Volumetric Assessment of the Insula in a Normally Functioning Human Brain Using Magnetic Resonance Imaging / Evaluación Volumétrica de la Ínsula en un Cerebro Humano que Funciona Normalmente Utilizando Imágenes de Resonancia Magnética

SUMMARY: Volumetric assessment of brain structures is an important tool in neuroscience research and clinical practice. The volumetric measurement of normally functioning human brain helps detect age-related changes in some regions, which can be observed at varying degrees. This study aims to estimate the insular volume in the normally functioning human brain in both genders, different age groups, and side variations. A cross-sectional retrospective study was conducted on 42 adult Sudanese participants in Al-Amal Hospital, Sudan, between May to August 2022, using magnetic resonance imaging (MRI) and automatic brain segmentation through a software program (BrainSuite). The statistical difference in total insular volume on both sides of the cerebral hemisphere was small. The insular volume on the right side was greater in males, while the left side showed no difference between both genders. A statistically significant difference between males and females was found (p > 0.05), and no statistical difference in different age groups was found according to the one-way ANOVA test (p>0.05). Adult Sudanese males showed a larger insular volume than females. MRI can be used to morphometrically assess the insula to detect any pathological variations based on volume changes.

La evaluación volumétrica de las estructuras cerebrales es una herramienta importante en la investigación y la práctica clínica de la neurociencia. La medición volumétrica del cerebro humano, que funciona normalmente, ayuda a detectar cambios relacionados con la edad en algunas regiones, las cuales se pueden observar en diversos grados. Este estudio tuvo como objetivo estimar el volumen insular en el cerebro humano que funciona normalmente, en ambos sexos, de diferentes grupos de edad y sus variaciones laterales. Se realizó un estudio retrospectivo transversal en 42 participantes sudaneses adultos en el Hospital Al-Amal, Sudán, entre mayo y agosto de 2022, utilizando imágenes de resonancia magnética y segmentación automática del cerebro a través de un software (BrainSuite). Fue pequeña la diferencia estadística en el volumen insular total, en los hemisferios cerebrales. El volumen insular del lado derecho fue mayor en los hombres, mientras que el lado izquierdo no mostró diferencia entre ambos sexos. Se encontró una diferencia estadísticamente significativa entre hombres y mujeres (p > 0,05), y no se encontró diferencia estadística en los diferentes grupos de edad, según la prueba de ANOVA de una vía (p> 0,05). Los hombres sudaneses adultos mostraron un mayor volumen insular que las mujeres. La resonancia magnética se puede utilizar para evaluar morfométricamente la ínsula y para detectar cualquier variación patológica basada en cambios de volumen.

The effect of primary tumor volume on the prognosis of nasopharyngeal carcinoma in era of volumetric modulated arc therapy: a propensity score matched cohort study

Abstract Objective The role of Primary Tumor Volume (PTV) in Nasopharyngeal Carcinoma (NPC) treated with Volumetric Modulated Arc Therapy (VMAT) is still unclear. The aim of this study was to access the effect of PTV in prognosis prediction of nasopharyngeal carcinoma in era of VMAT. Methods Between January 20 and November 2011, 498 consecutive NPC patients with stage I-IVA disease who received VMAT at a single center were retrospectively analyzed. Receiver Operating Characteristic (ROC) was performed to access the cut-off point of PTV. Univariate Kaplan-Meier and multivariate Cox regression analyses were used to evaluate prognostic value for PTV. The Propensity Score Matching (PSM) was used to adjust baseline potential confounders. Results The 5-year Locol-Regional Failure-Free (L-FFR), Distant Failure-Free Survival (D-FFR), Disease-Free Survival (DFS) and Overall Survival (OS) were 90.6%, 83.7%, 71.5% and 79.3%, respectively. Before PSM, the 5-year L-FFR, D-FFR, DFS, OS rates for NPC patients with PTV ≤ 38 mL vs. PTV > 38 mL were 94.1% vs. 90.4% (p= 0.063), 87.9% vs. 76.3% (p< 0.001), 78.5% vs. 58.5% (p< 0.001) and 86.3% vs. 66.7% (p< 0.001) respectively. Multivariate analysis showed PTV was an independent prognostic factor for D-FFS (p= 0.034), DFS (p= 0.002) and OS (p= 0.001). PTV classified was still an independent prognostic factor for OS after PSM (HR = 2.034, p= 0.025. Conclusions PTV had a substantial impact on the prognosis of NPC patients treated with VMAT before and after PSM simultaneously. PTV > 38 mL may be considered as an indicator of the clinical stage of nasopharyngeal carcinoma. Level of evidence III.

Correlation between monitor units and pass rate of plan dose verification in VMAT plan for different cancers / 中华放射肿瘤学杂志

Objective:To analyze the correlation between the monitor units and pass rate of plan dose verification in the volumetric intensity modulated arc therapy (VMAT) plan.Methods:VMAT plans for 20 patients with nasopharyngeal carcinoma (NPC) and 30 patients with cervical cancer who underwent radiotherapy at Liuzhou Workers' Hospital from January to October 2020 were retrospectively chosen. The Detector 1500 array and Octavius 4D phantom from German PTW company were used for dose measurement. The pass rates of dose verification of relevant plans were analyzed under the conditions of 3%/2 mm and 2%/2 mm. The correlation between the monitor units and pass rate of plan dose verification in VMAT plans was assessed by Pearson's bivariate correlation analysis.Results:Under the condition of 3%/2 mm, the correlation coefficients between the monitor units and gamma pass rate were -0.873 ( P<0.001), -0.800 ( P<0.001), -0.781 ( P<0.001), -0.493 ( P=0.006) for NPC_1Arc, NPC_2Arc, NPC_1Arc+NPC_2Arc and Cervix_2Arc, respectively. Under the condition of 2%/2 mm, the correlation coefficients between the monitor units and gamma pass rate were -0.842 ( P<0.001), -0.770 ( P<0.001), -0.748 ( P<0.001) and -0.531 ( P=0.003) for NPC_1Arc, NPC_2Arc, NPC_1Arc+NPC_2Arc and Cervix_2Arc, respectively. Conclusion:Significant negative correlation can be observed between the monitor units and plan dose verification pass rate in VMAT plan.

