Objective:To evaluate the feasibility of using a visual positioning system for both motion phantom and clinical quality control.Methods:A phantom experiment was conducted using the Dynamic Thorax Phantom from CIRS. Different ranges of motion were simulated to assess the discrepancies between camera-recorded positions and actual movements. Visual markers were also attached to the treatment bed and the collimator head, and their movements were simulated as part of the experiment. The experiment was repeated for three times. Discrepancies between system measurements and manual measurements were recorded and analyzed to assess the accuracy and reliability of the system.Results:In the motion phantom test, the deviation between the actual motion distance of the phantom and the system's recorded measurement was (0.18±0.07) mm. For linear motion analysis along the X, Y, and Z axes on the treatment table, the measurement errors were (0.14±0.08) mm, (0.15±0.09) mm, and (0.16±0.08) mm, respectively. Additionally, the measurement error in the rotational direction of the treatment couch was 0.18°±0.09°. For the rotational direction of the collimator head, the measurement error was 0.11°±0.02°. Conclusion:The system demonstrates good accuracy and stability, and has potential clinical application value.

Objective:To evaluate the feasibility of a novel liver fiducial marker implantation method for internal fixation and removal of rabbit livers, in order to use in Cyberknife tracking therapy.Methods:Experiments were conducted in vivo and in vitro. In the in vivo experiment, three fiducial markers were implanted percutaneously in each liver of ten rabbits under anesthesia, and the fourth fiducial marker with an external catheter and fixed thin wire was implanted ten days later. After the reference group (the first and the second maker), and the casing group (the first and the fourth marker) were respectively registered and tracked with the Cyberknife, the implantation success rate, registration accuracy, and removal safety of fiducial markers were assessed. The tensile test was performed using liver in vitro by measuring the resistance required to dislodge the spring coil fiducial markers and the fiducial markers without spring coil from liver. Results:The intrahepatic catheter implantation and removal of fiducial marker in rabbit liver had a success rate of 100% and no distant migration. The operation-related and postoperative complications were not occurred. All fiducial markers were successfully traced. Compared to the reference group, the casing group had slightly higher translational errors in supero-inferior and antero-posterior directions ( Z=-11.77, -4.57, P<0.05), and lower translational errors in left-right direction ( Z=-2.52, P<0.05). The dislodgement forces for spring coil fiducial markers was (2.23±0.85) N, significantly different with (0.81±0.13) N for fiducial markers without spring coil ( Z=- 2.31, P < 0.05). Conclusions:The spiral coil structure provides superior fixation in the punctured needle channel, the thin line limits the distant displacement of the fiducial marker outside the liver, and the catheter establishes a channel for the removal. The general operation is simple and easy.

Objective:To investigate the necessity and feasibility of the virtual simulation teaching experiment software of the bronchoscopy intelligent navigation-based fiducial marker implantation technology in the clinical application of radiotherapy.Methods:This study developed a 3D virtual operation and interactive system using the Unity3D engine, tools including 3Dmax and Maya, and the SQL database. The scenes in the system were produced using the currently popular next-generation production process. Targeting the priorities and difficulties in the implantation of fiducial markers, the system developed in this study allowed for simulated demonstration and training based on 12 steps and 10 knowledge points. Internal tests and remote evaluation tests were adopted in this system to obtain the test result of each subject. Then, the application value of the system was analyzed based on the test result.Results:As of May 1, 2022, the system had received 2 409 views and 425 test participants, with an test completion rate of 100% and an experiment pass rate of 96.5%. Moreover, this system won unanimous praise from 167 users, primarily including the students majoring in multilevel medical imaging technology and medical imaging science from the Fujian Medical University, as well as the radiotherapy-related staff of this university.Conclusions:The virtual simulation teaching experiment software of the bronchoscopy intelligent navigation-based fiducial marker implantation technology can be applied to the teaching of students and the training of related professionals.