Biomechanical evaluation of individual 3D-printed vertebrae.

PurposeThree-dimensional (3D) printing is popular for many applications including the production of photocatalysts. This paper aims to focus on developing of 3D-printed photocatalyst-nano composite lattice structure. Digital light processing (DLP) 3D printing of photocatalyst composites was performed using photosensitive resin mixed with 0.5% Wt. of TiO2 powder and varying amounts (0.025% Wt. to 0.2% Wt.) of graphene nanoplatelet powder. The photocatalytic efficiency of DLP 3D-printed photocatalyst TiO2 composite was investigated, and the effects of nano graphite powder incorporation on the photocatalytic activity, thermal and mechanical properties were investigated.Design/methodology/approachMethods involve 3D computer-aided design modeling, printing parameters and comprehensive characterization techniques such as structural equation modeling, X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared (FTIR) and mechanical testing.FindingsResults highlight successful dispersion and characteristics of TiO2 and graphene nanoplatelet (GNP) powders, intricate designs of 3D-printed lattice structures, and the influence of GNPs on thermal behavior and mechanical properties.Originality/valueThe study suggests applicability in wastewater treatment and environmental remediation, showcasing the adaptability of 3 D printing in designing effective photocatalysts. Future research should focus on practical applications and the long-term durability of these 3D-printed composites.Graphical abstract

This study aims to determine a printing material that has both elastic property and radiology equivalence close to the real aorta for simulation of endovascular stent-graft repair of aortic dissection. With the rapid development of Three-Dimensional (3D) printing technology, a patient- specific 3D printed model is able to help surgeons to make a better treatment plan for Type B aortic dissection patients. However, the radiological properties of most 3D printing materials have not been well characterized. This study aims to investigate the appropriate materials for printing human aorta with mechanical and radiological properties similar to the real aortic Computed Tomography (CT) attenuation. Quantitative assessment of CT attenuation of different materials used in 3D printed models of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B aortic dissection. A 25-mm length of aorta model was segmented from a patient's image dataset with a diagnosis of type B aortic dissection. Four different elastic commercial 3D printing materials, namely Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness. Totally four models were printed out and CT scanned twice on a 192-slice CT scanner using the standard aortic CT angiography protocol, with and without contrast inside the lumen. Five reference points with the Region Of Interest (ROI) of 1.77 mm2 were selected at the aortic wall, and intimal flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of original CT images. The comparison between the patient's aorta and models was performed through a paired-sample t-test to determine if there is any significant difference. The mean CT attenuation of the aortic wall of the original CT images was 80.7 HU. Analysis of images without using contrast medium showed that the material of Agilus A50 produced the mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation measured at images acquired with the other three materials was significantly lower than that of the original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average CT attenuation of 90.6 HU, which is close to that of the original images without a statistically significant difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU, respectively, which is significantly higher than that of original CT images (p<0.05). Both Visijet CE-NT and Agilus have tensile strength and elongation close to actual patient's tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection. Due to the lack of body phantoms in the experiments, further research with the simulation of realistic anatomical body environment should be conducted.

