Реферат
Purpose: To describe the acoustic characteristics of a classroom, voice quality, fatigue, and vocal load of university professors. Methods: Exploratory, observational, longitudinal, and descriptive study with a single group of participants, including vocal monitoring data over two weeks. Acoustic characterization of the classroom, perceptual-auditory evaluation, and acoustic analysis of voice samples were conducted before and after classes. Vocal dosimetry was performed during classes, and the Vocal Fatigue Index (VFI) was assessed at the beginning of each week. Descriptive analysis of the findings was conducted, and randomization test was performed to verify the internal reliability of the judge. Results: All participants reported speaking loudly in the classroom, with the majority reporting vocal changes in the past six months, and only one participant reported a current vocal change. The classroom had acoustical measures and estimations that deviated from established standards. The professors used high vocal intensities during classes. After the classes, an increase in the absolute values of the aggregated data for CAPE-V, jitter, and fundamental frequency was found, varying within the range of normality. Furthermore, there was an observed increase in both post-lesson intensity and VFI when comparing the two-week period. Conclusions: Vocal intensities and VFI were possibly impacted by the acoustics of the classroom. The increase in average VFI between the weeks may be attributed to a cumulative fatigue sensation. Further research with a larger number of participants and in acoustically conditioned classrooms is suggested in order to evaluate collective intervention proposals aimed at reducing the vocal load on teachers.
Objetivo: Describir las características acústicas, calidad vocal, fatiga y carga vocal de profesores universitarios. Métodos: Estudio exploratorio, observacional, longitudinal, descriptivo con un solo grupo de participantes y datos de monitoreo vocal durante dos semanas. Se realizó caracterización acústica de la sala, evaluación auditiva-perceptiva y acústica de muestras de voz antes y después de las clases. Se realizó dosimetría vocal durante las clases y se verificó el Índice de Fatiga Vocal (IFV) en dos semanas. Se realizó un análisis descriptivo de los hallazgos y una prueba de aleatorización para verificar la confiabilidad interna del juez. Resultados: Todos los participantes informaron hablar en voz alta en clase, la mayoría informó cambios vocales en los últimos seis meses y solo uno informó cambios vocales actuales. La sala presentó mediciones y estimaciones acústicas fuera de las normas establecidas. Los profesores utilizaron intensidades vocales altas durante las clases. Hubo un aumento en los valores absolutos de los datos agrupados para CAPE-V, jitter y frecuencia fundamental, variando dentro de los límites normales, después de las clases. La intensidad después de las clases y el IFV, en la comparación entre las dos semanas, mostraron un aumento. Conclusiones: La dosis vocal y el IFV posiblemente se vieron afectados por la acústica del aula. El aumento del IFV medio entre semanas pudo deberse a la sensación de cansancio acumulada. Se sugieren nuevas investigaciones con un mayor número de participantes y que se realicen en la sala acondicionada acústicamente para evaluar propuestas de intervención colectiva, con el objetivo de reducir la carga vocal de los docentes.
Реферат
Objective:To design and evaluate the application value of intracavitary-interstitial brachytherapy (IC-ISBT) applicator template for locally advanced cervical cancer.Methods:MRI data of 100 patients with ⅡB-ⅣA stage cervical cancer (International Federation of Gynecology and Obstetrics 2018 staging system) before and after external beam radiation therapy (EBRT) admitted to Sun Yat-sen University Cancer Center from March 2019 to September 2020 were collected. The range of primary cervical lesions was retrospectively analyzed and compared. Based on the residual mass of patients, the corresponding high-risk clinical target volume (HR-CTV) was delineated, and the IC-ISBT applicator template was designed and initially applied to cervical cancer patients. Dosimetry analysis and efficacy evaluation were compared between the applicator template-guided ( n=37) and free-hand implantation groups ( n=63). Chi-square test or Fisher exact test was performed for categorical variables, and t-test or U-test for continuous variables. Results:The median distance between the residual tumor margin (clockwise 3, 6, 9, 12 o'clock) and the center of 100 patients with ⅡB-ⅣA stage cervical cancer after EBRT was 16.5, 14.0, 17.0 and 13.0 mm, respectively. The corresponding HR-CTV was superimposed to reconstruct the three-dimensional diagram, and the cylindrical IC-ISBT applicator template with mushroom-like head was designed and manufactured: the longest and shortest diameter of the head was 35 and 20 mm, respectively; the central channel was adapted to the uterine tube, the C1-C12 channels was arranged in inner circle, and the peripheral B1-B5 and A1-A4 pin channels were expanded bilaterally. In terms of dose coverage, there was no significant difference between the HR-CTV D 90% [(635.12±22.65) vs. (635.80±25.84) cGy], bladder D 2 cm3 [(473.79±44.78) vs. (463.55±66.43) cGy)], rectum D 2 cm3 [(396.99±73.54) vs. (408.00±73.94) cGy] and sigmoid colon D 2 cm3 [(293.07±152.72) vs. (311.31±135.77) cGy] between the template-guided and free-hand implantation groups (all P>0.05), but the HR-CTV D 98% was significantly higher [(544.78±32.07) vs. (536.78±32.04) cGy, P=0.007] and the rectum D 1 cm3 and D 0.1 cm3 were significantly lower [(438.62±69.65) vs. (453.97±67.89) cGy, P=0.016; (519.46±70.67) vs. (543.82±81.24) cGy, P=0.001] in the template-guided implantation group. In addition, there was no significant difference in the complete response rate between two groups (86% vs. 83%, P>0.05). Conclusions:This IC-ISBT applicator template is reasonably designed, and the therapeutic efficacy of the template-guided implantation is equivalent to that of free-hand implantation. The dose coverage of the target area meets the clinical demand with a better protection of the organs at risk. The applicator template has the potential to be widely used as a conventional template in clinical practice as the applicator-guided implantation is convenient to operate and repeat.
