POC Device Pairs Optics, Ultrasound to Improve Thyroid Screening

An EU-funded development project for detecting thyroid cancer has produced an optical device that could give doctors a reliable, low-cost way to determine whether a thyroid nodule is malignant or benign. The five-year project, named Laser and Ultrasound Co-analyzer for Thyroid Nodules (LUCA), was coordinated by Spain’s ICFO photonics research center.

The different technologies of LUCA are embedded in a single portable device. It is a multimodal platform that combines near-infrared time-resolved spectroscopy (TRS), near-infrared diffuse correlation spectroscopy (DCS), and a clinical ultrasound system and probe.

When LUCA is integrated inside the thyroid nodule screening work flow, it can provide additional physiological information at the same time as a clinical ultrasound examination is performed. It simultaneously analyzes tissue hemodynamics, the chemical constitution of the tissue, and anatomical information from ultrasound.

“This project has allowed us to develop a unique optical-ultrasound platform that we are confident will find a use in clinical thyroid cancer screening,” professor Turgut Durduran, coordinator of the LUCA project and group leader of the ICFO medical optics research group, said.

Setup for thyroid repeatability measurements of the in vivo characterization tests with a healthy patient. Courtesy of ICFO/LUCA.

The TRS and DCS modules consist of custom-made components, that include off-the-shelf-electronics, and that enable the LUCA device to obtain high-quality measurements. The device can probe more than 1 cm deep into tissue — deep enough to uncover substantial information about the surrounding tissue — and it provides real-time monitoring and evaluation capabilities.

The researchers built a LUCA prototype that allows the measurement protocol to be managed by the doctor through an ultrasound touch-screen interface that visualizes and stores the results of the optical measurements along with the real-time ultrasound images. The doctor uses a separate monitor to control and optimize advanced parameters related to the optical subsystems.

The LUCA project team tested the device using established protocols for phantom validation and an in vivo performance assessment. To validate the performance of the optical modules, the researchers phantom-tested the TRS and DCS modules independently. They used a set of solid phantoms with different absorptions and scatterings to assess the TRS module’s capability to detect absorption and scattering changes. For the DCS module, they used a set of liquid phantoms with different viscosities to assess how accurately the module could measure the movement of the particles in suspension in the liquid phantom.

The researchers then performed a series of in vivo characterization tests on a healthy patient. They scanned the patient’s thyroid gland simultaneously with ultrasound imaging, TRS, and DCS several times a day on different days and weeks to test how precisely LUCA could measure the hemodynamic parameters related to the thyroid gland. In vivo testing demonstrated that the LUCA device is capable of performing high-quality measurements, with a precision in determining in vivo tissue optical and dynamic properties of better than 3%, and a reproducibility of better than 10% after ultrasound-guided probe repositioning.

LUCA was then moved into a clinical environment and tested on 18 healthy volunteers and 47 patients who were diagnosed with thyroid nodules. Through analyses of the metabolic rate of oxygen consumption and total hemoglobin concentration, LUCA classified 13 benign and four malignant nodules with a sensitivity of 100% and specificity of 77%. Conventional ultrasound techniques classified the nodules as unclear cases.

“The need to improve the current standards of thyroid cancer diagnosis has driven us to participate in this multidisciplinary project,” researcher Mireia Mora, from the August Pi i Sunyer Biomedical Research Institute, said. “We have taken the first steps in preclinical testing, but are sure that with this technology we will be able to avoid unnecessary surgeries and thus improve the quality of life of our patients.”

The project team believes that diffuse optical techniques could be applied to breast, head, neck, and abdominal cancer screening and therapy monitoring, as well as cerebrovascular accidents, and even used for COVID-19 testing. “We have learned a lot and are anxious to continue working in this line of research, because we believe that this technique could substantially improve the quality of measurements, narrow down diagnosis, and help assess possible treatments of patients,” Durduran said.

The research was published in Biomedical Optics Express (www.doi.org/10.1364/BOE.416561).