Objective To explore the correlation value of high-resolution MRI on the cause,location and degree of nerve root com-pression and clinical symptoms of lumbar intervertebral foramen stenosis.Methods Patients with sciatic neuralgia underwent con-ventional MRI examination of the lumbar spine before treatment.MRI thin layer(1 mm)intervertebral disc axial scan was performed on patients with suspected L4/L5 and L5/S1 intervertebral foramen stenosis,and the value of conventional MRI and high-resolution MRI on intervertebral foramen stenosis location,etiology and Elisabeth typing was compared and analyzed.Intervertebral foramen mor-phometric indicators,nerve root length and short diameter were measured on high-resolution MRI post-processed images and their correlation with visual analogue scale(VAS)scores of clinical symptoms was analyzed.Results Sixty-one patients were effectively diagnosed with intervertebral foramen stenosis and nerve root compression after surgery or conservative treatment.The diagnosis rate of conventional MRI for the cause of intervertebral foramen stenosis was 75.4％,and the diagnosis rate of high-resolution MRI post-processed was 91.8％.The Elisabeth typing of lumbar intervertebral foramen stenosis was positively correlated with clinical symp-toms,while the nerve root short diameter and peri-nerve fat space area were negatively correlated with VAS score.Conclusion High-resolution MRI is significantly better than conventional MRI for the diagnosis of nerve root compression in intervertebral fora-men stenosis.It visually shows the location,cause and degree of nerve root compression,which can better guide the clinical and accu-rate minimally invasive surgery.

Objective To analyze the occupational hazards and protective measures for personnel in an iodine-125(¹²⁵I) seed source production company. Methods In 2022, a ¹²⁵I seed source production enterprise in Guangdong Province was selected as the research subject. The occupational hazards in the workplace of the research subject was identified using the system engineering analysis method. The FLUAK program based on Monte Carlo method was used to simulate the blocking protection of the production of the ¹²⁵I seed source, and to estimate the dose of internal and external irradiation of seed source that affected workers. Results The main occupational radiation hazards in the seed production were non-sealed radioactive materials, including external irradiation from X-ray and γ ray and internal irradiation from aerosols formed by iodine volatilization. Estimated maximum dose equivalent rate around the chest and eye lens for workers were 0.52 and 0.02 μSv/h, respectively. The expected annual effective dose for workers in each work site was 0.035 mSv, and the expected annual equivalent dose to the eye lens for all workers in various work sites was 0.001 mSv. The maximum annual equivalent dose of operator's hand was 80.620 mSv. The maximum dose of internal irradiation to the worker was 18.750 mSv, which was caused by the volatilization of nuclides. Conclusion With effective protection measures for internal and external irradiation in place, the annual exposure doses for seed production personnel and operator’s hand are below the national limits. Adequate measures should be taken on hand protection.

Objective To analyze the dose distribution of induced radiation in fixed proton beam therapy room and the influence of shielding materials, and to provide a basis for radiation protection and shielding material selection in proton therapy. Methods FLUKA was used to simulate the dose distribution of induced radiation in fixed proton beam therapy room, the dose over time, and the influence of different concrete materials. Results The dose of induced radiation was mainly concentrated around the target, and the dose rapidly decreased to 1/5-1/10 of the value at the time of stopping irradiation after cooling for 3-5 min. The induced radiation in concrete formed a slightly higher dose area at the end of the main beam near the inner side of the shield. The content of Fe, O, and H in concrete had significant effects on induced radiation (P < 0.01), and the dose was negatively correlated with the content of Fe. Conclusion The patients after proton therapy as well as the induced radiation in air and shielding materials are the main sources of external radiation dose for workers, and waiting for a period of time is the most effective way to protect the staff. Without considering the difficulty in construction and based on the analysis of shielding materials in protection against external irradiation and their influence on induced radiation, heavy concrete with a relatively high level of Fe is the best choice of the shielding material for proton therapy room.

Objective:To compare clinical features of patients with pyogenic liver abscesses with and without septated lobulations.Methods:Patients diagnosed to have pyogenic liver abscesses who were treated in our hospital from January 2011 to March 2021 were enrolled into this retrospective study. There were 203 males and 132 females, with age of (56±14) years old. The patients were divided into two groups by findings on computed tomography and ultrasound into the septated lobulation group ( n=68) and the non-septated lobulation group ( n=267). The clinical data of these patients were compared. Results:In the septated lobulation group, the neutrophil count was 9.17(5.97, 12.33)×10 9/L and the TBil was 17.65(11.92, 27.84) μmol/L. These were significantly higher than the corresponding figures of 7.81(5.42, 10.81)×10 9/L, 12.90(9.00, 19.68) μmol/L, respectively in the non-septated lobulation group ( P<0.05). The difference in the maximum diameters of the septated lobulation group was also significantly larger than the non-septated lobulation group ( P=0.032). Additionally, pus culture showed the proportion of Klebsiella pneumoniae positive patients in the septated lobulation group was significantly higher than that in the non-septated lobulation group [41.18% (28/68) vs. 25.84% (69/267), P=0.013]. The use of fluoroquinolones in patients in the septated lobulation group was higher than that in the non-septated lobulation group [20.59% (14/68) vs. 10.11% (27/267), χ 2=5.54, P=0.019]. Conclusion:Compared to patients without septated lobulations, those with septated lobulations had a larger diameter of abscesses, a higher positive rate of Klebsiella pneumoniae on pus culture and a higher proportion of patients receiving fluoroquinolones.

