3D printed rodent skin-skull-brain model: A novel animal-free approach for neurosurgical training

A 3D-Printed Dummy for Training Distal Phalanx Amputation in Mice

The development of realistic dummies for training the distal phalanx amputation (DPA) technique in mouse pups is a promising alternative to reduce and replace animals in training for research and teaching. To test this, we obtained micro-CT data from postnatal day-five mouse pups, meticulously segmented them, and converted them into a 3D mesh format suitable for 3D printing. Once the dummy was printed, it was evaluated during actual training courses in two different groups: in the first group, users received no dummies to train the DPA, and in the second group, users were trained with three dummies. To assess the effectiveness of the dummy, we conducted a survey followed by an expert veterinarian evaluation. Our results showed that DPA is a complex procedure, and it is commonly poorly performed. When implementing the dummies, users who were not provided with dummies to practice only had an 8.3% success rate in DPA, while users provided with three dummies had a 45.5% success rate, respectively. Despite additional research being needed, our dummy offered improved practical training by providing a safe and effective alternative in line with ethical considerations while demonstrating the feasibility of using 3D printing technology to promote the 3Rs in experimental research.

Development of an US, MRI, and CT imaging compatible realistic mouse phantom for thermal ablation and focused ultrasound evaluation

Tissue mimicking phantoms (TMPs) play an essential role in modern biomedical research as cost-effective quality assurance and training tools, simultaneously contributing to the reduction of animal use. Herein, we present the development and evaluation of an anatomically accurate mouse phantom intended for image-guided thermal ablation and Focused Ultrasound (FUS) applications. The proposed mouse model consists of skeletal and soft tissue mimics, whose design was based on the Computed tomography (CT) scans data of a live mouse. Advantageously, it is compatible with US, CT, and Magnetic Resonance Imaging (MRI). The compatibility assessment was focused on the radiological behavior of the phantom due to the lack of relevant literature. The X-ray linear attenuation coefficient of candidate materials was estimated to assess the one that matches best the radiological behavior of living tissues. The bone part was manufactured by Fused Deposition Modeling (FDM) printing using Acrylonitrile styrene acrylate (ASA) material. For the soft-tissue mimic, a special mold was 3D printed having a cavity with the unique shape of the mouse body and filled with an agar-based silica-doped gel. The mouse phantom accurately matched the size and reproduced the body surface of the imaged mouse. Tissue-equivalency in terms of X-ray attenuation was demonstrated for the agar-based soft-tissue mimic. The phantom demonstrated excellent MRI visibility of the skeletal and soft-tissue mimics. Good radiological contrast between the skeletal and soft-tissue models was also observed in the CT scans. The model was also able to reproduce realistic behavior during trans-skull sonication as proved by thermocouple measurements. Overall, the proposed phantom is inexpensive, ergonomic, and realistic. It could constitute a powerful tool for image-guided thermal ablation and FUS studies in terms of testing and optimizing the performance of relevant equipment and protocols. It also possess great potential for use in transcranial FUS applications, including the emerging topic of FUS-mediated blood brain barrier (BBB) disruption.