Comprehensive comparison between Halcyon 2.0 and Truebeam VMAT plans for different treatment sites: dosimetric quality and plan complexity / 中华放射肿瘤学杂志

Objective:To analyze the differences in dosimetric quality and plan complexity of volumetric modulated arc therapy (VMAT) plans based on Halcyon 2.0 and Truebeam for different treatment sites of the patients.Methods:Halcyon 2.0 VMAT plans in head & neck, chest, abdomen, and pelvis treatment sites of 49 cases were retrospectively selected and the VMAT plans were re-designed based on Truebeam with the same optimization parameters. The differences in dosimetric metrics and plan complexity between the two types of plans were compared and analyzed. P<0.05 was considered as statistically significant. Results:In terms of PTV, Halcyon 2.0 plans showed better homogeneity index (HI), conformal index (CI) in the head & neck and chest. Besides, Halcyon 2.0 plans yielded better D 98% and CI in the abdomen and better D 2% in the pelvis. For organs at risk (OAR), the D 20% and D mean of bilateral lungs, and D meanof heart for Halcyon 2.0 plans in the chest were lower than those for Truebeam plans (all P<0.05). For the complexity metrics, the median average aperture area variability (AAV) of Halcyon 2.0 plans in the head & neck, abdomen and pelvis were 0.414, 0.425 and 0.432, which were better than 0.385, 0.368 and 0.361 of Truebeam plans in the corresponding sites, respectively. In the abdomen and pelvis, Halcyon 2.0 plans showed better median modulation complexity score (MCS) than Truebeam plans (0.320 vs. 0.268, 0.303 vs. 0.282; both P<0.05). The median small aperture score (SAS) for all plans of Halcyon 2.0 were better than that of Truebeam plans (all P<0.05), and the median plan average beam area (PA) of all plans of Halcyon 2.0 were larger than that of Truebeam plans (all P<0.05). Conclusions:Compared with conventional fractionated VMAT plans based on Halcyon 2.0 and Truebeam, Halcyon 2.0 plans have similar or even better dosimetric quality. However, Halcyon 2.0 plans have lower plan complexity, which makes it an advantage in clinical application.

Effect of rotational errors on dose of positive lymph nodes in cervical cancer VMAT plan and its coping strategies / 中华放射肿瘤学杂志

Objective:To evaluate the effect of rotational errors (antero-posterior) on dosimetric parameters of positive lymph nodes in the long target volumetric modulated arc therapy (VMAT) plan for advanced cervical cancer and investigate its coping strategies.Methods:Clinical data of patients with cervical cancer complicated with para-aortic or inguinal lymph node metastasis admitted to Affiliated Hospital of North Sichuan Medical College were randomly selected and retrospectively analyzed. The target areas of the lymph nodes at different distances from the center of the plan were outlined according to the requirements. After designing the VMAT plan on the CT images of each case, the rotational errors (antero-posterior) were introduced by changing the parameters of the treatment couch, and the dose distribution was reconstructed by dose calculation with other parameters unchanged. Then, the external boundary of the original lymph node target was added according to d=2πr(α/360) ( r is the distance from the center of the lymph node to the plan center), re-planned, and the changes of dosimetric parameters in the target area of the original lymph node were analyzed after the corresponding rotational errors were introduced. Results:When the distance between the lymph node target area and the plan center was 6 cm with an error of 3°, the distance was 9 cm and 12 cm with an error of 2.5°, the distance was 15 cm with an error of 2°, and the distance was 18 cm with an error of 1.5°, the mean change of D 95% was more than 5%. When the rotational errors were ≤1°, the mean change of D 95% in lymph node target area was less than 5%, and when the lymph node was 18 cm away from the treatment plan center, the mean change was more than 3%, reaching 3.75%. When the rotational errors were 0.5° and the distance from the plan center was 18 cm (0.5°, 18 cm), the dose change of lymph node target was more than 5%, reaching 5.58%. At (1°, 15 cm), the V 100% change reached 8.96%, and at (1°, 18 cm), the V 100% change was 14.5%. The D 95% and V 100% parameters of the original lymph node target were changed by less than 1% after adding the external boundary of the original lymph node target and introducing corresponding rotational errors. Conclusions:In the long target area radiotherapy of cervical cancer, the variation of dosimetric parameters of lymph node target was increased with the increase of rotational errors and with the increase of distance from the plan center. It is recommended to increase the efferent boundary of lymph nodes in different positions to avoid underdose by d=2πr(α/360).

Application of bedside ultrasound in the evaluation of volume responsiveness in patients with septic shock / 中国医师杂志