Реферат
Objective:To investigate the necessity of adaptive re-planning during radiotherapy for nasopharyngeal carcinoma (NPC) and its impact on dose improvement.Methods:Clinical data of 89 NPC patients admitted to Sun Yat-sen University Cancer Center from July 2014 to December 2017 were retrospectively analyzed. All patients received 25+7 rounds of adaptive re-planning during radiotherapy. Plan-A was defined as the initial CT scan-based 25-fraction radiotherapy plan, while plan-B was defined as the re-planned 7-fraction radiotherapy plan based on a subsequent CT scan. The changes in the target and parotid gland volumes were compared between plan-A and plan-B. Plan-I was a one-time simulation of plan-A extended to 32 fraction radiotherapy plan, and plan-II was generated through registration and fusion of the plan-A and plan-B for adaptive re-planning. The differences in dose metrics, homogeneity index (HI), conformity index (CI), and dose to organs at risk (OAR) were compared between plan-I and plan-II. Statistical analysis was performed by using paired t-test. Results:Compared with plan-A, the gross tumor volume of massive bleeding lesions (GTV nx) and parotid gland volume of plan-B were decreased by 13.14% and 11.12%, respectively (both P<0.001). While planning clinical target volume of metastatic lymph nodes (PCTV nd) of plan-B was increased by 7.75%( P<0.001). There were significant changes in the lymph nodes of plan-A and plan-B. The D mean, D 5%, D 95% of massive bleeding lesions planning target volume (PTV nx) and D 5% of high risk planning target volume (PTV1) in plan-II were all significantly higher than those in plan-I (all P<0.05). The CI of PTV nx and PTV1 in plan-II was closer to 1 than that in plan-I. In all assessed OAR, the D mean, D 50%, and D max of plan-II were significantly lower than those of plan-I (all P<0.05). Conclusions:During radiotherapy, NPC patients may experience varying degrees of primary tumor shrinkage, parotid gland atrophy, and lymph node changes. It is necessary to deliver re-planning and significantly improve the dose of target areas and OAR.
Реферат
Objective To evaluate the characteristics of dose distribution of neuronal networks in vitro on microelectrode arrays(MEAs)under 2.6 GHz radiofrequency(RF)exposure.Methods The MEAs were coupled with a real-time RF exposure setup,and electromagnetic simulation software was used to calculate the RF dose absorbed in cultured neuronal networks.A fiber-optic temperature probe was used for experimental validation and monitoring of the cell temperature during RF exposure.The MEAs were used to record the electrical activity of neurons.Results For an input power of 1 W,a specific absorption rate(SAR)level of(15.51±2.48)W/kg was calculated,and the variability of the SAR distribution was 16%.In our experimental system,the temperature elevation of neurons was up to 0.15℃for an SAR of 4 W/kg RF exposure.Conclusion The exposure device can provide high SAR efficiency and uniformity in the 2.6 GHz band,which is suitable for studying the real-time effects of RF fields on the electrical activity of neuronal networks in the 5G network band.
Реферат
Objective To explore the feasibility of automatic segmentation of clinical target volume(CTV)and organs at risk(OARs)for cervical cancer using AccuLearning(AL)based on geometric and dosimetric indices.Methods Seventy-five CT localization images with manual contouring data of postoperative cervical cancer were enrolled in this study.Sixty cases were randomly selected to trained to generate automatic segmentation model by AL,and the CTV and OARs of the remaining 15 cases were automatically contoured.Radiotherapy plans on the automatic segmentation contours were imported on the CT images of manual contours.The efficiency,Dice similarity coefficient(DSC),Hausdorff distance(HD)and dosimetric parameters were compared between the two methods.Results The time of automatic segmentation was significantly shorter than that of the manual contour(P<0.05).The DSC of all structures were≥0.87.The HD of bowel bag and rectum were about 10 mm,and that of the rest of OARs were less than 5 mm.CTV(D98,V90% ,V95% ,Dmean,HI),bowel bag(V50)and bladder(V50)had significant differences in dosimetric comparison(P<0.05).Conclusion The automatic segmentation model based on AL can improve the efficiency of radiotherapy.Automatic segmentation of OARs has the potential of clinical application,while that of CTV still needs to be further modified.
