The Uptake and Distribution Evidence of Nano- and Microplastics in vivo after a Single High Dose of Oral Exposure / 生物医学与环境科学（英文）

OBJECTIVE@#Tissue uptake and distribution of nano-/microplastics was studied at a single high dose by gavage in vivo.@*METHODS@#Fluorescent microspheres (100 nm, 3 μm, and 10 μm) were given once at a dose of 200 mg/(kg∙body weight). The fluorescence intensity (FI) in observed organs was measured using the IVIS Spectrum at 0.5, 1, 2, and 4 h after administration. Histopathology was performed to corroborate these findings.@*RESULTS@#In the 100 nm group, the FI of the stomach and small intestine were highest at 0.5 h, and the FI of the large intestine, excrement, lung, kidney, liver, and skeletal muscles were highest at 4 h compared with the control group ( P < 0.05). In the 3 μm group, the FI only increased in the lung at 2 h ( P < 0.05). In the 10 μm group, the FI increased in the large intestine and excrement at 2 h, and in the kidney at 4 h ( P < 0.05). The presence of nano-/microplastics in tissues was further verified by histopathology. The peak time of nanoplastic absorption in blood was confirmed.@*CONCLUSION@#Nanoplastics translocated rapidly to observed organs/tissues through blood circulation; however, only small amounts of MPs could penetrate the organs.

Effects of hypoxia preconditioning on hematology-related indexes through hypoxia inducible factor-1α/ stromal cell-derived factor-1 pathway in rats / 解剖学报

[Abstract] Objective To study the role of hypoxia inducible factor-1α (HIF-1α) / stromal cell-derived factor-1 (SDF-1) pathway in high altitude hypoxia preconditioning in rat. Methods Seventy-six adult male SD rats, which through fed in low-pressure oxygen chamber (altitude 5000 m) and Xining (altitude 2260 m) to establish the rat model of hypoxia preconditioning. Rats randomly divided into 6 groups: control group (Ctrl), high altitude hypoxic preconditioning 1 day group (HHP-1d), high altitude hypoxic preconditioning 4 days group (HHP-4d), high altitude hypoxic preconditioning 15 days group (HHP-15d), high altitude hypoxic preconditioning 30 days group (HHP-30d), medium altitude hypoxic preconditioning group (MHP). 7. 0 T small animal MRI was used to observe the intracranial structure, diameter of basilar artery and cerebral blood flow in the hippocampus and brainstem regions by the sequences of T2 weighted images (T2WI) and arterial spin labeling (ASL) in the groups of Ctrl, HHP-4d, HHP-30d and MHP. In each group, blood routine was tested, the concentrations of HIF-1α, SDF-1 in serum, platelet activating factor (PAF)and P-selectin (SELP) in plasma were detected by the method of ELISA. Results In the hypoxia preconditioning groups, intracranial structure and diameter of basilar artery had no significant difference, while cerebral blood flow in the regions of brainstem and hippocampus increased significantly (P<0. 05). Meanwhile, red blood cell and white blood cell increased significantly, while platelet decreased significantly in the groups of hypoxia preconditioning (P<0. 05). Red blood cell and platelet in MHP group were closer to Ctrl group. The concentrations of HIF-1α and SDF-1 (except HHP-1d group) increased significantly in hypoxia preconditioning groups (P<0. 05).The concentrations of PAF and SELP increased significantly in HHP-1d and HHP-15d groups. The concentration of PAF decreased significantly in the HHP-4d and HHP-30d groups, and SELP decreased significantly in HHP-4d group (P<0. 05). Conclusion Hypoxia preconditioning can increase oxygen storage and immune defense capacity, improve brain reserve capacity and play the effect of brain protection through HIF-1α/ SDF-1 pathway. The best effect preconditioning was feed at medium altitude (altitude 2260 m) for 30 days.

