Noise in computed tomography (CT) is inevitably generated, which lowers the accuracy of disease diagnosis. The non-local means approach, a software technique for reducing noise, is widely used in medical imaging. In this study, we propose a noise reduction algorithm based on fast non-local means (FNLMs) and apply it to CT images of a phantom created using 3D printing technology. The self-produced phantom was manufactured using filaments with similar density to human brain tissues. To quantitatively evaluate image quality, the contrast-to-noise ratio (CNR), coefficient of variation (COV), and normalized noise power spectrum (NNPS) were calculated. The results demonstrate that the optimized smoothing factors of FNLMs are 0.08, 0.16, 0.22, 0.25, and 0.32 at 0.001, 0.005, 0.01, 0.05, and 0.1 of noise intensities, respectively. In addition, we compared the optimized FNLMs with noisy, local filters and total variation algorithms. As a result, FNLMs showed superior performance compared to various denoising techniques. Particularly, comparing the optimized FNLMs to the noisy images, the CNR improved by 6.53 to 16.34 times, COV improved by 6.55 to 18.28 times, and the NNPS improved by 10-2 mm2 on average. In conclusion, our approach shows significant potential in enhancing CT image quality with anthropomorphic phantoms, thus addressing the noise issue and improving diagnostic accuracy.

The microbial enrichment of traditional biocarriers is limited due to the inadequate consideration of spatial structure and surface charging characteristics. Here, capitalizing on the ability of 3D printing technology to fabricate high-resolution materials, we further designed a positively charged sodium alginate/ε-poly-l-lysine (SA/ε-PL) printing ink, and the 3D printed biocarriers with ideal pore structure and rich positive charge were constructed to enhance the microbial enrichment. The rheological and mechanical tests confirmed that the developed SA/ε-PL ink could simultaneously satisfy the smooth extrusion for printing process and the maintenance of 3D structure. The utilization of the ε-PL secondary cross-linking strategy reinforced the 3D mechanical structure and imparted the requisite physical properties for its application as a biocarrier. Compared with traditional sponge carriers, 3D printed biocarrier had a faster initial attachment rate and a higher biomass of 14.58 ± 1.18 VS/cm3, and the nitrogen removal efficiency increased by 53.9 %. Besides, due to the superior electrochemical properties and biocompatibility, the 3D printed biocarriers effectively enriched the electroactive denitrifying bacteria genus Trichococcus, thus supporting its excellent denitrification performance. This study provided novel insights into the development of new functional biocarriers in the wastewater treatment, thereby providing scientific guidance for practical engineering.

The development of 3D printing technology has brought new risks and challenges to stamp impression identification. To prevent potential risks, a total of 45 stamps were printed using three types of 3D printers: fused deposition molding (FDM) printer, stereo lithography (SLA) printer, and liquid crystal display (LCD)-based SLA 3D printer, including 6 stamps replicated using LCD-based SLA 3D printer. A preliminary study was conducted on the printed stamps and stamped impressions, and the results showed that stamp are influenced by various factors such as printer type, printing material, the technology level of the producer, mold parameters such as font, size, printing parameters, slicing direction, and polishing process, etc., resulting in significant differences in characteristics. However, there are some obviously common characteristics such as missing of strokes, exposure of white and mottled phenomenon in the impression stamped by the 3D produced stamp. The impression of stamp replicated with an LCD 3D printer can be easily identified since it is difficult to achieve consistency with the real impression in detail characteristics.

BACKGROUND: Renal calculi are one of the most frequent diseases in urology, and percutaneous nephrolithotomy (PCNL) being the gold standard for treating renal calculi larger than 2 cm. However, traditional rigid nephroscope cannot bend, presents significant limitations during PCNL. This study aims to develop a novel digital flexible nephroscope for PCNL and verify its safety and efficacy using 3D printed models and ex vivo porcine kidney models, providing new equipment for PCNL.
METHODS: Based on the determined technical parameters, the novel digital flexible nephroscope was manufactured. First, 3D-printed model and ex vivo porcine kidney models were utilized to simulate the PCNL procedures. Then, the traditional rigid nephroscope and the novel digital flexible nephroscope were utilized to simulate the PCNL procedures on 10 ex vivo porcine kidneys for comparison. We observed and recorded the renal calyces visualized and accessed by both the traditional rigid nephroscope and the novel digital flexible nephroscope.
RESULTS: In both the 3D printing and ex vivo porcine kidney models, the novel percutaneous digital flexible nephroscope smoothly entered the renal collecting system through the percutaneous renal tract. It freely changed angles to reach most target calyces, demonstrating significant advantages over the traditional rigid nephroscope.
CONCLUSIONS: The successful development of the novel percutaneous digital flexible nephroscope allows it to be used either independently or as an adjunct in complex stone cases, providing more effective and safer surgical equipment for percutaneous nephrolithotomy.

