Objective To explore the potential relationship between 6 single nucleotide polymorphisms (SNPs) of mitochondrial DNA (mtDNA) coding region and Parkinson's disease (PD) in northern Chinese population.Methods Samples from 353 patients with PD and 389 control participants,collected in our hospital from April 2010 to November 2015,were genotyped by multiplex polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) techniques.Six SNPs (T4216C within the ND1 gene,A4917G within the ND2 gene,A11084G within the ND4 gene,A12308G within the tRNA gene,A13966G within the ND5 gene,and G15928A within the tRNA gene) in mtDNA were amplified in multiplex PCR systems and subsequently genotyped by digestion with endonucleases.Results An efficient,rapid,and economical way of multiplex genotype SNPs was successfully established.No significant differences were observed in the 6 loci and corresponding haplotypes between PD and control cohorts (P＞0.05).After stratification by gender,however,frequencies of allele 11084G and the haplotype T-A-G-A-A-G in female group with PD were all higher than those in control ones,with significant differences (P＜0.05).Conclusions The 6 SNPs may not be susceptible factors in the northern Chinese population.The A11084G missense mutation might be related to PD in female patients.

Objective To investigate effect of high dose irradiation on the performances of thermolumines-cence detectors (LiF:Mg, Cu, P). Methods The high-dose irradiated thermoluminescence detector was annealed by a thermoluminescence annealing furnace until the annealing was completed, and then the annealed thermoluminescent detector was irradiated 0.5Gy by 137Cs irradiator to verify the accuracy of the thermoluminescentdetector. Results The thermoluminescence detector after high-dose irradiation could not be completely annealed under the temperature condition of 240 ℃, and it could be completely annealed at a high temperature as 400℃. After 0.5 Gy irradiation by 137Cs irradiator, the measurement results of the annealed thermoluminescence detector were significantly smaller, and the dose response and dispersion of the detector were also changed significantly. Conclusions After a more than 5 Gy irradiation, the crystal structure of the thermoluminescence detector has changed, and a high temperature peak above 240 ℃ has appeared, which leads to the failure to completely anneal at normal temperature. Therefore, the thermoluminescence detector can no longer be used for dosimetry after high-dose irradiation.

Objective:To investigate the segmentation methods of pancreatic ductal adenocarcinoma (PDAC) tumor regions in 18F-fluorodeoxyglucose (FDG) PET/CT images, as well as their impact on radiomic features-based pathological grade prediction. Methods:A total of 72 patients (46 males, 26 females, age range: 25-87 years) with pathologically confirmed PDAC and a preoperative 18F-FDG PET/CT scan in Peking Union Medical College Hospital between September 2010 and January 2016 were enrolled retrospectively. The cohort of patients was classified as well differentiated group and non-well differentiated group based on the pathological grade of PDAC, and patients were divided into training set and validation set in the ratio of 3∶1 randomly. Two physicians performed manual contours in the tumor region (referred as region of interest (ROI)_M1 and ROI_M2) and semi-automatic ROIs based on standardized uptake value (SUV) gradient edge search (referred as ROI_G) and 40% threshold applied to the maximum SUV (SUV max; referred as ROI_S) were drawn. The four types of segmentation results were compared in terms of volume and Dice similarity coefficient (DSC). Shape, first-order, and texture features were extracted from PET/CT original and preprocessed images, and the interclass correlation coefficient (ICC) was used to assess each feature′s consistency across all segmentations. Kruskal-Wallis rank sum test, independent-sample t test or z test were used to analyze the data. The area under the receiver operating characteristic curve was used to assess model accuracy, and cross validation was used to assess generalization ability. Results:There were 55 patients in the training set (14 well differentiated cases and 41 non-well differentiated cases) and 17 patients in the validation set (4 well differentiated cases and 13 non-well differentiated cases). A total of 44 selected features were predictive of the pathological grade of PDAC among 20 feature groups. There was significant difference among the volumes of ROI_M1, ROI_M2, ROI_G and ROI_S (10.29(4.01, 19.43), 9.34(4.26, 17.27), 11.86(5.52, 19.74) and 15.08(9.62, 27.44) cm 3; H=18.641, P<0.05). The degree of contour coincidence and feature consistency between ROI_M1 and ROI_M2 were both higher (DSC=0.86 (0.76, 0.90), ICC=0.86 (0.74, 0.94)). Compared to manual contours, the degree of contour coincidence and feature consistency of ROI_G (DSC: 0.86(0.75, 0.91), 0.91(0.85, 0.96); ICC: 0.87(0.72, 0.94), 0.94(0.88, 0.98)) were better. There was no statistically significant difference in model accuracy or generalization ability between ROI_M1 and ROI_G ( z=1.052, t=0.712, both P>0.05). The accuracy of ROI_M2 was better than ROI_G ( z=3.031, P=0.002), but the generalization ability of ROI_M2 was insufficient ( t=3.086, P=0.012). Conclusions:Although the manual contour prediction models are highly accurate, their performance are unstable. Semi-automatic contouring based on gradient can achieve comparable accuracy to manual contouring, and the model′s generalization ability is stronger.