Establishment of acute radiation-induced esophagitis model of Wistar rats based on a small animal precision radiotherapy platform / 中华放射医学与防护杂志

Objective:To establish an in vivo model of acute radiation esophagitis in Wistar rats based on a small animal precision radiotherapy platform (SARRP). Methods:Thirty-six Wistar rats were randomly divided into control group, 40, 60 and 75 Gy groups. Based on MRI images, the esophageal target area of rats was outlined and the radiotherapy plan was formulated. The rats were respectively irradiated with 0, 8, 12 and 15 Gy per day for 5 consecutive days. The changes of body weight, food intake, esophageal pathology and magnetic resonance imaging were observed.Results:The body weight of rats in 75 Gy group decreased significantly on the 6th day after irradiation (IR) ( P<0.05). The esophageal tissue of rats in each IR group was thicker than that in control ( F = 14.20, P < 0.05). HE staining showed that the formation rate of radiation-induced esophagitis in 40 Gy and 60 Gy groups were 4/5 and 5/5, respectively, mainly mild. In 75 Gy group, the incidence of radiation-induced esophagitis approached to 5/5, of which 3/5 was severe at 9 d post-IR. The pathological injury scores [ M( Q1, Q3)] of rats in each group were 0, 1.0 (0.5, 2.5), 1.0 (1.0, 2.5) and 4.0 (1.5, 6.0) on the 9th day after IR. There was significant difference between the 75 Gy group and the control group ( H=12.69, P<0.05). After dynamic monitoring of neck MRI images, it was found that the esophageal signal of rats in each IR group increased and widened at 9 d post-irradiation. Conclusions:The animal model of acute radiation-induced esophagitis in rats was successfully established based on a small animal precision radiotherapy platform combined with MRI. 75 Gy was the best irradiation dose and the 9th day was the best observation time point.

Effects of different irradiators on the establishment of osteoradionecrosis model of rat mandible / 华西口腔医学杂志

OBJECTIVES@#To compare the effects of different irradiators on the establishment of osteoradionecrosis of jaw model (ORNJ) to explore an ideal modeling method.@*METHODS@#A total of 33 adult SD rats were included and randomly divided into three groups according to the radiation equipment, namely, the blank control (CN, 3 rats), group A (linear accelerator irradiation, 15 rats), and group B (small-animal irradiator irradiation, 15 rats). Groups A and B were irradiated with daily fractions of 7, 8, and 9 Gy for 5 days and further divided into three subgroups as follows: group A@*RESULTS@#At 3 weeks after dental extractions, complete gingival healing was found in the regions of dental extractions in groups A@*CONCLUSIONS@#Small-animal irradiator irradiation is an ideal device for establishing ORNJ model.

Echocardiographic features of pre- and postcapillary pulmonary hypertension with a focus on the right ventricle in dogs

ABSTRACT: Pulmonary hypertension (PH) in dogs is a syndrome that can occur secondary to several causes, including left heart disease (postcapillary) and chronic respiratory disease (precapillary). This study evaluates morphological and functional consequences in the right ventricle (RV) of dogs with pre- and postcapillary PH through echocardiography, and also considers the severity of PH (mild, moderate or severe). Echocardiography was performed on 66 dogs of various breeds and weights (age >3 years old) which were assigned to three groups: postcapillary PH, which included mitral valve disease/endocardiosis, precapillary PH, which included chronic respiratory diseases (bronchitis, collapse of the trachea and primary lung cancer or metastasis), and finally, a healthy group of controls. The parameters for RV morphology were RV1, RV2, and RV3 for systole and diastole. The following measurements were used to assess RV systolic function: tricuspid annular plane systolic excursion (TAPSE), TAPSE:Ao (aorta), maximum velocity of the tricuspid systolic wave obtained by tissue Doppler (S), S:Ao, right ventricle end-diastolic area (RVEDA); RVEDA:BSA (body surface area); flow velocity integral (FVI) and FVI:Ao. The variables were assessed using ANOVA. The results showed that RV3d, RV1s, S:Ao, S, and FVI were able to distinguish cases of pre- and postcapillary PH in this study. Remodeling of the RV of dogs with PH was observed, which can be influenced by the pre- or postcapillary origin of the PH, with dilation in dogs with postcapillary PH and severe PH. The results for RV systolic function were similar, with FVI and FVI:Ao showing that RV ejection function is reduced in dogs with postcapillary PH and with severe PH.

