Objective:To design a phonocardiographic gating device that was used in cardiac magnetic resonance imaging(MRI),so as to explore feasibility of synchronized acquisition for cardiac MRI.Methods:A phonocardiographic gating device was designed,which structure included a head of stethoscope,transmission pipeline,microphone and amplification filtering circuit,computer,and pseudo-electrocardiogram(ECG)trigger output circuit.The computer's runs included phonocardiographic recognition neural network of one-dimensional dilated convolutional layer and gating recurrent unit(GRU)layer,which parameters were determined by pre-train.The feasibility of using the phonocardiographic gating device in acquisition of cardiac MRI was explored by comparing the preparation time of examination and image quality for phonocardiographic gating device and ECG gating technique.Results:The average preparation time for the phonocardiographic gating device was(10.46±1.75)seconds,which was significantly shorter than that for ECG gating technique[(32.07±5.26)seconds](t=-11.02,P＜0.05).There were no statistically significant difference in the clarity of short-axis images of heart at end-systole and end-diastole,and the indicators of cardiac function between the two methods(P＞0.05).Conclusion:The phonocardiographic gating device can replace ECG gating for MRI examinations,which can effectively conduct triggering for phonocardiographic gating while reducing preparation time.It holds clinical application value,especially in equipment with high field strength.

Objective:To investigate the enhancement effect of deep progressive reconstruction (DPR) algorithm on image quality and standardized uptake value (SUV) of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in obese patients. Methods:The images of a total of 27 obese patients,who underwent 18F-FDG PET/CT in Affiliated Nanjing Hospital of Nanjing Medical University from September 2023 to May 2024,were retrospectively enrolled. The images of all patients were collected by using uMI 780 PET/CT. Ordered subset expectation maximization (OSEM) iterative algorithm and DPR algorithm were adopted to reconstruct PET images,and measure counting rate of scattering coincidence of PET/CT images,counting rate of true coincidence,noise equivalent counting rate (NECR) and scattering fraction (SF). The quality indicators of PET images included signal-to-noise ratio (SNR),the maximum SUV (SUVmax) of lesions,the tumor-to-background ratio (TBR),the contrast-to-noise ratio (CNR) and the visual scores of 18F-FDG PET/CT images on livers were evaluated. The differences and consistency of various indicators between DPR and OSEM reconstruction algorithms were further analyzed. Results:The average 18F-FDG PET/CT injection activity of 27 patients was (0.12±0.01) mCi (1 mCi=37 MBq)/kg,and the counting rate of true coincidence,NECR and SF of PET images were respectively (153.73±25.09),(44.81±8.47) kcps and (36.77±1.91)％. The SNR of liver obtained by DPR algorithm was (15.83±3.60),which was significantly higher than that (9.06±1.87) of OSEM algorithm,with statistically significant (t=20.6,P<0.05),and there was significantly correlation in liver SNR between two algorithms (R2=0.91,P<0.05). In 27 uptake 18F-FDG PET/CT lesions,the SUVmax,TBR and CNR of lesions that were obtained from OSEM algorithm were respectively (5.86±1.49),(1.95±0.49) and (17.74±4.77),which were lower than corresponding those of DPR algorithm,and the differences were significant (t=9.03,8.79,15.49,P<0.05),respectively. There were significant correlations in SUVmax,TBR and CNR between the two algorithms (R2=0.71,0.70,0.76,P<0.05),respectively. The visual scores of PET images obtained from the DPR algorithm was 4 (3,5) scores,which was significantly higher than 3 (2,4) scores of OSEM algorithm,and the difference of that between two algorithms was significant (U=396,P<0.05). Conclusion:The scattering effect of 18F-FDG PET/CT imaging is stronger in obese patients,whose counting rate of equivalent effect of noise is lower. The DPR reconstruction algorithm can significantly improve the SNR and lesion contrast of PET images than the OSEM algorithm,which has significant gain effect on the SUVmax of lesions,and it can significantly improve the quality of 18F-FDG PET/PET images in obese patients.

