3D Printing of Medical Models: A Literature Review

Author(s):  
Xingjian Wei ◽  
Li Zeng ◽  
Zhijian Pei

Medical models are physical models of human or animal anatomical structures such as skull and heart. Such models are used in simulation and planning of complex surgeries. They can also be utilized for anatomy teaching in medical curriculum. Traditionally, medical models are fabricated by paraffin wax or silicone casting. However, this method is time-consuming, of low quality, and not suitable for personalization. Recently, 3D printing technologies are used to fabricate medical models. Various applications of 3D printed medical models in surgeries and anatomy teaching have been reported, and their advantages over traditional medical models have been well-documented. However, 3D printing of medical models bears some special challenges compared to industrial applications of 3D printing. This paper reviews more than 50 publications on 3D printing of medical models between 2006 and 2016, and discusses knowledge gaps and potential research directions in this field.

Author(s):  
T. M. Amulya ◽  
K. G. Siree ◽  
T. M. Pramod Kumar ◽  
M. B. Bharathi ◽  
K. Divith ◽  
...  

The scope and applications of biomaterials have spread out throughout a broad spectrum. Particularly in pharmacy, biomaterials are an attractive choice because they can be modified to decrease toxicity, increase the targeting ability among many other aspects of drug delivery. Extensive studies have led to the development of many metal-based, ceramic, biocompatible and biodegradable biomaterials for medical purposes among many others. The utilization of 3D printing in this discipline is a very novel research subject with infinite potential. Personalized and customized nasal implants are a great option to increase patient compliance and 3D printed accurate anatomical structures are rendered to be effective tools of learning. One of the disadvantages of biomaterial-based implants is the formation of a thick fibrous capsule formation around the implant, others being breakage, soft tissue loss and so on. Regulatory aspects are less explored for nasal implants. 3D printing is a unique technique that allows for a high degree of customisation in pharmacy, dentistry and in designing of medical devices. Current research in 3D printing indicates towards reproducing an organ in the form of a chip; paving the way for more studies and opportunities to perfecting the existing technique.


2020 ◽  
Vol 8 (2) ◽  
pp. 50-56
Author(s):  
Maheswaran Viyannan ◽  
Pananghat A. Kumar ◽  
Sreedharkumar Eswarswamy ◽  
Gunaseelan Murugesan ◽  
Karthikeyan Ramaraju

Background: The present medical curriculum aims at training the students to be proficient in performing techniques required for clinical practice. This is best achieved through clinical simulation, which has emerged as a successful method for clinical learning. Residents in respiratory medicine need to be trained in the procedure of bronchoscopy for which a functional model of the airway is required. Airway mannequins for this purpose can be produced using 3D printing technology, which involves the usage of sophisticated software. Subjects and Methods: Serial axial CT images of the chest, revealing details of the respiratory tract were selected as the base resource to recreate the bronchial tree by 3D printing. This DICOM (Digital Imaging and Communications in Medicine) images after conversion into STL (Stero lithography) format were transferred into a 3D printer and physical models were made from these data, using Vero clear and rubber. This model which had a life-like form and consistency required for practicing the skill was connected to an airway mannequin using an adaptor to practice the skill. Conclusions: Axial CT scan images provide the base data for reconstructing the airway of a patient, using 3D printing technology and appropriate software. Such reconstructions can be used to produce a functional model of the airway, which can be used for training in bronchoscopy. The training system could be connected to a monitor thereby facilitating tracking of the probe of the bronchoscope. Repeated trials make the trainees perfect their technique. Our attempt to replicating the tracheobronchial tree for such training has been a success.