Quality Assurance Tests for 3D Printed Bolus Used in Radiation Therapy

3D printing could offer the versatility to design and manufacture energy storage devices on demand. The precision and material flexibility of 3D printing is ideal for integrating porous electrodes that can enhance electrochemical performance[1]. This work analyzes the electrical conductivity of 3D-printed mesoscale strut lattices at the 100 μm – 1 mm scale with 40 – 90 % volumetric porosity to develop optimal electrodes for energy storage devices. We use a graph-theory-based model[2] to compute the conductivity of multiple 3D lattice types with either solid conducting struts or struts coated with conductive material. These structures show 3 – 5X higher conductivity than random conductive foams that lack an internal periodic mesostructure[3]. Using microstereolithography, we 3D print samples with high-resolution struts (< 70 µm) that maintain their shape and achieve high conductivity after carbonization at 700 ˚C. By tuning the lattice architecture, we manipulate the tradeoff between conductivity, weight, and porosity, validating our simulations with experimental measurements. These results demonstrate that that body-centered cubic (BCC) strut lattices have optimal conductivity per weight compared with other lattice types. Implementing these 3D-printed conductive lattices as supercapacitor electrodes, we see that the lattice architecture impacts the gravimetric capacitance of the devices as well as the mechanical strength, with octet structures outperforming both cubic and BCC lattices. Electrochemical impedance spectroscopy (EIS) shows that 3D-printed electrodes with higher porosity exhibit higher gravimetric double layer capacitance and lower charge transfer resistance, making them ideal candidates for use in supercapacitor electrodes as free-standing 3D hosts for active materials. CV characterization of the electrodes also illustrates how our graph theory-based model for 3D lattices can predict the optimal structure for energy storage. This model can also serve to predict electrode performance and tailor design for integration of higher surface area nanoporous materials on these conductive 3D printed scaffolds. This allows us to guide the design of 3D printed electrodes to minimize charge transfer resistance and achieve an optimal balance between gravimetric and volumetric energy density for device applications.[1] J. Zhao, Y. Zhang, X. Zhao, R. Wang, J. Xie, C. Yang, J. Wang, Q. Zhang, L. Li, C. Lu, Y. Yao, Advanced Functional Materials 2019, 29, 1900809.[2] J. E. Huddy, M. S. Rahman, A. B. Hamlin, Y. Ye, W. J. Scheideler, Cell Reports Physical Science 2022, 3, 100786.[3] F. G. Cuevas, J. M. Montes, J. Cintas, P. Urban, J Porous Mater 2008, 16, 675. Figure showing (a) designed octet (blue), cubic (orange), and BCC (red) lattice types as well as (b) SEM images of their experimental 3D-printed counterparts and (c) measured electrical resistance. Figure 1

The widespread use of digital imaging can now be combined with additive three-dimensional (3D) printing, changing traditional clinical dentistry, especially in challenging cases. Visualizing the bone and soft tissue anatomy using computed tomography (CT) and intraoral scanning generated digital files that can be further processed for 3D printing. Among the popular 3D printing approaches, fused filament fabrication (FFF) and stereolithography (SLA) are broadly used due to their rapid production, precision, and ease of use. The current case series outlines three challenging clinical scenarios where a combination of CT and intraoral scans were utilized for digital planning. FFF multicolor anatomical models and SLA surgical guides were produced using 3D printing technology. The first case outlines the utility of this approach to place the optimal surgical window at the lateral sinus lift with anticipated difficult access. In the second case, distinct sites for autogenous bone harvesting were identified while preserving critical adjacent structures with surgical simulation. Finally, the third case outlines this strategy for optimal surgical access to expose an impacted second premolar. Both clinicians and patients benefited from the educational use of FFF‒SLA 3D-printed models, and all cases were successfully treated without complications. These cases demonstrate the significant utility of these digital technologies and rapid prototyping for improved pre-surgical planning, patient motivation, and didactic training that contribute to improved quality of clinical care. To the authors' knowledge, this is the first case reports employing both fused filament fabrication (FFF) and stereolithography (SLA) printing techniques in dental surgery. This innovative approach addresses a range of clinically challenging scenarios presented in this report. Computed tomography (CT) and intraoral scanning are essential for three-dimensional (3D) reconstruction. Specialized software is required to design the guide with precise specifications, and FFF and SLA printers are necessary for fabricating the 3D model. Three-dimensional reconstruction can be time-intensive, particularly when manual segmentation is necessary. Acquiring proficiency in the software may require additional time, and multicolor 3D printing also demands extended printing durations. This study explores how digital imaging and three-dimensional (3D) printing can improve complex dental surgeries. Using tools such as computed tomography scans and intraoral scans, dentists can create detailed 3D models of a patient's bone and soft tissues. Two popular 3D printing methods-fused-filament fabrication (FFF) and stereolithography (SLA)-were used to make these models, which help with surgical planning. The study includes three cases where 3D-printed models were used to prepare for difficult dental procedures. In the first case, the 3D model helped plan the best way to access a difficult area for sinus surgery. The second case used the model to identify the best sites for bone harvesting. The third case used the model to plan how to safely expose an impacted tooth. These helped both the dentist and the patient understand the procedure better. All surgeries were successful, demonstrating how FFF and SLA 3D printing enhance planning, making advanced dental surgeries safer and more efficient.

