Phantoms in medicine: The case of ophthalmology (2025)

New eye phantom for ophthalmic surgery

Journal of Biomedical Optics, 2014

In this work, we designed and realized a new phantom able to mimic the principal mechanical, rheological, and physical cues of the human eye and that can be used as a common benchmark to validate new surgical procedures, innovative vitrectomes, and as a training system for surgeons. This phantom, in particular its synthetic humor vitreous, had the aim of reproducing diffusion properties of the natural eye and can be used as a system to evaluate the pharmacokinetics of drugs and optimization of their dose, limiting animal experiments. The eye phantom was built layer-by-layer starting from the sclera up to the retina, using low cost and easy to process polymers. The validation of the phantom was carried out by mechanical characterization of each layer, by diffusion test with commercial drugs into a purposely developed apparatus, and finally by a team of ophthalmic surgeons. Experiments demonstrated that polycaprolactone, polydimethylsiloxane, and gelatin, properly prepared, are the best materials to mimic the mechanical properties of sclera, choroid, and retina, respectively. A polyvinyl alcohol-gelatin polymeric system is the best for mimicking the viscosity of the human humor vitreous, even if the bevacizumab half-life is lower than in the human eye.

Introduction: Feature Issue on Phantoms for the Performance Evaluation and Validation of Optical Medical Imaging Devices

Biomedical Optics Express, 2012

The editors introduce the Biomedical Optics Express feature issue on "Phantoms for the Performance Evaluation and Validation of Optical Medical Imaging Devices." This topic was the focus of a technical workshop that was held on November 7-8, 2011, in Washington, D.C. The feature issue includes 13 contributions from workshop attendees.

Ocular Phantom-Based Feasibility Study of an Early Diagnosis Device for Glaucoma

Sensors (Basel, Switzerland), 2021

Glaucoma causes total or partial loss of vision in 10% of people over the age of 70, increasing their fragility and isolation. It is characterised by the destruction of the optic nerve fibres, which may result from excessively high intraocular pressure as well as other phenomena. Diagnosis is currently reached through a combination of several checks, mainly of the eyes’ fundus, tonometry and gonioscopy. Prior to validation for human subjects, the objective of this study is to validate whether ocular phantom-based models could be used to diagnose glaucoma using an onboard system, which could, even at home, prevent the early-stage development of the pathology. Eight phantoms modelling healthy eyes and eight phantoms modelling eyes with glaucoma due to excessive intraocular pressure were measured using an onboard system, including lens and electrophysiology electronics. We measured the actual average Zr (real part of impedance) impedance of 160.9 ± 24.3 ohms (glaucoma ocular phantom mo...

Phantom Eye Syndrome: A Review of the Literature

TheScientificWorldJournal, 2014

The purpose of this literature review was to describe the main features of phantom eye syndrome in relation to their possible causes, symptoms, treatments, and influence of eye amputation on quality of life of anophthalmic patients. For this, a bibliographical research was performed in Pubmed database using the following terms: "eye amputation," "eye trauma," "phantom eye…

Patient-specific neurosurgical phantom: assessment of visual quality, accuracy, and scaling effects

3D printing in medicine, 2018

Training in medical education depends on the availability of standardized materials that can reliably mimic the human anatomy and physiology. One alternative to using cadavers or animal bodies is to employ phantoms or mimicking devices. Styrene-ethylene/butylene-styrene (SEBS) gels are biologically inert and present tunable properties, including mechanical properties that resemble the soft tissue. Therefore, SEBS is an alternative to develop a patient-specific phantom, that provides real visual and morphological experience during simulation-based neurosurgical training. A 3D model was reconstructed and printed based on patient-specific magnetic resonance images. The fused deposition of polyactic acid (PLA) filament and selective laser sintering of polyamid were used for 3D printing. Silicone and SEBS materials were employed to mimic soft tissues. A neuronavigation protocol was performed on the 3D-printed models scaled to three different sizes, 100%, 50%, and 25% of the original dime...