2020 ◽  
Vol 26 (6) ◽  
pp. 1113-1129
Author(s):  
Lai Jiang ◽  
Xiaobo Peng ◽  
Daniel Walczyk

Purpose This paper aims to summarize the up-to-date research performed on combinations of various biofibers and resin systems used in different three-dimensional (3D) printing technologies, including powder-based, material extrusion, solid-sheet and liquid-based systems. Detailed information about each process, including materials used and process design, are described, with the resultant products’ mechanical properties compared with those of 3D-printed parts produced from pure resin or different material combinations. In most processes introduced in this paper, biofibers are beneficial in improving the mechanical properties of 3D-printed parts and the biodegradability of the parts made using these green materials is also greatly improved. However, research on 3D printing of biofiber-reinforced composites is still far from complete, and there are still many further studies and research areas that could be explored in the future. Design/methodology/approach The paper starts with an overview of the current scenario of the composite manufacturing industry and then the problems of advanced composite materials are pointed out, followed by an introduction of biocomposites. The main body of the paper covers literature reviews of recently emerged 3D printing technologies that were applied to biofiber-reinforced composite materials. This part is classified into subsections based on the form of the starting materials used in the 3D printing process. A comprehensive conclusion is drawn at the end of the paper summarizing the findings by the authors. Findings Most of the biofiber-reinforced 3D-printed products exhibited improved mechanical properties than products printed using pure resin, indicating that biofibers are good replacements for synthetic ones. However, synthetic fibers are far from being completely replaced by biofibers due to several of their disadvantages including higher moisture absorbance, lower thermal stability and mechanical properties. Many studies are being performed to solve these problems, yet there are still some 3D printing technologies in which research concerning biofiber-reinforced composite parts is quite limited. This paper unveils potential research directions that would further develop 3D printing in a sustainable manner. Originality/value This paper is a summary of attempts to use biofibers as reinforcements together with different resin systems as the starting material for 3D printing processes, and most of the currently available 3D printing techniques are included herein. All of these attempts are solutions to some principal problems with current 3D printing processes such as the limit in the variety of materials and the poor mechanical performance of 3D printed parts. Various types of biofibers are involved in these studies. This paper unveils potential research directions that would further widen the use of biofibers in 3D printing in a sustainable manner.


2021 ◽  
Author(s):  
◽  
Ana Morris

<p>Novel technologies that produce medical models which are synthetic equivalents to human tissue may forever change the way human anatomy and medicine are explored. Medical modelling using a bitmap-based additive manufacturing workflow offers exciting opportunities for medical education, informed consent practices, skills acquisition, pre-operative planning and surgical simulation. Moving medical data from the 2D-world to tactile, highly detailed 3D-printed anatomical models may significantly change how we comprehend the body; revamping everything – from medical education to clinical practice.  Research Problem The existing workflow for producing patient-specific anatomical models from biomedical imaging data involves image thresholding and iso-surface extraction techniques that result in surface meshes (also known as objects or parts). This process restricts shape specification to one colour and density, limiting material blending and resulting in anatomically inequivalent medical models. So, how can the use of 3D-printing go beyond static anatomical replication? Imagine pulling back the layers of tissue to reveal the complexity of a procedure, allowing a family to understand and discuss their diagnosis. Overcoming the disadvantages of static medical models could be a breakthrough in the areas of medical communication and simulation. Currently, patient specific models are either rigid or mesh-based and, therefore, are not equivalents of physiology.  Research Aim The aim of this research is to create tangible and visually compelling patient-specific prototypes of human anatomy, offering an insight into the capabilities of new bitmap-based 3D-printing technology. It proposes that full colour, multi-property, voxel-based 3D-printing can emulate physiology, creating a new format of visual and physical medical communication.  Data Collection and Procedure For this study, biomedical imaging data was converted into multi-property 3D-printed synthetic anatomy by bypassing the conversion steps of traditional segmentation. Bitmap-based 3D-printing allows for the precise control over every 14-micron material droplet or “voxel”.  Control over each voxel involves a process of sending bitmap images to a high-resolution and multi-property 3D-printer. Bitmap-based 3D-printed synthetic medical models – which mimicked the colour and density of human anatomy – were successfully produced.  Findings This research presented a novel and streamlined bitmap-based medical modelling workflow with the potential to save manufacturing time and labour cost. Moreover, this workflow produced highly accurate models with graduated densities, translucency, colour and flexion – overcoming complexities that arise due to our body’s opaqueness. The presented workflow may serve as an incentive for others to investigate bitmap-based 3D-printing workflows for different manufacturing applications.</p>


2021 ◽  
Vol 11 ◽  
Author(s):  
Xiran Wang ◽  
Xuetao Wang ◽  
Zhongzheng Xiang ◽  
Yuanyuan Zeng ◽  
Fang Liu ◽  
...  