Реферат
Objective To sort out and summarize the research hotspots and trends of Chinese medicine nursing technolo-gy at the present stage.Methods We searched the research literature on TCM nursing technology included in China Knowledge,Wanfang,and Wipu build-up to November 30,2023,and used CiteSpace 6.1.R6 software to perform co-occurrence analysis of research institutions and keyword clustering,timeline,and emergence analysis.Results A total of 5 771 documents were in-cluded,with a general upward trend in the number of publications,peaking at 692 publications in 2021.5 206 documents from 673 journals were included in the research literature,of which 19 journals had ≥50 publications(35.47％).2 087 research or-ganizations were involved,of which 27 had ≥20 publications(13.24％).Involving 9 484 authors,there were a total of 8 au-thors ≥5 in the cluster,indicating the existence of stable teamwork in the cluster.The keyword co-occurrence analysis yielded the research hotspots of TCM nursing technology as TCM nursing,training,nursing management,clinical efficacy,complica-tions,and quality of life.Conclusion Based on the econometrics and visualization analysis of the literature on TCM nursing technology,we explored the research hotspots and trends in this field,and provided two theoretical paths for medical institution managers to construct and optimize the management system of TCM nursing technology:to standardize the TCM nursing technology in hospitals and establish a clinical access management system;and based on the multidimensional management method,to inno-vate the training system of TCM nursing technology.
Реферат
Objective The present situation and hotspots of KM mouse research were visualized by CiteSpace software,which provided a reference for breaking through the bottleneck of KM mouse research and finding new ideas in China.Methods A total of 3981 articles were retrieved from CNKI and Web of Science databases from January 1,2004 to June 10,2023,of which the number of publications,countries(regions),institutions,author cooperation network,keyword co-occurrence,clustering,burst words,and cited English literature for analysis.Results The number of documents published in Chinese was decreased and the number of documents published in English was increased gradually in KM mouse research.The three countries with the most published articles were China,the United States,and Japan,where the leading research institutions were the China Agricultural University,Chinese Academy of Sciences,and Nanjing University of Chinese Medicine.The main authors at home and abroad were Liu Weihui,Li Guangwu,and Zhao Xin.The domestic research focused on the toxicology,immunology,and reproduction of KM mouse,and the foreign research focused on the cell biology and physiology of KM mouse.Conclusions KM mouse have been used and popularized in our country for more than 70 years,mainly focusing on toxicology,immunology,and reproduction.Although the use of KM mouse has led tove made allowed some achievements in experiments,certain it is necessary to solve their problems in the future,such as the standardization of population breeding,the discovery of the dominant research fields,and the further promotion of animal ethics,should be resolved.
Реферат
Objective To identify the exact locations of the brain being irradiated in advanced nasopharyngeal carcinoma(NPC)patients during radiotherapy,and to analyze the differences in brain dose distribution between advanced NPC patients treated with intensity-modulated radiotherapy(IMRT)and volumetric modulated arc therapy(VMAT).Methods Based on the CT brain template provided by the Montreal Neurological Institute,the brain dose distribution was analyzed with voxel-based method.Results For advanced NPC patients,VMAT plans did not demonstrate superiority in normal brain tissue sparing,while IMRT performed better,with advantages observed in regions such as the brainstem,the posterior lobe of the cerebellum,the anterior lobe of the cerebellum,temporal lobes,occipital lobes,limbic lobes,and certain areas of the subcortical regions.Conclusion IMRT is advantageous over VMAT in protecting the normal brain tissues in advanced NPC patients.
