3D printing and medical imaging

Unveiling the Drug Formulation Code: A Journey to Three-Dimensional Precision

Magistral formulations emerged years ago and were of great help in the personalization of treatments for patients. Over time, innovation began in this area with new technologies such as three-dimensional (3D) printing, which has brought greater benefits, ease of preparation, new scopes, and even cost reduction. Three-dimensional printing of medicines opened the way to create personalized multi-dose, controlled-release, multi-drug tablets, among others. In addition, this technology manages to be more specific in adjusting pharmacokinetics, doses, and even organoleptic qualities, which is precisely what is sought since the medication is being personalized for a patient due to a particular case or condition. Throughout the research, some studies can be observed that function as a base that provides safety and effectiveness for the subsequent use of other pharmaceuticals in the 3D printing of medicines.

A Biologically Degradable and BioseniaticTM Feedstock for the High-Quality 3D Printing of Anatomical Models

A Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) -based filament was evaluated as an alternative feedstock for Fused Deposition Modeling (FDM) of instructional and clinical medical specimens. PHBHHx-based prints of domestic cat vertebrae, skull bone, and an aortic arch cast were found comparable to conventional materials. PHBHHx-based filament and extrudate samples were evaluated for biological degradability, to meet the BioseniaticTM standard, defined by the University of Georgia New Materials Institute. Both samples achieved more than 90% mineralization within 32 days in industrial composting conditions.

Assessing the impact of 3D image segmentation workshops on anatomical education and image interpretation: A prospective pilot study

Three-dimensional (3D) segmentation, a process involving digitally marking anatomical structures on cross-sectional images such as computed tomography (CT), and 3D printing (3DP) are being increasingly utilized in medical education. Exposure to this technology within medical schools and hospitals remains limited in the United Kingdom. M3dicube UK, a national medical student, and junior doctor-led 3DP interest group piloted a 3D image segmentation workshop to gauge the impact of incorporating 3D segmentation technology on anatomical education. The workshop, piloted with medical students and doctors within the United Kingdom between September 2020 and 2021, introduced participants to 3D segmentation and offered practical experience segmenting anatomical models. Thirty-three participants were recruited, with 33 pre-workshop and 24 post-workshop surveys completed. Two-tailed t-tests were used to compare mean scores. From pre- to post-workshop, increases were noted in participants' confidence in interpreting CT scans (2.36 to 3.13, p = 0.010) and interacting with 3D printing technology (2.15 to 3.33, p = 0.00053), perceived utility of creating 3D models to aid image interpretation (4.18 to 4.45, p = 0.0027), improved anatomical understanding (4.2 to 4.7, p = 0.0018), and utility in medical education (4.45 to 4.79, p = 0.077). This pilot study provides early evidence of the utility of exposing medical students and healthcare professionals in the United Kingdom to 3D segmentation as part of their anatomical education, with additional benefit in imaging interpretation ability.

Enhancing medical education in respiratory diseases: efficacy of a 3D printing, problem-based, and case-based learning approach

OBJECTIVES

The present study aims to investigate the efficacy of utilizing three-dimensional (3D) printing technology in concert with Problem-Based Learning (PBL) and Case-Based Learning (CBL) pedagogical approaches in educating senior undergraduate clinical medical students on respiratory diseases.

METHODS

A cohort of 422 fourth-year clinical medicical students of from Anhui Medical University, pursuing a five-year program, were arbitrarily segregated into two distinct groups. The experimental group was subjected to a combined pedagogical approach, which included 3D printing technology, PBL and CBL (referred to as DPC). Conversely, the control group was exposed to conventional teaching methodologies for respiratory disease education. The effectiveness of the teaching methods was subsequently appraised using both theoretical test scores and custom questionnaires.

RESULTS

Post-quiz scores indicated a statistically significant improvement in the DPC group as compared to the traditional group (P < 0.01). Self-evaluation and satisfaction questionnaires revealed that the DPC group's self-assessment scores outperformed the traditional group in several aspects, including clinical thinking ability, learning initiative, self-study ability, anatomical knowledge mastery, confidence in learning, ability to analyze and solve problems, comprehension of the knowledge, help to clinical thinking and level of satisfaction on the teaching methods (P < 0.01). However, within the unsatisfied DPC sub-group, none of these self-assessment aspects, except for comprehension of the knowledge, impacted the learning efficacy (P > 0.05).