During the procedure of radiotherapy for superficial tumors, the key to treatment is to ensure that the skin surface receives an adequate radiation dose. However, due to the presence of the built-up effect of high-energy rays, equivalent tissue compensators (boluses) with appropriate thickness should be placed on the skin surface to increase the target radiation dose. Traditional boluses do not usually fit the skin perfectly. Wet gauze is variable in thickness day to day which results in air gaps between the skin and the bolus. These unwanted but avoidable air gaps lead to a decrease of the radiation dose in the target area and can have a poor effect on the outcome. Three-dimensional (3D) printing, a new rising technology named “additive manufacturing” (AM), could create physical models with specific shapes from digital information by using special materials. It has been favored in many fields because of its advantages, including less waste, low-cost, and individualized design. It is not an exception in the field of radiotherapy, personalized boluses made through 3D printing technology also make up for a number of shortcomings of the traditional commercial bolus. Therefore, an increasing number of researchers have tried to use 3D-printed boluses for clinical applications rather than commercial boluses. Here, we review the 3D-printed bolus’s material selection and production process, its clinical applications, and potential radioactive dermatitis. Finally, we discuss some of the challenges that still need to be addressed with the 3D-printed boluses.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vivek Kumar Tiwary ◽  
Arunkumar P. ◽  
Vinayak R. Malik

Purpose Three-dimensional (3D) printing, one of the important technological pillars of Industry 4.0, is changing the landscape of future manufacturing. However, the limited build volume of a commercially available 3D printer is one inherent constraint, which holds its acceptability by the manufacturing business leaders. This paper aims to address the issue by presenting a novel classification of the possible ways by which 3D-printed parts can be joined or welded to achieve a bigger-sized component. Design/methodology/approach A two-step literature review is performed. The first section deals with the past and present research studies related to adhesive bonding, mechanical interlocking, fastening and big area additive manufacturing of 3D printed thermoplastics. In the second section, the literature searches were focused on retrieving details related to the welding of 3D printed parts, specifically related to friction stir welding, friction (spin) welding, microwave and ultrasonic welding. Findings The key findings of this review study comprise the present up-to-date research developments, pros, cons, critical challenges and the future research directions related to each of the joining/welding techniques. After reading this study, a better understanding of how and which joining/welding technique to be applied to obtain a bigger volume 3D printed component will be acquired. Practical implications The study provides a realistic approach for the joining of 3D printed parts made by the fused deposition modeling (FDM) technique. Originality/value This is the first literature review related to joining or welding of FDM-3D printed parts helping the 3D printing fraternity and researchers, thus increasing the acceptability of low-cost FDM printers by the manufacturing business leaders.


2021 ◽  
Vol 144 (4) ◽  
Author(s):  
Dylan Joralmon ◽  
Evangeline Amonoo ◽  
Yizhen Zhu ◽  
Xiangjia Li

Abstract Lightweight and cost-effective polymer matrix composites (PMCs) with extraordinary mechanical performance will be a key to the next generation of diverse industrial applications, such as aerospace, electric automobile, and biomedical devices. Limpet teeth made of mineral-polymer composites have been proved as nature’s strongest material due to the unique hierarchical architectures of mineral fiber alignment. Here, we present an approach to build limpet teeth inspired structural materials with precise control of geometric morphologies of microstructures by magnetic field-assisted 3D printing (MF-3DP). α-Iron (III) oxide-hydroxide nanoparticles (α-FeOOHs) are aligned by the magnetic field during 3D printing and aligned α-FeOOHs (aFeOOHs) bundles are further grown to aligned goethite-based bundles (aGBs) by rapid thermal treatment after printing. The mechanical reinforcement of aGBs in PMCs can be modulated by adjusting the geometric morphology and alignment of α-FeOOHs encapsulated inside the 3D printed PMCs. In order to identify the mechanical enhancement mechanism, physics-based modeling, simulation, and tests were conducted, and the results further guided the design of bioinspired goethite-based PMCs. The correlation of the geometric morphology of self-assembled α-FeOOHs, curing characteristics of α-FeOOHs/polymer composite, and process parameters were identified to establish the optimal design of goethite-based PMCs. The 3D printed PMCs with aGBs show promising mechanical reinforcement compared with PMCs without aGBs. This study opens intriguing perspectives for designing high strength 3D printed PMCs on the basis of bioinspired architectures with customized configurations.