Реферат
Objective To evaluate the dosimetric effect of three-dimensional(3D)printed headrests made of different materials in radiotherapy for head and neck tumor,and to evaluate whether the existence of customized 3D-printed headrest can be neglected during planning phase by comparing differences in target area doses,homogeneity index(HI),conformity index(CI),monitor units(MU),and organ-at-risk(OAR)dose.Methods Ten patients with head and neck tumors,including 5 cases with nasopharyngeal carcinoma and 5 with other head and neck tumors,were enrolled.The headrest contours were outlined using Monaco treatment planning system,and with the same calculation parameters,treatment plans were generated for scenarios without a headrest,with a standard headrest,and with 3D-printed headrests made of 10%filled polylactic acid and thermoplastic polyurethane.The target area doses,OAR dose,MU,and other results were recorded and subjected to statistical analysis.Results No significant differences were observed among the 4 groups(ignoring headrest,standard headrest,3D-printed headrests with 10%filled polylactic acid and thermoplastic polyurethane)in parameters such as D95,D5,Dmean,HI,CI,MU,and OAR dose(the maximum dose to the spinal cord)(P>0.05).Considering the presence of the headrest,significant differences were found in CI for nasopharyngeal carcinoma and other head and neck tumors(P<0.05).Conclusion During the planning phase,the existence of customized 3D-printed headrest can be ignored,but it should be noted that the presence of a headrest may reduce the MU in radiotherapy plans.When considering the headrest,the average CI of patients with other head and neck tumors is significantly higher than that with nasopharyngeal carcinoma.
Реферат
Objectives: This was a single-subject study, aimed to demonstrate different vocal demand situations that are typical for primary school and teacher's vocal demand response under two acoustical conditions, with and without voice amplification, during five working days. Methods: The long-term voice dosimetry with Vocal Holter Med (PR.O. Voice Srl) was carried out on a 49-year-old female teacher with voice disorders during daily teaching activities. A sound field amplification system (SFAS) PentaClass Runa was installed in the classroom. Voice dosimetry was provided under two different acoustical conditions: without SFAS (2 days) and with SFAS (3 days). Results: Phonation time percentage, sound pressure level (SPL), SPL SD, fundamental frequency (F0), F0 SD, cycle, and distance doses were investigated in seven communication scenarios (lessons, group/individual classes, sports lessons in the gym and schoolyard, breaks, lunch breaks, and other activities). The median scores of all voice parameters differed significantly between different vocal demand contexts. The significant statistical difference in the vocal demand response was in the communication situations with and without SFAS. In addition, the number of children, reverberation time, and ambient air relative humidity impacted voice SPL and the cycle dose. Conclusions: Lessons, sports lessons held in the gym or schoolyard, breaks, and lunch breaks were considered as high vocal demand communication situations requiring higher voice intensity and fundamental frequency, higher phonation time percentage, cycle, and distance doses. Group/individual work and other teacher activities during the day, unrelated to direct work with students, were categorized as low vocal demand communication scenarios.
Objetivos: Este fue un estudio de sujeto único, cuyo objetivo fue demostrar diferentes situaciones de demanda vocal típicas de la escuela primaria y la respuesta vocal de los docentes bajo dos condiciones acústicas, con y sin amplificación de voz, durante cinco días laborables. Métodos: Se llevó a cabo dosimetría vocal a largo plazo con Vocal Holter Med (PR.O. Voice Srl) durante las actividades diarias de enseñanza en una docente de 49 años con trastornos de la voz. Se instaló un sistema de amplificación de campo sonoro (SFAS) PentaClass Runa en el aula. La dosimetría vocal se realizó bajo dos condiciones acústicas diferentes: sin SFAS (2 días) y con SFAS (3 días). Resultados: Se investigaron el porcentaje de tiempo de fonación, el nivel de presión sonora (SPL), SPL SD, la frecuencia fundamental (F0), F0 SD, ciclos y dosis de distancia en siete escenarios de comunicación diferentes (clases, clases grupales/individuales, clases de educación física en el gimnasio y el patio de la escuela, recreos, almuerzos y otras actividades). Las puntuaciones medias de todos los parámetros vocales diferían significativamente entre los diferentes contextos de demanda vocal. La diferencia estadísticamente significativa en la respuesta a la demanda vocal se observó en las situaciones de comunicación con y sin SFAS. Además, el número de niños, el tiempo de reverberación y la humedad relativa del aire ambiente afectaron al SPL de la voz y la dosis de ciclo. Conclusiones: Las lecciones, las clases de educación física en el gimnasio o el patio de la escuela, los recreos y los almuerzos se consideraron situaciones de comunicación de alta demanda vocal, que requerían una mayor intensidad y frecuencia fundamental de la voz, un mayor porcentaje de tiempo de fonación y dosis de ciclo y distancia más altas. El trabajo grupal/individual y otras actividades del profesor durante el día no relacionadas con el trabajo directo con los estudiantes se categorizaron como escenarios de comunicación de baja demanda vocal.