Objective:To evaluate the value of bedside ultrasound in evaluating volume responsiveness of patients with septic shock.Methods:A total of 102 patients with septic shock admitted to ICU of the First Affiliated Hospital of Hebei North University from April 2018 to February 2021 were selected. Patients were divided into response group and non-response group according to the value of stroke volume increase (ΔSV) after volume loading test (VE), and the hemodynamic parameters before and after VE were compared between the two groups. Pearson correlation was used to analyze the relationship between ΔSV and hemodynamic indexes. Receiver operating characteristic (ROC) curve was drawn to analyze the sensitivity and specificity of each hemodynamic index in evaluating volumetric reactivity in patients with septic shock.Results:Of the 102 patients, 54 responded and 48 did not. Before VE, the distensibility index of inferior vena cava (ΔIVC 1), espiratory variability index of inferior vena cava (ΔIVC 2), respiratory variability of aortic peak velocity (ΔVpeak AO), brachial artery maximum velocity variability (ΔVpeak BA) and respiratory rate of peak flow velocity of femoral artery (ΔVpeak CFA) in response group were higher than those in non-response group (all P<0.05), but there was no statistical significance in heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) between 2 groups (all P>0.05). After VE, the HR, ΔIVC 1, ΔIVC 2, ΔVpeak AO, ΔVpeak BA and ΔVpeak CFA in response group were significantly decreased, while MAP and CVP were significantly increased (all P<0.05). The CVP was significantly decreased in the non-response group ( P<0.05), while other indexes were not significantly changed. Before VE, the ΔIVC 1, ΔIVC 2, ΔVpeak AO, ΔVpeak BA and ΔVpeak CFA were positively correlated with ΔSV ( r=0.589, 0.647, 0.697, 0.621, 0.766; all P<0.05). There was no correlation between CVP and ΔSV ( r=-0.345, P>0.05). Before VE, the area under the curve of ΔIVC 1, ΔIVC 2, ΔVpeak AO, ΔVpeak BA and ΔVpeak CFA were all >0.7, indicating high sensitivity and specificity. Conclusions:Bedside ultrasound monitoring ΔIVC, ΔVpeak AO, ΔVpeak BA and ΔVpeak CFA can better evaluate the volume response of patients with septic shock, and can provide a reference basis for clinical fluid resuscitation treatment.

Study on the sensitivity of a volumetric modulated arc therapy plan verification equipment on multi-leaf collimator opening and closing errors and its gamma pass rate limit / 生物医学工程学杂志

To investigate the γ pass rate limit of plan verification equipment for volumetric modulated arc therapy (VMAT) plan verification and its sensitivity on the opening and closing errors of multi-leaf collimator (MLC), 50 cases of nasopharyngeal carcinoma VMAT plan with clockwise and counterclockwise full arcs were randomly selected. Eight kinds of MLC opening and closing errors were introduced in 10 cases of them, and 80 plans with errors were generated. Firstly, the plan verification was conducted in the form of field-by-field measurement and true composite measurement. The γ analysis with the criteria of 3% dose difference, distance to agreement of 2 mm, 10% dose threshold, and absolute dose global normalized conditions were performed for these fields. Then gradient analysis was used to investigate the sensitivity of field-by-field measurement and true composite measurement on MLC opening and closing errors, and the receiver operating characteristic curve (ROC) was used to investigate the optimal threshold of γ pass rate for identifying errors. Tolerance limits and action limits for γ pass rates were calculated using statistical process control (SPC) method for another 40 cases. The error identification ability using the tolerance limit calculated by SPC method and the universal tolerance limit (95%) were compared with using the optimal threshold of ROC. The results show that for the true composite measurement, the clockwise arc and the counterclockwise arc, the descent gradients of the γ passing rate with per millimeter MLC opening error are 10.61%, 7.62% and 6.66%, respectively, and the descent gradients with per millimeter MLC closing error are 9.75%, 7.36% and 6.37%, respectively. The optimal thresholds obtained by the ROC method are 99.35%, 97.95% and 98.25%, respectively, and the tolerance limits obtained by the SPC method are 98.98%, 97.74% and 98.62%, respectively. The tolerance limit calculated by SPC method is close to the optimal threshold of ROC, both of which could identify all errors of ±2 mm, while the universal tolerance limit can only partially identify them, indicating that the universal tolerance limit is not sensitive on some large errors. Therefore, considering the factors such as ease of use and accuracy, it is suggested to use the true composite measurement in clinical practice, and to formulate tolerance limits and action limits suitable for the actual process of the institution based on the SPC method. In conclusion, it is expected that the results of this study can provide some references for institutions to optimize the radiotherapy plan verification process, set appropriate pass rate limit, and promote the standardization of plan verification.

A preliminary survey of female breast characteristics based on three-dimensional images of breast cone-beam computed tomography / 中国辐射卫生

Objective To establish a method to characterize the size and density of the female breast based on three-dimensional images of breast cone-beam computed tomography (CBCT), and describe the breast characteristics of women in a region of China, and to explore its value in dosimetric assessment for breast CBCT examinees. Methods We retrospectively surveyed the breast CBCT images of 203 women in a grade A tertiary hospital in a southwestern city of China from January 2021 to March 2023. The effective diameter of the breast at the chest-wall (Deff), chest wall-to-nipple length (CNL), the effective diameter of the breast at half of CNL (Dh/2), breast volume (BV), glandular volume (GV), and volumetric breast density (VBD) were measured using the specific tools of the Koning Imaging Viewer system. The differences between groups were assessed using the Kruskal-Wallis H test. The correlation between variables was assessed using the Spearman’s correlation coefficient. Results The median values of Deff, Dh/2, CNL, BV, GV, and VBD of the surveyed population were 11.9 cm, 8.3 cm, 6.5 cm, 327.7 cm3, 47.0 cm3, and 15.4%, respectively. GV and VBD had significant negative correlations with age. Deff, Dh/2, CNL, and BV were significantly negatively correlated with VBD. Conclusion We established a quantitative method to analyze female breast characteristics based on three-dimensional breast CBCT images, and preliminarily characterized the female breast in a region of China, which can provide methodological support for the investigation of female breast characteristics in various regions of China in the future.

