An EM-Tracked Approach for Calibrating the 3D Pose of Flexible Endoscopes

Flexible endoscopes are ideal instruments for visualizing and diagnosing the inner surfaces of organs via a minimally invasive incision. Calibrating a flexible endoscope is a troublesome yet inevitable process in image-based tools tracking. Aiming to simplify the calibration process, we propose an electromagnetic (EM)-tracked calibration approach that does not require any predefined poses of the EM sensor. A three-stage calibration protocol was presented in an extensor. First, the orientation of the endoscope tube was derived by conducting a circular rotation of the endoscope around its axis utilizing a pair of tightly bearing stands. Second, the 3D position of the endoscope tip was acquired by having the tip come into contact with a flat plane. Third, the pose model of the bending section was derived and transformed into the local coordinate system of the EM sensor attached to the endoscope handle. To assess the accuracy of the proposed calibration approach, two experiments were designed and performed. Experimental results indicate accuracies of 0.09 ± 0.06 deg and 0.03 ± 0.19 deg in the estimation of the endoscope tube orientation and 0.52 ± 0.29, 0.33 ± 0.11, and 0.29 ± 0.17 mm in the x, y, and z estimations of the endoscope tip position, respectively. The proposed approach is accurate and easy to operate, does not require the employment of custom calibration markers, and can be used not only in surgical training systems but also in the endoscopic-based tools tracking.

Deteriorated bone microarchitecture caused by sympathetic overstimulation in pheochromocytoma and paraganglioma

PURPOSE

Despite the potentially destructive effect of sympathetic activity on bone metabolism, its impact on bone microarchitecture, a key determinant of bone quality, has not been thoroughly investigated. This study aims to evaluate the impact of sympathetic activity on bone microarchitecture and bone strength in patients with pheochromocytoma and paraganglioma (PPGL).

METHODS

A cross-sectional study was conducted in 38 PPGL patients (15 males and 23 females). Bone turnover markers serum procollagen type 1 N-terminal propeptide (P1NP) and β-carboxy-terminal crosslinked telopeptide of type 1 collagen (β-CTX) were measured. 24-h urinary adrenaline (24hUE) and 24-h urinary norepinephrine levels (24hUNE) were measured to indicate sympathetic activity. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in PPGL patients and 76 age-, sex-matched healthy controls (30 males and 46 females). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously.

RESULTS

PPGL patients had a higher level of β-CTX. HR-pQCT assessment revealed that PPGL patients had notably thinner and more sparse trabecular bone (decreased trabecular number and thickness with increased trabecular separation), significantly decreased volume BMD (vBMD), and bone strength at both the radius and tibia compared with healthy controls. The deterioration of Tt.vBMD, Tb.Sp, and Tb.1/N.SD was more pronounced in postmenopausal patients compared with the premenopausal subjects. Moreover, subjects in the highest 24hUNE quartile (Q4) showed markedly lower Tb.N and higher Tb.Sp and Tb.1/N.SD at the tibia than those in the lowest quartile (Q1). Age-related bone loss was also exacerbated in PPGL patients to a certain extent.

CONCLUSIONS

PPGL patients had significantly deteriorated bone microarchitecture and strength, especially in the trabecular bone, with an increased bone resorption rate. Our findings provide clinical evidence that sympathetic overstimulation may serve as a secondary cause of osteoporosis, especially in subjects with increased sympathetic activity.

ArthroNavi framework: stereo endoscope-guided instrument localization for arthroscopic minimally invasive surgeries

Significance

As an example of a minimally invasive arthroscopic surgical procedure, arthroscopic osteochondral autograft transplantation (OAT) is a common option for repairing focal cartilage defects in the knee joints. Arthroscopic OAT offers considerable benefits to patients, such as less post-operative pain and shorter hospital stays. However, performing OAT arthroscopically is an extremely demanding task because the osteochondral graft harvester must remain perpendicular to the cartilage surface to avoid differences in angulation.

Aim

We present a practical ArthroNavi framework for instrument pose localization by combining a self-developed stereo endoscopy with electromagnetic computation, which equips surgeons with surgical navigation assistance that eases the operational constraints of arthroscopic OAT surgery.

Approach

A prototype of a stereo endoscope specifically fit for a texture-less scene is introduced extensively. Then, the proposed framework employs the semi-global matching algorithm integrating the matching cubes method for real-time processing of the 3D point cloud. To address issues regarding initialization and occlusion, a displaying method based on patient tracking coordinates is proposed for intra-operative robust navigation. A geometrical constraint method that utilizes the 3D point cloud is used to compute a pose for the instrument. Finally, a hemisphere tabulation method is presented for pose accuracy evaluation.

Results

Experimental results show that our endoscope achieves 3D shape measurement with an accuracy of < 730    μ m . The mean error of pose localization is 15.4 deg (range of 10.3 deg to 21.3 deg; standard deviation of 3.08 deg) in our ArthroNavi method, which is within the same order of magnitude as that achieved by experienced surgeons using a freehand technique.

Conclusions

The effectiveness of the proposed ArthroNavi has been validated on a phantom femur. The potential contribution of this framework may provide a new computer-aided option for arthroscopic OAT surgery.

[Establishment of a digital remote platform for respiratory support and intelligent early warning in intensive care units]

During the disease progression or treatment of critically ill patients with lung injury, the changes in respiratory mechanics are continuous and dynamic. Establishing a digital platform for respiratory support in the ICU, which enables the continuous recording, dynamic analysis, and real-time alerting of numerical and waveform data from mechanical ventilation, can help intensivists improve their understanding of "dynamic respiratory mechanics", improve respiratory therapy and patient outcomes, as well as reduce workload and increase work efficiency. The construction of a dedicated database for mechanical ventilation, based on ventilator waveforms provides essential data support for projects such as respiratory mechanics data algorithm models. This will facilitate the establishment of an auxiliary decision-making system, enable the realization of intelligent mechanical ventilation, and create a new era of dynamic respiratory mechanics.

[A case report of autosomal recessive bestrophinopathy]

The patient is a 40-year-old male who presented to the ophthalmology clinic due to easy visual fatigue for the past 3 months. Two months ago, the patient was misdiagnosed with "bilateral posterior uveitis", but the diagnosis was ruled out after ineffective treatment with corticosteroids. During the current visit, fundus examination revealed yellow-white material exudation below the macular center in both eyes. Considering the results of the ophthalmic examination and the genetic testing of the patient and his son, the patient was diagnosed with autosomal recessive bestrophinopathy.