Реферат
ABSTRACT: The aim of this work is to provide a methodology for evaluating the committed effective dose E(50) due to the incorporation of [18F] FDG in the occupationally exposed worker (OEW) of the Cyclotron-PET/CT Laboratory of the Centro de Investigación en Ciencias Atómicas, Nucleares y Moleculares (CICANUM) at Universidad de Costa Rica using in vivo measurements. The measurement system was calibrated to perform in vivo measurements and defined as the corresponding bioassay function for the radiopharmaceutical used. The conversion factor was assessed with a known activity of 18F in the geometry and measurement time established. Among the most relevant results, the measurement parameters and the calibration procedure were defined. A value of 1.73 x 103 Bq/cps for in vivo brain measurements was obtained as a conversion factor. This study provides a methodology, to evaluate the committed effective dose due to the incorporation of 18F-FDG in a radionuclide production and diagnostic center
Тема - темы
Radiation Protection , Occupational Exposure/adverse effects , Cyclotrons/instrumentation , Radiation DosageРеферат
Abstract Objective: To develop an automated co-registration system and test its performance, with and without a fiducial marker, on single-photon emission computed tomography (SPECT) images. Materials and Methods: Three SPECT/CT scans were acquired for each rotation of a Jaszczak phantom (to 0°, 5°, and 10° in relation to the bed axis), with and without a fiducial marker. Two rigid co-registration software packages-SPM12 and NMDose-coreg-were employed, and the percent root mean square error (%RMSE) was calculated in order to assess the quality of the co-registrations. Uniformity, contrast, and resolution were measured before and after co-registration. The NMDose-coreg software was employed to calculate the renal doses in 12 patients treated with 177Lu-DOTATATE, and we compared those with the values obtained with the Organ Level INternal Dose Assessment for EXponential Modeling (OLINDA/EXM) software. Results: The use of a fiducial marker had no significant effect on the quality of co-registration on SPECT images, as measured by %RMSE (p = 0.40). After co-registration, uniformity, contrast, and resolution did not differ between the images acquired with fiducial markers and those acquired without. Preliminary clinical application showed mean total processing times of 9 ± 3 min/patient for NMDose-coreg and 64 ± 10 min/patient for OLINDA/EXM, with a strong correlation between the two, despite the lower renal doses obtained with NMDose-coreg. Conclusion: The use of NMDose-coreg allows fast co-registration of SPECT images, with no loss of uniformity, contrast, or resolution. The use of a fiducial marker does not appear to increase the accuracy of co-registration on phantoms.
Resumo Objetivo: Desenvolver corregistro automático e testar seu desempenho com ou sem marcador fiducial em imagens de tomografia computadorizada de emissão de fóton único (SPECT). Materiais e Métodos: Três SPECT/CTs foram adquiridas para cada rotação de um simulador de Jaszczak em relação ao eixo da maca (0°, 5° e 10°), com e sem fiducial. Dois métodos de corregistro inelástico foram aplicados - SPM12 e NMDose-coreg -, e a porcentagem do erro quadrático médio (%RMSE) foi usada para analisar a qualidade do corregistro. Uniformidade, contraste e resolução foram medidos antes e após o corregistro. NMDose com corregistro automático foi usado para calcular a dose renal de 12 pacientes tratados com 177Lu-DOTATATE e comparado com OLINDA/EXM. Resultados: A marcação fiducial não modificou a qualidade do corregistro das imagens SPECT, medida pela %RMSE (p = 0,40). Não houve impacto na uniformidade, contraste e resolução após o corregistro de imagens adquiridas com ou sem fiduciais. Aplicação clínica preliminar mostrou tempo total de processamento de 9 ± 3 min/paciente para NMDose e 64 ± 10 min/paciente para OLINDA/EXM, com alta correlação entre ambos, apesar de menor dose renal em NMDose. Conclusão: NMDose-coreg permite o corregistro rápido de imagens SPECT, sem perda de uniformidade, contraste ou resolução. O uso da marcação fiducial não aumentou a precisão do corregistro em fantomas.
Реферат
Objective:To comprehensively evaluate the effects of different bolus usages in postmastectomy intensity-modulated radiotherapy (PM-IMRT) on doses.Methods:Fifty patients receiving PM-IMRT at Fudan University Shanghai Cancer Center from April to October 2021 were retrospectively studied. The planning target volume (PTV) was divided into four parts, namely chest wall (CW), internal mammary node, retained axillary lymph node, and supraclavicular node. The prescription dose was 50 Gy/25 fractions. Three PM-IMRT plans applying boluses with different thicknesses (3, 5 and 10 mm) were designed for each patient. The effects of different thicknesses and usage frequencies of boluses on PTV coverage, high dose volume of the CW skin, and dose to surrounding normal tissues were comprehensively evaluated.Results:When boluses were applied throughout the PM-IMRT, the PTV V95% of plans applying 10 mm-thick boluses was lower than that of plans applying 3 and 5 mm-thick boluses ( F=3.340, P < 0.05), the CI of plans applying 3 mm-thick boluses was higher than that of plans applying 5 and 10 mm-thick boluses ( F = 50.05, P < 0.05), and there was no statistically significant differences in the skin V105% and V110% of three plans( P > 0.05). Both PTV V95% and skin V105% were reduced with a decrease in the usage frequency of boluses. At a frequency of 20, PTV V95% decreased slightly (< 1%), while skin V105% decreased sharply to nearly half of the original values. At a frequency of 15, the PTV V95%, CI, and HI in the three plans showed no statistically significant dosimetric differences ( P > 0.05). The PTV Dmax of plans applying 3 mm-thick boluses was lower than that of plans applying 5 and 10 mm-thick boluses ( F = 9.21, P < 0.05). As for the dose to surrounding normal tissues, different bolus thicknesses and frequencies had negligible effects on doses to heart and lung, causing little different biological effects. Conclusions:For PM-IMRT, different bolus thicknesses have similar effects on doses to the PTV, skin, heart, and lung. Bolus usage frequency, rather than thickness, was the major factor determining the PTV coverage and the dose to CW skin.