Determinação do período de estabilidade de soluções volumétricas rotineiramente utilizadas em laboratórios de análises químicas / Determination of the stability period of volumetric solutions routinely used in chemical analysis laboratories / Determinación del período de estabilidad de las soluciones volumétricas utilizadas habitualmente en los laboratorios de análisis químicos

As soluções volumétricas são rotineiramente utilizadas nos laboratórios, principalmente nos processos de síntese de produtos e nas análises quantitativas de matéria-prima e/ou produto acabado, entretanto poucos são os estudos que abordam a estabilidade destas soluções. Considerando que a qualidade das soluções volumétricas pode afetar os procedimentos de análises químicas e consequentemente induzir a erros, e ainda que, a Farmacopeia Brasileira (2010) não cita tempo máximo de utilização dessas soluções padronizadas, a avaliação da estabilidade das mesmas é importante. Sendo assim, o objetivo do trabalho foi avaliar a estabilidadede 10 soluções volumétricas, empregadas rotineiramente em laboratórios de análises químicas, com o intuito de estabelecer o período que essas soluções permanecem estáveis, isto é, sem sofrer alteração na concentração. As metodologias de preparo e padronização das soluções volumétricas seguiram os métodos descritos na Farmacopeia Brasileira (2010), sendo as mesmas padronizadas no momento do preparo e a cada 20 dias, por um período de 180 dias. As soluções contendo ácidos e bases, bem como as soluções de iodato de potássio e nitrato de prata, permaneceram constantes durante o período de análises. As soluções de EDTA, iodo, nitrito de sódio, permanganato de potássio e tiossulfato de sódio apresentaram estabilidade inferior a 180 dias, tornando necessária a realização de padronização periódica. As soluções volumétricas utilizadas nos laboratórios apresentam diferentes estabilidades, o que ressalta a importância da determinação do período que as mesmas se mantêmcom as concentrações estáveis, evitando possíveis alterações de resultados nas análises químicas.

Volumetric solutions are routinely used in laboratories, mainly in product synthesis processes and in quantitative analyzes of raw materials and/or finished products, however there are few studies that address the stability of these solutions. Considering that the quality of volumetric solutions can affect chemical analysis procedures and consequently induce errors, and even though the Brazilian Pharmacopoeia (2010) does not mention the maximum time for using these standardized solutions, the evaluation of their stability is important. Therefore, the aim of this work was to evaluate the stability of 10 volumetric solutions, routinely used in chemical analysis laboratories, in order to establish the period that these solutions remain stable without changing their concentrations. The methodologies for preparing and standardizing the volumetric solutions followed the methods described in the Brazilian Pharmacopoeia (2010), being standardized at the time of preparation and every 20 days, for a period of 180 days. Solutions containing acids and bases, as well as potassium iodate and silver nitrate solutions, were stable during the analysis period. The solutions of EDTA, iodine, sodium nitrite, potassium permanganate and sodium thiosulfate showed stability less than 180 days, making it necessary to carry out periodic standardization of these solutions. The volumetric solutions used in the laboratories have different stabilities, which highlights the importance of determining the period in which they remain stable, avoiding possible changes in results in chemical analyzes.

Las soluciones volumétricas se utilizan de forma rutinaria en los laboratorios, principalmente en los procesos de síntesis de productos y en el análisis cuantitativo de materias primas y/o productos acabados. Sin embargo, existen pocos estudios que aborden la estabilidad de estas soluciones. Considerando que la calidad de las soluciones volumétricas puede afectar los procedimientos de análisis químico y consecuentemente inducir a errores, y también que, la Farmacopea Brasileña (2010) no menciona el tiempo máximo de uso de estas soluciones estandarizadas, la evaluación de su estabilidad es importante. Así, el objetivo del trabajo fue evaluar la estabilidad de 10 soluciones volumétricas, utilizadas rutinariamente en los laboratorios de análisis químico, con el fin de establecer el período en que estas soluciones permanecen estables, es decir, sin sufrir alteraciones en la concentración. Las metodologías de preparación y estandarización de las soluciones volumétricas siguieron los métodos descritos en la Farmacopea Brasileña (2010), siendo las mismas estandarizadas en el momento de la preparación y cada 20 días, por un período de 180 días. Las soluciones que contienen ácidos y bases, así como las soluciones de yodato de potasio y nitrato de plata, permanecieron constantes durante el periodo de análisis. Las soluciones de EDTA, yodo, nitrito de sodio, permanganato de potasio y tiosulfato de sodio fueron estables durante menos de 180 días, por lo que fue necesario realizar estandarizaciones periódicas. Las soluciones volumétricas utilizadas en los laboratorios presentan diferentes estabilidades, lo que pone de manifiesto la importancia de determinar el periodo que permanecen con concentraciones estables, evitando posibles cambios en los resultados en los análisis químicos.

Capnografia volumétrica para monitoração respiratória de pacientes submetidos a colonoscopia diagnóstica com insuflação de ar comprimido e gás carbônico / Volumetric capnography for respiratory monitoring of patients during routine colonoscopy with room-air and carbon dioxide insufflation

ABSTRACT Background: Capnography and carbon dioxide (CO2) insufflation during gastrointestinal endoscopy under sedation are associated with safety and comfort improvements, respectively. Capnography can provide early detection of apnea and hypoxemia, whereas CO2 insufflation causes lower periprocedural discomfort. This is the first study to report the application of volumetric capnography in colonoscopy. Objective: This study aimed to evaluate the use of volumetric capnography with room air (RA) and CO2 insufflation during routine colonoscopy. Methods: In this prospective cohort study, 101 patients who underwent routine colonoscopy under sedation with volumetric capnography monitoring were included. Insufflation with RA was used to distend the intestinal lumen in group 1 (n=51), while group 2 (n=50) used CO2 insufflation. The primary endpoints were episodes of hypoxia, alveolar hypoventilation, and end-tidal CO2 (EtCO2). The secondary endpoints were tidal volume per minute, consumption of sedation medications, and post-procedure pain using the Gloucester modified pain scale. Results: The number of episodes of hypoxia (SpO2<90%) was similar between the groups: four episodes in Group 1 and two episodes in Group 2. The duration of hypoxia was significantly longer in group 2 (P=0.02). Hypoalveolar ventilation (EtCO2) occurred more frequently in Group 2 than in Group 1 (27 vs 18 episodes, P=0.05). Regarding EtCO2, Group 2 showed higher values in cecal evaluation (28.94±4.68 mmHg vs 26.65±6.12 mmHg, P=0.04). Regarding tidal volume per minute, Group 2 had significantly lower values at the cecal interval compared to Group 1 (2027.53±2818.89 vs 970.88±1840.25 L/min, P=0.009). No episodes of hypercapnia (EtCO2 > 60 mmHg) occurred during the study. There was no difference in the consumption of sedation medications between the groups. Immediately after colonoscopy, Group 2 reported significantly less pain than Group 1 (P=0.05). Conclusion: In our study, volumetric capnography during colonoscopy was feasible and effective for monitoring ventilatory parameters and detecting respiratory complications. CO2 insufflation was safe and associated with less pain immediately after colonoscopy.

