OBJECTIVE: To investigate the influence of different scanning conditions on the image quality of medical electron accelerator cone-beam computed tomography (CBCT) and provide a reference for the selection of scanning conditions for different body parts. Methods Set different scanning conditions, the Catphan 503 phantom was scanned using CBCT parameters to analyze the influence of spatial resolution, noise, uniformity, spatial geometric accuracy, and low-contrast resolution on the image quality of CBCT. RESULTS: For the head, chest, and abdomen, with the increase in scanning parameter values, the noise value decreased by 47.4%, 26.1%, and 51.3% respectively, and the uniformity values decreased by 30.2%, 26.6%, and 47.9% respectively. The low-contrast resolution values decreased by 50.6%, 34.2%, and 12.0%. The influence of different scanning conditions on spatial geometric accuracy and spatial resolution is not significant. CONCLUSION Different scanning parameters have a certain influence on the image quality of medical electron accelerator CBCT. Lower scanning parameters can be selected based on individual patients to reduce the additional radiation dose, providing a reference for the safe application of CBCT image guidance in radiotherapy.
Cone-Beam Computed Tomography/instrumentation* ; Phantoms, Imaging ; Particle Accelerators

This study explored a novel digital design and fabrication method for a double constrained split orthodontic miniscrew guide to improve the accuracy and safety of clinical miniscrew implantation and reduce related complications. A patient requiring miniscrew implantation was selected, and data were acquired using cone beam computed tomography (CBCT) and intraoral optical scanning. For the construction of a double constrained split guide including a screw-hole guide and an insertion rod guide, different types of software such as Mimics 24.0, Geomagic wrap 2021, and Materialise magics 21.0 were utilized for 3D reconstruction, model integration, and guide design. The guide was then fabricated via laser metal 3D printing. Model and intraoral try-in results demonstrated that the guide fitted well and was stable. Postoperative CBCT verified that the final miniscrew implantation site was consistent with the preoperative design, and no related complications occurred. This double constrained split orthodontic miniscrew guide provides a precise and safe digital solution for clinical miniscrew implantation.
Humans ; Bone Screws ; Cone-Beam Computed Tomography ; Printing, Three-Dimensional ; Orthodontic Anchorage Procedures/instrumentation* ; Imaging, Three-Dimensional ; Computer-Aided Design

Four-dimensional cone beam CT (4D-CBCT) imaging can provide accurate location information of real-time breathing for imaging-guided radiotherapy. How to improve the accuracy of 4D-CBCT reconstruction image is a hot topic in current studies. PICCS algorithm performs remarkably in all 4D-CBCT reconstruction algorithms based on CS theory. The improved PICCS algorithm proposed in this paper improves the prior image on the basis of the traditional PICCS algorithm. According to the location information of each phase, the corresponding prior image is constructed, which completely eliminates the motion blur of the reconstructed image caused by the mismatch of the projection data. Meanwhile, the data fidelity model of the proposed method is consistent with the traditional PICCS algorithm. The experimental results showed that the reconstructed image using the proposed method had a clearer organization boundary compared with that of images reconstructed using the traditional PICCS algorithm. This proposed method significantly reduced the motion artifact and improved the image resolution.
Algorithms ; Cone-Beam Computed Tomography ; methods ; Four-Dimensional Computed Tomography ; Humans ; Image Processing, Computer-Assisted ; Organ Motion ; Radiographic Image Enhancement ; instrumentation ; methods ; Respiration

OBJECTIVE: To establish a cone beam computed tomography (ECBCT) system for high-resolution imaging of the extremities. METHODS: Based on three-dimensional X-Ray CT imaging and high-resolution flat plate detector technique, we constructed a physical model and a geometric model for ECBCT imaging, optimized the geometric calibration and image reconstruction methods, and established the scanner system. In the experiments, the pencil vase phantom, image quality (IQ) phantom and a swine feet were scanned using this imaging system to evaluate its effectiveness and stability. RESULTS: On the reconstructed image of the pencil vase phantom, the edges were well preserved with geometric calibrated parameters and no aliasing artifacts were observed. The reconstructed images of the IQ phantom showed a uniform distribution of the CT number, and the noise power spectra were stable in multiple scanning under the same condition. The reconstructed images of the swine feet had clearly displayed the bones with a good resolution. CONCLUSIONS The ECBCT system can be used for highresolution imaging of the extremities to provide important imaging information to assist in the diagnosis of bone diseases.
Algorithms ; Animals ; Artifacts ; Calibration ; Cone-Beam Computed Tomography ; instrumentation ; methods ; Equipment Design ; Extremities ; diagnostic imaging ; Image Processing, Computer-Assisted ; methods ; Phantoms, Imaging ; Radiographic Image Enhancement ; instrumentation ; methods ; Swine

Cone-Beam Computed Tomography ; Dental Pulp Cavity ; diagnostic imaging ; Humans ; Root Canal Therapy ; instrumentation