The field of three-dimensional (3D) printing has witnessed significant advancements in recent years, and its potential for revolutionizing medical applications is rapidly emerging. This review aims to provide an overview of the current state and scope of 3D printing in the medical field. The review begins by highlighting the various 3D printing technologies currently employed in healthcare settings, including stereolithography, selective laser sintering, fused deposition modeling, and inkjet printing. Each technology's advantages and limitations are discussed, shedding light on their suitability for different medical applications. Next, the review delves into the diverse range of medical applications where 3D printing has shown promise. These applications include the fabrication of patient-specific anatomical models for preoperative planning, surgical guides and tools, customized implants and prosthetics, tissue engineering scaffolds, and drug delivery systems. The potential benefits of using 3D printing in these areas, such as enhanced surgical accuracy, improved patient outcomes, reduced surgery time, and personalized medicine, are explored. Furthermore, the review addresses the challenges and limitations associated with implementing 3D printing in medical settings. These challenges include regulatory concerns, standardization of processes, material biocompatibility, cost-effectiveness, and scalability. The ongoing efforts to overcome these barriers and the future directions of 3D printing in medicine are also discussed. In conclusion, 3D printing holds immense potential for transforming various aspects of medical practice. While considerable progress has been made, there are still challenges to be addressed before widespread adoption can be achieved. With continued research and development, coupled with regulatory support and collaboration between academia, industry, and healthcare professionals, 3D printing is poised to International Journal of Scientific Research in Engineering and Management (IJSREM) Volume: 07 Issue: 07 | July - 2023 SJIF Rating: 8.176 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM24845 | Page 2 make a substantial impact in the field of medicine, improving patient care and treatment outcomes. Key words: Additive manufacturing (AM); Bio-medical; Fused Deposition Modelling (FDM); Selective Laser Sintering (SLS); Stereolithography (SLA); Digital Light Processing (DLP); Binder Jetting; Material Jetting; Direct Energy Deposition (DED).

Lightweight structural design is greatly valued in the aviation, aerospace, and automotive industries. Three-dimensional (3D) printing techniques provide viable and popular technical pathways for the rapid design and manufacturing of lightweight lattice structures. Unlike the conventional design idea of a geometrically homogenized lattice structure, this work provides a design method for structurally heterogeneous lattice according to the spatial stress state of 3D-printed parts. Following the quasi-static stress numerical simulations of solid components, finite element mesh units were inconsistently replaced by lattice units with different specific rigidities corresponding to the localized stress levels. Relying on the topology optimization further lightened the lattice structure under quasi-static stress after removing some parts with extremely low stress from the overall structure. As an embodiment of this design idea, face-centered cubic (FCC) lattice units with different strut diameters were employed to non-uniformly and adaptively fill a solid part under localized loading. The topological optimization was conducted on the solid part globally. Then, the topologically optimized solid and the heterogeneous lattice structure were subjected to the geometric Boolean operation. Stereolithographic 3D printing was utilized to fabricate the homogeneous and heterogeneous lattice structural parts for comparative tests of three-point bending. Three evaluation indicators were defined for the standardized assessment of the geometrically complex lattice structures for the performance evaluation. This demonstrated that the heterogeneous lattice part exhibited better comprehensive mechanical performance than the uniform lattice. This work proved the feasibility of this new perspective on 3D-printed lightweight structure design and topology optimization.

The aim of this study is to introduce a new filament and novel 3D printing technique to adjust the density of a printing job in order to mimic the radiological properties of different tissues. We used a special filament, Light Weight PLA (LW-PLA), which utilizes foaming technology triggered by temperature. Cylindrical samples were printed at various temperatures, flow rates, print speeds, and diameters. A computed tomography (CT) scan was performed to identify their radiological properties in terms of the mean Hounsfield Unit (HU). The densities of the samples ranged from 0.36 g/cm3 to 1.21 g/cm3, corresponding to mean HU values between −702.7 ± 13.9 HU and +141.4 ± 7.1 HU. Strong linear correlations were observed between the flow rate and density as well as the flow rate and mean HU. The axial homogeneity of the samples was reported as being comparable to that of distilled water. A reduction in the mean HU was observed at a lower print speed and it changed slightly with respect to the sample size. Reproducibility assessments confirmed consistent results for identical printing jobs. Comparisons with regular PLA samples revealed a superior homogeneity in the LW-PLA samples. The findings of this study suggest a practical and accessible solution for mimicking all of the soft tissues, including the lungs, by using a single filament.