RESUMO Contexto: A capnografia e a insuflação de gás carbônico (CO2) durante endoscopia digestiva sob sedação são associados à maior segurança e conforto do paciente, respectivamente. A capnografia pode detectar precocemente a apneia e hipoxemia, enquanto a insuflação de CO2 causa menor desconforto periprocedimento. Relatos da aplicação da capnografia volumétrica em colonoscopias são escassos. Objetivo: Avaliar o uso de capnograifa volumétrica durante colonoscopia diagnóstica com insuflação de ar comprimido e CO2. Métodos: Em estudo prospectivo de coorte, foram incluídos um total de 101 pacientes submetidos a colonoscopia diagnóstica sob sedação com monitoração respiratória por meio de capnografia volumétrica. Insuflação com ar comprimido foi usado para distender o lúmen intestinal no Grupo 1 (n=51), enquanto o Grupo 2 (n=50) utilizou CO2 para insuflação. Objetivos primários foram avaliar episódios de hipóxia, hipoventilação alveolar e CO2 expirado (EtCO2). Objetivos secundários foram avaliar o volume alveolar por minuto, consumo de sedativos e a dor pós-colonoscopia por meio da Escala de Dor Modificada de Gloucester. Resultados: O número de episódios de hipóxia (SpO2 <90%) foi semelhante entre os grupos: quatro episódios no Grupo 1 e dois episódios no Grupo 2. A duração da hipóxia foi significativamente maior no Grupo 2 (P=0,02). A hipoventilação alveolar (EtCO2 ≥25% do valor basal) ocorreu mais frequentemente no Grupo 2 quando comparado ao Grupo 1 (27 vs 18 episódios, P=0,05). Em relação ao EtCO2, o Grupo 2 apresentou valores maiores no momento de aferição cecal (28.94±4.68 vs 26.65±6.12 mmHg, P=0,04). Quanto ao volume alveolar por minuto, o Grupo 2 apresentou valores significativamente menores no momento de aferição cecal quando comparado ao Grupo 1 (2027.53±2818.89 vs 970.88±1840.25 L/min, P=0,009). Não houve ocorrência de hipercapnia durante o estudo (EtCO2 >60 mmHg). Não houve diferença em relação ao consumo de sedativos entre os dois grupos. Imediatamente após a colonoscopia, o Grupo 2 apresentou significativamente menos dor que o Grupo 1 (P=0,05). Conclusão: Em nosso estudo, a capnografia volumétrica durante colonoscopia foi factível e eficaz para monitorar parâmetros ventilatórios e detectar complicações respiratórias, e a insuflação com CO2 foi segura e associada a menor dor imediatamente pós-colonoscopia.

The application and correlation study of γ rule and DVH evaluation for VMAT dose verification evaluation of cervical cancer patients / 中华放射肿瘤学杂志

Objective:To evaluate the volumetric modulated arc therapy (VMAT) dose verification of cervical cancer based on γ rule and dose volume histogram (DVH) and to perform correlation analysis between the evaluation results and the dose differences.Methods:Twenty cervical cancer VMAT plans were selected and performed on TrueBeam Linac. The delivered point and surface dose was measured by FC-65 G and ArcCheck and the results were compared to those calculated by Eclipse. The dose of patients was reconstructed by 3DVH. Then, differences between the reconstructed and plan value of D mean, D 95%, D 98% and D 2% of PTV, V 20Gy of left and right femoral head, V 40Gy of rectum, D 1cm 3 of cord, D 98%, D 2% and D 50% of the 50% prescription iso-dose volume (IDV), were evaluated and 3-dimensional (3D) γ was assessed for each organ. Lastly, Pearson’s correlation coefficient was used to analyze the relationship between point dose difference, 2D γ pass-rate (γ%), γ mean and 3D γ% of each organ and the dose difference. Results:Small differences were found between the point dose measured, reconstructed and the plan value. Differences between D mean of PTV, all dose parameters of IDV and plan values were all within 3% and V 40Gy of rectum showed the largest difference. As for the 3D γ%, the maximum pass rate was found for the left and right femoral head and the maximum variance for cord D 1cm 3. There was a moderate correlation between measured and reconstructed point dose deviation and dose difference of each organ, while no significant correlation was found for 2D γ%. Strong correlation was found between 3D γ% of target and D 50% of PTV/IDV and no correlation was found for other organs. Conclusion:The performance of both γ-and DVH-based evaluation can reveal dose error for dose verification, but both of them have some limitations and should be combined in clinical practice.

