for heterogeneity in tumour response, which is believed to contribute to treatment resistance.