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Objective:To develop the real-time radiotherapy monitoring system of three-dimensional (3D) point cloud by using depth camera and verify its feasibility.Methods:Taking the depth camera coordinate system as the world coordinate system, the conversion relationship between the simulation CT coordinate system and the world coordinate system was obtained from the calibration module. The patient's simulation CT point cloud was transformed into the world coordinate system through the above relationship, and registered with the patient's surface point cloud obtained in real-time manner by the depth camera to calculate the six-dimensional (6D) error, and complete the positioning verification and fractional internal position error monitoring in radiotherapy. Mean and standard deviation of 6D calculation error, Hausdorff distance of point cloud after registration and the running time of each part of the program were calculated to verify the feasibility of the system. Fifteen real patients were selected to calculate the 6D error between the system and cone beam CT (CBCT).Results:In the phantom experiment, the errors of the system in the x, y and z axes were (1.292±0.880)mm, (1.963±1.115)mm, (1.496±1.045)mm, respectively, and the errors in the rotation, pitch and roll directions were 0.201°±0.181°, 0.286°±0.326°, 0.181°±0.192°, respectively. For real patients, the translational error of the system was within 2.6 mm, the rotational error was approximately 1°, and the program run at 1-2 frames/s. The precision and speed met the radiotherapy requirement. Conclusion:The 3D point cloud radiotherapy real-time monitoring system based on depth camera can automatically complete the positioning verification before radiotherapy, real-time monitoring of body position during radiotherapy, and provide error visual feedback, which has potential clinical application value.
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In the spirit of curriculum-centered principle, the research group actively explored the content construction, operation mode and teaching method reform of comprehensive experimental course of basic medicine. Guided by diseases and application, experimental teaching courses based on the preparation and intervention process of animal models of diseases were extensively carried out, and "innovative" experimental items were added to ensure that the course contents reflected the frontier and the times. The course construction was guided by the training of biomedical frontier methods, making efforts to cultivate students' learning ability, practical ability and innovative ability. In addition, on the basis of optimizing the course content construction oriented to practical application and innovation, a virtual simulation experiment project is built, combined with online-offline hybrid teaching, to improve the comprehensive practical ability of trainees.
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@#<b>Objective</b> To investigate the dosimetric effect of truncated regions in computed tomography (CT) images on the targets and organs at risk in volumetric modulated arc therapy (VMAT) for middle thoracic esophageal cancer. <b>Methods</b> CT images of 15 patients with middle thoracic esophageal cancer were selected. Circle masks were used to make the volume of the truncated region account for 10%, 20%, 30%, and 40% of the arm volume, and the corresponding truncated CT images were obtained. The real CT was denoted as CT0. Two radiotherapy plans were made on CT0. One plan was VMAT_1F with full arcs, and the other one was VMAT_3F with arm avoidance. The plans were transplanted to four truncated CT, respectively, and the dosimetric differences between different plans were compared using Wilcoxon signed-rank test. <b>Results</b> Compared with VMAT_1F in CT0, <i>D</i><sub>mean</sub> and <i>V</i><sub>5</sub> of the lung decreased in VMAT_3F, but <i>D</i><sub>max</sub> of the spinal cord, <i>D</i><sub>mean</sub> of the heart, and <i>V</i><sub>20</sub> of the lung increased. In VMAT_3F, there was no statistically significant difference between the dosimetric parameters in the four truncated CT and those in CT0 (all <i>P</i> > 0.05). In VMAT_1F, except for homogeneity index and <i>D</i><sub>max</sub> of the spinal cord, the dosimetric parameters in four truncated CT were significantly different from those in CT0 (<i>P</i> < 0.05). The dosimetric difference increased with the increase in truncated region-to-volume ratio. <b>Conclusion</b> Complete CT data should be collected in clinical practice, and the radiation field avoiding the truncated regionshould be set if necessary to reduce the influence of the truncated region on dosimetry.