Gaucher′s disease (GD) is a lysosomal storage disease, and the etiology of GD is the decreased activity of glucocerebrosidase, which leads to the accumulation of glucocerebroside in the lysosomes of macrophages. Because GD is rare and lacks specific clinical manifestations, it is easy to be misdiagnosed, which delays the best time for treatment. Early diagnosis, clinical evaluation, and regular monitoring of the disease have important clinical significance for enzyme replacement therapy in patients with GD. Recent studies have found that radionuclide imaging is playing an increasingly important role in the diagnosis and treatment of GD. This article introduces the application of radionuclide imaging in the diagnosis and management of GD.

Objective:To investigate the application of different imaging methods of 99Tc m-pyrophosphate (PYP) in the diagnosis and pathological classification of cardiac amyloidosis (CA). Methods:A total of 31 patients (22 males, 9 females, age 21-81(57.2±13.4) years) with suspected CA who underwent 99Tc m-PYP dual-phase scintigraphy (early-phase: 1 h, delay-phase: 2-3 h) and SPECT/CT (1 h) between December 2018 and December 2019 in Peking Union Medical College Hospital were retrospectively included. Taking clinical diagnosis as the standard, the results of visual score (≥2, positive) and semi-quantitative values (heart to contralateral lung (H/CL)≥1.5, positive) of 99Tc m-PYP uptake in dual-phase scintigraphy and SPECT/CT imaging were analyzed. One-way analysis of variance and Bonferroni test were used to analyze the data. Results:Among 31 patients with suspected CA, 15 were clinically diagnosed as CA (5 patients with transthyretin-related CA (ATTR-CA) and 10 patients with light chain CA (AL-CA)) and 16 were diagnosed as non-CA. All 5 patients with ATTR-CA had positive dual-phase scintigraphy and SPECT/CT imaging results. Three out of 10 patients with AL-CA had positive early-phase scintigraphy whereas negative delay-phase scintigraphy and SPECT/CT imaging results. Sixteen patients who were clinically diagnosed as non-CA had negative dual-phase scintigraphy and SPECT/CT imaging results. The sensitivity (5/5), specificity (10/10), positive predictive value (5/5), negative predictive value (10/10) and accuracy (15/15) of delay-phase scintigraphy and SPECT/CT imaging were the same. Among 31 patients, 16 patients carried transthyretin-related (TTR) gene mutation, and 4 of them who clinically diagnosed as variant ATTR (ATTRv) had positive image findings while 12 of them who not clinically diagnosed as CA had negative image findings. There were significant differences in H/CL between ATTR-CA group and AL-CA group in early-phase (2.11±0.24 vs 1.31±0.07) and delay-phase (2.02±0.19 vs 1.30±0.05; F values: 75.41 and 87.15, Bonferroni test, both P<0.01). Conclusions:99Tc m-PYP delay-phase scintigraphy and SPECT/CT have high diagnostic efficiencies in ATTR-CA, helping to determine the pathological classification of CA; while early-phase scintigraphy has false positive results. Moreover, 99Tc m-PYP imaging is helpful to detect CA in patients with TTR gene mutation.

Transthyretin-related amyloid cardiomyopathy (ATTR-CM) is a disease caused by the depo-sition of insoluble amyloid fibers formed by the misfolding of transthyretin precursor protein in the intercellular space of cardiomyocytes. This lesion may lead to myocardial dysfunction, cogestive heart failure, and death.When diagnosed earlier, the patient can be treated with drugs as soon as possible to intervene in the progress of the disease, so as to effectively improve the patient's prognosis.^99mtechnetium-pyrophosphate (⁹⁹Tc^m-PYP)single-photon emission computed tomography (SPECT) has been widely used in the imaging examination of cardiac amyloidosis (CA) in recent years. While achieving early non-invasive diagnosis, accurate pathological classification can be obtained through Perugini visual score analysis, semi-quantitative analysis of heart to contralateral lung (H/CL) ratio, and SPECT image analysis. This article presents the application, methods, and the precautions of ⁹⁹Tc^m-PYPSPECT in the diagnosis of ATTR-CM, aiming to provide clinical reference for the application of this technology.