[The 501st case: elevated blood glucose, chronic pancreatitis, and post- pancreatoduodenectomy malnutrition]

A 50-year-old man with a 15-year history of elevated blood glucose and an approximately 2-year history of diarrhea was admitted to the Peking Union Medical College Hospital. The initial diagnosis was type 2 diabetes. After repeated pancreatitis and pancreatoduodenectomy, severe pancreatic endocrine and exocrine dysfunction including alternating high and low blood glucose and fat diarrhea occurred. Tests for type 1 diabetes-related antibodies were all negative, C-peptide levels were substantially reduced, fat-soluble vitamin levels were reduced, and there was no obvious insulin resistance. Therefore, a diagnosis of pancreatic diabetes was clear. The patient was given small doses of insulin and supplementary pancreatin and micronutrients. Diarrhea was relieved and blood glucose was controlled. The purpose of this article is to raise clinicians' awareness of the possibility of pancreatic diabetes after pancreatitis or pancreatic surgery. Timely intervention and monitoring may reduce the occurrence of complications.

High prevalence of vertebral deformity in tumor-induced osteomalacia associated with impaired bone microstructure

PURPOSE

Patients with tumor-induced osteomalacia (TIO) often suffer from irreversible height loss due to vertebral deformity. However, the prevalence of vertebral deformity in TIO patients varies among limited studies. In addition, the distribution and type of vertebral deformity, as well as its risk factors, remain unknown. This study aimed to identify the prevalence, distribution, type and risk factors for vertebral deformity in a large cohort of TIO patients.

METHODS

A total of 164 TIO patients were enrolled in this retrospective study. Deformity in vertebrae T4-L4 by lateral thoracolumbar spine radiographs was evaluated according to the semiquantitative method of Genant. Bone microstructure was evaluated by trabecular bone score (TBS) and high-resolution peripheral QCT (HR-pQCT).

RESULTS

Ninety-nine (99/164, 60.4%) patients had 517 deformed vertebrae with a bimodal pattern of distribution (T7-9 and T11-L1), and biconcave deformity was the most common type (267/517, 51.6%). Compared with patients without vertebral deformity, those with vertebral deformity had a higher male/female ratio, longer disease duration, more height loss, lower serum phosphate, higher bone turnover markers, lower TBS, lower areal bone mineral density (aBMD), lower peripheral volumetric BMD (vBMD) and worse microstructure. Lower trabecular vBMD and worse trabecular microstructure in the peripheral bone and lower spine TBS were associated with an increased risk of vertebral deformity independently of aBMD. After adjusting for the number of deformed vertebrae, we found little difference in clinical indexes among the patients with different types of vertebral deformity. However, we found significant correlations of clinical indexes with the number of deformed vertebrae and the spinal deformity index.

CONCLUSION

We reported a high prevalence of vertebral deformity in the largest cohort of TIO patients and described the vertebral deformity in detail for the first time. Risk factors for vertebral deformity included male sex, long disease duration, height loss, abnormal biochemical indexes and bone impairment. Clinical manifestation, biochemical indexes and bone impairment were correlated with the number of deformed vertebrae and degree of deformity, but not the type of deformity.

Hemisphere Tabulation Method: An Ingenious Approach for Pose Evaluation of Instruments Using the Electromagnetic-Based Stereo Imaging Method

Drilling of a bone surface often occurs in clinical orthopaedic surgery. The position and orientation of the instrument are the most important factors in this process. Theoretically, some mechanical components may assist in orienting an instrument to certain bone shapes, such as the knee joint and caput femoris. However, the mechanical assisting component does not seem to work in some confined spaces where the bone shape is a free-form surface. In this paper, we propose an ingenious hemisphere tabulation method (HTM) for assessing the pose accuracy of an instrument. The acquisition and assessment of HTM is conducted based on an electromagnetic-based stereo imaging method using a custom-made optical measurement unit, and the operation steps of HTM are described in detail. Experimental results based on 50 tests show that the HTM can identify ideal poses and the evaluated pose of an instrument location on a hemisphere model. The mean error of pose localisation is 7.24 deg, with a range of 1.35 to 15.84 and a standard of 3.66 deg, which is more accurate than our previous method.

The efficacy and safety of different doses of calcitriol combined with neutral phosphate in X-linked hypophosphatemia: a prospective study

The present study was the first prospective cohort evaluated the efficacy and safety of different doses of calcitriol in XLH children. The results suggested that a dose of 40 ng/kg/day calcitriol, compared with 20 ng/kg/day, was more effective in relieving the rickets, with similar safety outcomes. Further investigations were expected to set more dose groups.

INTRODUCTION

Dose recommended for calcitriol in X-linked hypophosphatemia (XLH) varies in different studies. Therefore, we aimed to compare the efficacy as well as the safety of 20 ng/kg/d and 40 ng/kg/d calcitriol in Chinese XLH pediatrics population.

METHODS

A 2-year, randomized, open-label, prospective study recruited 68 XLH children, which were randomized to receive either 40 ng/kg/day or 20 ng/kg/day calcitriol. Efficacy endpoints were the total Thacher ricket severity score (RSS) change from baseline to month 12 and 24, the difference in serum TALP level, fasting serum phosphate level, body height Z-score, and frequency of dental abscess. Safety assessments were done using renal ultrasound nephrocalcinosis grades (0-4), fasting serum and 24 h urine calcium level, and the occurrence of hyperparathyroidism.

RESULTS

The decrease in the total RSS from baseline was more significant in the high-dose group at 12 (difference 0.87, p = 0.049) and 24 month (difference 1.23, p = 0.011). The serum TALP level was significantly lower in the high-dose group at 6 months. Pi level, height Z-score change, frequency of dental abscess and ratio of de novo nephrocalcinosis were comparable. A lower incidence of secondary hyperparathyroidism was seen in the high-dose group (p < 0.0001).

CONCLUSION

For the first time in this prospective cohort, 40 ng/kg/d calcitriol was shown to be the more effective therapy in XLH children than the 20 ng/kg/d. Moreover, 40 ng/kg/d calcitriol was not associated with increasing adverse events.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT 03,820,518.