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Objective:To explore the volume resolution of prostate motion target by four-dimensional (4D) ultrasound.Methods:The prostate ultrasound model was selected, and the group comparison study was conducted using 4D ultrasound to outline the prostate target under different motion amplitudes (A) and motion period (T). The simulated A value was set as 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, respectively. The T value was set as 1 s, 2 s, 3 s, and 4 s, respectively. The volume of the target of the model prostate was calculated, and the static ultrasound image of the target was used as the control group to analyze the difference between two groups.Results:When the model was still, the size of the target of ultrasound was consistent with that of CT scan ( P>0.05). When the A values were 0.5 mm and 1 mm, there was no statistical difference between the volume in period 1-4 s and the volume in the target at rest (all P>0.05). When the A values were 2 mm and 3 mm, and the T values were 1 s, 2 s and 3 s there was statistical difference between the volume of target and that of of static ultrasonic target (all P<0.05). When the A value was 2 mm and the T value was 4 s, there was no statistical difference between the target volume and the static target volume ( P=0.710). The range within the group was 6.7 cm 3, and the standard deviation was 1.15 cm 3. When the A value was 3 mm and the T value was 4 s, the volume repeatability of the target was poor, and the range within the group was 14.4 cm 3; when the A values were 4 mm and 5 mm, and the T values were 1-4 s, the range within the group was 3.27-17.63 cm 3 and 6.51-21.02 cm 3, respectively. The volume repeatability of the target under each period was extremely poor, which could not meet the clinical requirements. Conclusion:4D ultrasound can provide reliable reference data for patients′ target delineation within 1-4 s of motion cycle and within 1 mm of motion amplitude, which exerts on effect upon the original position of probe.
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Objective:To develop a 3D visualization technology-assisted patient positioning system for radiotherapy and compare it with traditional patient positioning method for breast and pelvic radiotherapy.Methods:A total of 40 patients receiving radiotherapy in Changzhou No.2 People′s Hospital from June 2020 to April 2021 were selected for this study, including 20 patients with breast cancer and 20 patients with pelvic cancer.3D visualization reconstruction was carried out using the CT data of the patients for positioning. Then the 3D visualization models were integrated with the real treatment environment and were then shifted to the isocentral positions of accelerators through interactive operations. Based on this, the patients were actually positioned. Every week, all of the patients were firstly treated with traditional positioning, followed by 3D visualization-guided positioning. As a result, 240 times of positioning data of all patients were collected in three weeks. They were compared with the data of cone-beam CT(CBCT)-guided positioning, which served as the gold standard.Results:The absolute positioning errors of 3D visualization-guided positioning along x, y and z axes were (1.92±1.23), (2.04±1.16), and (1.77±1.37)mm, respectively for patients with breast cancer and were (2.07±1.08), (1.33±0.88), and (1.99±1.25)mm, respectively for patients with pelvic cancer. Compared with traditional positioning method , the accuracy of 3D visualization-guided positioning along x、 y, and z axes was increased by 38.83%, 52.40% and 33%, respectively for patients with breast cancer and was improved by 36.84%, 54.04% and 52.58% for patients with pelvic cancer, with all differences being statistically significant along y and z axes ( t=2.956-5.734, P< 0.05). Meanwhile, the error distribution of the two positioning method was statistically significant along in y axis for patients with breast cancer( χ2=7.481, P<0.05) and was statistically significant along each axis for patients with pelvic cancer( χ2=5.900, 6.415, 7.200, P<0.05). Conclusions:The positioning method guided by 3D visualization technology can effectively improve the positioning accuracy of patients with breast cancer and patients with pelvic cancer and is of value in potential clinical application.
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Medical images play an important role in clinical diagnosis and treatment. During the radiotherapy, CT can be available for the location and definition of the target volume. The medical images from multiple modalities are used to obtain the information on pathological body from many angles. However, obtaining multiple-modality medical images could be more resource-consuming, and difficult to guarantee the consistency of patients′ state. Medical image translation between multiple modalities can achieve the predication from one modality to another. The studies on medical images from multiple modalities such as CT, ultrasound, MRI and PET are reviewed in detail in this paper, , with discussions provided about characteristics of multiple modalities and challenges faced, as well as the research areas to be developed.