CONCLUSION

The deployment of the DPC pedagogical approach may confer unique experiential learning opportunities for students, potentially enhancing theoretical test scores and promoting self-evaluation and satisfaction in the context of respiratory disease education. Hence, it may be instrumental in augmenting the overall teaching efficacy.

Assessment of post-infarct ventricular septal defects through 3D printing and statistical shape analysis

BACKGROUND

Post-infarct ventricular septal defect (PIVSD) is a serious complication of myocardial infarction. We evaluated 3D-printing models in PIVSD clinical assessment and the feasibility of statistical shape modeling for morphological analysis of the defects.

METHODS

Models (n = 15) reconstructed from computed tomography data were evaluated by clinicians (n = 8). Statistical shape modeling was performed on 3D meshes to calculate the mean morphological configuration of the defects.

RESULTS

Clinicians' evaluation highlighted the models' utility in displaying defects for interventional/surgical planning, education/training and device development. However, models lack dynamic representation. Morphological analysis was feasible and revealed oval-shaped (n = 12) and complex channel-like (n = 3) defects.

CONCLUSION

3D-PIVSD models can complement imaging data for teaching and procedural planning. Statistical shape modeling is feasible in this scenario.

Influence of Parameters and Performance Evaluation of 3D-Printed Tungsten Mixed Filament Shields

Currently, protective clothing used in clinical field is the most representative example of efforts to reduce radiation exposure to radiation workers. However, lead is classified as a substance harmful to the human body that can cause lead poisoning. Therefore, research on the development of lead-free radiation shielding bodies is being conducted. In this study, the shielding body was manufactured by changing the size, layer, and height of the nozzle, using a 90.7% pure tungsten filament, a 3D printer material, and we compared its performance with existing protection tools. Our findings revealed that the shielding rate of the mixed tungsten filament was higher than that of the existing protective tools, confirming its potency to replace lead as the most protective material in clinical field.

Application of medical imaging methods and artificial intelligence in tissue engineering and organ-on-a-chip

Organ-on-a-chip (OOC) is a new type of biochip technology. Various types of OOC systems have been developed rapidly in the past decade and found important applications in drug screening and precision medicine. However, due to the complexity in the structure of both the chip-body itself and the engineered-tissue inside, the imaging and analysis of OOC have still been a big challenge for biomedical researchers. Considering that medical imaging is moving towards higher spatial and temporal resolution and has more applications in tissue engineering, this paper aims to review medical imaging methods, including CT, micro-CT, MRI, small animal MRI, and OCT, and introduces the application of 3D printing in tissue engineering and OOC in which medical imaging plays an important role. The achievements of medical imaging assisted tissue engineering are reviewed, and the potential applications of medical imaging in organoids and OOC are discussed. Moreover, artificial intelligence - especially deep learning - has demonstrated its excellence in the analysis of medical imaging; we will also present the application of artificial intelligence in the image analysis of 3D tissues, especially for organoids developed in novel OOC systems.

Evaluating the Suitability of 3D Bioprinted Samples for Experimental Radiotherapy: A Pilot Study

Radiotherapy is an important component in the treatment of lung cancer, one of the most common cancers worldwide, frequently resulting in death within only a few years of diagnosis. In order to evaluate new therapeutic approaches and compare their efficiency with regard to tumour control at a pre-clinical stage, it is important to develop standardized samples which can serve as inter-institutional outcome controls, independent of differences in local technical parameters or specific techniques. Recent developments in 3D bioprinting techniques could provide a sophisticated solution to this challenge. We have conducted a pilot project to evaluate the suitability of standardized samples generated from 3D printed human lung cancer cells in radiotherapy studies. The samples were irradiated at high dose rates using both broad beam and microbeam techniques. We found the 3D printed constructs to be sufficiently mechanically stable for use in microbeam studies with peak doses up to 400 Gy to test for cytotoxicity, DNA damage, and cancer cell death in vitro. The results of this study show how 3D structures generated from human lung cancer cells in an additive printing process can be used to study the effects of radiotherapy in a standardized manner.

