Effect of dwell time deviation constraint on the three-dimensional brachytherapy plans for cervical cancer / 中华放射肿瘤学杂志

Objective:To investigate the effect of dwell time deviation constraint of inverse optimization on the quality and position error robustness of three-dimensional (3D) brachytherapy plans for cervical cancer.Methods:A total of 20 patients with cervical cancer receiving 3D brachytherapy treatment in Xiangya Hospital Central South University from August 2020 to August 2021 were retrospectively selected. All plans were designed using the Eclipse treatment planning system, and the dwell time deviation constraint parameter smooth value in the system were set to 0.00, 0.25, 0.50, 0.75, and 1.00, respectively. An inverse dose volume optimization algorithm was used to generate plans with various smooth values, and the optimization conditions were the same as the original clinical plans. Key dosimetric metrics and total dwell time differences were comparatively analyzed. The applicators were intentionally subjected to position errors (0.2-1.0 cm) in 6 directions (left-right, anterior-posterior, head-foot), and the effect of various smooth values on plan quality and robustness was assessed. There were 133 plans per case and 2 660 plans for 20 patients. The results were statistically analyzed using the Wilcoxon signed-rank nonparametric test.Results:As the smooth value was increased, the modulation factor was gradually decreased and the D 2 cm3 of the bladder and rectum was increased. Plans with smooth values of 0.25, 0.50, 0.75, 1.00 had modulation factors of 0.72±0.09, 0.63±0.08, 0.55±0.08, 0.51±0.06, respectively, lower than 0.75±0.05 of the plan with the smooth value of 0.00, and all differences were statistically significant ( P=0.004, 0.002, 0.002, 0.002). The bladder D 2 cm3 of plans with smooth values of 0.50, 0.75, 1.00 were (475.4±41.0) cGy, (483.7±46.2) cGy, and (489.0±46.8) cGy, respectively, higher than (469.8±41.8) cGy of the plan with the smooth value of 0.00, with statistically significant differences (all P=0.002). The rectum D 2 cm3 of plans with smooth values of 0.50 and 0.75 plans were (413.2±93.3) cGy and (418.6±96.4) cGy, both higher than (410.2±91.5) cGy of the plan with the smooth value of 0.00, with statistically significant differences ( P=0.006, 0.010). When positional errors were introduced, the high risk clinical target volume (HR-CTV) D 90% was close for different smooth plans at most positional errors, and the differences were not statistically significant. The organs at risk D 2 cm3 of plans with the smooth value of 0.00 was lower than those of plans with other smooth values, and for the bladder and rectum, the differences were statistically significant at most positional errors (all P<0.01). Conclusions:The dwell time deviation constraint parameter exerts significant effect on the plan quality, and the smaller the value of the constraint parameter, the higher quality of the plan. The dwell time deviation constraint parameter has slight impact on the positional error robustness of dosimetric indices of targets and key organs at risk.

Relationship between central line-associated bloodstream infection and catheter dwell time in neonates / 中华危重病急救医学

The central line-associated bloodstream infection (CLABSI) is a common and serious complication of central venous catheterization, which can lead to various short-term and long-term adverse outcomes. Neonatal CLABSI did not increase linearly with the prolongation of peripherally inserted central catheter (PICC). When the umbilical venous catheter (UVC) is retained for more than 1-2 weeks, the incidence of neonatal CLABSI may increase significantly; PICC replacement at 7-10 days after UVC indwelling may reduce the incidence of CLABSI, but it has not been supported by evidence-based medicine. This article reviews the related studies between neonatal CLABSI and catheter dwell time, in order to plan the indwelling time more reasonably and prevent CLABSI better.

Study of the effects of dwell time deviation constraints on inverse planning simulated annealing optimized plans of intracavitary brachytherapy of cancer cervix