Breast imaging technology plays an important role in breast cancer planning and treatment. Recently, three-dimensional (3D) printing technology has become a trending issue in phantom constructions for medical applications, with its advantages of being customizable and cost-efficient. However, there is no current practice in the field of multi-purpose breast phantom for quality control (QC) in multi-modalities imaging. The purpose of this study was to fabricate a multi-purpose breast phantom with tissue-equivalent materials via a 3D printing technique for QC in multi-modalities imaging. We used polyvinyl chloride (PVC) based materials and a 3D printing technique to construct a breast phantom. The phantom incorporates structures imaged in the female breast such as microcalcifications, fiber lesions, and tumors with different sizes. Moreover, the phantom was used to assess the sensitivity of lesion detection, depth resolution, and detectability thresholds with different imaging modalities. Phantom tissue equivalent properties were determined using computed tomography (CT) attenuation [Hounsfield unit (HU)] and magnetic resonance imaging (MRI) relaxation times. The 3D-printed breast phantom had an average background value of 36.2 HU, which is close to that of glandular breast tissue (40 HU). T1 and T2 relaxation times had an average relaxation time of 206.81±17.50 and 20.22±5.74 ms, respectively. Mammographic imaging had improved detection of microcalcification compared with ultrasound and MRI with multiple sequences [T1WI, T2WI and short inversion time inversion recovery (STIR)]. Soft-tissue lesion detection and cylindrical tumor contrast were superior with mammography and MRI compared to ultrasound. Hemispherical tumor detection was similar regardless of the imaging modality used. We developed a multi-purpose breast phantom using a 3D printing technique and determined its value for multi-modal breast imaging studies.

Due to its advanced automation and design freedom, 3D concrete printing (3DCP) is gaining popularity in the building and construction (B&C) industry. Unlike traditional reinforced concrete (RC) structures, the fresh-state cementitious material is pumped and extruded layer by layer with no formwork support. Thus, comprehensive research is essential to evaluate the performance of 3D printing concrete at various stages: during printing, after concrete hardening, and when utilized as structural members. These stages correspond to three levels of investigations in this thesis: research on 3DCP buildability, examination of the mechanical properties of small-scale 3DCP units, and assessment of the structural behavior of large-scale 3DCP structural members, respectively. Correspondingly, four key themes were addressed as follows: Firstly, for the extrusion-based 3D printing process, high buildability is essential to resist printing failure. While this failure is often attributed to the strength and elastic modulus of the 3DCP material, the quantitative relationship between the 3DCP failure criterion and material fresh properties remains unclear. Through the stress analysis of the 3DCP member, this study identified the critical areas in the 3DCP member are uniaxially and biaxially compressed areas which have the same compressive strength. By comparing the stress states between the 3DCP member and tested samples, this study revealed that the compressive strength of the uniaxially compressed area can be determined through the unconfined uniaxial compression tests (UUCTs). Consequently, this study has successfully established a quantitative connection between the 3DCP failure criterion and the fresh properties of materials. Secondly, in small-scale 3DCP units, the mechanical performance of anisotropy has often been associated with interlayers. Recent studies have suggested that pore anisotropy may also influence the mechanical anisotropy of 3DCP units. However, the corresponding relationship between pore anisotropy and the mechanical anisotropy of 3DCP units remains at a qualitative level. Through computed tomography (CT) scans, this study observed that pores within 3DCP units can be represented by a biconvex lens pore without a specific orientation along the printing direction (PDir), which contracts with the conclusions of early studies. Subsequently, finite element (FE) models were constructed based on CT scan images incorporating both pores and solid elements of concrete. In the developed CT-scan-based FE model, concrete followed an isotropic constitutive model, which was determined by the inverse method with pores being the only variable. The CT-scan-based simulation results showed strong agreement with mechanical test results, which validated the feasibility of CT-scan-based simulation in assessing the mechanical performance of 3DCP units. This good agreement further substantiated the quantitative relationship between the pore properties and the mechanical performance of 3DCP units. Thirdly, the second study has demonstrated the correlation between the mechanical anisotropy of 3DCP units and the presence of high porosity at interlayers and pore anisotropy. However, there is still limited exploration into methods for adjusting the mechanical anisotropy of 3DCP units, and the mechanism that different printing parameters attribute to high porosity at interlayers and pore anisotropy remains unclear. In the third study, a specialized nozzle with an expanded flow channel was designed to modify the mechanical anisotropy of 3DCP units. Various printing parameters, such as overflow ratio, stand-off distance, and flow rate, were compared using experimental and numerical methods. Through a combination of CT scans, uniaxial compression tests, and computational fluid dynamics (CFD) simulations, this study revealed that the size of the nozzle flow channel and the printing parameters influence interlayer porosity and pore anisotropy by influencing the normalized local pressure at interlayers and fluid velocity gradients, consequently altering the mechanical anisotropy of 3DCP units. Finally, within large-scale 3DCP structures, the steel cable reinforcement method and the reinforced concrete confined by the 3DCP formwork (RC-3DPF) method stand out as potential approaches combining the reinforcement and 3DCP members due to high-level design freedom and automation. However, steel cables offer limited reinforcement along the direction perpendicular to PDir, and the load resistance of RC-3DPF fails to meet the requirements of traditional construction due to the weak bonding between inner cast concrete and 3DCP formwork. In the fourth study of this thesis, a hybrid approach combining the steel cable reinforcement method and the RC-3DPF method was proposed and applied as the steel rebar reinforced column confined by the steel cable reinforced 3D concrete printing permanent formwork (RC-SC-3DPF). Axial compression tests and theoretical analysis were conducted to examine the axial performance of RC-SC-3DPF. The results from axial compression tests indicated that the increasing quantity of steel cables enhances the structural behavior of RC-SC-3DPF. When the steel cable confinement ratio (Cf) is larger than 0.534%, the structural performance of RC-SC-3DPF is comparable to or even superior to those of the traditional case. Additionally, a theoretical model was developed to effectively assess the structural behavior of RC-SC-3DPF.