Some patients who have neck tumor but cannot tolerate the thermoplastic immobilization may be supported by simple cushions, and are marked on the neck skin during CT simulation. We therefore set 5 mm as the spinal cord-planning risk volume margin in the intensity-modulated radiotherapy plans in our Centre. Cone beam CT (CBCT) scans were acquired for three times, and matched with the simulation CT images in each radiotherapy. The mean and the standard deviation of the individual, the root mean-square and the standard deviation of the individual were calculated. The matched results of the third CBCT were used to calculate the spinal cord- planning risk volume margin. The results showed that the interfraction error was significantly reduced and the intrafraction error was stable by CBCT guiding. CBCT and 5 mm spinal cord-planning organ is feasible and safe without threatening volume margin to high dose radiotherapy for the patients with neck tumor and not able to tolerate thermoplastic immobilization.
Cone-Beam Computed Tomography ; Head and Neck Neoplasms ; diagnostic imaging ; radiotherapy ; Humans ; Patient Positioning ; methods ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy Setup Errors ; prevention & control ; Radiotherapy, Image-Guided ; methods ; Radiotherapy, Intensity-Modulated ; instrumentation ; methods

The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic adults with normal occlusion were taken to measure the cortical bone thickness in both jaws. One-way analysis of variance (ANOVA) was used to analyze the differences in cortical bone thickness. Buccal cortical bone in the mandible was thicker than that in the maxilla. In the maxilla, cortical bone thickness was thicker in the buccal side than in the palatal side. Buccal cortical bone thickness in the mandible was thickest at the site distal to the first molar, and in the maxilla it was thickest at the site mesial to the first molar, while in the palatal side of maxilla it was thickest at the site mesial to the second premolar. The changing pattern of cortical bone thickness varies at different sites. In the buccal side of maxilla, the thinnest cortical bone thickness was found to be at 4 mm level from the alveolar crest, while the thickest was at 10 mm level (except for the site mesial to the first premolar). The buccal cortical bone thickness at the sites mesial or distal to the first molar in the mandible and palatal cortical bone thickness of maxilla tended to increase with increasing distance from the alveolar bone.
Adult ; Bone Screws ; Cone-Beam Computed Tomography ; methods ; Dental Implantation, Endosseous, Endodontic ; instrumentation ; methods ; Female ; Humans ; Male ; Mandible ; diagnostic imaging ; surgery ; Maxilla ; diagnostic imaging ; surgery ; Radiography, Dental ; methods ; Reproducibility of Results ; Sensitivity and Specificity ; Surgery, Computer-Assisted ; methods ; Young Adult

Cone beam computer tomography (CBCT) has advantages of high precision, low radiation and high image quality. It has been developing quickly since it was applied clinically. In order to control X-ray TUBE HEAD effectively in Dental CBCT, X-ray TUBE HEAD Control System was designed and realized in this study. This control system is the core of CBTC system, which includes the communication between CBCT system and computer, the control of X-ray tube head by CBCT system main control board and the synchronization between main control board and the flat panel detector. Control circuit of the control system and corresponding operating software were designed with PIC16F877A as the core. This control system has been put into use in current CBCT system successfully.
Algorithms ; Cone-Beam Computed Tomography ; instrumentation ; Equipment Design ; Software

OBJECTIVETo establish a convenient, objective and applicable method to assess gingival biotype using periodontal probing.

METHODSA total of 66 maxillary anterior teeth from 14 volunteers (6 males, 8 females) with healthy gingiva, aged from 20 to 30 years, were recruited in this study. The gingival biotypes were evaluated by whether or not the outline of the periodontal probe was clear inside the gingiva. Gingival thickness of the cemento-enamel junction (CEJ) in upper anterior teeth was measured by cone-beam CT (CBCT).

RESULTSThe method of periodontal probing-assessed gingival biotype had good consistency and repeatability. The result of probing-assessed gingival biotype was consistent with that obtained by CBCT. The mean thickness of gingiva in thin, compromised and thick gingival biotype was (1.02 ± 0.20), (1.28 ± 0.25) and (1.46 ± 0.25) mm. These differences were significant for all three comparisons (P = 0.001, respectively).

CONCLUSIONSPeriodontal probing-assessed gingival biotype is a simple, relatively objective and suitable method for clinical examination.

Adult ; Cone-Beam Computed Tomography ; Female ; Gingiva ; anatomy & histology ; diagnostic imaging ; Humans ; Male ; Periodontal Index ; Periodontics ; instrumentation ; Tooth Cervix ; diagnostic imaging ; Young Adult

In order to solve the time-consuming problem in volume CT image reconstruction field, we brought forward a fast reconstructive algorithm method to fit the clinic medicine. First, using the great parallel and Floating-Point power of graphic processing unit (GPU), we proposed a volume CT GPU- based reconstruction method. Second, in order to reduce the repetitive operation, we separated the geometry computation and pixel computation. As a result, the computation efficiency was further improved. At last, based on the background of medical engineering, the parallel of volume CT scan and reconstruction was implemented. The results demonstrated that the volume CT reconstruction time could reduce up to 70 times compared to the previous one in common PC by the fast reconstructive algorithm method.
Algorithms ; Computer Graphics ; Cone-Beam Computed Tomography ; instrumentation ; methods ; Humans ; Image Processing, Computer-Assisted ; methods ; Radiographic Image Enhancement ; methods ; Radiographic Image Interpretation, Computer-Assisted ; methods