A novel Deep Raman spectroscopy platform for non-invasive in situ molecular analysis of disease specific tissue compositional changes.

Recently, we have pioneered a portfolio of revolutionary optical technologies in the area of laser spectroscopy, namely deep Raman spectroscopy, for non-invasive molecular probing of biological tissue. The developments have the potential of making a step-change in many fields of medicine including cancer diagnosis. The techniques comprise spatially offset Raman spectroscopy (SORS) and Transmission Raman (both patented by the applicants). The methods are described in detail in a tutorial review: http://www.rsc.org/Publishing/Journals/CS/article.asp?doi=b614777c .
There is an urgent clinical need for early objective diagnosis and prediction of likely treatment outcomes for many types of subsurface cancers. This is not addressed by existing technologies. There are numerous steps along the cancer clinical pathway where real-time, in vivo, molecular specific disease analysis would have a major impact. This would allow for more accurate and immediate diagnosis at first presentation, by improving screening or surveillance techniques, leading to earlier diagnosis and better treatment outcomes. Secondly it would allow surgical margin assessment and treatment monitoring in real-time and thirdly identification of metastatic invasion in the lymphatic system during routine surgery. There are numerous other areas where a rapid molecular analysis of a tissue sample in the clinic or theatre environment would allow improved clinical decision-making. Clearly these approaches would be beneficial to the patient by reducing cancer recurrence rates; but also by minimising the numbers of invasive procedures required, thus reducing costs and patient anxiety.
Raman spectroscopy is a highly molecular-specific method, which itself has proven to be a useful tool in early epithelial cancer diagnostics, although it has been restricted to sampling the tissue surface of less than 1 mm deep. Our new technology unlocks unique access to tissue abnormalities of up to several cm's deep, i.e. at depths one to two orders of magnitude higher than those previously possible with conventional Raman.
We propose to make major breakthroughs in this area and advance diagnostics (including cancer margin assessment and staging) particularly focussed on breast cancer and lymph node metastasis initially as focused case studies and then potentially applied to prostate cancers (not included directly in this proposal). This will be explored as a joint cross-disciplinary venture between Profs Stone and Matousek, the two key researchers in this area, who between them have pioneered the concepts and have established a team of cross-disciplinary scientists and clinicians to advance this field.
To fully capitalise on our international lead, we now seek funding to progress this work in a timely manner by developing a novel medical diagnostic platform. We propose to bring together key players from multidisciplinary areas covering physical sciences, spectroscopy, radiology, cancer diagnostic and therapeutic surgery, and histopathology to exploit all of the relevant skills and develop a critical mass of researchers. The principal collaborating teams at the heart of the programme will include: 1) Matousek group in Central Laser Facility at Rutherford Appleton Laboratory focussing on maximising the potential of the technique by implementing further technological developments. 2) Stone group with 17 years experience of applied clinical spectroscopy to develop and evaluate the technology applied to human tissues and undertake complex multivariate analysis to distil the data into relevant diagnostic outputs.

Here we plan to develop an advanced engineering platform for the next generation of non-invasive diagnosis of subsurface cancers. This will be facilitated by translating the SORS and Transmsision Raman spectroscopy from its current pharmaceutical and security application into the medical arena. Due to the complexity of the biological tissue and the presence of inherent low level analytes/markers a dramatically higher instrumental sensitivity and penetration depth will be required for medical applications. This improvement will be facilitated by increasing the signal collection capability of the technique by two orders of magnitude by implementing a range of innovative engineering solutions. The new platform will unlock a range of novel medical applications and have a knock out effect also on other areas where high sensitivity is required.

Successful completion of this project would pave the way for establishing the new technique of deep Raman spectroscopy to provide a reliable measure of the benign or malignant state of breast lesions; to non-invasively assess cancer margins at the operating theatre and to non-invasively assess breast lymph nodes for the presence of metastatic cancer cells.

The long term potential is highly significant. We expect ultimately to be able to construct a device for use as an adjunct to x-ray mammography (or ultrasound), which is highly sensitive to cancerous lesions but provides very poor specificities, by picking up many non-cancerous conditions. The deep Raman molecular composition signal would be expected to provide the required chemical specificity to overcome this major limitation of the screening programme. Furthermore, optical radiation is inherently safe at the low powers we propose to use, whereas X-ray screening can induce cancers in the screened population. We would expect to have a significant impact on reducing the numbers of patients with benign lesions recalled for additional tests and biopsies. In addition the deep Raman technique could potentially be utilised to monitor patients diagnosed with lower grades of ductal carcinoma in situ: to safely detect any changes towards higher grade DCIS or invasive malignancy. This may lead to increased mammographic screening effectiveness and reduced over treatments.

The technique when proven to be applicable to the soft tissue margins and identification of metastatic lymph nodes in the breast can then easily be applied to other solid cancers, such as the prostate. Furthermore, other soft tissue lesions could be explored or risky surgical margins in sensitive organs such as the brain could be probed and target areas identified. On the basis that the many drugs have strong and distinct Raman signals to soft tissues, it would be expected that treatment monitoring and drug penetration could be measured in situ in real-time.

Some recent work by the applicants in collaboration with the Graham group at Strathclyde has led to the first demonstrations that we can probe the unique signals provided by labelled surface enhanced Raman nanoparticles buried within tissues. This could lead to multiplexed imaging of nanoparticles in vivo in the distant future too.

FIT TO EPSRC STRATEGY
The proposed program of work is strongly aligned with EPSRC Healthcare Strategy, in particular, with 'Diagnostics' and 'Design and Technologies for Public Health' themes delivered here through research areas 'Clinical Technologies' and 'Medical Imaging' (both currently supported at 'Maintain' level by the EPSRC).