Purpose: High Dose Rate (HDR) remote afterloading brachytherapy machine and advanced treatment planning system have made it possible to make variations in individual dwell times across a catheter according to tumour density and for sparing normal structures. New inverse planning technique such as Inverse Planning Simulated Annealing (IPSA) has also been introduced. But very few institutions are venturing towards volume based IPSA optimised intracavitary brachytherapy. This study focuses on dwell time deviation constraint (DTDC) feature of IPSA based optimization which restricts the large variation of dwell time across the catheter. Methods and Material: For this retrospective study we have generated IPSA optimised intracavitary brachytherapy plans for 20 cancer cervix applications. The initial DTDC value of each IPSA plan was kept 0.0. Later on gradual increment was made in DTDC values in step of 0.2. Plan modulation index (M) defined by Ryan L. Smith et al was used for characterising the variation of dwell time modulation with respect to gradual increase in DTDC parameter. Results: Plan modulation index gradually decreases with increasing value of DTDC from 0.0 to 1.0. There was the 83% decrease in M value from IPSA of DTDC 0.0 to fully constrained IPSA of DTDC1.0. There is reduction of 8.26% and 6.95% for D2cc values of rectum and bladder respectively for DTDC 1.0 compared to DTDC 0.0. Conclusions: One of the benefits of applying DTDC constrained in IPSA plan is that, it removes local hot spots. It's another advantage is the reduction in rectum and bladder dose.

O lar e o habitar para moradores de Serviço Residencial Terapêutico / The home and the dwelling for residents of Residential Therapeutic Service

Este estudo tem como objetivo investigar o entendimento de atuais moradores de um Serviço Residencial Terapêutico (SRT) acerca do significado de lar e de habitar. Foi realizada pesquisa qualitativa por meio de entrevistas semiestruturadas com moradores de Residências Terapêuticas (RT) situadas em cidades da região metropolitana de Vitória (ES). A análise temática de conteúdo indicou núcleos de sentido que evidenciaram a casa e o habitar atrelados à presença da família, à liberdade, à autonomia, à proteção. Foi demonstrado que a RT não é um lar para todos, bem como apontada a importância da participação do ex-interno do hospital psiquiátrico no processo de passagem da internação para a residência terapêutica e o fortalecimento de laços afetivos do morador.

The therapeutic residences are dwellings inserted in the community, destined to ex- patients of long admission in psychiatric hospitals that allow the social insertion of these people. Qualitative research was performed through semi-structured interviews, which sought to understand the meaning of living for residents of Therapeutic Residences. Participated in the research, five residents of Therapeutic Residences located in cities in the metropolitan region of southeastern Brazil. The thematic analysis of the contents indicated nuclei of meaning that evidenced the home and the dwelling, linked to the presence of the family, to freedom, to autonomy, to protection and as milestones of the rupture of this locus of existence, psychic suffering and hospitalization. It is pointed out the importance of the participation of the ex-inmate of the psychiatric hospital in the process of moving from hospitalization to therapeutic residency.

Effect of Data Acquisition Parameters on Characterization of Gold Nanoparticles By Single Particle Inductively Coupled Plasma-Mass Spectrometry / 分析化学

Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is a new tool that can provide the element composition, size distribution, and number concentration of nanoparticles. Here we discussed the effects of dwell time and settling time on analysis of nanoparticles by SP-ICP-MS. We analyzed standard materials of gold nanoparticles (30, 40 and 60 nm AuNPs, from NIST and NCNST), showing that better signal-to-noise ratio and higher determination efficiency could be achived when using shorter dwell time and settling time. We utilized a nano mode for SP-ICP-MS, in which the dwell time was set as 0. 05 ms and the settling time was 0. The size of NIST AuNP standard material determined here was in accord with the certified size using the developed method. The detection limits of size and number concentration of AuNPs were 8 nm and 1. 1×105 particle / L, respectively.

Tunnelled Peripherally Inserted Central Catherer- How We Do Them

In the current study, we report a new technique to place a tunnelled peripherally inserted central catheter (PICC) at the upper arm of patient under real-time ultrasound-guided venipuncture using disposal equipment provided within a standard PICC set. The tunnelling of the PICC required an extra time of 5 minutes but was well tolerated by all patients involved in the study. The tunnelled PICC was applied on 50 patients and the infection rate as well its catheter dwell time were compared to another 50 patients with conventional PICC. The rate of patients who developed infection decreased from 34% for conventional PICC to 16% in tunnelled PICC patients. The central line-associated blood stream infections rate was also decreased from 4.4 per 1000 catheter-days for conventional PICC to 1.3 per 1000 catheter-days for tunnelled PICC. The mean time to infection development for tunnelled PICC (24 days) was longer than those observed with conventional PICC (19 days). Tunnelled PICC has also increased the mean catheter dwell time from 27 days (for conventional PICC) to 47 days. Tunnelling a PICC has the potential to reduce the infection rate while increase the catheter dwell time.