RESUMO: A hipertensão pulmonar (HP) em cães é uma síndrome que pode ocorrer secundária às diversas causas, dentre elas, a doença cardíaca esquerda (pós-capilar) e a doença respiratória crônica (pré-capilar). Essa é uma condição importante que motivou os objetivos do estudo: avaliar ecocardiograficamente as consequências morfológicas e funcionais no ventrículo direito (VD) dos cães acometidos com HP pré- e pós-capilar, considerando também o estágio de severidade da HP (leve, moderada ou severa). A ecocardiografia foi realizada em 66 cães de diversas raças e pesos, com pelo menos quatro anos de idade, que compuseram um grupo com doença valvar mitral, ou endocardiose, outro com doença respiratória crônica (bronquite, colapso de traqueia e neoplasia pulmonar primária ou metástase), e por último, um grupo saudável. Os parâmetros para a morfologia do VD foram RV1, RV2 e RV3 na sístole e na diástole. Para a avaliação da função sistólica do VD foram mensurados: excursão sistólica do plano anular tricúspide (TAPSE), TAPSE:Ao (aorta), velocidade máxima da onda sistólica da tricúspide obtida pelo doppler tecidual (S), S:Ao, área do ventrículo direito no final da diástole (RVEDA); RVEDA:BSA (body superficie area); integral tempo velocidade (FVI) e FVI:Ao. As variáveis foram avaliadas por meio da ANOVA. Os resultados mostraram que RV3d, RV1s, S:Ao, S e FVI foram capazes de distinguir casos de HP pré e pós-capilar neste estudo. Observou-se que há remodelamento do VD de cães com HP e este pode ser influenciado pela origem pré ou pós-capilar da HP, encontrando-se dilatado em cães com HP pós capilar e com HP severa. Os resultados para a função sistólica do VD foram similares, uma vez que o FVI e FVI:Ao mostraram que a capacidade de ejeção do VD está reduzida nos cães com HP pós-capilar e com HP severa.

Echocardiographic features of pre- and postcapillary pulmonary hypertension with a focus on the right ventricle in dogs / Características ecocardiográficas da hipertensão pulmonar pré e pós-capilar em cães com foco no ventrículo direito

Pulmonary hypertension (PH) in dogs is a syndrome that can occur secondary to several causes, including left heart disease (postcapillary) and chronic respiratory disease (precapillary). This study evaluates morphological and functional consequences in the right ventricle (RV) of dogs with pre- and postcapillary PH through echocardiography, and also considers the severity of PH (mild, moderate or severe). Echocardiography was performed on 66 dogs of various breeds and weights (age >3 years old) which were assigned to three groups: postcapillary PH, which included mitral valve disease/endocardiosis, precapillary PH, which included chronic respiratory diseases (bronchitis, collapse of the trachea and primary lung cancer or metastasis), and finally, a healthy group of controls. The parameters for RV morphology were RV1, RV2, and RV3 for systole and diastole. The following measurements were used to assess RV systolic function: tricuspid annular plane systolic excursion (TAPSE), TAPSE:Ao (aorta), maximum velocity of the tricuspid systolic wave obtained by tissue Doppler (S'), S':Ao, right ventricle end-diastolic area (RVEDA); RVEDA:BSA (body surface area); flow velocity integral (FVI) and FVI:Ao. The variables were assessed using ANOVA. The results showed that RV3d, RV1s, S':Ao, S', and FVI were able to distinguish cases of pre- and postcapillary PH in this study. Remodeling of the RV of dogs with PH was observed, which can be influenced by the pre- or postcapillary origin of the PH, with dilation in dogs with postcapillary PH and severe PH. The results for RV systolic function were similar, with FVI and FVI:Ao showing that RV ejection function is reduced in dogs with postcapillary PH and with severe PH.(AU)