Skin-sparing effect causes the radiation dose at a certain depth to be higher than at the skin surface. A tissue-equivalent material namely bolus is required to increase the radiation dose to the skin surface. Conventional bolus is widely used, it poorly conforms to irregular surface, leading to air gaps and compromising dose distribution accuracy. The three-dimensional (3D) printing technology enables the fabrication of 3D-printed boluses to minimize the air gap in conventional bolus applications. In addition, 3D printing is allowed to modify its infill percentage and infill patterns, minimizing both printing time and material usage but resulting in different radiological and dosimetric characteristics. Therefore, it is crucial to evaluate the radiological characteristics of 3D-printed bolus before its application in breast cancer radiotherapy. In this study, the radiological characteristics of 3D-printed Polyethylene Terephthalate Glycol (PETG) and Thermoplastic Polyurethane (TPU) boluses at different infill percentages have been evaluated. This research utilized eight plate-shaped 3D-printed bolus samples with dimensions of 12 cm × 12 cm × 1 cm, at the infill percentages of 20%, 40%, 60%, and 80%. Each bolus sample was scanned using a CT-Simulator to determine its Hounsfield Unit (HU) values and linear attenuation coefficients. The obtained HU values were compared with the HU values of human tissues. The results indicate that both 3D-printed PETG and TPU boluses demonstrate similar equivalency to adipose tissue. Consequently, based on radiological evaluation, PETG and TPU materials are suitable for use in fabricating 3D-printed bolus for breast cancer radiotherapy application.

Three-dimensional (3D) printing of mesenteric artery (MA) anatomy preprocedurally for endovascular interventions can allow strategic preprocedure planning and improve procedure-related clinical outcomes. Three patients with computed tomography angiography (CTA) of the abdomen and pelvis who subsequently underwent MA interventions were 3D printed retrospectively, and 2 patients with symptoms and severe MA stenosis on CTA, who had not undergone intervention, were 3D printed for procedure-related planning and anatomy-specific implications. The 3D-printed models (3D-PMs) were painted with acrylic paint to highlight anatomy. Reference vessel size, lesion length (LL), and renal artery (RA) to MA distance were determined using a digital millimeter caliper. Each of the 5 patients with variable anatomy, including an MA chronic total occlusion (CTO), were successfully 3D printed. A digital caliper allowed determination of vessel size, LL, and RA to MA distance, which were then compared with intraprocedural MA angiograms and intravascular imaging when available. Further complex anatomies, such as intraprocedural navigation in the setting of prior abdominal aortic endograft and CTO assessment with relevance to cap morphology, small branch arteries, and collateral flow, were also successfully 3D printed. Preprocedural 3D printing of MA anatomy for interventions can theoretically lead to decreases in contrast use, radiation dose, and fluoroscopic and procedural times, as well as enhance comprehension of complex patient-specific anatomy.