Testing a phantom eye under various signal-to-noise ratio conditions using eleven different OCT devices

Biomedical Optics Express

We compared eleven OCT devices in their ability to quantify retinal layer thicknesses under different signal-strength conditions, using a commercially available phantom eye. We analyzed a medium-intensity 50 µm layer in an identical manner for all devices, using the provided log-scale images and a reconstructed linear-scale tissue reflectivity metric. Thickness measurements were highly comparable when the data were analyzed in an identical manner. With optimal signal strength, the thickness of the 50 µm layer was overestimated by a mean of 4.3 µm in the log-scale images and of 2.7 µm in the linear-scale images.

Anthropomorphic Phantoms - Potential for More Studies and Training in Radiology

International Journal of Radiology & Radiation Therapy, 2017

Anthropomorphic phantoms are used for the assessment of image quality and to simulate a medical procedure. They can be likewise developed for training and teaching for all modalities of imaging. Phantoms built from tissue-equivalent materials provide a physical representation of the anatomy of the human body and attenuation characteristics, allowing researchers to calculate absorbed organ doses, improving treatments effectiveness and protecting healthy tissues. Now a days, physical phantoms have been used as a comparison to computational models for validation of Monte Carlo codes, which are computational phantoms. The more complex the tissue is structured, the more difficult it gets to design the phantom. With the development of 3D printers, new phantoms can be built from medical imaging. However, current 3D printers do not use a wide variety of materials, so it is not possible yet to create phantoms for functional imaging. Studies must be performed to optimize current imaging techniques and elevate their accuracy, which would provide visual, practical, hands-on training of the medical staff, with real-world simulations, ideally patient-specific. This technological advance should be made with physical and computational phantoms in parallel since validation has a high value to the reliability of this scientific method. When it comes to radiation protection of patients and staff, new anthropomorphic phantoms could also provide data for new dosimetry and radiation protection studies, serving as a foundation for the progress of radiological safety throughout the world.

Evaluation of a point-of-care ultrasound curriculum and ocular phantom in residency training

Journal of Ultrasound, 2021

Specialized training in ocular ultrasound is not a focus for most emergency medicine residencies, despite the fact that it allows physicians to quickly and accurately identify ocular pathology and prioritize emergency ophthalmological consultations. Therefore, we tested the value of utilizing normal and pathologic ocular ultrasound phantoms as a training tool for residents. Twenty emergency medicine residents were given a pre-test including written and practical skills diagnosis of ocular phantom pathologies, a short video on common ocular pathologies, practice time with the phantoms and a post-test including written and scanning components. Residents were then asked to complete an overall evaluation of the learning activity. After didactic and hands-on training with phantoms, residents demonstrated a significant increase in knowledge, skills and preparedness for diagnosing real patients with ocular pathologies. Overall, the phantoms allowed residents an unrestricted opportunity to ...

A tissue-equivalent upper abdominal phantom

Journal of Ultrasound in Medicine, 1983

A novelty technique for the fabrication of biomedical optics phantoms with cyst-mimicking inclusions

Journal of Near Infrared Spectroscopy, 2017

The construction of standardised phantoms for biomedical optics experiments is still a developing research field. Particularly, the application of diffusive optics techniques to tissues with low or non-scattering heterogeneities, such as cysts, where the diffuse approximation does not apply, has been studied during the last years. The reported phantoms for mimicking cysts have inclusions that consist of hollow cylinders filled with low or non-scattering fluids, being thus more representative of a 2D geometry rather than a 3D geometry. We present here an innovative proposal, to our knowledge not reported before, for the manufacture of solid diffusive phantoms with spherical, liquid inclusions, with low or nonscattering properties, intended to reproduce cysts. To this end, we used the inverse spherification technique from the molecular gastronomy. The constructed phantoms were optically characterised by two approaches, namely whole field continuous wave transmittance imaging and time-resolved experiments, both in the near infrared at ¼ 785 nm. After optical characterisation, the phantoms were also dissected, showing that the inclusions remained in place and preserved their shape after the whole fabrication process. Some results were also validated by Monte Carlo simulations.