BACKGROUND: Clinical repair of critical-sized bone defects (CBDs) in the tibial diaphysis presents numerous challenges, including inadequate soft tissue coverage, limited blood supply, high load-bearing demands, and potential deformities. This study aimed to investigate the clinical feasibility and efficacy of employing 3D-printed prostheses for repairing CBDs exceeding 10 cm in the tibial diaphysis.
METHODS: This retrospective study included 14 patients (11 males and 3 females) with an average age of 46.0 years. The etiologies of CBDs comprised chronic osteomyelitis (10 cases) and aseptic non-union (4 cases), with an average defect length of 16.9 cm. All patients underwent a two-stage surgical approach: (1) debridement, osteotomy, and cement spacer implantation; and (2) insertion of 3D-printed prostheses. The interval between the two stages ranged from 8 to 12 weeks, during which the 3D-printed prostheses and induced membranes were meticulously prepared. Subsequent to surgery, patients engaged in weight-bearing and functional exercises under specialized supervision. Follow-up assessments, including gross observation, imaging examinations, and administration of the Lower Extremity Functional Scale (LEFS), were conducted at 3, 6, and 12 months postoperatively, followed by annual evaluations thereafter.
RESULTS: The mean postoperative follow-up duration was 28.4 months, with an average waiting period between prosthesis implantation and weight-bearing of 10.4 days. At the latest follow-up, all patients demonstrated autonomous ambulation without assistance, and their LEFS scores exhibited a significant improvement compared to preoperative values (30.7 vs. 53.1, P < 0.001). Imaging assessments revealed progressive bone regeneration at the defect site, with new bone formation extending along the prosthesis. Complications included interlocking screw breakage in two patients, interlocking screw loosening in one patient, and nail breakage in another.
CONCLUSIONS: Utilization of 3D-printed prostheses facilitates prompt restoration of CBDs in the tibial diaphysis, enabling early initiation of weight-bearing activities and recovery of ambulatory function. This efficacious surgical approach holds promise for practical application.

OBJECTIVE: To investigate the biomechanical properties and practical application of absorbable materials in orbital fracture repair.
METHODS: The three-dimensional (3D) model of orbital blowout fractures was reconstructed using Mimics21.0 software. The repair guide plate model for inferior orbital wall fracture was designed using 3-matic13.0 and Geomagic wrap 21.0 software. The finite element model of orbital blowout fracture and absorbable repair plate was established using 3-matic13.0 and ANSYS Workbench 21.0 software. The mechanical response of absorbable plates, with thicknesses of 0.6 and 1.2 mm, was modeled after their placement in the orbit. Two patients with inferior orbital wall fractures volunteered to receive single-layer and double-layer absorbable plates combined with 3D printing technology to facilitate surgical treatment of orbital wall fractures.
RESULTS: The finite element models of orbital blowout fracture and absorbable plate were successfully established. Finite element analysis (FEA) showed that when the Young\'s modulus of the absorbable plate decreases to 3.15 MPa, the repair material with a thickness of 0.6 mm was influenced by the gravitational forces of the orbital contents, resulting in a maximum total deformation of approximately 3.3 mm. Conversely, when the absorbable plate was 1.2 mm thick, the overall maximum total deformation was around 0.4 mm. The half-year follow-up results of the clinical cases confirmed that the absorbable plate with a thickness of 1.2 mm had smaller maximum total deformation and better clinical efficacy.
CONCLUSIONS: The biomechanical analysis observations in this study are largely consistent with the clinical situation. The use of double-layer absorbable plates in conjunction with 3D printing technology is recommended to support surgical treatment of infraorbital wall blowout fractures.

UNASSIGNED: Trigeminal neuralgia (TN) is a common form of craniofacial pain, and Radiofrequency thermocoagulation (RFT) has become a commonly utilized treatment modality for TN. However, the complex anatomical configuration of the maxillofacial region and the difficulties inherent in positioning the neck in a hyperextended manner can present challenges for CT-guided punctures.
UNASSIGNED: The objective of this study is to assess the effectiveness and safety of 3D printed tooth-supported template(3D-PTST) guided RFT in patients who have previously undergone unsuccessful CT-guided puncture.
UNASSIGNED: Patients with TN undergoing RFT at the Department of Pain Medicine, PLA General Hospital, from January 2018 to January 2023, were assessed. 3D-PTST guided RFT was employed as an alternative when percutaneous puncture failed. Clinical, demographic, and follow-up data were collected. The duration of the procedure was determined by subtracting the time of anesthesia administration from the time of surgical drape removal. Pain intensity was assessed using the Numerical Rating Scale-11 scale. Treatment effects were evaluated utilizing the Barrow Neurological Institute scale. Incidences of complications related to RFA were documented.
UNASSIGNED: Six TN patients underwent 3D-PTST guided RFT. With tooth-supported template guidance, five patients achieved therapeutic target puncture in one attempt with one CT scan. One patient required two attempts with two CT scans. Operation duration ranged from 18 to 46 mins (mean 30 mins). All completed 3D-PTST-guided RFT without difficulty, significantly improving pain symptoms. Four patients had no pain recurrence at 12, 18, 36 and 37 months follow-up, respectively. Recurrence occurred in two patients (at 1 and 13 months). No serious treatment-related complications were observed.
UNASSIGNED: 3D-PTST guided RFT is an effective, repeatable, safe, and minimally invasive treatment method for patients with TN who have failed due to difficulty in puncture.