Реферат
Objective:To investigate the level of radiation doses to adults caused by CT examination in Huai′an, and explore the local CT diagnostic reference levels (DRLs).Methods:Totally 45 CT scaners were selected to investigate the information on hospitals, equipment, scanning parameters, and radiation doses. Empirical formula were used to estimate the effective dose to adults. Nonparametric rank sum tests were used to analyze differences in radiation dose level between CT service age and hospital grade.Results:A total of 3 483 patients were collected, including 890 for head examinations, 890 for chest, 846 for abdomen, and 857 for lumbar spine. The 75% percentile values of CTDI vol to adult patients from CT scanning for head, chest, abdomen, lumbar spine examinations were 63.0, 12.4, 20.0 and 24.0 mGy, respectively. The 75% percentile values of DLP were 858.6, 416.0, 620.7 and 559.2 mGy·cm, respectively. The 75% percentile values of DLP for males was higher than those for females. There were significant statistical differences in radiation doses dependent on equipment service (head: U =10 326.00, P<0.05; chest: U=36 094.50, P<0.05; abdomen: U= 7 859.00, P<0.05; lumbar spine: U=42 408.00, P<0.05), and hospital grade (head: H=14.280, P<0.05; chest: H=17.85, P<0.05; abdomen: H=97.18, P<0.05; lumbar spine: H=138.94, P<0.05). Conclusions:The CT radiation dose levels in Huai′an city is basically consistent with standard-reommended values, which is in line with the current status of CT equipment dose levels in the country. It is necessary to strengthen the quality control and maintenance of CT equipment.
Реферат
Objective:To compare the dosimetric differences between the VenusX accelerator with an orthogonal dual-layer multi-leaf collimator (MLC) and the Varian′s CLINAC IX and EDGE accelerators with a single-layer MLC for hippocampus protection in the whole-brain radiotherapy (WBRT).Methods:Forty patients with multiple brain metastases admitted to the Radiotherapy Department of the Shanghai General Hospital from June 2021 to February 2023 were selected in this study. Three whole-brain treatment plans were designed based on the above three accelerators for each patient. Under the same prescription dose, radiation field, and plan constraints, the three plans were compared in terms of the dosimetric differences in target volumes, hippocampi, and adjacent organs at risk (OARs), as well as the execution efficiency.Results:For the planning target volume (PTV), there were statistically significant differences in approximate maximum dose ( D2) between the VenusX and IX plans ( t = 4.94, P < 0.05), in approximate minimum dose ( D98) between the VenusX and EDGE plans ( t = 5.98, P < 0.05), in the target conformity indices (CIs) between VenusX plan and EDGE plans, and between the VenusX and IX plans ( t = -6.84, -14.30; P < 0.05), and dose homogeneity indices (HIs) between the VenusX and IX plans ( t = 3.48, P < 0.05). For OARs, the maximum doses ( Dmax) and average doses ( Dmean) to bilateral hippocampi of the VenusX plan were lower than those of the EDGE and IX plans ( t = 8.59-17.11, P < 0.05); the maximum doses ( Dmax) to bilateral lenses, bilateral optic nerves, and optic chiasma of the VenusX plan were lower than those of the other two plans ( t = 2.10-20.80, P < 0.05); and the differences between the maximum doses ( Dmax) to the brain stem of the VenusX and EDGE plans were statistically significant ( t = 3.86, P < 0.05). In terms of plan execution efficiency, the number of machine jumps (MU) and the treatment time of the VenusX plan were higher than those of the EDGE and IX plans, with statistically significant differences ( t = -56.48, -56.90, P < 0.05). Conclusions:The doses to target volumes of the three treatment plans all meet the prescription requirements, and the VenusX plan outperforms the EDGE and IX plans in the protection of OARs. Despite the reduced execution efficiency, the VenusX plan shortens the actual treatment time by improving the dosage rate, thus meeting the clinical requirements.