A hipertensão pulmonar (HP) em cães é uma síndrome que pode ocorrer secundária às diversas causas, dentre elas, a doença cardíaca esquerda (pós-capilar) e a doença respiratória crônica (pré-capilar). Essa é uma condição importante que motivou os objetivos do estudo: avaliar ecocardiograficamente as consequências morfológicas e funcionais no ventrículo direito (VD) dos cães acometidos com HP pré- e pós-capilar, considerando também o estágio de severidade da HP (leve, moderada ou severa). A ecocardiografia foi realizada em 66 cães de diversas raças e pesos, com pelo menos quatro anos de idade, que compuseram um grupo com doença valvar mitral, ou endocardiose, outro com doença respiratória crônica (bronquite, colapso de traqueia e neoplasia pulmonar primária ou metástase), e por último, um grupo saudável. Os parâmetros para a morfologia do VD foram RV1, RV2 e RV3 na sístole e na diástole. Para a avaliação da função sistólica do VD foram mensurados: excursão sistólica do plano anular tricúspide (TAPSE), TAPSE:Ao (aorta), velocidade máxima da onda sistólica da tricúspide obtida pelo doppler tecidual (S'), S':Ao, área do ventrículo direito no final da diástole (RVEDA); RVEDA:BSA (body superficie area); integral tempo velocidade (FVI) e FVI:Ao. As variáveis foram avaliadas por meio da ANOVA. Os resultados mostraram que RV3d, RV1s, S':Ao, S' e FVI foram capazes de distinguir casos de HP pré e pós-capilar neste estudo. Observou-se que há remodelamento do VD de cães com HP e este pode ser influenciado pela origem pré ou pós-capilar da HP, encontrando-se dilatado em cães com HP pós capilar e com HP severa. Os resultados para a função sistólica do VD foram similares, uma vez que o FVI e FVI:Ao mostraram que a capacidade de ejeção do VD está reduzida nos cães com HP pós-capilar e com HP severa.(AU)

Mechanism of Wenjingtang on Improving Endometriosis in Rats Based on Regulating HIF-1α Expression / 中国实验方剂学杂志

Objective:To observe the effect of Wenjingtang on the expression of hypoxia inducible factor-1α （HIF-1α） and ultrastructure of mitochondria in rats with endometriosis （EMs）， and to explore the mechanism of Wenjingtang in the treatment of EMs. Method:The EMs model rat was established by autogenous intimal transplantation， and the volume of ectopic lesions was measured by small animal ultrasound imaging system. According to the volume of ectopic lesions， rats successfully modeled were randomly divided into model group， low， middle ang high dose Wenjingtang group （4.85， 9.7， 19.4 g·kg-1） and gestrinone group （0.25 mg·kg-1）， 10 in each group， another 10 rats were recruited in a sham operation group. After 6 weeks of drug treatment， the volume of ectopic lesions was measured by ultrasound imaging system and caliper， the morphology of ectopic endometrium was observed by hematoxylin-eosin （HE） staining， the levels of interleukin-1β （IL-1β）， tumor necrosis factor-α （TNF-α） and transforming growth factor-β1 （TGF-β1） in peritoneal fluid were measured by enzyme linked immunosorbent assay （ELISA）， the mRNA and protein expression of HIF-1α in eutopic or ectopic endometrial tissues were detected by Real-time fluorescent quantitative polymerase chain reaction （Real-time PCR） and Western blot， and the ultrastructure of mitochondria in ectopic endometrium was observed by transmission electron microscope （TEM）. Result:Compared with sham operation group， ectopic lesions were found in model group， showing vesicular structure， and the typical endometrial tissue morphology was found in the lesions. The contents of IL-1β， TNF-α， TGF-β1 and the expression of HIF-1α mRNA and protein were significantly increased than those in the sham operation group （P<0.05，P<0.01）. TEM showed that the number of mitochondria in the cytoplasm of ectopic endometrium increased and the structure was intact. Compared with model group， the volume of ectopic focus was significantly decreased in all Wenjingtang groups （P<0.01）， and the results of ultrasonic examination were basically consistent with those of caliper measurement， HE staining showed that the columnar epithelial cells of ectopic endometrium were damaged or exfoliated and the interstitial cells were loose， the content of TNF-α in each dose group of Wenjingtang was significantly decreased， the content of IL-1β and TGF-β1 in the medium dose and high dose groups of Wenjingtang was significantly decreased （P<0.05，P<0.01）， the expression of HIF-1α mRNA and protein were significantly decreased in all Wenjingtang groups （P<0.05，P<0.01）. The mitochondria of ectopic endometrium were obviously swollen， the crest was broken or even disappeared， some of the mitochondria were vacuolar degeneration and the outer membrane was ruptured. Conclusion:Wenjingtang has a good therapeutic effect on experimental EMs in rats， and the mechanism is related to reducing the expression of HIF-1α， improving hypoxia in ectopic lesions and inducing mitochondrial damage in ectopic endometrium.