The realization modes of non-coplanar radiotherapy technology / 中华放射肿瘤学杂志

Non-coplanar radiotherapy is a kind of radiotherapy technology which employs multiple non-coplanar fixed fields or non-coplanar arcs. The non-coplanar field can be defined that the central axis of each field is not on the same plane, while the non-coplanar arc can be described that the trajectory formed by each arc is not on the same plane. Compared with coplanar radiotherapy, non-coplanar radiotherapy can achieve multi-angle or multi-radian irradiation, which effectively improves the focusing level of ray and is beneficial to enlarge the radiation dose of the target area between the surrounding normal tissues. Its dosimetric advantages have been proven in multiple types of tumors, such as intracranial tumors, liver cancer and lung cancer, etc. Multiple approaches can be employed to realize non-coplanar radiotherapy, which can be divided into the non-coplanar conic radiotherapy, non-coplanar conformal radiotherapy, non-coplanar intensity-modulated radiotherapy and non-coplanar volumetric modulated arc therapy according to the established sequence. In this review, the development process and principal characteristics of these implementations were summarized.

Feasibility and safety of simultaneous integrated boost in volumetric modulated arc therapy for early breast cancer after breast-conserving surgery / 肿瘤研究与临床

Objective:To investigate the feasibility and adverse reactions of simultaneous integrated boost (SIB) in volumetric modulated arc therapy (VMAT) for early breast cancer after breast-conserving surgery.Methods:A total of 67 patients with early breast cancer after breast-conserving surgery at Zhongshan People's Hospital from September 2019 to May 2021 were enrolled. All patients received VMAT-SIB to the whole breast and tumor bed. The total breast dose and tumor bed dose were 40.5Gy/15 times every 3 weeks and 48 Gy/15 every 3 weeks respectively. The exposure dose of organs at risk and acute adverse reactions of radiotherapy were evaluated.Results:The average doses of planning target volume of the whole brease (PTV WB) and planning target volume of the boost(PTV BOOST) were (42.0±2.1) Gy and (49.9±0.8) Gy, respectively. The V 95% and V 105% of PTV WB and PTV BOOST were (98.8±1.2)% and (31.4±11.3)%, (99.8±0.6)% and (22.9±10.2)%, respectively. The V 5Gy, V 20Gy, V 30Gy and mean dose (D mean) of ipsilateral lung were (52.4±12.0)%, (15.3±4.5)%, (6.7±2.2)% and (11.0±2.4) Gy respectively. The V 18Gy, V 40Gy and D mean of heart were 3.80% (0.48%,9.60%), 0 (0,0.16%) and (6.7±2.1) Gy respectively. At the end of radiotherapy, 19 patients (29%) of all 67 patients had no acute skin toxicity, 41 patients (61%) showed radiation erythema, 5 patients (7%) had radioactive dry peeling and 2 patients (3%) had wet peeling mainly located in the nipple, areola area and breast folds. None of the patients had grade 3-4 acute skin reactions. Breast swelling and breast pain were found respectively in 9 patients (13%) and 7 patients (10%). No local recurrence or distant metastases were observed during the follow-up period. The 2-year disease-free survival rate was 100%. Conclusions:VMAT combined with SIB is feasible in the treatment of early breast cancer. The adverse reactions of radiotherapy are mild and well tolerated.

Complexity score-based plan quality control of VMAT / 中华放射肿瘤学杂志

Objective:To explore the difference in the complexity of different treatment planning systems, multi-leaf collimator (MLC) types and treatment sites of volume-modulated arc therapy (VMAT), and propose a complexity score for plan quality control.Methods:Statistical analysis of 12 complexity metrics including Monaco and Eclipse, Agility, Millennium and High-definition MLC, nasopharyngeal, lung and cervical cancer was performed. Spearman correlation coefficient between complexity metrics was calculated. Principal component analysis was conducted to reduce the dimensionality of the original data set to the first two principal components and explain its physical meaning. Complexity score based on the principal components was calculated to establish warning and action thresholds for plan quality control. The correlation between complexity metrics and γ pass rate was analyzed.Results:Except cervical cancer aperture sub-regions metric, other metrics had significant differences between Monaco and Eclipse. Monaco MLC had a more regular field but higher MU, smaller leaf gap, and longer leaf travel distance. High-definition MLC with smaller leaf width significantly added MLC aperture-related metrics. The first two principal components explained over 80% of the total variance of the original dataset, complexity score was weighted average of first two principal components. The distribution of complexity score for different equipment and sites was different. The warning threshold was expressed as the average plus standard deviation, and the action threshold was expressed as the average plus 2 standard deviations. Complexity metrics and complexity scores had small correlation with γ pass rate, showing weak or irrelevant but statistically significant. Conclusions:Different planning systems, MLC types, and treatment site complexity metrics are significantly different. The complexity score is a useful tool for plan quality control.

Preliminary imaging study on the distribution of female Volumetric Breast Density / 中华放射医学与防护杂志

Objective:To describe the distribution of volumetric breast density(VBD) in different ages of Chinese women based on X-ray mammograms.Methods:Based on mammographic images of 1 140 patients from January 2010 to December 2016 in a hospital in Beijing, the VBD of women was assessed by Volpara 1.5.1 and graded according to breast imaging reporting and data system published by American College of Radiology. The patients were divided into two groups according to the median age, and the two independent samples t-test was used to compare them. The patients were also divided into four groups according to age ( <40 years, 40-49 years, 50-59 years, ≥ 60 years), and the breast thickness, breast volume, glandular volume, and VBD were compared using a One-way ANOVA analysis. Results:The median age was 50 years. The compressed breast thickness and breast volume in patients over 50 years were significantly higher than those in patients below 50 years ( t= -8.99, -7.92, P<0.001), while glandular volume and VBD were significantly lower than those below 50 years ( t= 8.11, 18.49, P<0.001). The compressed breast thickness, breast volume, glandular volume, and VBD were statistically significant different among four groups ( F=27.10, 22.34, 25.70, 122.03, P<0.001). Patients over 60 years had the lowest VBD ( t=-12.56, -15.27, -4.57, P<0.001). VBD was negatively correlated with ages ( r=0.47, P<0.001). Conclusions:The compressed breast thickness and breast volume increased with ages, while the glandular volume and VBD decreased with ages.