Реферат
In recent years, the issue of "reproducibility" of scientific research results has become more and more prominent. Radiobiology is a medical science that studies the biological effect of radiation on living organisms, and there is also a serious problem of "reproducibility of findings". Inaccuracy of physical dose or incomplete dosimetric reports is one of the main causes. Use of guidelines, specifications and recommendations for dosimetric measurement, such as the standardized scoring system for dosimetric reports, will help improving the standardization and accuracy of physical dose measurement in radiobiological research. In this article, multiple guidelines and recommends for improving collaboration between radiobiology and radiation physics, as well as for dose standardization of radiobiological research were evaluated, aiming to provide reference for improving the reproducibility of radiobiological research.
Реферат
Objective:To compare dosimetric and radiobiological parameters between automatic and manual uARC plans in the treatment of esophageal cancer patients, aiming to provide reference for clinical application.Methods:High-quality uARC plans of 100 patients with esophageal cancer were selected, and the mean values of the dosimetric parameters in the target area and organs at risk (OAR) were counted, and the goal table of uRT-TPOIS intelligent plan was established. Automatic and manual uARC plans were generated with UIH (United Imaging) treatment planning system (TPS) for 21 esophageal cancer patients. The differences in mean dose (D mean), approximate minimum (D 98%) and maximum (D 2%) dose of planning target volume (PTV), homogeneity index (HI) and conformity index (CI), dose of OAR, mean planning time, monitor unit (MU), tumor control probability (TCP) and normal tissue complication probability (NTCP) were compared between automatic and manual uARC plans. Normally distributed data between two groups were compared by paired t-test, and non-normally distributed data were assessed by nonparametric Wilcoxon test. Results:The D 98% (PTV 60 Gy: P<0.001, PTV 54 Gy: P=0.001) , CI (PTV 60 Gy: P<0.001, PTV 54 Gy: P=0.002) and target volume of area covered by prescription dose (V 54 Gy: P<0.001) of the automatic uARC plans were better than those of manual uARC plans (all P<0.05). There was no significant difference in D mean or HI between the two plans [PTV 54 Gy (59.32±1.87) Gy vs. (59.13±1.64) Gy, (0.19±0.02) vs. (0.18±0.02), all P>0.05]. The D mean and D max of spinal cord of the automatic plan were better than those of the manual plan [(13.22±4.27) Gy vs. (13.75±4.44) Gy, P=0.020 and (36.99±1.67) Gy vs. (38.14±1.31) Gy, P=0.011]. There was no significant difference in the mean dose of V 20 Gy of the lung between two plans ( P>0.05), whereas the mean doses of V 5 Gy and V 10 Gy of the lung of the manual plan were less than those of the automatic plan ( both P<0. 001). Automatic uARC plan had a significantly shorter mean planning time than manual uARC plan [(11.79±1.71) min vs. (53.36±8.23) min, P<0.001]. MU did not significantly differ between two plans [(762.84±74.83) MU vs. (767.41±80.63) MU, P>0.05]. The TCP of the automatic plan was higher than that of the manual plan (PTV 60 Gy 89.15%±0.49% vs. 86.75%±6.46%, P=0.004 and PTV 54 Gy 79.79%±3.48% vs. 77.51%±5.04%, P=0.006). However, manual plan had a lower NTCP of the lung than automatic uARC plan (0.46%±0.40% vs. 0.35%±0.32%, P<0.001). There was no significant difference in NTCP of heart and spinal cord between two plans (all P>0.05). Conclusion:It is feasible to generate automatic uARC plan with uRT-TPOIS TPS for esophageal cancer patients, which can increase the target CI and shorten the plan design time.
Реферат
Objective To explore the feasibility of quartz glass for radiotherapy dosimetry through the experimental study of the thermoluminescence characteristics of synthetic quartz glass. Methods The thermoluminescence glow curves of quartz glass under different annealing conditions were analyzed, the thermoluminescence characteristics of quartz glass were studied, and the measurement parameters were optimized. Using the Co-60 reference radiation field in the National Secondary Standard Dosimetry Laboratory, the quartz glass samples under different annealing conditions were irradiated following the dose levels of radiotherapy, i.e., 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 Gy, respectively. According to the relationship between the absorbed dose of quartz glass and the relative thermoluminescence signal intensity, the linearity and dispersion of the dose response of quartz glass were obtained, and the feasibility of quartz glass for radiotherapy dosimetry was analyzed. Results The linear correlation coefficient of dose response of quartz glass under annealing condition of 430℃ for 10 min was 0.9984, and the dose response dispersion was 0.97% at the absorbed dose of 2 Gy. The linear correlation coefficient of dose response of quartz glass under annealing condition of 600℃ for 1 h was 0.9911, and the dose response dispersion was 1.4% at the absorbed dose of 2 Gy. Conclusion Preliminary results suggest that quartz glass with annealing condition of 430℃ for 10 min has the potential to be used for radiotherapy dosimetry.