Dosimetric influence of dwell weight standard deviation and applicator displacement in patients with cervical cancer / 中华放射肿瘤学杂志

Objective To investigate the dosimetric influence of dwell weight standard deviation (DWSD) and applicator displacement in cervical cancer patients treated with three-dimensional brachytherapy.Methods A total of 20 cervical cancer patients who had completed radical treatment were selected in this study.The Fletcher applicator (Nucletron#189.730) was used for these patients.A new plan,based on the former CT images and structures,was designed for each patient.In former and new plans,dwell weight was recorded,and DWSD was calculated.Two groups,low-DWSD (LDWSD,0.141-0.299) and high-DWSD (HDWSD,0.211-0.337),were set according to the DWSD size for the two plans.Dosimetric effects from ± 1 mm displacement of tandem applicator or ovoid applicator were simulated with Oncentra (R) Brachy V4.3 treatment planning system.D100,D90,and V150 for clinical target volume (CTV)and D0.1cc,D1cc,and D2cc for the bladder,rectum,and sigmoid were evaluated.Dosimetric comparisons were made between the LDWSD group and HDWSD group to study the dosimetric effects of DWSD and applicator displacement in cervical cancer patients.Results The dosimetric effects from applicator displacement increased with increasing DWSD.If there was a 1 mm displacement of tandem applicator or ovoid applicator,D100,D90,and V150 of CTV were 3.0％,23.8％,and 4.8％ higher or 0.5％,1.2％,and 5.2％ higher in the HDWSD group than in the LDWSD group;D0.1cc,D1cc,and D2cc of the bladder and rectum were significantly higher in the HDWSD group than in the LDWSD group,particularly for the sigmoid (up 44.0％,22.8％,and 16.8％) and (up 10.3％,14.4％,and 12.4％).Conclusions DWSD should be considered in plan evaluation for cervical cancer patients treated with three-dimensional brachytherapy.The dosimetric influence from applicator displacement can be decreased by reducing DWSD properly.

Arquitetura vernacular e paisagem amazônica: um caminho na busca pelo habitar poético / Vernacular architecture and the amazon landscape: a path in search of a poetic dwelling / Arquitectura vernácula y el paisaje del amazonas: un camino en busca del habitar poético

Relatar uma pesquisa é o principal objetivo deste texto. Tal pesquisa refere-se à dissertação de mestrado (Programa de Pós Graduação em arquitetura e Urbanismo - UFF) se desenvolveu em um dos lugares no qual o imaginário humano invade as profundezas da Terra. Assim a Amazônia é o lugar no qual o fenômeno estudado se revelou: o habitar poético através do qual o ribeirinho se "demora" sobre a Terra, travando com ela uma relação visceral. Tomando como abordagem metodológica os princípios fenomenológicos, é com base na ontologia Heideggeriana e tendo a poética de Bachelard como meio de abertura para o mundo, que o trabalho se desenrola, e apresenta assim a maneira como o povo ribeirinho no Amazonas habita, habitar esse que podemos ver revelado através da materialidade de suas casas - de sua arquitetura - compondo e completando a paisagem que os cerca e os invade por completo.

Report a search is the main objective of this text. This research refers to the master's thesis (Graduate Program in Architecture and Urbanism - UFF) has developed into one of the places in which the human imagination invades the depths of the earth. So Amazon is the place where the studied phenomenon was revealed: the poetic dwelling through which the river habitant is-live on Earth, catching her a visceral relationship. Taking as methodological approach the phenomenological principles proposed by Hurssel is based on Heideggerian ontology and having the Bachelard poetics as a means of opening to the world, the work unfolds, and so has the way the riverine people in Amazonas lives , inhabit this we can see revealed through the materiality of their homes, -from his Architecture-writing and completing the landscape that surrounds and invades completely.

Informará de la búsqueda es el objetivo principal de este texto. Esta investigación se refiere a la tesis de maestría (Programa de Graduados en Arquitectura y Urbanismo - UFF) se ha convertido en uno de los lugares en los que la imaginación humana invade las profundidades de la tierra. Así que Amazon es el lugar donde se reveló el fenómeno estudiado: el habitar poético a través del cual el río es-vivo en la Tierra, la captura de ella una relación visceral. Tomando como enfoque metodológico de los principios fenomenológicos com base en la ontología heideggeriana y tener la poética Bachelard como medio de apertura al mundo, el trabajo se desarrolla, y también lo ha hecho la forma en que las personas fluviales en la vida de Amazonas, habitan esto podemos ver revelado a través de la materialidad de sus hogares, - desde su Arquitectura-escritura y completar el paisaje que rodea e invade por completo.