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At present, a common lack of basic scientific research training in the undergraduate education is one of the reasons restricting the innovation ability of undergraduates. Cultivating scientific research ability of undergraduates is one of the effective ways to improve the undergraduate professional education as well as the innovation ability. Therefore, after exploration and summary for years, we have formed a relatively mature new mode that cultivates the undergraduates' comprehensive abilities in scientific research, namely, the training system of scientific research ability of medical undergraduates guided by literature reading. It has improved the basic scientific quality and innovation ability of medical undergraduates in our university, and trained a group of outstanding undergraduates who have obtained various achievements, contributing to the construction of excellent postgraduate talents in our university. In addition, it is also an effective and feasible new teaching mode.
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Objective An improved method for obtaining pseudo-computed tomography (CT ps) based on ultrasound deformation field.Methods The three-dimensional image data of computed tomography and ultrasound for three postoperative cervical cancer patients were selected,including the CT (CTsim) and ultrasound (USsim) images obtained during the simulated positioning stage,and the cone beam CT (CBCT) and ultrasound images obtained during the positioning verification stage of the treatment one week later.Binary masks of the OROI and OROW were created and applied in ultrasound image registration;thus,the deformation field was obtained.The deformation field was applied to CTsim images and different pseudo-CT images were obtained.Similarities between these pseudo-CT images and those of CBCT were compared,and registration accuracies between pseudo-CT images under different binary masks and CTsim were discussed.Results The averages of the correlation coefficient between pseudo-CT based on OROI,OROW,no binary mask and CBCT were 0.95,0.82 and 0.64 respectively.The average of the normalized mean square Error were 0.12,0.42 and 0.57 respectively.Conclusion The pseudo-CT based on OROI binary mask matches the best with CTsim and achieves the highest similarity with CBCT.
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With the deepening of the reform of management system of higher medical education in China and the comprehensive advancement of quality education , the teaching laboratories in medical colleges have evolved from traditional laboratories serving the needs of a single discipline to medical laboratory centers classified by subject groups and their corresponding functions. Applying the concept of collaborative innovation, practical explorations in such aspects as building a "big experimental teaching center", establishing a new system of experimental teaching courses, exploring a new model of innovative practical education, and building an excellent teacher team engaging in experimental teaching by means of synergic work have been made by the Army Medical University in its construction of an experimental teaching center for basic medical sciences, which also provides practical reference for the construction of experimental teaching centers in the future.
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In this paper,we have made a preliminary analysis on the necessity,main contents and difficulties in teaching medical undergraduates the principles and applications of optogenetics experimental technology.We focused on theory and practice teaching and emphasized on the most important technological principles,including how to achieve selective intervention of specific neural pathways;how to achieve twoway control of cell excitation or inhibition effect and the main process of the experiment.Finally,we have summarized our recent experience in the teaching process,to provide reference for basic medical experiments teaching in related medical colleges,so as to promote optogenetics experimental teaching for undergraduates in domestic medical colleges.
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Optogenetics is one of the biggest breakthroughs in neurobiology in recent decades,which is a revolutionary approach to precise intervention of specific cell functions through the combination of optical and genetic engineering techniques.However,this technique involves the interdisciplinary theoretical knowledge and methods,and it requires expensive equipments and long experimental period.Thus,it is not convenient to carry out widely in experiment teaching for undergraduates except the virtual simulation teaching.In present virtual simulation experiment,we aim to learn the basic principle,operation and application of optogenetics and achieve the desired teaching effects by simulating the process of the virus package,simulating the process of the animal selection,surgery and virus stereotactic microinjection,simulating the expression process of photosensitive channel,the extracellular verification process of photosensitive channel function in vivo,and simulating the observation process that optogenetic inhibition of glutamate neurons in the amygdala affect animal fear behavior.In this paper,the content design of the script making of the virtual experiment has been discussed in the above ways.