Treatment-related adverse events as predictive biomarkers of efficacy in patients with advanced neuroendocrine tumors treated with surufatinib: results from two phase III studies

Background

No validated biomarkers currently exist for predicting the efficacy outcomes in patients with neuroendocrine tumors (NETs) treated with antiangiogenic therapy. We aimed to evaluate the association between treatment-related adverse events (TRAEs) and efficacy outcomes of surufatinib in patients with advanced NET.

Patients and methods

We included patients with NET treated with surufatinib in two multicenter, randomized, double-blind, placebo-controlled, phase III trials (SANET-p and SANET-ep) in this study. The main exposure was the presence of any of the TRAEs including hypertension, proteinuria, and hemorrhage in the first 4 weeks of surufatinib treatment. The primary outcome of the study was investigator-assessed progression-free survival (PFS). PFS outcomes were estimated using the Kaplan–Meier method with the log-rank test. Hazard ratios (HRs) were calculated by using univariable and multivariable Cox proportional hazard regression models. Blinded independent image review committee (BIIRC) assessments and 4-week landmark analysis were also performed as supportive evaluations.

Results

During the study period, a total of 242 patients treated with surufatinib were included in the analysis, and 164 (68%) patients had at least one of hypertension, proteinuria, and hemorrhage in the first 4 weeks of treatment. The presence of TRAEs in the first 4 weeks was associated with prolonged median PFS [11.1 versus 9.2 months; HR 0.67, 95% confidence interval (CI) 0.47-0.97; P = 0.036]. In multivariable Cox regression analysis, the presence of TRAEs was also significantly associated with longer PFS (HR 0.65, 95% CI 0.44-0.97; P = 0.035). Similar results were obtained in the BIIRC assessments and 4-week landmark analysis.

Conclusions

Treatment-related hypertension, proteinuria, and hemorrhage could be potential biomarkers to predict antitumor efficacy of surufatinib in patients with advanced NET. Future prospective studies are needed to validate the findings.

Trial registration

ClinicalTrials.govNCT02589821; https://clinicaltrials.gov/ct2/show/NCT02589821 and ClinicalTrials.gov NCT02588170; https://clinicaltrials.gov/ct2/show/NCT02588170

•

Treatment-related hypertension, proteinuria, or hemorrhage is associated with longer survival in NETs.

•

The association is confirmed by the BIIRC assessments and 4-week landmark analysis.

•

TRAEs can be biomarkers to predict antitumor efficacy in patients with NET.

[Treatment of 11 cases of juvenile idiopathic arthritis by intra-articular injection of adalimumab]

Objective: To evaluate the efficacy and safety of intra-articular injection of adalimumab (ADA) in the treatment of refractory oligoarticular juvenile idiopathic arthritis (JIA). Methods: This was a retrospective study. Clinical data on age, gender, and symptoms of joint swelling and pain were collected from 11 children with refractory oligoarticular JIA involving only knee joints admitted to Department of Rheumatism and Immunology of Children's Hospital, Capital Institute of Pediatrics from November 2019 to October 2020. The physician and parent-child evaluation of disease activity, the number of active joints, and the level of erythrocyte sedimentation rate (ESR) at different treatment time points were analyzed at every 4-week observation point after drug administration, and the non-parametric Kruskal-Wallis test was used to compare the differences in clinical evaluation indicators and changes in laboratory tests at different treatment times. The follow-up period was 6 months. Results: Among the 11 children, 5 were boys and 6 were girls. The age was 3.0 (2.8) years. All 11 children had symptoms of joint swelling and pain as well as limitation of movement. After 3 intra-articular injections of ADA, the joint symptoms of 11 children were better than before treatment; the joint symptoms of 7 children disappeared completely, and no recurrence occurred during the 6-month follow-up period. At different treatment times, physician and parent-child evaluation of disease activity, a gradual decrease in the number of active joints in the children, ESR, and juvenile arthritis disease activity score with 27 joints were all statistically significant (χ²=53.99, 59.37, 32.87, 40.07, 54.00, all P<0.001).No significant adverse drug reactions were observed in any of the 11 children during treatment and follow-up. Conclusion: Intra-articular injection of ADA in the treatment of refractory oligoarticular JIA has a significant effect in controlling joint symptoms and is relatively safe.

Differential effects of aquatic anaesthetics on the pharmacokinetics of antibiotics: Examples using florfenicol in Nile tilapia (Oreochromis niloticus)

Anaesthetics are commonly applied in pharmacokinetic (PK) studies to assure smooth handling of experimental procedures or to promote animal welfare. However, the influence of anaesthetics on the PK of co-administered drug is generally unknown but assumes ignorable. The goal of the study was to investigate the effect of tricaine methanesulfonate (MS-222), 2-phenoxyethanol (2-PE) and eugenol (EUG) on the PK of florfenicol (FF) in Nile tilapia. Twenty-eight fish were repeatedly exposed to 90 ppm EUG, 300 ppm MS-222 or 900 ppm 2-PE before FF oral administration (15 mg/kg) and each successive blood sampling. The serum concentration-time profiles were analysed by a 2-compartmental model, and the generated parameters in the control (without anaesthetic) and anaesthetic groups were statistically compared. The results demonstrated that the serum concentrations of each anaesthetic were similar at every FF sampling times (70 μg/ml for MS-222; 277 μg/ml for 2-PE; and 61 μg/ml for EUG). In comparison with the control group, the repeated use of MS-222 did not result in a statistical difference in most of the PK parameters. In contrast, the elimination half-lives of the 2-PE and EUG groups were significantly longer whereas the absorption and distribution half-lives of the 2-PE group were significantly shorter than the control, resulting in altered optimal dosages in the simulation modelling. Whether or not the numbers and extent of PK parameters change mitigate subsequent estimations of other PK-derived secondary values such as dosing regimen and withdrawal time remains to be elucidated, but the auxiliary use of anaesthetics in PK studies should not assume uninfluential.

[Technology specification of bedside hypertonic saline-contrast electrical impedance tomography of lung perfusion and clinical application]

Bedside hypertonic saline-contrast electrical impedance tomography (EIT) method for lung perfusion evaluation has several advantages of bedside, simple, noninvasive and radiation-free. For a long time, EIT perfusion image of hypertonic saline was mostly limited to animal experiments, and related clinical research is in the ascendant. This technical specification for clinical application is reached based on our previous researches, review of literatures in this field. The purpose of this technical specification is to facilitate the unified and standardized use of hypertonic saline-contrast EIT technology for regional lung perfusion, to evaluate the safety and quality control of the technology, and to unify the results.