Реферат
Objective:To analyze the cardiac dosimetry of lymph node irradiation in the internal breast region after left-sided breast cancer surgery and to assess its impact on patients' quality of life.Methods:The clinical data of 108 patients who underwent inverse intensity modulated radiotherapy (IMRT) after left-sided breast cancer surgery in Cancer Hospital of Nantong University from May 2019 to May 2021 were collected and retrospectively analyzed, and divided into a study group (with internal breast, 55 cases) and a control group (without internal breast, 53 cases) according to whether the postoperative radiotherapy included lymph node irradiation in the internal breast region. The dosimetric indexes of planned target area (PTV) , cardiac tolerance, serum myocardial injury markers and quality of life before and after radiotherapy were compared between the two groups.Results:In terms of PTV dosimetry, the conformality index (CI) of the study group and the control group were 0.73±0.07 and 0.75±0.08, the homogeneity index (HI) were 0.17±0.03 and 0.17±0.02, the D max were (55.69±1.02) Gy and (55.46±1.13) Gy, the D mean were (50.54±0.23) Gy and (50.48±0.21) Gy respectively, there were no statistically significant differences ( t=1.38, P=0.169; t<0.01, P>0.999; t=1.11, P=0.269; t=1.41, P=0.160) . In terms of cardiac receptivity, the D mean of the two groups were (5.93 ± 0.32) Gy, (5.64 ± 0.30) Gy, V 40 were (0.47 ± 0.10) %, (0.41 ± 0.11) %, and V 30 were (2.48 ± 0.51) %, (2.06 ± 0.49) % respectively, and there were statistically significant differences ( t=4.86, P<0.001; t=2.97, P=0.004; t=4.36, P<0.001) . The levels of serum troponin Ⅰ (cTnⅠ) before radiotherapy in the study group and the control group were (0.09±0.02) ng/ml and (0.09±0.01) ng/ml, creatine kinase isoenzyme MB (CK-MB) were (0.27±0.08) U/L and (0.25±0.08) U/L, myoglobin (MYo) were (3.84±1.02) μg/L and (3.69±0.97) μg/L, and brain natriuretic peptide (BNP) were (172.35±16.24) pg/ml and (169.81±15.93) pg/ml respectively, there were no statistically significant differences ( t<0.01, P>0.999; t=1.30, P=0.197; t=0.78, P=0.436; t=0.82, P=0.414) . One month after radiotherapy, the levels of serum cTnⅠ in the two groups were (0.09±0.03) ng/ml and (0.09±0.02) ng/ml, CK-MB were (0.29±0.09) U/L and (0.28±0.08) U/L, MYo were (4.06±1.08) μg/L and (4.01±1.03) μg/L, and BNP were (175.13±17.09) pg/ml, (172.47±16.28) pg/ml respectively, there were no statistically significant differences ( t<0.01, P>0.999; t=0.61, P=0.544; t=0.25, P=0.806; t=0.83, P=0.410) . The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) scores before radiotherapy in the study and the control groups were (60.24±5.13) points and (61.19±5.46) points, (74.12±7.20) points and (75.35±7.88) points at 1 month after radiotherapy, (77.53±7.14) points and (78.95±7.08) points at 6 months after radiotherapy, and (75.02±6.93) points and (76.68±6.74) points at 1 year after radiotherapy respectively, there were no statistically significant differences ( t=0.93, P=0.353; t=0.85, P=0.399; t=1.04, P=0.302; t=1.26, P=0.210) . The EORTC QLQ-C30 scores at 1 month, 6 months, and 1 year after radiotherapy were higher than those before radiotherapy in the two groups, and there were statistically significant differences (all P<0.001) . Conclusion:IMRT containing lymph node irradiation in the internal breast region after left breast cancer surgery brings a certain degree of increased cardiac dose, but it is feasible to control it within a certain range and does not affect the patients' cardiac function or quality of life in the short term.
Реферат
The purpose of this study is to establish and apply a correction method for titanium alloy implant in spinal IMRT plan, a corrected CT-density table was revised from normal CT-density table to include the density of titanium alloy implant. Dose distribution after and before correction were calculated and compared to evaluate the dose deviation. Plans were also copied to a spinal cancer simulation phantom. A titanium alloy fixation system for spine was implanted in this phantom. Plans were recalculated and compared with the measurement result. The result of this study shows that the max dose of spinal cord showed significant difference after correction, and the deviation between calculation results and measurement results was reduced after correction. The method for expanding the range CT-density table, which means that the density of titanium alloy was included, can reduce the error in calculation.