Author(s):  
Arivazhagan Pugalendhi ◽  
◽  
SenthilMurugan Arumugam ◽  
Rajesh Ranganathan ◽  
Sivakumar Ganesan ◽  
...  

Evolution of 3D printing from medical image datasets are escalating and has widespread in healthcare applications such as anatomical models, surgical guides, and customized implants. In 3D printing, solid objects are fabricated by the frequently added the thin layers of material as per the digital model. This paper demonstrates the fabrication of 3D printed patient-specific bone models of leg and ankle foot from Digital Imaging and Communications in Medicine (DICOM) files. Processing of DICOM file is prepared by D2P (DICOM to PRINT) software and physical models are produced by Stratasys uPrint 3D printer. This 3D printed anatomical model eliminates the requirement of actual human bones, significance of preservation and mistakes in assembly of bones. The results of the study not only encourage education, surgical planning and validating medical devices but stimulate exciting innovations.


2021 ◽  
Author(s):  
◽  
Stephen Tane Hill

<p>A common misconception about additive manufacturing (3D printing) is that any shape can be made in any material at the press of a button. The reality is that each process and material requires distinct Computer Aided Design (CAD) files that need to be optimised to the physical limitations of the manufacturing process. This optimisation process can have significant effects on the designer’s aesthetic intentions. Selective Laser Melting (SLM) is the new benchmark for functional 3D printed titanium designs where the optimisation process plays an important role in the outcome of the end product. The limitations imposed by the manufacturing process include build support material, heat transfer and post processing and designs are required to be optimised before the manufacturing process can commence. To date, case studies written on the SLM process have focused largely on engineering and functional applications in particular within the medical industry. However; this process has not been extensively studied from a visual and aesthetic industrial design perspective. This research will gather specific knowledge about the technical limitations involved in the Selective Laser Melting process and explore through a case study approach how a designer s intentions can be maintained or even enhanced when using this technology. With greater understanding of the SLM technology, the optimisation process may further provide positive outcomes to the designer by saving time, money and waste.  This case study is built on an existing product design file as a base model. Refinements to the model were made based on findings from existing design research as well as digital and physical models. The existing design research was focused on challenges designers encounter using 3D printing technologies including SLM as well as the optimisation process. Models and design iterations were developed using Nigel Cross’s four step model of exploration, generation, evaluation and communication. By iteratively redesigning aspects of the model to conform to the SLM limitations, this study reviews opportunities for areas to reduce material without compromising the design intent.</p>


Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 61
Author(s):  
John Ryan C. Dizon ◽  
Ciara Catherine L. Gache ◽  
Honelly Mae S. Cascolan ◽  
Lina T. Cancino ◽  
Rigoberto C. Advincula

Additive manufacturing, commonly known as 3D printing, is an advancement over traditional formative manufacturing methods. It can increase efficiency in manufacturing operations highlighting advantages such as rapid prototyping, reduction of waste, reduction of manufacturing time and cost, and increased flexibility in a production setting. The additive manufacturing (AM) process consists of five steps: (1) preparation of 3D models for printing (designing the part/object), (2) conversion to STL file, (3) slicing and setting of 3D printing parameters, (4) actual printing, and (5) finishing/post-processing methods. Very often, the 3D printed part is sufficient by itself without further post-printing processing. However, many applications still require some forms of post-processing, especially those for industrial applications. This review focuses on the importance of different finishing/post-processing methods for 3D-printed polymers. Different 3D printing technologies and materials are considered in presenting the authors’ perspective. The advantages and disadvantages of using these methods are also discussed together with the cost and time in doing the post-processing activities. Lastly, this review also includes discussions on the enhancement of properties such as electrical, mechanical, and chemical, and other characteristics such as geometrical precision, durability, surface properties, and aesthetic value with post-printing processing. Future perspectives is also provided towards the end of this review.


Sign in / Sign up

Export Citation Format

Share Document