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Objective To investigate the impact on registration accuracy with the different registration ranges of CBCT images and CT images.Methods CBCT and CT scans were performed on the of 5 patients.The registration ranges of five patients' images of abdomen,head and chest performed CBCT and CT scanning were processed with four modes.Mode 1:the registration range of CT images was larger than the registration range of CBCT images,mode 2:the registration range of CT images and CBCT images were equally,mode 3:taking a 5 cm translation of CT images range from mode 2,mode 4:The CBCT range and CT range reduced 2 cm both sides simultaneously from mode 2.Using the registration program from Insight Segmentation and Registration Toolkit (ITK) to the four modes,the Mean Square Difference (MSD) metric values of four modes after registration were compared and the relationship between mode 2 and another three modes was analyzed by paired t test.Results For the MSD metric values,mode 3 was maximum,mode 2 and 4 were minimum,and mode 1 was centered.The difference between the mode 2 and mode 4 was not statistically significant(P ＞ 0.05).The difference between the mode 2 and mode 1 was statistically significant(t =-4.586,-4.164,-5.618,P ＜ 0.05).The difference between the mode 2 and mode 3 was statistically significant(t =-6.423,-8.109,-19.601,P＜0.05).Conclusion The registration ranges of CBCT and CT images has a certain extent of influence on the accuracy of image registration.The closer the registration range of CBCT and CT is,the higher the registration accuracy is.
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Objective To apply metal artifact reduction algorithm to reduce metal artifacts based on 12 bit and 16 bit CT images,and aimed to analyze the effects on CT value and dose distribution.Methods The metal implant was inserted into the phantom,and the original 12 bit CT image and original 16 bit CT image were derived from CT scanning.The images were processed using NMAR algorithm,so the corrected 12 bit image and corrected 16 bit image were obtained.A patient's CT was chosen with artificial femur,and used the NMAR algorithm to reduce metal artifacts.Furthermore,the CT values of original images and corrected images were compared and analyzed.In the planning system,dose distribution was calculated based on each image by same radiation treatment plan.The dose distribution difference of each image was compared and analyzed.Results For the 12 bit image,the CT value of metal was 3 071 HU,which was much smaller than the metal's actual CT value ll 080 HU.The metal's CT value for the 16bit image was 11 098 HU,which was very close to the actual value.The original CT images contained a lot of artifacts around the metal,resulting in a large deviation of CT values from the reference image.After NMAR correction,metal artifacts were reduced significantly,and the CT values were close to the reference images.The dose distribution of the corrected 16 bit image was closest to that of the reference image.The maximum dose deviation on the central axis was 1.8％.The difference between the 12 bit image and the reference image downstream the metal was notable,and the maximum dose deviation on the central axis was 81.6％.The X-rays passed through the artifact region in original image,the dose distribution was obviously different from the reference image,and the maximum dose deviation was 21.6％.Conclusions For the patient with metal implant,using the NAMR algorithm on the 16 bit image result in accurate CT value of CT image,so that the accurate dose distribution will be obtained.
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Radiomics refers to the comprehensive quantification of information such as tumor biological feature and heterogeneity through assessing a large number of quantitative image features from ROI of CT,MRI and PET images.With the development of data science,radiomics has been paid more and more attention.Feature extraction is an important step of Radiomics.The processes in feature extraction of radiomics were reviewed in this paper.