Objective To investigate the radiation dose at the entrance of the accelerator treatment room, and to guide the radiation protection detection at the entrance of the treatment room. Methods The FLUKA program was used to build the model of accelerator head and treatment room. Under the simulation conditions of 10 MV and 600 cGy/min for the accelerator, the radiation dose rate inside the entrance of the treatment room was measured at different gantry angles, irradiation conditions, and labyrinths. Results The entrance dose rate with a water tank was significantly higher than that without a water tank under different inner labyrinth wall thicknesses and gantry angles. The entrance dose rate reached the maximum at the inner labyrinth wall thickness of 1800 mm and the gantry angle of 90°. When the inner labyrinth wall thickness was 1000 mm and the gantry angles were 0° and 180°, the entrance dose rate was significantly higher than that at other conditions. The dose rate at the entrance of the treatment room reached (82.26 ± 48.95) μSv/h to (314.09 ± 96.34) μSv/h under the following conditions: the inner labyrinth wall thickness of 1800 mm, the gantry angle of 90°, with a water tank, and the width of the inner labyrinth entrance of 1400-2200 mm. Conclusion The dose at the entrance of the accelerator treatment room mainly comes from the scattering and leakage radiation of the useful wire harness on the patient’s body surface, and the entrance dose rate increases with the increase in the width of the inner labyrinth entrance. In the entrance protection test, the gantry angle should be determined considering the inner labyrinth wall thickness, and the test should be performed at four angles in the uncertain case to ensure the comprehensiveness and accuracy of test results.

Objective To study the dose level of proton beams outside the main shield of the 230 MeV proton therapy room with six different types of concrete as the main wall, and to obtain the shielding performance of six different types of concrete. Methods The FLUKA program was used to build a calculation model, and different concrete compositions were introduced into the FLUKA program to simulate the change in ambient dose equivalent rate of the focus with concrete thickness under 230 MeV proton beam irradiation. The transmission curves of six different types of concrete were fitted to obtain shielding performance parameters. Results On the condition that the 230 MeV proton beam irradiated to the water target in 90° direction and the concrete thickness exceeded 40 cm, the proton beam was exponentially decayed for six different types of concrete, and the fitted decay curves had a R² of > 0.99. The linear attenuation coefficients for normal concrete, barite concrete, magnetite concrete, limonite concrete, phosphorite concrete, and ferrosilicate concrete were 0.0148 cm⁻¹, 0.0172 cm⁻¹, 0.0196 cm⁻¹, 0.0219 cm⁻¹, 0.0256 cm⁻¹, and 0.0290 cm⁻¹, respectively. Conclusion The composition and proportion of elements in concrete materials directly affect the shielding ability of concrete against proton beams to a large extent, and the shielding performance of six different types of concrete against proton beams varies greatly. Therefore, shielding materials for the proton therapy room should be selected by a comprehensive consideration of the material compositions and shielding performance of concrete, the difficulty of construction, and construction cost.

Establishing a targeted and suitable professional healthcare training model for pediatricians at primary level and exploring an effective, sustainable and innovative strategy for talent training are required in caring for children at large. The current study explored the methods and efficacy of " apprenticeship" mode originated from traditional Chinese medicine practice in primary pediatricians training. It is suggested that based on the framework of pediatric alliance, the " apprenticeship" mode could establish a fixed and precise one-to-one teaching mode in a short period, form a close, standard and persistent training system for talented pediatricians, thus effectively improving primary pediatric health care service.

Objective:To investigate the basic information and implementation of medical assistance for children of illness-caused poverty families.Methods:From March through September 2019, a customized questionnaire was used to collect by means of both field survey and on-site verification, the information of the sick children from such families registered on file from 17 counties in 6 provinces. These counties were the first to carry out the assistance pilot work under " Chinese Children Poverty Alleviation by Healthcare Program" . The data so acquired were subject to descriptive analysis.Results:A total of 312 questionnaires were recovered, and the median age of these child patients was 8.54 years. Diseases causing family poverty were mostly those in the circulatory system, nervous system, neoplastic disease of childhood and hematological disease, while unaffordability of medical bills ranked the top challenge when they seek medical services. Hierarchical diagnosis and treatment was made for 251 children: 193(76.89%)of them could be admitted to provincial or lower medical institutions, 43 children needed chronic disease management, and 15 children needed to be admitted by the National Children′s Medical Center for further diagnosis.Conclusions:The assistance for such families in poverty-stricken areas can be upgraded, by such means as disease prevention publicity and education, publicity of healthcare poverty alleviation policy awareness, improvement of medical competency of primary medical institutions and rational application of medical resources.