UNASSIGNED: 3D printing is one of the fastest-growing technologies in medicine, but it is essential to have a system for 3D printing documentation that is accessible for not only clinical engineers and surgeons, but also quality managers and data-privacy officers in hospitals. Dedicated software such as product lifecycle management (PLM) software could enable comprehensive management and traceability of all data relevant to 3D printing tasks in a hospital and would highly beneficial. Therefore, customizable software called 3Diamond was developed for 3D printing in medicine.
UNASSIGNED: The software development process involved several stages, including setting specifications based on end-user requirements, design, implementation, and testing. In order to ensure the software\'s long-term success and smooth operation, critical phases were also considered, such as deployment and maintenance.
UNASSIGNED: The developed software provides immediate and complete traceability of all preparations and controls, as well as management of reports, orders, stock, and post-operative follow-up of tasks related to 3D printing in a hospital. Based on user requirements, software testing is provided automatically with each release. The software was implemented in a natural clinical environment with a developed 3D printing center.
UNASSIGNED: Although 3D printing has potential for innovation in the medical profession, it is nevertheless subject to regulations. Even though there are exemptions for patient-specific products, the effects of their local legal implementations related to 3D printing cannot be fully overseen. To this end, 3Diamond provides a robust system for 3D printing documentation that is accessible to different personnel in hospitals.

UNASSIGNED: Maxillary reconstruction is often a challenging task for the surgeons because of the complex anatomy. However, with the advances in virtual surgical planning (VSP) and 3D printing technology there is a new avenue for the surgeons which offers a suitable alternative to conventional flap-based reconstructions.
UNASSIGNED: In this article, we have described 4 case scenarios which were managed with the help of VSP and additive manufacturing technology for complex maxillary reconstruction procedures. Use of the technologies aided the clinician in achieving optimal outcomes with regards to form, function and esthetics.
UNASSIGNED: Virtual surgical planning (VSP) has gained a lot of impetus in past 1 decade. These aides the surgeon in determining the extent of disease and also carry out the treatment planning. In addition to VSP, the concept of additive manufacturing provides a viable alternative to the conventional reconstruction modalities for maxillary defect rehabilitation. Increased accuracy, rehabilitation of normal anatomical configuration, appropriate dental rehabilitation, decreased intra-operative time and post-operative complications are some of the advantages. In addition, patient-specific implants eliminate the need for a separate donor site. Apart from the treatment of pathologies, they also can be used for reconstruction of post-traumatic defect, where endosteal implant placement is not possible.
UNASSIGNED: These modalities show promising results for reconstruction of complex maxillary defects.

UNASSIGNED: In recent years, 3D printing technology has made significant strides in the medical field. With the advancement of orthopedics, there is an increasing pursuit of high surgical quality and optimal functional recovery. 3D printing enables the creation of precise physical models of fractures, and customized personalized steel plates can better realign and more comprehensively and securely fix fractures. These technologies improve preoperative diagnosis, simulation, and planning for complex limb fractures, providing patients with better treatment options.
UNASSIGNED: Five typical cases were selected from a pool of numerous patients treated with 3D printing technology combined with personalized custom steel plates at our hospital. These cases were chosen to demonstrate the entire process of printing 3D models and customizing individualized steel plates, including details of the patients\' surgeries and treatment procedures. Literature reviews were conducted, with a focus on highlighting the application of 3D printing technology combined with personalized custom steel plates in the treatment of complex limb fractures.
UNASSIGNED: 3D printing technology can produce accurate physical models of fractures, and personalized custom plates can achieve better fracture realignment and more comprehensive and robust fixation. These technologies provide patients with better treatment options.
UNASSIGNED: The use of 3D printing models and personalized custom steel plates can improve preoperative diagnosis, simulation, and planning for complex limb fractures, realizing personalized medicine. This approach helps reduce surgical time, minimize trauma, enhance treatment outcomes, and improve patient functional recovery.