Iron deficiency plays essential roles in the trigger, treatment, and prognosis of autosomal dominant hypophosphatemic rickets

By analyzing iron status of 14 ADHR patients, we found that iron deficiency was an important trigger of ADHR. Correcting iron deficiency significantly improved patients' symptoms. Meanwhile, patients' serum phosphate showed positive correlations with iron metabolism parameters and hemoglobin-related parameters, suggesting the necessity of monitoring and correcting the iron status in ADHR.

INTRODUCTION

Autosomal dominant hypophosphatemic rickets (ADHR) is unique for its incomplete penetrance, variety of disease onsets, and waxing and waning phenotypes. Iron deficiency is a trigger of ADHR. This study aimed to clarify the role of iron deficiency in ADHR.

METHODS

Data of clinical manifestations and laboratory examinations were collected from patients among eight kindreds with ADHR. Multiple regression and Pearson's correlation tests were performed to test the relationships of serum phosphate levels and other laboratory variables during the patients' follow-ups.

RESULTS

Among 23 ADHR patients with fibroblast growth factor 23 (FGF23) mutations, 14 patients presented with obvious symptoms. Ten patients had iron deficiency at the onset of ADHR, coinciding with menarche, menorrhagia, pregnancy, and chronic gastrointestinal bleeding. Two patients who did not have their iron status tested presented with symptoms after abortion and pregnancy in one patient each, which suggested that they also had iron deficiency at onset. Patients were treated with ferrous succinate tablets, vitamin C, and neutral phosphate and calcitriol. With correction of the iron status, the patients' symptoms showed notable improvement, with increased serum phosphate levels. Two patients' FGF23 levels also declined to the normal range. There were strong correlations between serum phosphate and serum iron levels (r = 0.7689, p < 0.0001), serum ferritin levels (r = 0.5312, p = 0.002), iron saturation (r = 0.7907, p < 0.0001), and transferrin saturation (r = 0.7875, p < 0.001). We also examined the relationships between serum phosphate levels and hemoglobin-related indices, which were significant (hemoglobin: r = 0.71, p < 0.0001; MCV: r = 0.7589, p < 0.0001; MCH: r = 0.8218, p < 0.0001; and MCHC: r = 0.7751, p < 0.0001). Longitudinal data of six patients' follow-up also showed synchronous changes in serum phosphate with serum iron levels.

CONCLUSIONS

Iron deficiency plays an important role in triggering ADHR. Monitoring and correcting the iron status are helpful for diagnosing and treating ADHR. Iron metabolism parameters and hemoglobin-related parameters are positively correlated with serum phosphate levels in patients with ADHR and iron deficiency, and these might serve as good indicators of prognosis of ADHR.

[Infliximab in infantile Takayasu arteritis: a case report and literature review]

Objective: To analyze the clinical characteristics of infantile Takayasu arteritis and the efficacy of infliximab (IFX). Methods: Clinical manifestations, laboratory investigations and infliximab intervention of a case with infantile Takayasu arteritis, who was admitted to Department of Rheumatism and Immunology, Children's Hospital, Capital Institute of Pediatrics in January 2018, were reviewed and analyzed. The related literature published from the beginning to March 2020 were retrieved from CNKI, Wanfang, SinoMed and PubMed with the keywords of"Takayasu arteritis","Infant" in both Chinese and English. Results: This case was a 70-day-old boy admitted due to recurrent fever for 20 days. On admission, his blood pressure were 104/90, 95/59, 125/80, and 152/125 mmHg (1 mmHg=0.133 kPa) in the right arm, left arm, right leg, and left leg, respectively. The complete blood cell count showed leukocytosis (22.6×10⁹/L), thrombocytosis (858×10⁹/L) and mild anemia (80 g/L). He also had elevated erythrocyte sedimentation rate (119 mm/1h), serum ferritin (598 μg/L) and C-reactive protein (112 mg/L). Computed tomographic angiography (CTA) showed narrowing of the thoracic and abdominal aorta, with thickening and heterogenous enhancement of the vessel wall. Coronary artery ultrasound detected dilatation and wall thickening of the bilateral coronary arteries, and uneven dilatation of the middle segment of the right coronary artery, showing bead-like change. Vessel wall thickening was also found in the other main arteries, including both femoral arteries, axillary arteries, carotid arteries, and subclavian arteries, and both superficial femoral arteries were slightly narrowed in the distal segments. The diagnosis of TA was confirmed, and the boy was treated with infliximab monotherapy (5 mg/(kg·every time), a total of 13 times). Then his body temperature and all inflammatory markers were normalized, and the vascular pathology was resolved according to the radiography. No side effects such as allergy or infection were noted during the treatment. During the 2 years and 6 months of follow-up, the boy maintained normal growth and development. Literature review found 8 related articles, and one of them was in Chinese but had limited information. In the other 7 papers, a total of 7 infants with TA were reported. The most common symptom was fever (5 cases), and inflammatory markers usually elevated, and the most common affected artery was abdominal aorta (6 cases). Most cases were treated with glucocorticoid. Conclusions: TA is a rare disease in infants, usually presents with fever and increased inflammatory markers. At the early stage, infliximab monotherapy could effectively control the symptoms and ensure normal growth and development.

Research on protective mechanism of ibuprofen in myocardial ischemia-reperfusion injury in rats through the PI3K/Akt/mTOR signaling pathway

OBJECTIVE

To study the protective mechanism of ibuprofen (Ib) in myocardial ischemia-reperfusion (I/R) injury in rats, and to analyze its regulatory effect on the phosphatidylinositol 3-hydroxy kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway.

MATERIALS AND METHODS

The rat model of myocardial I/R injury was established via ligation of the left main coronary artery (LCA) for 30 min and then reperfusion for 120 min. A total of 36 Sprague-Dawley (SD) rats were randomly divided into sham group (S group, n=12), model group (I/R group, n=12) and Ib group (n=12). The levels of serum creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in each group were detected. The rats were executed, the heart was isolated and the area of myocardial infarction was determined via 2,3,5-triphenyltetrazolium chloride (TTC) staining. The expression levels of vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1 (HIF-1) and apoptosis-related proteins in myocardial tissues in each group were detected via Western blotting. Moreover, the content of inflammatory factors in myocardial tissues in each group was detected using the enzyme-linked immunosorbent assay (ELISA) kit. The expression levels of related proteins in the PI3K/Akt/mTOR signaling pathway in myocardial tissues were further analyzed.