Use of Surface Scanner to Create Prior CT 3D-Printed Bolus to Increase Efficiency for Radiation Therapy Treatment of Patients with Immobilization Masks

Background and aim Synthetic composite bone models (reinforced solid foam) have become the standardised material used in practical orthopaedic education. However, with discussions regarding whether composite foam truly replicates human bone, there has been a drive to explore other available models. Three-dimensional (3D) printing has risen in both popularity and availability, providing a new option in the creation of anatomically accurate bone models. We designed a pilot study to assess whether a new formulation of synthetic bone provides the same tactile feedback that is essential for training purposes. Method Orthopaedic trainees of various grades across two London hospital trusts were invited to participate in a distal radius fixation workshop. As part of the workshop, trainees were asked to complete the following three tasks on the two different models: Kirschner-wire driving, pilot hole drillingand screw insertion. Participants were blinded in this trialand not informed which model was made via 3D printing or the conventional composite bone. Following completion, participants provided feedback on tactile feedback for each task on each model. Results Twenty-three orthopaedic trainees participated in the workshop, with overall majority agreement in all clinical skills that the 3D-printed model provided better tactile feedback. Three-dimensional models were rated superior in K-wire driving (mean score 7.39 vs 4.82; p<0.001) and pilot hole drilling (7.87 vs 4.96; p<0.001), with no significant difference in screw insertion. Qualitative feedback from testers noted a more anatomical representation of the 3D-printed bone, in addition to an overall better representation of the corticomedullary junction. Conclusion Overall, 3D printed models provide a new high-fidelity and sustainable option when seeking bone models for modern-day orthopaedic training. At present composite bone remains the standard for workshops. However, with the growing availability of 3D-printing models, and as supported by this study, they crucially provide the medium for future orthopaedic surgeons to learn and gain confidence.

Deformable lung phantoms have been proposed to investigate four-dimensional (4D) imaging and radiotherapy delivery techniques. However, most phantoms mimic only the lung and tumor without pulmonary airways. The purpose of this study was to develop a reproducible, deformable lung phantom with three-dimensional (3D)-printed airways. The phantom consists of: (a) 3D-printed flexible airways, (b) flexible polyurethane foam infused with iodinated contrast agents, and (c) a motion platform. The airways were simulated using publicly available breath-hold computed tomography (CT) image datasets of a human lung through airway segmentation, computer-aided design modeling, and 3D printing with a rubber-like material. The lung was simulated by pouring liquid expanding foam into a mold with the 3D-printed airways attached. Iodinated contrast agents were infused into the lung phantom to emulate the density of the human lung. The lung/airways phantom was integrated into our previously developed motion platform, which allows for compression and decompression of the phantom in the superior-inferior direction. We quantified the reproducibility of the density (lung), motion/deformation (lung and airways), and position (airways) using breath-hold CT scans (with the phantom compressed and decompressed) repeated every two weeks over a 2-month period as well as 4D CT scans (with the phantom continuously compressed and decompressed) repeated twice over four weeks. The density reproducibility was quantified with a difference image (created by subtracting the rigidly registered baseline and the repeated images) in each of the compressed and decompressed states. Reproducibility of the motion/deformation was evaluated by comparing the baseline displacement vector fields (DVFs) derived from deformable image registration (DIR) between the compressed and decompressed phantom CT images with those of repeated scans and calculating the difference in the displacement vectors. Reproducibility of the airway position was quantified based on DIR between the baseline and repeated images. For the breath-hold CT scans, the mean difference in lung density between baseline and week 8 was -1.3 (standard deviation 33.5) Hounsfield unit (HU) in the compressed state and 0.4 (36.8)HU in the decompressed state, while large local differences were observed around the high-contrast structures (caused by small misalignments). By visual inspection, the DVFs (between the compressed and decompressed states) at baseline and last time point (week 8 for the breath-hold CT scans) demonstrated a similar pattern. The mean lengths of displacement vector differences between baseline and week 8 were 0.5 (0.4)mm for the lung and 0.3 (0.2)mm for the airways. The mean airway displacements between baseline and week 8 were 0.6 (0.5)mm in the compressed state and 0.6 (0.4)mm in the decompressed state. We also observed similar results for the 4D CT scans (week 0 vs week 4) as well as for the breath-hold CT scans at other time points (week 0 vs weeks 2, 4, and 6). We have developed a deformable lung phantom with 3D-printed airways based on a human lung CT image. Our findings indicate reproducible density, motion/deformation, and position. This phantom is based on widely available materials and technology, which represents advantages over other deformable phantoms.