Objective To observe the effect of automatic segmentation of prostate cancer(PCa)in 68Ga-prostate specific membrane antigen(PSMA)-11 PET/MRI based on diffusion models.Methods A dataset contained 68Ga-PSMA-11 PET/MRI of 125 cases of PCa was preprocessed.Segmentation network was designed based on Faster-RCNN and spatial and channel reconstruction convolution(SCConv)Diffusion cascade,in which the first-level was used to coarsely localize the prostate and seminal vesicle glands using Faster-RCNN,and the second-level SCConv Diffusion network based on diffusion model was used to segment PCa.The effect of the above models for segmenting PCa in 68Ga-PSMA-11 PET/MRI were observed.Results The Dice similarity coefficient(DSC),intersection over union(IoU),and 95％Hausdorff distance(HD)of the Faster-RCNN+SCConv Diffusion model for segmenting PCa in 68Ga-PSMA-11 PET/MRI was 0.76,0.63 and 20.02 mm,all superior to those of nnU-Net(0.73,0.62 and 21.20 mm)and Faster-RCNN+nnU-Net(0.75,0.62 and 20.70 mm)models,and the segmentation for both single and multiple PCa were all accurate,with less missegment non-tumor tissue.Conclusion Diffusion model based on Faster-RCNN+SCConv diffusion cascade network could be used to completely and accurately segment PCa in 68Ga-PSMA-11 PET/MRI.

Objective:To investigate the enhancement effect of deep progressive reconstruction (DPR) algorithm on image quality and standardized uptake value (SUV) of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in obese patients. Methods:The images of a total of 27 obese patients,who underwent 18F-FDG PET/CT in Affiliated Nanjing Hospital of Nanjing Medical University from September 2023 to May 2024,were retrospectively enrolled. The images of all patients were collected by using uMI 780 PET/CT. Ordered subset expectation maximization (OSEM) iterative algorithm and DPR algorithm were adopted to reconstruct PET images,and measure counting rate of scattering coincidence of PET/CT images,counting rate of true coincidence,noise equivalent counting rate (NECR) and scattering fraction (SF). The quality indicators of PET images included signal-to-noise ratio (SNR),the maximum SUV (SUVmax) of lesions,the tumor-to-background ratio (TBR),the contrast-to-noise ratio (CNR) and the visual scores of 18F-FDG PET/CT images on livers were evaluated. The differences and consistency of various indicators between DPR and OSEM reconstruction algorithms were further analyzed. Results:The average 18F-FDG PET/CT injection activity of 27 patients was (0.12±0.01) mCi (1 mCi=37 MBq)/kg,and the counting rate of true coincidence,NECR and SF of PET images were respectively (153.73±25.09),(44.81±8.47) kcps and (36.77±1.91)％. The SNR of liver obtained by DPR algorithm was (15.83±3.60),which was significantly higher than that (9.06±1.87) of OSEM algorithm,with statistically significant (t=20.6,P<0.05),and there was significantly correlation in liver SNR between two algorithms (R2=0.91,P<0.05). In 27 uptake 18F-FDG PET/CT lesions,the SUVmax,TBR and CNR of lesions that were obtained from OSEM algorithm were respectively (5.86±1.49),(1.95±0.49) and (17.74±4.77),which were lower than corresponding those of DPR algorithm,and the differences were significant (t=9.03,8.79,15.49,P<0.05),respectively. There were significant correlations in SUVmax,TBR and CNR between the two algorithms (R2=0.71,0.70,0.76,P<0.05),respectively. The visual scores of PET images obtained from the DPR algorithm was 4 (3,5) scores,which was significantly higher than 3 (2,4) scores of OSEM algorithm,and the difference of that between two algorithms was significant (U=396,P<0.05). Conclusion:The scattering effect of 18F-FDG PET/CT imaging is stronger in obese patients,whose counting rate of equivalent effect of noise is lower. The DPR reconstruction algorithm can significantly improve the SNR and lesion contrast of PET images than the OSEM algorithm,which has significant gain effect on the SUVmax of lesions,and it can significantly improve the quality of 18F-FDG PET/PET images in obese patients.

