SkIN hydrAtion Evaluation With TeRAhertz Scanning

The SINATRA study is pilot study with a primary aim to explore the feasibility of the trial methodology. In addition, secondary objectives of the study will investigate if THz light is able to detect subtle differences in skin hydration and their clinical relevance. Due to the unprecedented sensitivity of THz light to skin hydration, the investigators will also investigate if different skin types have a preferential uptake of certain emollients. This would include dry skin conditions such as eczema, psoriasis and post-operative scars. This will give us information on how to optimise the types of emollients used in future development of new moisturisers and sunscreens. This is already under investigation in a cohort of volunteers with unaffected skin (unpublished pilot study data, University of Warwick). Additionally, as part of the SINATRA study, the investigators will investigate if THz imaging is able to detect subclinical (invisible) skin cancer (residual basal cell carcinoma (BCC)) and enhance the diagnosis of suspected skin cancer (malignant melanoma) in vivo. Skin cancer is known to produce a localised inflammatory reaction and microscopic swelling and so the changes in skin hydration may be able to be objectively measured by THz skinometry.

Terahertz (1012 Hz) pulsed imaging is a new technique with high resolution and has only emerged recently as a potential new clinical tool for medical imaging. It is a safe imaging modality as the light is non-ionising - it has a million times lower energy than an x-ray and thus doesn't have enough energy to cause ionisation. The power levels used in the THz systems in this study are also very low such that there are no lasting effects. In particular, our in vivo THz imaging systems have a peak power less than 40mW and average power intensity less than 4 µW/cm2. Studies by Hough et al [2] have shown that even using peak power 50,000 times higher and an average intensity 30 times higher does not cause any change in gene expression. Therefore, power levels used in our THz in vivo imaging systems are safe and have no known side effects or risks

The SINATRA study will collect preliminary pilot data from participants in a two-arm feasibility observational study.

1. One arm will consist of 100 patients with known or suspected skin cancer (skin cancer defined as: incompletely excised BCC with histologically proven radial margin involvement; biopsy proven BCC, or pigmented lesions suspicious of malignant melanoma). Images will be taken in the clinic prior to planned skin surgery and later compared to the formal histology results after the primary (melanoma) or residual (BCC) tumour has been removed.
2. The second arm will consist of 50 patients with benign dry skin conditions (eczema, psoriasis, skin grafts, scars etc.) and will compare the water content of their skin before and after application of a propriety emollients in common usage (e.g. E45®, Aveeno®, Doublebase®). This will add to the existing dataset that has been recorded from healthy non-patient volunteers (unpublished data, University of Warwick). This may help to guide patient-specific emollient selection in the future.

This will add to the knowledge base to define the appearance of skin cancers under THz skinometry. The spectroscopic findings will not influence the established management that will have been planned in conjunction with a Consultant Dermatologist or Plastic Surgeon and the patient.