Reconsidering treatment guidelines for acute myocardial infarction during the COVID-19 pandemic.

Background: COVID-19 affects healthcare resource allocation, which could lead to treatment delay and poor outcomes in patients with acute myocardial infarction (AMI). We assessed the impact of the COVID-19 pandemic on AMI outcomes.

Methods: We compared outcomes of patients admitted for acute ST-elevation MI (STEMI) and non-STEMI (NSTEMI) during a non-COVID-19 pandemic period (January-February 2019; Group 1, n = 254) and a COVID-19 pandemic period (January-February 2020; Group 2, n = 124).

Fracture Resistance of Roots in Mandibular Premolars Following Root Canal Instrumentation of Different Sizes.

Objective: To measure the fracture resistance of mandibular premolar roots following root canal instrumentation with different sizes.

Methods: A total of 100 human permanent mandibular premolars with a straight single canal were decoronated and assigned to 10 groups (n = 10) by block randomisation. In the control group, the roots were uninstrumented, whereas roots in the nine experimental groups were instrumented to different master apical files (MAF) and tapers (MAF/taper): 40/0.

Electrode Placing Sites affect Pulp Vitality Test of Human Incisors and Premolars.

Objective: To investigate electric pulp test thresholds at different sites on healthy incisors and premolars and determine appropriate test sites.

Methods: Overall, 47 volunteers aged 20 to 30 years were recruited, and 163 incisors and 140 premolars were tested at several sites with an Electric Pulp Tester. One-way analysis of variance and a Tukey test were used to analyse the threshold values among different tooth types and sites.

Comparison of the planning target volume based on three-dimensional CT and four-dimensional CT images of non-small-cell lung cancer.

Background And Purpose: To compare positional and volumetric differences of planning target volumes (PTVs) based on axial three-dimensional CT (3DCT) and four-dimensional CT (4DCT) for the primary tumor of non-small cell lung cancer (NSCLC).

Materials And Methods: Twenty-eight patients with NSCLC underwent 3DCT and 4DCT scans of the thorax during normal free breathing. PTV(vector) was defined on 3DCT using the individual tumor motion vector measured by 4DCT accounting for tumor motion; PTV(4D) was defined on all phases of 4DCT images.

[Comparison of overlap ratios of the target volume in different respiratory states with active breathing control for external-beam partial breast irradiation].

Objective: To explore the overlap ratio of the target volume in different respiratory statuses of active breath control (ABC) and their differences during external-beam partial breast irradiation (EB-PBI), and from the perspective of target volume overlap to determine the influence of the ABC-assisted breathing condition on intra-fractional target movement of EB-PBI.

Methods: The patients, who received breast-conserving surgery with silver clips marked at the margins of the cavity and were suitable for EB-PBI, were immobilized on the breast bracket to undertake CT simulation assisted by ABC device, six sets of CT simulation images including two sets of image in state of moderate deep inspiration breathing control (mDIBH), two sets of images in state of free breath (FB) and two sets of images in state of deep expiration breathing control (DEBH) were obtained. The six sets of images were transferred to Pinnacle(3) treatment planning system (TPS), then automatic fusion and registration between two sets of mDIBH images, two sets of FB images, two sets of DEBH images and mDIBH image and DEBH image were achieved separately.