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Phantoms for Medical Research
17 December 2020
On 15 December we hosted our final virtual mini-symposium of the year: Phantoms for Medical Research.
Following an introduction from Vanessa Diaz, Daniil Nikitichev began proceedings by giving a background on why 3D printing can be useful for medical applications, citing reasons such as the freedom of design, it’s efficiency in terms of producing little waste material, and that designs can be customised and shared electronically. He also described some of the work he has done with 3D printing such as developing a placenta phantom, a brain model and using dissolvable 3D printing materials to create phantoms with internal structures. Recently Daniil has been developing a new technology which uses a flexible material for 3D printing called Gel Wax, which has advantages including ultrasound compatibility.
Karol Murawski further elaborated on using Gel Wax for custom 3D printing of medical phantoms. Phantoms can be created based on patient data obtained from modalities such as CT scans. He described an example of his work in which he used Gel Wax to create a kidney phantom. This can be used to help inform PCNL surgery – a keyhole surgery for kidney stone removal.
Gaia Franzetti has also been making use of the Gel Wax printing technology to develop patient specific phantoms for haemodynamic studies. She explained how inter-patient variability is extremely important in haemodynamic studies, as the anatomy of our vessels can be extremely different, especially when diseased. She has been investigating how to produce materials with customised mechanical properties which can be used according to the phantom that they want to produce.
Next, Eleanor Mackle discussed her work on patient specific phantoms for minimally invasive surgeries, and specifically the applications for neurosurgery. Nora worked with Jonathan Shapey to help develop a phantom which could be used as a clinical training tool for skull based surgeries such as vestibular schwannoma, as well as to test a new neuronavigational system. Therefore, it was required that the phantom was anatomically realistic including a skull and soft tissue structures (made from tissue mimicking materials), as well as having realistic imaging properties.
To end the first session, Deepak Kalaskar spoke about his work on the use of 3D printing for treating debilitating musculoskeletal conditions. Most of Deepak’s work relates to building bespoke medical devices and implants which are patient centred. He described a case study of a patient with transverse myelitis, which had resulted in head drop from the severe weakness of the neck muscles and arm paralysis. Due to the patient’s anatomy, she would be unable to tolerate commercial collars, and therefore Deepak and his team used a 3D scan of the patient to design and develop a bespoke collar.
Rashpal Singh, one of the design engineers at Pure Imaging Phantoms - a company that designs and manufactures medical imaging phantoms for most modalities such as radiography, fluoroscopy and ultrasound - illustrated some examples of their products including a head phantom which uses tissue imitating materials including bone, soft tissue and brain (including both white and grey matter).
Following from this was a talk from Henry Pinchbeck and his colleagues Camille Ribolzi and David Collins from 3D LifePrints, a medical 3D printing company who make patient specific 3D medical devices. Their products include anatomical models, patient specific cutting guides and implants, but they also develop simulators and training devices, which are generally non-patient specific devices which are developed in collaboration with surgeons and clinicians.
Stephen Hilton, whose research generally focuses on medicinal chemistry, has recently been working on 3D printing. His research is spread across a wide range of areas, from 3D printing and catalysis, where they have modified stirrer beads to making mixing far more efficient and allowing the stirrer itself to be used as a catalyst, to continuous flow chemistry. In continuous flow chemistry reagents are moved through a heated tube to give products continuously, which helps to overcome some of the problems experienced with batch chemical synthesis, such as the fact that large flasks are needed for large amounts and the poor mixing of reagents. Stephen has developed a modular flow reactor which can be 3D printed.
To start the final session, Juling Ong gave his talk on using 3D technology in caring for children with rare conditions, highlighting that 3D imaging gives the ability to analyse post-operative images in great detail.
This was followed by Helge Wurdemann, who discussed his work using patient-specific phantoms for interventional medical device validation. Helge and his team have been working on developing a modular suturing catheter for minimally invasive surgical treatment of abdominal aortic aneurysm that allows for: endovascular repair without a stent; a continuous suture pattern to prevent type 1 endoleaks; semi-automated suturing due to limited imaging feedback; and continuous blood flow during the intervention. In order to validate and test this device they have been developing patient-specific, modular aortic vascular phantoms with clinically relevant mechanical properties. The phantoms they create are shaped according to patient-specific geometry and are placed inside a transparent box for housing which allows for direct visualisation.
In her research, Candice Majewski is looking at introducing antibacterial functionality for powdered-polymer 3D printed parts. The purpose of this is to address some of the ongoing issues surrounding anti-microbial resistance, which is a global problem. This antibacterial functionality could have a range of applications, from consumer goods through to medical applications. The approach being used by Candice and her colleagues is to combine laser sintering polymers with a sliver-based additive (silver has known anti-bacterial properties). Dispersion of the silver additive was good amongst the parts and it had no significant effects on the mechanical properties of the polymer.
To close the symposium, Hani Marcus discussed 3D printing in neurosurgery. Pre-operatively 3D printed models can be used to help convey information to patients to aid in their understanding of the procedure, and it can also be used by surgeon and trainees to rehearse the procedure. 3D printing can also be used during neurosurgery, for example the use of 3D printed patient-specific drill guides can be used to improve accuracy of surgery. Furthermore, patient-specific implants can be 3D printed which research has shown are well tolerated by patients.
Overall our symposium was a great success, generating lots of interesting questions from our 92 attendees from around the world. Save the date for our next symposium which will take place on Thursday 21 January 2021 – keep an eye out for details in due course!