RESULTS

Compared with those in S group, the levels of CK-MB and LDH were significantly increased (p<0.01), the area of myocardial infarction was significantly increased (p<0.01), the VEGF, HIF-1 and Cleaved caspase-3 protein levels in myocardial tissues were increased (p<0.01), while Bcl-2/Bax declined (p<0.01), the content of interleukin-1 (IL-1), IL-6 and tumor necrosis factor-α (TNF-α) in myocardial tissues was increased (p<0.01), while the content of IL-10 declined (p<0.01), and the expression levels of PI3K, p-Akt and p-mTOR proteins in myocardial tissues were significantly decreased (p<0.01) in I/R group. Compared with those in I/R group, the levels of CK-MB and LDH were significantly decreased (p<0.01), the area of myocardial infarction was significantly decreased (p<0.01), the VEGF, HIF-1 and Cleaved caspase-3 protein levels in myocardial tissues were decreased (p<0.01), while Bcl-2/Bax was increased (p<0.01), the content of IL-1, IL-6 and TNF-α in myocardial tissues declined (p<0.01), while the content of IL-10 was significantly increased (p<0.01), and the expression levels of PI3K, p-Akt and p-mTOR proteins in myocardial tissues were significantly increased (p<0.01) in Ib group.

CONCLUSIONS

Ib can activate the PI3K/Akt/mTOR signaling pathway, reduce the release of inflammatory factors and apoptosis, and alleviate the myocardial I/R injury in myocardial cells in rats.

Predicting the intervention threshold for initiating osteoporosis treatment among postmenopausal women in China: a cost-effectiveness analysis based on real-world data

This study built a micro-simulation Markov model to determine the treatment threshold of osteoporosis in postmenopausal women in Mainland China. Treatment with zoledronate is cost-effective when FRAX-based (Fracture risk assessment tool) fracture probability is over 7%.

INTRODUCTION

The purpose of this study is to estimate FRAX-based fracture probabilities in Mainland China using real-world data, at which intervention could be cost-effective.

METHODS

We developed a micro-simulation Markov model to capture osteoporosis states and relevant morbidities including hip fracture, vertebral fracture, and wrist fracture. Baseline characteristics including incidences of osteoporosis and distribution of risk factors were derived from the Peking Vertebral Fracture study, the largest prospective cohort study of postmenopausal women in Mainland China. We projected incidences of fractures and deaths by age groups under two treatment scenarios: 1) no treatment, and 2) zoledronate. We also projected total quality-adjusted life-years (QALY) and total costs including fracture management and osteoporosis drugs for cost-effectiveness analysis. Cost-effective intervention thresholds were calculated based on the Chinese FRAX model.

RESULTS

Treatment with zoledronate was cost-effective when the 10-year probability of major osteoporotic fracture based on FRAX was above 7%. The FRAX threshold increased by age from 51 to 65 years old, and decreased in elder age groups, ranging from 4% to 9%.

CONCLUSIONS

Using real-world data, our model indicated that widespread use of zoledronate was of both clinical and economic benefit among Chinese postmenopausal women. Using a FRAX-based intervention threshold of 7% with zoledronate should permit cost-effective access to therapy to patients and contribute to reducing the disease burden of osteoporosis in Mainland China.

[Gene mutation spectrum and clinical characteristics analysis of 178 patients with essential thrombocytosis]

目的

分析原发性血小板增多症（ET）患者基因突变谱及临床特征。

方法

对2009年2月1日至2018年11月1日收治的178例初诊ET患者进行回顾性分析。

结果

全部178例患者中，男89例，女89例，中位初诊年龄为49.5（3~86）岁。JAK2V617F基因突变频率为16.45%（1.67%~43.90%），CALR基因突变频率为40.00%（10.00%~49.15%），MPL基因突变频率为25.10%（25.00%~40.00%）。与CALR基因突变的患者相比，JAK2V617F基因突变患者具有较高的发病年龄（P=0.035）、初诊白细胞计数（P=0.040）、初诊血红蛋白浓度（P=0.001）和较低的初诊血小板计数（P=0.002）。47例（27.01%）患者诊断ET前发生血栓事件，3例（1.72%）诊断ET后发生血栓事件。多因素分析结果显示，年龄>60岁（P=0.013，OR=4.595，95%CI1.382~15.282）、心血管危险因素（P<0.001，OR=8.873，95%CI2.921~26.955）为血栓事件的危险因素，CALR基因突变（P=0.032，OR=0.126，95%CI0.019~0.838）为血栓事件的保护性因素。年龄>60岁（P=0.042，OR=4.045，95%CI1.053~15.534）是影响ET患者总生存时间的危险因素。年龄≤60岁、年龄>60岁患者的OS时间分别为（115.231±1.899）、（83.291±4.991）个月（χ²=6.406，P=0.011）。

结论

心血管危险因素、年龄>60岁为ET患者血栓事件的危险因素，CALR基因突变为血栓事件的保护性因素。年龄>60岁是影响ET患者总生存的危险因素。

Abstract P6-05-08: LINC02273 interacts with hnRNPL and promotes metastasis through directly activating AGR2 in breast cancer

The prognosis of breast cancer patients with metastasis is still poor even improved by current treatment modalities. Unveiling new biomarkers and molecular mechanisms that underlie metastasis are of vital importance for the treatment of breast cancer. The recent discovery of long noncoding RNAs (lncRNAs) has gained widespread attention. To identify critical lncRNAs that contributed to breast cancer metastasis, we profiled their expression in 5 pairs of primary tumors and lymph nodes metastasis loci by HTA2.0 microarray. LINC02273 is significantly upregulated in metastasis loci and its high expression is associated with poor diseases free survival in a validation set of 254 patients. LINC02273 was mainly located in the cell nucleus . RACE-PCR showed two isoforms and the longest one was the most abundant isoform in breast cancer. Through transwell assay, 3D spheroid invasion assay and mice xenograft metastasis model, we found that LINC02273 promoted breast cancer cell migration, invasion and metastasis. Via mass spectrometry, hnRNPL was found to interact with LINC02273 to enhance its stability, which was further confirmed by Actinomycin D inhibition assay and luciferase reporter assay. Furthermore, ChIRP-seq and ChIP-seq showed that LINC02273 stimulated oncogene AGR2 expression by directly binding to the AGR2 promoter region and increasing H3K27ac modification. Triplex formation assay was performed for verification. We demonstrated that the expression level and oncogenic ability of AGR2 were regulated by hnRNPL through LINC02273. Clinical data and mouse xenograft tumors also revealed the positive correlation of AGR2 and LINC02273. In conclusion, LINC02273, which is stabilized by hnRNPL can promote breast cancer metastasis through upregulation of AGR2 and may serve as a prognostic biomarker for breast cancer.