Optical coherence tomography angiography in preclinical neuroimaging

Preclinical neuroimaging allows for the assessment of brain anatomy, connectivity, and function in laboratory animals, such as mice and this imaging field has been a rapidly growing aimed at bridging the translation gap between animal and human research. The progress in the animal research could be accelerated by high-resolution in vivo optical imaging technologies. Optical coherence tomography-based angiography (OCTA) estimates the scattering from moving red blood cells, providing the visualization of functional micro-vessel networks within tissue beds in vivo without a need for exogenous contrast agents. Recent advancement of OCTA methods have expanded its application to neuroimaging of small animal models of brain disorders. In this paper, we overview the recent development of OCTA techniques for blood flow imaging and its preclinical applications in neuroimaging. In specific, a summary of preclinical OCTA studies for traumatic brain injury, cerebral stroke, and aging brain on mice is reviewed.

Antibreast cancer activity and mechanism study on appropriate components from Prunella vulgaris / 中草药

Objective: To study antibreast cancer activity and the mechanism of appropriate components of polysaccharides (P), triterpenes (T), the essential oil (V), and different compatibilities (PT, PV, TV, and PTV) of Prunella vulgaris in vivo. Methods: 4T1 breast cancer model was established to evaluate anti-breast cancer activity. The appropriate components of P. vulgaris were screened. The tumor volume and the shaded areas in breast cancer mice were detected by living small animal Micro-CT scan. The structural changes of each organ were detected by HE staining. TUNEL staining was used to detect apoptotic rate of tumor. The expression of PCNA, CD-31, and E-cadherin were detected by immunohistochemistry (IHC). Serum estradiol was detected by Elisa kit. Results: T and PTV had significant anti-breast cancer activity. There were inflammatory cells infiltration, degeneration and necrosis, tumor cell apoptosis in the T and PTV groups. T and PTV could inhibit cell proliferation by reducing the estradiol level and downregulating the overexpression of PCNA proteins. T and PTV could also reduce tumor angiogenesis by downregulating the protein expression of CD-31. T and PTV also inhibited the metastatic process by upregulating the protein expression of E-cadherin. Conclusion: T and PTV showed significant anti-breast cancer activities, suggesting that T and PTV can be a potential drug for breast cancer.

Introduction of image-guided stereotactic radiotherapy systems for small animals / 中华放射肿瘤学杂志

The theory and application of small animal radiotherapy models is critical for the research and development of radiobiology and clinical radiotherapy.Considering universality and cost effects,mouse models are widely used to explore the radiobiological mechanisms of cancerous and normal tissues.In recent years,there has been tremendous progress in image-guided stereotactic radiotherapy equipment for small animals,which could simulate the human radiotherapy process.This article introduces stereotactic radiotherapy systems for small animals guided by different imaging modalities,such as cone-beam computed tomography and magnetic resonance imaging,and then reviews small animal fluorescence imaging technology and summarizes the application of different bioluminescence and fluorescence imaging equipment in small animal imaging systems.Finally,we put forward the prospect of optimization direction of radiotherapy equipment for small animals in future.