The application of the RapidPlan module based on O-ring accelerator in volumetric modulated arc therapy for cervical cancer / 中华放射医学与防护杂志

Objective:To study the clinical feasibility and advantages of the RapidPlan module based on Halcyon 2.0 ring medical linear accelerator in the design of volumetric modulated arc therapy (VMAT) plans after cervical cancer surgery.Methods:The data of 98 clinical cervical cancer cases were selected from the database, and VMAT artificial radiotherapy plans were designed based on Halcyon 2.0. Then, the designed plans were imported into the RapidPlan module to train the module for a prediction model with high goodness of fit. Another 20 patients after cervical cancer surgery were selected as the validation set to compare the differences in dosimetry, plan consistency, and plan execution efficiency between the manual plans and RapidPlan automatic plans.Results:The RapidPlan automatic plans could obtain dose distribution of target volume and organs at risk with the same quality as the manual plans. The RapidPlan automatic plans provided slightly inferior protection of the femoral head but superior protection of the spinal cord compared to the manual plans, and the difference was statistically significant ( t = 4.71, P<0.001). The average MU of the RapidPlan automatic plans was 687.46, which was lower than that of the manual plan (815.34), and the difference was statistically significant ( t = 6.09, P < 0.05). The portal dosimetry (PD) verification revealed that the average γ passing rate (1 mm/1%) of the RapidPlan automatic plans was 89.48%and that of the manual plans was 88.22%, and the difference was statistically significant ( t = 3.35, P < 0.05). Conclusion:RapidPlan automatic plans based on the Halcyon 2.0 platform can meet the clinical needs of the VMAT program for cervical cancer and has certain advantages.

Impact of multi-leaf collimator positioning accuracy on quality control of volumetric modulation arc therapy plan for cervical cancer treated with Elekta linear accelerator / 南方医科大学学报

OBJECTIVE@#To investigate the influence of positioning accuracy of the multi-leaf collimators (MLC) on the passing rate of the plan dose verification for volumetric modulation arc therapy (VMAT) of cervical cancer using an Elekta linear accelerator.@*METHODS@#The dose distributions were measured using Sun Nuclear's Mapcheck and Arccheck semiconductors matrix before and after MLC calibration in30 cervical cancer patients undergoing VMAT. Dosimetric comparisons were performed with 2D and 3D gamma passing rates of 3%, 3 mm and 2%, and 2 mm. The 3D gamma distribution was reconstructed with respect to the patient's anatomy using 3DVH software to evaluate the possible influence of MLC positioning accuracy.@*RESULTS@#Before and after MLC calibration, the gamma passing rates of Mapcheck were (88.80±1.81)% and (99.25 ± 0.53)% under 3% and 3 mm standard, respectively, with an average increase of 10.45%. The corresponding gamma passing rates of Arccheck were (87.61±1.98)% and (98.13±0.99)%, respectively, with an average increase of 10.52%. The gamma passing rates of 3DVH were (89.87±2.28)% and (98.3±1.15)%, respectively, with an average increase of 8.43%.@*CONCLUSION@#The MLC positioning accuracy is one of the main factors influencing dosimetric accuracy of VMAT for cervical cancer. The application of Autocal software facilitates MLC calibration and improves the accuracy and safety of VMAT delivery for cervical cancer.

Dosimetric study of volumetric modulated arc therapy and tomo direct simultaneous integrated boost for patients receiving breast-conserving surgery for left breast cancer / 国际肿瘤学杂志

Objective:To explore the dosimetry difference between volumetric modulated arc therapy (VMAT) and tomo direct (TD) in tumor bed simultaneous push radiotherapy after left breast-conserving surgery, and to provide more dosimetry reference for clinic.Methods:A total of 22 patients with left breast cancer who underwent simultaneous quantitative radiotherapy after breast-conserving surgery were selected from the Department of Radiation Oncology, Yunnan Cancer Hospital from December 2018 to June 2020. The localized CT images and target organs at risk and other structural data were collected. Two radiotherapy plans, VMAT and TD, were designed for the same patient, and the dosimetry differences of target areas and organs at risk were compared and analyzed between the two groups.Results:In terms of target dosimetry, there were statistically significant differences in the D 2% [ (59.99±0.19) Gy vs. (59.55±0.51) Gy, t=4.09, P<0.001], D 98% [ (57.19±0.08) Gy vs. (57.46±0.22) Gy, t=-5.10, P<0.001], conformal index (CI) (0.76±0.05 vs. 0.58±0.13, t=8.19, P<0.001) and homogeneity index (HI) (0.05±0.00 vs. 0.04±0.01, t=4.89, P<0.001) of the planning gross tumor volume (PGTV) between VMAT and TD plans. However, there was no statistically significant difference in the D 50% [ (58.73±0.10) Gy vs. (58.73±0.24) Gy, t=-0.03, P=0.974]. There were statistically significant differences in the D 50% [ (52.21±0.33) Gy vs. (53.00±0.72) Gy, t=-4.81, P<0.001], D 98% [ (48.44±0.43) Gy vs. (49.09±0.21) Gy, t=-6.80, P<0.001], CI (0.83±0.06 vs. 0.67±0.06, t=10.52, P<0.001) and HI (0.20±0.01 vs. 0.19±0.01, t=8.75, P<0.001) of the planned target volume (PTV) between the two plans. However, there was no statistically significant difference in the D 2% [ (59.01±0.45) Gy vs. (59.00±0.48) Gy, t=0.22, P=0.830]. In terms of organs at risk, there were statistically significant differences in the V 20 [ (18.81±2.86) % vs. (22.03±1.91) %, t=-5.36, P<0.001] and D mean [ (11.66±1.32) Gy vs. (12.85±1.46) Gy, t=-4.10, P=0.007] of left lung, V 5 [ (5.70±2.90) % vs. (0.30±0.13) %, t=16.44, P<0.001] and D mean [ (2.45±0.29) Gy vs. (0.43±0.14) Gy, t=9.09, P<0.001] of right lung, D mean [ (3.22±0.72) Gy vs. (1.69±0.80) Gy, t=5.41, P<0.001] of right breast, D 2% [ (5.37±1.97) Gy vs. (0.46±0.09) Gy, t=11.75, P<0.001] of cord between VMAT and TD plans. There were no significant differences in the V 5 of left lung [ (53.00±5.99) % vs. (50.00±7.69) %, t=1.91, P=0.061], V 5 of right breast [ (11.51±4.60) % vs. (8.06±3.49) %, t=1.59, P=0.120], V 30 [ (1.49±0.69) % vs. (1.51±0.71) %, t=-0.06, P=0.952] and D mean [ (3.99±0.97) Gy vs. (3.90±1.03) Gy, t=0.56, P=0.581] of heart between the two plans. Conclusion:TD and VMAT can meet the clinical dosimetry requirements for patients with left breast cancer after breast-conserving surgery. However, the two techniques have their own characteristics. VMAT has better conformity and TD has better uniformity. TD is significantly better than VMAT in protecting the right lung, right breast and spinal cord of healthy organs at risk. VMAT is better in protecting the left lung. Both VMAT and TD basically achieve the same protection for heart.