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Objective To reconstruct 16?bit images of metal implants using the extended function of computed tomography ( CT) imaging, and to analyze the effect of the metal CT value on calculation of dose distribution by evaluation of metal CT values in different scanning conditions. Methods A stainless steel rod and a titanium rod were inserted in a phantom. The 12?and 16?bit images and CT value distribution of metal implants were obtained by scanning the phantom using 120 kV tube voltage and 230 mA tube current. The 16?bit images and CT value distribution of metal implants were obtained by scanning the phantom using fixed tube current ( 230 mA) with varied tube voltage ( 100, 120, and 140 kV) or fixed tube voltage ( 120 kV) with varied tube current ( 180, 230, and 280 mA) . In the Varian treatment planning system, a single?field plan and a parallel?opposed field plan were designed based on the CT images. The dose distribution was calculated and compared by the paired t test. Results The CT values of the stainless steel rod and the titanium rod were both 3 071 HU in 12?bit CT images. In 16?bit CT images;however, the CT value of the stainless steel rod was significantly larger than that of the titanium rod. There were no significant differences in CT value of 16?bit image and dose distribution in radiotherapy plan between three scanning conditions with different tube currents. Under three scanning conditions with different tube voltages, the maximum CT values were 13 568, 13 127, and 12 295 HU for the stainless steel rod and 8 420, 7 140, and 6 310 HU for the titanium rod, respectively. Conclusions High?density metal implants cannot be distinguished by 12?bit images, while the distribution of metal CT value can be obtained by 16?bit images. The dose distribution of metal implants based on 12?bit images is different from that based on 16?bit images. Changes in tube voltage cause substantial changes in the CT value for metal implants, leading to changes in dose distribution in radiotherapy. Variation of tube current within a certain range causes slight changes in metal CT value and dose distribution.
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Intensity-modulated radiation therapy is widely used in the treatment of tumor,and the dose distribution highly conforms to tumor target area in three-dimension.However,the factors such as complex beam,data error,algorithm error and machine error may cause large dose deviation in intensity-modulated radiation therapy,which may lead to unnecessary radiation accident.Therefore,standing on the patients' safety point of view,dose verification is usually performed before executing the treatment plan in order to ensure the safe implementation of the treatment plan and to avoid un-planned irradiation dose.Currently,there are many tools and methods of dose verification in clinic,including point dose verification tools like finger-shaped ionization chamber and thermoluminescence dosimeter;two-dimensional dose verification tools like Mapcheck,MatriXX and films;three-dimensional dose verification tools like ArcCHECK,Delta4 and the third-party software.These common clinical dose verification methods are reviewed in this paper.
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Objective To investigate the method of establishing a model of delay eyeblink condi-tioning ( DEC) in no surgical cynomolgus monkey and analyze the related acquisition rule.Methods Using the special monkey chairs to fix 6 adult male cynomolgus monkeys,they were sitting on the chairs and keep-ing awake,and heads could rotate freely during the whole training session.In the experiment,the 6 monkeys were trained in DEC with a tone (500 ms,85 dB) as the conditioned stimulus (CS),paired with a corneal oxygen-puff (100 ms,5 psi) as the unconditioned stimulus (US).There were 120 trials per-session,and 2 sessions per-day.During the experiments,an infrared emitter/detector attached to spectacles for eyeblink re-cording,the data of conditioned response ( CR) and startle response ( SR) were analyzed offline.Result-s Among the 6 cynomolgus monkeys,4 of them completed all of the training process of DEC and 3 monkeys had successful acquisition of DEC.The average CR rate in the last training session reached ( 64.67 ± 2.00)%,(P<0.01);1 monkey only showed a high acquisition rate( 85.00%) at the first training session, and the low CR rate in the next training sessions with the average rate of 18.16%,suggesting that the DEC model was failed to established.The SR rates in 4 cynomolgus monkeys were low with average rate of 5.47%. Conclusion Although the DEC behavior training of the cynomolgus monkey is easy to be influenced by many inside or outside factors,DEC can be obtained under the condition of non surgery and proper braking.
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@#Objective To quantize the synergistic force in movement of upper limbs between shoulders and elbows. Methods The trans-verse forces of elbows and shoulders during movement were recorded in a healthy adult with an upper-limb-force-measuring plate form which comprised of 2 three-dimensional force sensors, respectively. Then he performed shoulder abduction/adduction and elbow extension/flexion at 100%, 75%, 50%and 25%of the maximum contraction force, respectively. The ratio of the active action force and the joint action force (named assessment index) was used to assess the synergistic degree of the forearm and the upper arm. Results In the shoulder abduc-tion motion, the assessment index decreased as the strength of active action decreased, meant interference of joint action increased. Howev-er, it was almost stable in the shoulder adduction, increased in the elbow extensionas, and was irregular in the elbow flexion, as the active ac-tion strength decreased, respectively. Conclusion It may be more difficult to control upper arm than the forearm.