Citation Format: Xiu B, Chi Y, Ji W, Zhang Q, Wu J. LINC02273 interacts with hnRNPL and promotes metastasis through directly activating AGR2 in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-05-08.

Abstract P3-13-09: Increased mortality with repeat lumpectomy alone after ipsilateral breast tumor recurrence: A propensity-adjusted, population-based SEER analysis

Background: The benefit of repeat lumpectomy for ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery (BCS) is currently inconclusive. This issue has become even more important as small and isolated recurrent tumors were frequently diagnosed.

Methods: IBTR patients with definitive surgery were identified in the Surveillance, Epidemiology, and End Results registry between 1973 and 2013. The effect of different IBTR surgeries on overall and cancer-specific mortality was assessed using risk-adjusted Cox proportional hazard regression modeling and stratified propensity score matching analysis (PSMA).

Results: Based on the selection criteria, 5098 patients were recruited. Of those, 4048 (79.4%) women underwent mastectomy and 1050 (20.1%) underwent repeat lumpectomy after IBTR. Patients who received repeat lumpectomy had lower grade (23.7% vs 15% for well-differentiated) and smaller recurrent tumor (47% vs 36.2% for ≤ 1 cm) but earlier recurrence (23.9% vs 11.2% for interval times &lt; 48 months) than those who underwent mastectomy. A minority of each group (24.7% of those undergoing repeat lumpectomy and 3% of the mastectomy group) underwent RT after surgery. In multivariable Cox regression analysis, repeat lumpectomy was associated with increased overall mortality (Hazard ratio (HR) = 1.58, 95% CI = 1.353 to 1.844, P &lt; 0.001) and cancer-specific mortality (HR = 1.721, 95% CI = 1.345 to 2.202, P&lt; 0.001). Similar HRs were derived from the PSMA cohort. However, we found no significant difference in overall mortality for women who underwent repeat lumpectomy followed by RT compared with that for those who underwent mastectomy (P= 0.411). Moreover, IBTR patients with small tumors (≤ 1 cm) who underwent repeat lumpectomy with RT rather than without had similar overall and cancer-specific survival rates to those who underwent mastectomy (P= 0.189 and P= 0.604, respectively).

Conclusions: Our investigation suggests that compared with mastectomy, repeat lumpectomy for IBTR is associated with higher overall and cancer-specific mortality under real-world observational conditions. Furthermore, repeat lumpectomy with RT is equivalent to mastectomy with respect to overall mortality and may influence treatment decision making for patients with small IBTR.

Citation Format: Su Y, Guo R, Xue J, Chi Y, Wu J. Increased mortality with repeat lumpectomy alone after ipsilateral breast tumor recurrence: A propensity-adjusted, population-based SEER analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-09.

Abstract P5-03-13: ERVMER34 sensitizes the response of HER2 positive breast cancer to neoadjuvant therapy

Although anti-HER2/neu antibody therapy combined with chemotherapy has achieved an outstanding effect, many patients with HER2-positive breast cancer still succumb due to therapeutic resistance. Understanding the mechanisms of therapeutic resistance is of vital importance. In this study, core needle biopsy tissue from HER2-positive patients was collected before neoadjuvant chemotherapy. Differentially expressed RNAs between pCR and non-pCR group have been identified through RNA-seq. Here we found that ERVMER34, an endogenous retroviral envelope protein was significantly inhibited in non-pCR group compared to pCR group. High ERVMER34 expression was associated with good overall survival both in TCGA database and our own patients cohort. Further study showed that ERVMER34 could be glycosylated and secreted to cell supernatant. The IC50 of paclitaxel and trastuzumab in HER2 positive breast cancer cells was decreased by ectopic overexpression of ERVMER34. Furthermore, RNA-seq, FACS assay and western blot revealed that ERVMER34 could promote cell apoptosis and sensitize therapy response through inhibiting mTOR pathway in HER2 positive breast cancer cells. Via mass spectrometry, TRIM21, an E3 ligase was found to interact with ERVMER34 and promoted its ubiquitination degradation. Taken together, these data suggest that ERVMER34 may severve as a novel biomarker to predict therapy response in HER2 positive breast cancer.

Citation Format: Chi Y, Ji W, Xiu B, Zhang Q, Wu J. ERVMER34 sensitizes the response of HER2 positive breast cancer to neoadjuvant therapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-03-13.

Abstract P6-09-11: NFATC2 suppresses the metastatic cascade in breast cancer patients

For the patients with breast cancer, the pathological status of axillary lymph nodes is one of the most important predictor of prognosis. In recent years, the application of sentinel lymph node biopsy has provided us with an opportunity for the further study on the mechanism of lymph node metastasis in breast cancer. Through detailed pathological examination of sentinel lymph nodes, we can easily find patients who are in the early stage of lymph node metastasis - that is, the tumor cells from the primary tumor, invading the lymph nodes and successfully colonized, but not yet break through the lymph node microenvironment defense to the subsequent lymph node. It is the most important stage during lymph node metastasis.

In the present study, we selected the pairing samples from breast cancer patients with early stage lymph node metastasis to carry out differential genomics research. A total of 182 genes with significant function and involved in significant signal transduction pathways were obtained. Bioinformatics method was used to screen out the mRNA, microRNA and transcription factor in the process of lymph node metastasis of breast cancer. We investigated the role of activated T cells c2 (NFATC2) in the core transcription factors as a target for further clinical and basic research.

