Objective To investigate the techniques of lower limbs MRI. Methods 50 patients underwent lower limbs MRI examinations on 1.5T scanner using 4-channel torso coil, in which 28 were femur and 22 were tibia and fibula. Pulse sequences included FSE T2WI and SE T1WI. All FSET2WI were added with fat saturation. FOV is 42cm?42cm. Imaging planes included axial, coronal and saggital views. Slice thickness ranged from 8mm to10mm on axial and 4mm to 5mm on sagital or coronal view. Results Axial view could delineated the anatomical relationship of the lesions. Coronal or sagital view could show the global view and relation to the adjacent structure. Conclusion The proper scan skill, optimized parameters and proper pulse sequences are essential for better delineation of the anatomy of the lower extremities and helpful for the location and the diagnosis.

Objective To analyze the reasons of discarding as useless of ?-Se direct conversion digital flat panel detector (?-Se FPD). Methods (1) E-COM DR-2000CTM chest system, with high frequency X-ray machine made by CPI company of Canada, the X-ray tube made by VARIAN company of America and Direct Ray-1000 ?-Se FPD made by DRC company of America. (2) 50 cases were collected rondomizedly, each had 4 pieces of chest image and were analyzed by two experienced radiologists and two technicians. Results After about 14 months with 30,000 times exposure efficacious, some damage lines and points appeared in the detector. After about 34 months with 70,000 times exposure efficacious, a damage region (area is 6.7in*0.95in ) existed, this reduced the images' quality and at the end the detector was discarded as useless. Conclusion The ?-Se FPD needs maintenance and monitoring working circumstance.

Objective To research the structure,imaging mechanism and quality of dry view laser imaging film. Methods We extracted 60 pieces of dry view laser imaging film,wet view laser imaging film and ordinary film respectively. Each tape of films was divided into 3 groups in 100 pieces each. They were observed in the same temperature and humidity. Results Group A was observed after 300 minutes,the dry view laser films image of 10 pieces without package,4 pieces packed with plastic and 1 piece packed with paper changed. After 120 minutes,group B was observed; the dry view laser imaging film in different packing had the different changes. To the contrast,the wet laser imaging film's images didn't change in the same humidity and temperature after 420 minutes test. Conclusion The imaging of dry laser imaging film with different temperature,humidity and package will easily affect the image quality.

Objective To research the application value of direct digital radiograph (DDR) in nasal bone imaging. Methods One hundred cases were examined by DDR, 30 cases of them were examined by two methods both DDR and conventional radiography. All digital images were post-processed with “MUSICA”(Multi-Scale Image Contrast Amplification), incision and largamente, analyzed and diagnosed by experienced two radiologists and two technicians. Results One hundred cases of nasal bone, soft tissue of nose were showed excellent in DDR, and satisfactory cases were 95 and 92, respectively. Forty-six cases of nasal bone fractures were found. Thirty cases were examined by both DDR and conventional radiography, images of nasal bone, soft tissue of nose were showed, satisfactory cases were 28 in DDR; and satisfactory cases were 6(?2=20.05,P

Objective To explore the clinical value of thermal tomography (TT) in the diagnosis of breast diseases.Methods Totally 222 breast diseases patients underwent examinations by color Doppler ultrasound and TT.Some stable TT images were selected,and the TT curves of the lesions were analyzed according to the malignant tumor TT curve diagnosing standard,so that the benign and malignant tumors could be determined.Color Doppler ultrasound was used to describe the site,size and property of the lesion.Results Pathological examination found 95 cases of malignant tumors and 127 benign ones.TT had 198 results coincident with those by pathological examination while the remained 24 ones not,with 15 false positive results and 9 false negative ones.When compared with pathological examination,TT had the accuracy,sensitivity and specificity being 89.19％,90.43％ and 88.28％ respectively.Conclusion TT is non-invasive,accurate and sensitive when used to screen and diagnose breast diseases,and should be applied if possible in medical facilities.

Objective To: investigate the clinical value of MRI-guided argon-helium cyoablation in the treatment of tumors. Methods: MRI-guided argon helium cyoablation was performed in 90 tumor patients, including 52 cases of liver tumor, 10 of kidney tumor, 6 of chest wall tumor, 12 of pelvic tumor, 9 of limb tumors and 1 case of sciatic tumor. SE T1W, FSE T2W and SPGR T1W sequences were used to monitor the process of puncture and cyoablation. MRI findings and the complications during cyoablation were observed. Enhanced MRI was performed after cyoablation to evaluate the therapeutic efficacy. Results: All lesions could be clearly displayed with MRI during cyoablation, and the whole probes could be clearly showed on SPGR T1WI. A total of 24 patients with large lesions (maximum diameter 10.80-15.06 cm) underwent tumor cytoreduction therapy, the average times of cytoreduction therapy was 2.96±0.76. Among them, the part of lesion covered by ice-ball during cyoablaion showed no enhancement in 17 patients, while in the rest 7 patients, enhancement could be observed at the edge of lesions which became larger on enhanced MRI 1 month after the last treatment. In 66 patients underwent single time cyoablation, the lesions were all covered by the ice-ball during cyoablation treatment, and enhanced MRI showed complete ablation of lesions in 47 cases and partial ablation in 19 cases 1 month after cyoablation. Local bleeding around puncture point was observed in 11 patients, no serious complication occurred. Conclusion: MRI-guided argon-helium cyoablation can be used as an effective method in the treatment of tumor on different sites.

Objective To study the local efficacy of ultrasound-guided interstitial implantation of radioactive 125I seeds in the treatment of hepatic tumors at dangerous sites.Methods A retrospective study was conducted on 39 patients who were admitted into the First Medical Center,PLA General Hospital from November 2011 to January 2018.There were 23 males and 16 females.A three-dimensional planning before 125I seed implantation was performed for all these patients using the treatment planning system (TPS).The implantation was performed under ultrasound guidance.Liver CT scan was performed in all the patients after implantation to evaluate the actual distribution of the seeds in the tumors.Follow-up was performed at 2,4,6,9 and 12 months after implantation,respectively,to evaluate using complete response (CR),partial response (PR),steady disease (SD),progressive disease (PD) and local control rates (LCR).Results Implantation was successfully performed in all the 39 patients.CT scan showed that 5 patients (12.8％)required additional implantation.Follow-up imaging after implantation showed local control of the lesions was good.The rates of CR,PR,SD and LCR were 2.6％ (1/39),28.2％ (11/39),66.7％ (26/39) and 97.4％ (38/39),respectively.One patient (2.6％,1/39) showed local progressive disease.The LCR reached 97.4％ (38/39) at 12 months of follow-up.Conclusion Ultrasound-guided radioactive 125I seed implantation was efficacious in the treatment of hepatic tumors at dangerous sites.