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ObjectiveTo investigate the characteristic parameters and variation of acoustic startle reflex (ASR) and conditioning response (CR)during the acquisition of delay-trace eyeblink conditioning.Methods15healthy Kunming mice were randomly divided into 3 groups:single-task DEBC group ( n =5 ) ; single-task TEBC group ( n =5) ; dual delay/trace group ( n =5).Three groups received paired training of tone conditioned stimulus(CS)in different audio frequency (TEBC groups:2KHz; DEBC group:1KHz) and a 100 ms comeal oxygenpuff unconditioned stimulus(US).Then observed the characteristic parameters of ASR and CR.ResultsAfter pairing training for 10 days,ASR rate( ASR％ ) of single-task groups ( 10th day (38.00 ± 8.64) ％ and (38.55 ±12.41 ) ％ respectively,time effect:F =4.574,P =0.008 ; group effect:F =2.021,P =0.193 ) and dual delaytrace group ( 10th day (47.95 ± 14.23 ) ％ and (62.01 ± 9.03 ) ％ respectively,time effect:F =5,547 P =0.013 ;group effect:F =0.738,P =0.415) changed significantly with the following training but between single-task groups or dual delay-trace group.CR rate ( CR％ ) of single-task groups ( 10th day were (45.4 ± 5.39) ％ and (65.6 ± 6.77) ％ respectively,time effect:F =9.558,P =0.000 ; group effect:F =5.117,P =0.054 ) and dual delay/trace group ( 10th day (57.66 ± 4.34) ％ and (77.35 ± 7.36) ％ respectively,time effect:F =7.750,P =0.002 ;group effect:F=1.449,P=0.263 ) showed obvious change with the following training but between singletask groups or dual delay-trace group.Peak amplitude of single-task DEBC group ( time effect F =2.679,P =0.017 ) and dual delay-trace group ( F=3.452,P=0.034 ) had increased significantly with the following training.Peak latency showed no obvious change.ConclusionDual delay-trace conditioning procedure of classical eyeblink conditioning and single-task can be successfully established in Kunming mice.Although there are some variations,those can be controled and be weaken effect of them by taking targeted measures.
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Objective To observe and analyze the role of different subfields of medial prefrontal cortex (mPFC) in the expression course of startle reflex.Methods 24 healthy male British kind of albino guinea pigs were randomly divided into 4 groups:anterior cingulated cortex lesion ( n =6) and sham-lesion ( n =6) ( Experiment 1 ) ; prelimbic cortex lesion/joint lesion of prelimbic cortex and anterior cingulated cortex(n=6) and sham-lesion ( n =6) ( Experiment 2 ).The animals were injected lidocaine ( lesion ) or physiological saline ( sham-lesion ).Each group received paired training of conditioned stimulus( CS,a tone) and unconditioned stimulus (US,a air puff),to observe the acoustic startle reflex(ASR) change of these groups.Results As the results of experiment 1 suggested,SR rate did not change significantly after anterior cingulated cortex lesion ( time effect:F =15.421,P =0.098 ; group effect:F =14.753,P =0.084).As the results of experiment 2 suggested,SR rate did not change significantly after prelimbic cortex lesion ( time effect:F =14.975,P =0.178 ; group effect:F =18.643,P =0.089).When prelimbic cortex and anterior cingulated cortex were lesioned at the same time,SR rate declined significantly and didn ' t recover with the following training ( group effect:F =67.743,P =0.009 ).ConclusionLesions of the prelimbic cortex and anterior cingulated cortex in mPFC cause the significantly decline of acoustic startle reflex( ASR),which don' t recover with the following training.This study indicates that mPFC involves in the regulation of ASR,but the regulation mechanism needs to be discussed.