The expression of NFATC2 was detected in the tissue microarray prepared from 200 patients with primary breast cancer. After the median follow-up period of 89.5 months, it showed that the prognosis of patients with NFATC2 overexpression was significantly better than that of the control group (p = 0.022). We also measured the expression of NFATC2 in 50 pairs of breast cancer patients with lymph node metastasis. The results showed that the expression of NFATC2 in the primary tumor was significantly higher than that in the matched lymph node, suggesting that in patients with breast cancer, the down-regulate or deficiency of NFATC2 expression may be related with lymph node metastasis. We also attempted to add the expression of NFATC2 as a new parameter in the prediction model of lymph node metastasis based on preoperative clinical and pathological parameters. The area under the ROC curve obtained in the newly established model was 0.767, the expression state of NFATC2 had impact on the performance of the prediction model. Furthermore, when we removed the NFATC2 parameter, it could reduce the area under the ROC curve in the validation group, suggesting that the expression of NFATC2 in the primary tumor may be used as a predictor of the pathological state of axillary lymph nodes.

In vitro and in vivo experiments, we demonstrated that NFATC2 has a significant suppression effect on the proliferation, migration and invasion of breast cancer cells. The potential NFATC2-target genes were determined by RNAseq and Chipseq. Nine differentially expressed genes were found to be regulated by NFATC2 in the Chip-seq analysis and bound to the promoter region of the gene, whereas GRAMD3 and SRGAP2 in the subsequent validation showed a positive correlation with the expression of NFATC2, suggesting that the two genes are likely to have a positive regulatory relationship with NFATC2.

This study clarifies that NFATC2 may represent a therapeutic target for early metastasis breast cancer.

Citation Format: Xue J, Chi Y, Chen J, Wu J. NFATC2 suppresses the metastatic cascade in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-11.

Mutation update and long-term outcome after treatment with active vitamin D3 in Chinese patients with pseudovitamin D-deficiency rickets (PDDR)

Pseudovitamin D-deficiency rickets is a rare disease which is caused by CYP27B1. In this study, we identified 9 mutations in 7 PDDR patients. In addition, we observed the response to long-term treatment of calcitriol in 15 Chinese patients with PDDR, which showed that the biochemical abnormalities had been corrected satisfactorily after 1-year treatment.

INTRODUCTION

Pseudovitamin D-deficiency rickets is a rare autosomal recessive disorder resulting from a defect in 25-hydroxyvitamin D 1α-hydroxylase, which is encoded by CYP27B1. The purpose of this study was to identify the CYP27B1 mutations and investigate the response to long-term treatment of calcitriol in Chinese patients with PDDR.

METHODS

We investigated CYP27B1 mutations in seven individuals from six separate families. To investigate the response to long-term (13 years) treatment with calcitriol in PDDR patients, we additionally collected clinical data of eight families from our previous report and analyzed their biochemical parameter and radiographic changes during the treatment.

RESULTS

Nine different mutations were identified: two novel missense mutations (G194R, R259L), three novel and one reported deletion mutations (c1442delA, c1504delA, c311-321del, and c. 48-60del), two novel nonsense mutations (c.85G>T, c.580G>T), and a reported insertion mutation (c1325-1332insCCCACCC). The statistical analysis revealed that parathyroid hormone (PTH) and ALP significantly decreased after 6-month and 1-year treatment with calcitriol respectively. Urine calcium was measured in all the patients without kidney stones being documented. After 6-year treatment, the radiographic abnormalities had also been improved. Two patients who had reached their final height are both with short stature (height Z-score below - 2.0).

CONCLUSIONS

We identified seven novel mutations of CYP27B1 gene in seven Chinese PDDR families. Our findings revealed after 1-year treatment of active vitamin D₃, PTH and ALP significantly decreased. The correction of the biochemical abnormalities had not improved the final height satisfactorily.

The functions of caspase in whitefly Bemisia tabaci apoptosis in response to ultraviolet irradiation

Whiteflies (Bemisia tabaci) are phloem feeders, and some invasive species are composed of cryptic species complexes that cause extensive crop damage, particularly via the direct transmission of plant viruses. Apoptosis is a type of programmed cell death essential for organismal development and tissue homeostasis. The caspases belong to a family of cysteine proteases that play a central role in the initiation of apoptosis in many organisms. Here, we employed a comprehensive genomics approach to identity caspases in B. tabaci Middle East Asia Minor 1 (MEAM1), an invasive whitefly that carries a cryptic species complex that is devastating to crops. Four caspase genes were identified, and their motif compositions were predicted. Structures were relatively conserved in both putative effector and initiator caspases. Expression patterns of caspase genes differed across insect developmental stages. Three caspase genes were induced immediately after ultraviolet (UV) treatment. Expression levels of Bt-caspase-1 and Bt-caspase-3b increased in the midgut and salivary glands during apoptosis induced by UV treatments, whereas silencing of both genes reduced UV-triggered apoptosis. Our study demonstrates that Bt-caspase-1 and Bt-caspase-3b, respectively, act as putative initiator and effector apoptotic caspases in the MEAM1 whitefly.

Abstract P5-07-05: LOC283299 suppress the lymphnode metastatic cascade in breast cancer patients

Background

Long non-coding RNAs (lncRNAs) have been proved to play an essential role in cancer metastasis. The accuracy of intraoperative assessment of lymph nodes metastasis need to be improved. In this study, we aimed to define the lncRNA biomarker ectopic expressed in breast cancer patients' metastatic lymph nodes, and to explore the potential molecular mechanisms.

Experimental Design

RNA-seq analyses in 3 paired breast cancer patients' primary tumor and metastatic lymph node was used as training set to determine differentially expressed lncRNAs that may be associated with lymph node metastasis. The other 40 patients were analyzed as validation set to test the accuracy of lncRNAs identification by quantitative real-time PCR. The correlation between LOC283299 expression level and prognosis in other 282 breast cancer patients was confirmed. In parallel, in vitro and in vivo analyses were carried out to determine the potential mechanisms of LncRNA-dependent lymph node metastases and prognosis.