Objective To observe the effect of automatic segmentation of prostate cancer(PCa)in 68Ga-prostate specific membrane antigen(PSMA)-11 PET/MRI based on diffusion models.Methods A dataset contained 68Ga-PSMA-11 PET/MRI of 125 cases of PCa was preprocessed.Segmentation network was designed based on Faster-RCNN and spatial and channel reconstruction convolution(SCConv)Diffusion cascade,in which the first-level was used to coarsely localize the prostate and seminal vesicle glands using Faster-RCNN,and the second-level SCConv Diffusion network based on diffusion model was used to segment PCa.The effect of the above models for segmenting PCa in 68Ga-PSMA-11 PET/MRI were observed.Results The Dice similarity coefficient(DSC),intersection over union(IoU),and 95％Hausdorff distance(HD)of the Faster-RCNN+SCConv Diffusion model for segmenting PCa in 68Ga-PSMA-11 PET/MRI was 0.76,0.63 and 20.02 mm,all superior to those of nnU-Net(0.73,0.62 and 21.20 mm)and Faster-RCNN+nnU-Net(0.75,0.62 and 20.70 mm)models,and the segmentation for both single and multiple PCa were all accurate,with less missegment non-tumor tissue.Conclusion Diffusion model based on Faster-RCNN+SCConv diffusion cascade network could be used to completely and accurately segment PCa in 68Ga-PSMA-11 PET/MRI.

Objective:To design a phonocardiographic gating device that was used in cardiac magnetic resonance imaging(MRI),so as to explore feasibility of synchronized acquisition for cardiac MRI.Methods:A phonocardiographic gating device was designed,which structure included a head of stethoscope,transmission pipeline,microphone and amplification filtering circuit,computer,and pseudo-electrocardiogram(ECG)trigger output circuit.The computer's runs included phonocardiographic recognition neural network of one-dimensional dilated convolutional layer and gating recurrent unit(GRU)layer,which parameters were determined by pre-train.The feasibility of using the phonocardiographic gating device in acquisition of cardiac MRI was explored by comparing the preparation time of examination and image quality for phonocardiographic gating device and ECG gating technique.Results:The average preparation time for the phonocardiographic gating device was(10.46±1.75)seconds,which was significantly shorter than that for ECG gating technique[(32.07±5.26)seconds](t=-11.02,P＜0.05).There were no statistically significant difference in the clarity of short-axis images of heart at end-systole and end-diastole,and the indicators of cardiac function between the two methods(P＞0.05).Conclusion:The phonocardiographic gating device can replace ECG gating for MRI examinations,which can effectively conduct triggering for phonocardiographic gating while reducing preparation time.It holds clinical application value,especially in equipment with high field strength.

Objective To propose an improved discrete wavelet transform (DWT ) and to apply it in multimodal medical im‐age fusion .Methods Firstly ,the source medical images were initially transformed into the high frequency and low frequency images by DWT ;then the high frequency part adopted the big direction absolute values ,which effectively preserved the detailed informa‐tion of image ,while the low frequency part used the fusion rule of local energy ratio for preserving the most of image information ;finally ,the discrete wavelet reverse transform was used for reconstructing the fusion sub‐images into fusion image .Results By comparing the fusion images by 3 groups of medical images ,this proposed algorithm was superior to other existing algorithms in the aspects of subjective visual effect and objective evaluation indicators .Conclusion The proposed algorithm of medical image fusion is rapid and accurate ,has excellent performance in the noise environment and clinical examples ,can obtain the high quality fusion im‐age and has higher clinical application value .

Objective: To analyze the effects of technetium99 conjugated with methylene diphosphonate(99Tc-MDP) on adjuvant arthritis in rats.Methods: Thirty SD rats were randomly and equally divided into a normal control group an adjuvant arthritis control group and a 99Tc-MDP treatment group.Intraperitoneal injection of 99Tc-MDP(2.5?10-3?g/kg) was given to the rats in the treatment group on the tenth day and repeated every other day after arthritis induction.The left-right diameter of the left hind ankle,arthritic index,serum TNF and IL-1? levels,articular radionuclide imaging and histopathological changes were observed.Results: Compared with the adjuvant arthritis group,the diameter of the left hind ankle,arthritic index,the serum TNF and IL-1? levels and the T/NT value were decreased in the treatment group,and histopathology showed less synovium hyperplasia and fewer infiltration of inflammatory cells in the group treated with 99Tc-MDP intraperitoneal injection than in the adjuvant arthritis control group.Conclusion: 99Tc-MDP intraperitoneal injection is effective for adjuvant arthritis in rats.