Objective To investigate the safety and efficacy of re-irradiation with stereotactic body radiotherapy(SBRT) for treating locally recurrent advanced pancreatic cancer.Methods From 2014 to 2017,7 patients with stage Ⅲ pancreatic cancer were treated by re-irradiated with SBRT at Shanghai Changhai Hospital.SBRT was delivered via the G4 type cyberknife robotic stereotactic radiosurgery system in all the patients.The median dose of the first SBRT was 35Gy/5-7 fx,and the median dose of re-irradiation with SBRT was 31 Gy/5-8 fx.6 patients had undergone sequential chemotherapy either with gemcitabine or S-1 based therapy except one patient who refused the chemotherapy.Results There were 5 male and 2 female patients.The median overall survival (OS) of 7 patients was 30 months.Patients were re-irradiated with SBRT after a median interval of 10 months after the first SBRT.Median OS and locally relapse-free survival (LFRS) from re-irradiation were 13 months and 11 months,respectively.Three months after re-irradiation,3(42.9％) patients had partial remission and 4 patients had stable disease.Pain disappeared in 4 patients at the end of reirradiation and significant pain was alleviated in 2 patients 1 month after re-irradiation.There were no toxicities of grade 3 or higher grade during two courses of SBRT.Conclusions For patient with locally recurrent advanced pancreatic cancer,SBRT re irradiation regimen was associated with acceptable toxicity,which can effectively alleviate the pain,prolong the survival and improve the life quality.

Background Cornea astigmatism can be effectively corrected by implanting Toric intraocular lens (IOL) during cataract surgery and therefore improve visual acuity of patients.However,the decentration and rotation position errors were inevitable sometime.What's the difference of effect of position errors on quality of image between spherical IOL and Toric IOL needs further research.Objective This study was to evaluate the optical performance and wavefront with rotation and decentration of Toric IOL.Methods Different decentration for SN60AT IOL(spherical IOL) and Toric IOL in Hwey-Lan Lion model eyes was set with the role as follows:decentration 0.25 mm to 0.75 mm in a 5°-interval from 0° to 90°.Furthermore,Toric IOL was rotated at 5° and 10°,respectively.Then the image performances of SN60AT IOL and Toric IOL at different decentration distances and rotated degrees were evaluated with modulation transfer function (MTF) and value of wavefront aberration under all conditions.Results At the centration,the MTF curves of spherical IOL and Toric IOL were similar under 3,4 and 5 mm pupil diameter at each spatial frequency.Under the condition of 4 mm pupil diameter,when the decentration was 0.25 mm,the MTF values of SN60AT IOL at 6 c/d and 12 c/d were 0.581 087 and 0.411 960,respectively.T3 IOL were 0.454 259 and 0.382 313,T4 IOL were 0.426 020 and 0.360 490,T5 IOL were 0.425 606 and 0.359 877.When the decentration was 0.50 mm,the MTF values of SN60AT at 6 c/d and 12 c/d were 0.573 073 and 0.412 787,respectively.T3 IOL were 0.450943 and 0.379481,T4 IOL were 0.423 153 and 0.356 664,T5 IOL were 0.422 881 and 0.356 230.When the decentration was 0.75 mm,the MTF values of SN60AT at 6 c/d and 12 c/d were 0.560 038 and 0.413 624,respectively.T3 IOL were 0.445 597 and 0.374 322,T4 IOL were 0.418 522 and 0.350 087,T5 IOL were 0.418 468 and 0.349 976.When the IOL decentralized along 0°,5°,10°,90°meridian line,the MTF values were almostly same.The root mean square (RMS) of spherical IOL and Toric IOL was increased when the IOL decentralized from 0 mm to 0.75 mm,with the most increasing level in coma aberration and slight increase in trefoil aberration.When the T4 IOL decentralized from centre to 0.75 mm,the coma increased from 0 to C(3,-1)-0.049 79 μm,C (3,1)-0.037 59 μm and the trefoil aberration increased from 0 to C (3,3) 0.005 72 μm,C (3,-3) 0.004 64 μm.With the increase of rotation degrees (from 5°to 10°) of Toric IOL,the MTF was worse at high spatial frequency.Toric IOL rotation caused the increase of astigmatism and residual astigmatism and spherical error,but not high order aberration.Conclusions The tolerance of Toric IOL to decentration is very close to the spherical IOL,and optical performance is only associated with the amount of decentration but not direction.The aberration caused by Toric IOL decentration is mainly coma.The rotation of Toric IOL causes astigmatism error but not high order aberrations.