Results

RNA-seq analyses in the training set revealed significant correlation between high expression level of LOC283299 and lower lymph node metastasis potential in breast cancer patients. We further validated that the expression level of LOC283299 was significantly higher in tumor primary tissue than that in paired metastatic lymph node (P=0.0245), and higher LOC283299 expression level was markedly associated with good metastasis-free survival in breast cancer patients (P=0.04). In breast cancer cell lines, CRISPR-on overexpression of LOC283299 inhibited proliferation, migration, invasion, and metastases both in vivo and in vitro. shRNA knockdown LOC283299 promotes the ability of tumor proliferation and metastasis. The molecular mechanisms by which LOC283299 as metastasis-suppressing lncRNAs regulates recurrence and metastasis may involve regulation of epithelial to mesenchymal transition (EMT), cellular invasion and microenvironment in breast cancer cells.

Conclusion

Our study revealed a strong correlation between LOC283299 expression and lymph node metastases in breast cancers. High level of LOC283299 was associated with better metastasis-free survival. The changed metastasis phenotype may be mediated by the interaction of LOC283299 and breast cancer cells. Therefore, LOC283299 may represent a potential predictive biomarker for early lymph node metastasis in breast cancer.

Citation Format: Guo R, Xue J, Su Y, Xiu B, Ji W, Chi Y, Wu J. LOC283299 suppress the lymphnode metastatic cascade in breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-07-05.

A new method to reconstruct intra-fractional prostate motion in volumetric modulated arc therapy

Intra-fractional motion is a concern during prostate radiation therapy, as it may cause deviations between planned and delivered radiation doses. Because accurate motion information during treatment delivery is critical to address dose deviation, we developed the projection marker matching method (PM³), a novel method for prostate motion reconstruction in volumetric modulated arc therapy. The purpose of this method is to reconstruct in-treatment prostate motion trajectory using projected positions of implanted fiducial markers measured in kV x-ray projection images acquired during treatment delivery. We formulated this task as a quadratic optimization problem. The objective function penalized the distance from the reconstructed 3D position of each fiducial marker to the corresponding straight line, defined by the x-ray projection of the marker. Rigid translational motion of the prostate and motion smoothness along the temporal dimension were assumed and incorporated into the optimization model. We tested the motion reconstruction method in both simulation and phantom experimental studies. We quantified the accuracy using 3D normalized root-mean-square (RMS) error defined as the norm of a vector containing ratios between the absolute RMS errors and corresponding motion ranges in three dimensions. In the simulation study with realistic prostate motion trajectories, the 3D normalized RMS error was on average [Formula: see text] (range from [Formula: see text] to [Formula: see text]). In an experimental study, a prostate phantom was driven to move along a realistic prostate motion trajectory. The 3D normalized RMS error was [Formula: see text]. We also examined the impact of the model parameters on reconstruction accuracy, and found that a single set of parameters can be used for all the tested cases to accurately reconstruct the motion trajectories. The motion trajectory derived by PM³ may be incorporated into novel strategies, including 4D dose reconstruction and adaptive treatment replanning to address motion-induced dose deviation.

S-1 chemotherapy and intensity-modulated radiotherapy after D1/D2 lymph node dissection in patients with node-positive gastric cancer: a phase I/II study

BACKGROUND

This phase I/II clinical trial investigated S-1 administered with intensity-modulated radiotherapy (IMRT) as adjuvant therapy for node-positive gastric cancer. Patients had undergone radical resection and D1/D2 lymph node dissection.

METHODS

In phase I, patients received adjuvant chemoradiotherapy of IMRT (45 Gy in 25 fractions) with concurrent S-1 administered on a dose-escalation schedule to determine the recommended dose (RD). In phase II, the safety and efficacy of the RD of S-1 combined with IMRT were assessed.

RESULTS

We consecutively enrolled 73 patients (56 men; median age, 53 years; range, 29-73 years) and the phase I portion of the study included 27 patients. The RD of S-1 administered concomitantly with IMRT was 80 mg m^-2 day^-1 orally, twice daily. The phase II analysis included 52 patients (46 new patients plus 6 from phase I). 8 patients (15.4%) developed grade 3 or 4 toxicities. There were 21 recurrence events and 15 deaths (1 bowel obstruction, 14 gastric cancer). Three-year disease-free survival and overall survival were 62.2% (95% confidence interval (CI), 48.5-75.9) and 70.0% (95% CI, 56.3-83.7), respectively. The median time to recurrence was 17.5 months (range, 3.8-42.0). The median time from recurrence to death was 7.0 months (range, 1.5-28.7).

CONCLUSIONS

S-1 combined with IMRT adjuvant chemoradiotherapy is safe and efficacious for advanced gastric cancer.

Stenosis detection and quantification on cardiac CTCA using panoramic MIP of coronary arteries

In this work, we proposed to demonstrate the entire 3D coronary tree using panoramic maximum intensity projection (MIP) of coronary arteries, and to detect and quantify coronary stenosis from computed tomography coronary angiography (CTCA). The performance of the proposed method was assessed in comparison with invasive coronary angiography (ICA) as reference standard. Six anonymized CTCA datasets were tested. MIP method achieved a sensitivity of 82% and a specificity of 95% for the stenosis detection with a good reproducibility (i.e. Cohen's kappa coefficient of 0.74 for the intra-rater agreement, and 0.45 for the inter-raters agreement). In stenosis quantification, three image options are provided. The original density images resulted in an accuracy of 0.85. The edge map images resulted in an accuracy of 0.79. The image combination had a better accuracy of 0.89 than any single image option. In conclusion, the panoramic MIP provided fast and accurate way for the stenosis detection and quantification. It may be helpful to assist the radiologist in identifying the location of the greatest narrowing in clinical practice.

The beam energy feedback system for Beijing electron positron collider II linac

A beam-energy feedback system has been developed for the injection linac to meet the beam quality needed for the Beijing electron positron collider II storage ring. This paper describes the implementation and commissioning of this system in detail. The system consists of an energy measurement unit, application software, and an actuator unit. A non-intersecting beam energy monitor was developed to allow real-time online energy adjustment. The beam energy adjustment is achieved by adjusting the output microwave phase of the RF power source station. The phase control mechanism has also been modified, and a new control method taking the return difference of the phase shifter into account is used to improve the system's performance. This system achieves the design aim and can adjust the beam center energy with a rate of 2 Hz. With the energy feedback system, the stability of the injection rate is better; the fluctuation range is reduced from 20 mA/min to 10 mA/min, while the stability of the beam center energy is maintained within ±0.1%.