Three-dimensional printing in ophthalmology and eye care: current applications and future developments

Three-dimensional (3D) printing uses a process of adding material in a layer-by-layer fashion to form the end product. This technology is advancing rapidly and is being increasingly utilized in the medical field as it becomes more accessible and cost-effective. It has an increasingly important role in ophthalmology and eyecare as its current and potential applications are extensive and slowly evolving. Three-dimensional printing represents an important method of manufacturing customized products such as orbital implants, ocular prostheses, ophthalmic models, surgical instruments, spectacles and other gadgets. Surgical planning, simulation, training and teaching have all benefitted from this technology. Advances in bioprinting seem to be the future direction of 3D printing with possibilities of printing out viable ocular tissues such as corneas and retinas in the future. It is expected that more ophthalmologists and other clinicians will use this technology in the near future.

Usefulness of an Additional Filter Created Using 3D Printing for Whole-Body X-ray Imaging with a Long-Length Detector

We recently developed a long-length detector that combines three detectors and successfully acquires whole-body X-ray images. Although the developed detector system can efficiently acquire whole-body images in a short time, it may show problems with diagnostic performance in some areas owing to the use of high-energy X-rays during whole-spine and long-length examinations. In particular, during examinations of relatively thin bones, such as ankles, with a long-length detector, the image quality deteriorates because of an increase in X-ray transmission. An additional filter is primarily used to address this limitation, but this approach imposes a higher load on the X-ray tube to compensate for reductions in the radiation dose and the problem of high manufacturing costs. Thus, in this study, a newly designed additional filter was fabricated using 3D printing technology to improve the applicability of the long-length detector. Whole-spine anterior–posterior (AP), lateral, and long-leg AP X-ray examinations were performed using 3D-printed additional filters composed of 14 mm thick aluminum (Al) or 14 mm thick Al + 1 mm thick copper (Cu) composite material. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and radiation dose for the acquired X-ray images were evaluated to demonstrate the usefulness of the filters. Under all X-ray inspection conditions, the most effective data were obtained when the composite additional filter based on a 14 mm thick Al + 1 mm thick Cu material was used. We confirmed that an SNR improvement of up to 46%, CNR improvement of 37%, and radiation dose reduction of 90% could be achieved in the X-ray images obtained using the composite additional filter in comparison to the images obtained with no filter. The results proved that the additional filter made with a 3D printer was effective in improving image quality and reducing the radiation dose for X-ray images obtained using a long-length detector.

Use of Three-Dimensional Printing in Modelling an Anatomical Structure with a High Computed Tomography Attenuation Value: A Feasibility Study

Introduction: Three-dimensional (3D) printing provides an opportunity to develop anthropomorphic computed tomography (CT) phantoms with anatomical and radiological features mimicking a range of patients’ conditions, thus allowing development of individualised, low dose scanning protocols. However, previous studies of 3D printing in CT phantom development could only create anatomical structures using potassium iodide with attenuation values up to 1200 HU which is insufficient to mimic the radiological features of some high attenuation structures such as cortical bone. This study aimed at investigating the feasibility of using 3D printing in modelling cortical bone with a non-iodinated material. Methods: This study had 2 stages. Stage 1 involved a vat photopolymerisation 3D printer to directly print cube phantoms with different percentage compositions of calcium phosphate (CP) and resin (approach 1), and approach 2 using a material extrusion 3D printer to develop a cube mould for infilling of the CP with hardener as the phantom. The approach able to create the cube phantom with the CT attenuation value close to that of a tibial mid-diaphysis cortex of a real patient, 1475±205 HU was employed to develop a tibial mid-diaphysis phantom. The mean CT numbers of the cube and tibia phantoms were measured and compared with that of the original CT dataset through unpaired t-test. Results: All phantoms were scanned by CT using a lower extremity scanning protocol. The moulding approach was selected to develop the tibia middiaphysis phantom with CT attenuation value, 1434±184 HU which was not statistically significantly different from the one of the original dataset (p = 0.721). Conclusion: This study demonstrates the feasibility to use the material extrusion 3D printer to create a tibial mid-diaphysis mould for infilling of the CP as an anthropomorphic CT phantom and the attenuation value of its cortex matches the real patient’s one.