Application of helical tomotherapy in the treatment of synchronous bilateral breast cancer / 中华放射医学与防护杂志

Objective:To study the differences in the dosimetry and delivery time between helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) in postoperative radiotherapy of synchronous bilateral breast cancer (SBBC) and to explore the feasibility of clinical application of the HT technology.Methods:A retrospective analysis was conducted for nine SBBC patients who underwent modified radical postoperative radiotherapy in the Fourth Affiliated Hospital of Guangxi Medical University from February 2017 to May 2022. For each patient, the Precision planning system was used to formulate the HT plan, and the RayStation planning system was employed to develop the VMAT plan. All plans obtained were divided into HT group and VMAT group according to plan type. The paired sample t-test was used to compare the dosimetric parameters of the target volume and organ at risk (OAR) and delivery time between the two radiotherapy technologies. Results:The plans of both groups could meet the clinical treatment requirements. The coverage ( D95% and V100%), conformity index (CI), average dose ( Dmean), and median dose ( D50%) of the target volumes in the HT group were better than those in the VMAT group, and the differences were statistically significant ( t=-3.21, -3.39, -5.03, 3.76, 4.97, P < 0.05). The differences in the maximum dose ( D2%), minimum dose ( D98%), high dose volumes ( V107% and V110%), and homogeneity index (HI) of the target volumes between the two groups were not statistically significant ( P > 0.05). Regarding the OAR, the V20 and Dmean of both lungs in the HT group were significantly lower than those in the VMAT group, but the irradiation volume V5 of both lungs in the HT group was significantly higher than that in the VMAT group ( t=-3.01, 3.83, -2.81, P < 0.05). Moreover, V20, V30, V40, and Dmean of heart and the V20 and Dmean of liver in the HT group were significantly lower than those in the VMAT group, with statistically significant differences ( t=3.76, -2.83, -2.74, 5.93, 4.57, 4.48, P < 0.05). There was no significant difference in the radiation doses to other OARs (spinal cord, thyroid gland, and humerus head, P > 0.05). The delivery time of the HT group was significantly higher than that of the VMAT group ( t = 11.32, P < 0.05). Conclusions:Compared with VMAT, HT has greater dosimetric advantages, and can provide higher target coverage, conformability and average dose, and significantly reduce the overall radiation doses to both lungs, heart, and liver in OARs. However, the irradiation volume V5 at low-dose areas of both lungs and the delivery time in the HT group are higher than those in the VMAT group, but still meet the clinical treatment requirements. Therefore, it is feasible to apply the HT technology to the modified radical postoperative radiotherapy of SBBC.

Diagnostic value of two-dimensional ultrasound combined with volume contrast imaging and MRI in fetal corpus callosum dysplasia / 国际生物医学工程杂志

Objective:To investigate the diagnostic value of two-dimensional ultrasound combined with volumetric contrast imaging (VCI) and magnetic resonance imaging (MRI) for the developmental abnormalities of the fetal corpus callosum.Methods:Seventy-three fetuses who underwent cranial MRI within 1 week after suspected fetal corpus callosum dysplasia on ultrasound and received a definitive diagnosis in the neonatal period were retrospectively recruited for the study. The fetal corpus callosum was observed in the transverse, coronal, and sagittal views of the fetus, and the hyaline septal cavity, lateral ventricle, third ventricle, and corpus callosum were observed in the MRI scan. The diagnostic results and sensitivity of two-dimensional ultrasound combined with volumetric contrast imaging and MRI were analyzed.Results:Neonatal imaging showed that among 73 fetuses, 32 had agenesis of the corpus callosum, 29 had hypoplasia of the corpus callosum, and 12 had normal development of the corpus callosum. The differences in diagnostic results and sensitivity between 2D ultrasound combined with volumetric contrast imaging and MRI testing for agenesis of the corpus callosum were not statistically significant (all P>0.05), and the differences in diagnostic results and sensitivity for hypoplasia of the corpus callosum were statistically significant ( P<0.05). Conclusions:Both 2D ultrasound combined with volumetric contrast imaging and MRI are of high value for the diagnosis of partial-type agenesis of the corpus callosum, but MRI is more advantageous for the diagnosis of agenesis of the corpus callosum, and MRI can be a useful supplement and verification tool for ultrasound to provide a more accurate clinical diagnosis.