3D Printing Applications for Radiology: An Overview

Three-dimensional (3D) printing technologies are part of additive manufacturing processes and are used to manufacture a 3D physical model from a digital computer-aided design model as per the required shape and size. These technologies are now used for advanced radiology applications by providing all information through 3D physical model. It provides innovation in radiology for clinical applications, treatment planning, procedural simulation, medical and patient education. Radiological advancements have been made in diagnosis and communication through medical digital imaging techniques like computed tomography, magnetic resonance imaging. These images are converted into Digital Imaging and Communications in Medicine in Standard Triangulate Language file format, easily printable in 3D printing technologies. This 3D model provides in-depth information about pathologic and anatomic states. It is useful to create new opportunities related to patient care. This article discusses the potential of 3D printing technology in radiology. The steps involved in 3D printing for radiology are discussed diagrammatically, and finally identified 12 significant applications of 3D printing technology for radiology with a brief description. A radiologist can incorporate this technology to fulfil different challenges such as training, planning, guidelines, and better communications.

3D Bioprinted Cardiac Tissues and Devices for Tissue Maturation

Cardiovascular diseases are the leading cause of mortality worldwide. Given the limited endogenous regenerative capabilities of cardiac tissue, patient-specific anatomy, challenges in treatment options, and shortage of donor tissues for transplantation, there is an urgent need for novel approaches in cardiac tissue repair. 3D bioprinting is a technology based on additive manufacturing which allows for the design of precisely controlled and spatially organized structures, which could possibly lead to solutions in cardiac tissue repair. In this review, we describe the basic morphological and physiological specifics of the heart and cardiac tissues and introduce the readers to the fundamental principles underlying 3D printing technology and some of the materials/approaches which have been used to date for cardiac repair. By summarizing recent progress in 3D printing of cardiac tissue and valves with respect to the key features of cardiovascular tissue (such as contractility, conductivity, and vascularization), we highlight how 3D printing can facilitate surgical planning and provide custom-fit implants and properties that match those from the native heart. Finally, we also discuss the suitability of this technology in the design and fabrication of custom-made devices intended for the maturation of the cardiac tissue, a process that has been shown to increase the viability of implants. Altogether this review shows that 3D printing and bioprinting are versatile and highly modulative technologies with wide applications in cardiac regeneration and beyond.

Editorial for the Special Issue on 3D Printing for Tissue Engineering and Regenerative Medicine

Three-dimensional (3D) bioprinting uses additive manufacturing techniques to fabricate 3Dstructures consisting of heterogenous selections of living cells, biomaterials, and active biomolecules[1,2] [...].

3D printed PLA Army-Navy retractors when used as linear retractors yield clinically acceptable tolerances

BACKGROUND

Modern low-cost 3D printing technologies offer the promise of access to surgical tools in resource scarce areas, however optimal designs for manufacturing have not yet been established. We explore how the optimization of 3D printing parameters when manufacturing polylactic acid filament based Army-Navy retractors vastly increases the strength of retractors, and investigate sources of variability in retractor strength, material cost, printing time, and parameter limitations.

METHODS

Standard retractors were printed from various polylactic acid filament spools intra-manufacturer and inter-manufacturer to measure variability in retractor strength. Printing parameters were systematically varied to determine optimum printing parameters. These parameters include retractor width, thickness, infill percentage, infill geometry, perimeter number, and a reinforced joint design. Estimated retractor mass from computer models allows us to estimate material cost.

RESULTS

We found statistically significant differences in retractor strength between spools of the same manufacturer and between manufacturers. We determined the true strength optimized retractor to have 30% infill, 3 perimeters, 0.25 in. thickness, 0.75 in. width, and has "Triangle" infill geometry and reinforced joints, failing at more than 15X the threshold for clinically excessive retraction and costs $1.25 USD.

CONCLUSIONS

The optimization of 3D printed Army-Navy retractors greatly improve the efficacy of this instrument and expedite the adoption of 3D printing technology in many diverse fields in medicine not necessarily limited to resource poor settings.