Bone mineral density assessment for research purpose using dual energy X-ray absorptiometry

Dual energy X-ray absorptiometry (DXA) has become the most common method for measuring bone mineral density (BMD) of small animals in metabolic bone disease research, and errors should be minimized in all procedures involved in research studies in order to increase the accuracy of the study results. DXA is simpler and rapid compared to Micro-computed tomography for quantitative analysis of change in trabecular bone of test subject. In human research, measuring BMD is widely used; post-operative evaluation on orthopedic surgery, evaluation of osteoporosis medication in menopause and many other areas of study. For the study, the inspector should be trained by the equipment manufacturer regarding the utilization and analysis of the equipment and regular phantom testing should be conducted to ensure the stability of the equipment, and precision tests should be conducted to analyze the positioning and data analysis. They should also be familiar with the clinical trials and conduct studies based on the approval of the Institutional Review Board. In the absolute BMD measurement of the human body, it is necessary to apply and compare the position and condition, rotation degree, region of interest, and area of the scan in the follow-up test. In the case of small animals, animal selection, measurement and equipment should be modeled to match the research. Therefore, we would like to provide information for researchers to minimize the errors, effective data management and accurate data presentation. This article reviews the process of DXA measurement for research purpose including plan for DXA examination, BMD measurement in a human body study and small animal studies.

Establishment and preliminary evaluation of multiple drug delivery system of effective components of Angelica sinensis / 药学学报

The multiple drug delivery system of components of traditional Chinese medicine is a system composed of multiple components and multiple units. According to the characteristics of each component, different drug delivery units are designed and combined to achieve the purpose of improving bioavailability and enhancing drug efficacy. In this study, supercritical extracts, phenolic acids, and polysaccharides derived from Angelica sinensis were examined as research objects, and a pellet-based vehicle was applied to construct a multiple drug delivery system for the treatment and chemoprevention of colitis and colorectal cancer. The extrusion-spheronization method was used to prepare pellets of Angelica polysaccharides which should be released in the stomach. The yield in 18-24 mesh and plane critical angle served as the index. The Box-Behnken design and the orthogonal design were used to optimize the formulation and parameters of pellets. According to a previous study, the colon specific pellets loading supercritical extracts and phenolic acid extracts were prepared by the optimized process. These two units of pellets were combined into the multiple drug delivery system of effective components of Angelica sinensis, and the quality evaluation and in vitro release study were conducted. The dynamic observation of pellets in mice was evaluated using small animal in vivo imaging system. The prescription of the Angelica polysaccharides gastric releasing pellets was:microcrystalline cellulose 6.5 g, polysaccharide 3.3 g, silica 0.2 g and 7 mL of 60% ethanol as wetting agent. The process parameters were as follows:extrusion rate at 75 r·min-1, rounding rate at 1 800 r·min-1, and rounding time for 3 min. Both in vivo and in vitro studies indicate that the prepared multiple drug delivery system of effective components of Angelica sinensis produced good release properties. The polysaccharide pellets could be rapidly released in the artificial gastric fluid and in the stomach. The colon specific pellets showed good targeting. They released little in the artificial gastric fluid within 2 hours, released less than 20% in the artificial intestinal fluid for 4 hours, and released more than 90% in artificial colon fluid for 6 hours.

Preparation and evaluation of gastric adhesive-floating pellets for Bolo leaf phenols / 中国中药杂志

Gastric adhesive-floating pellets for Bolo leaf phenols (BLP) were prepared by extrusion-spheronization method, with chitosan as skeleton bioadhesive material, and stearyl alcohol as help-bleaching agent to evaluate its in vitro adhesivity, floatability and in vivo retention situation, and investigate its in vitro release characteristics. The in vitro adhesivity and floatability were evaluated respectively by in vitro tissue retention method and visual observation method. The retention of pellets in rats was investigated by in vivo tissue retention method and in vivo imaging of small animals. In addition, the in vitro release of p-coumaric acid and caffeic acid as the index components in pellets were evaluated. Results showed that the in vitro adhesivity of the prepared gastric adhesive-floating pellets reached (73.2±3.4)%, and the pellets could float immediately in simulated gastric fluid for more than 12 h; the retention rate of adhesive-floating pellets in rats reached more than 40% after 6 h, while the retention rate of common reference pellets was decreased by 15% as compared with the gastric adhesive-floating pellets, with significant difference (P<0.01); the drug in vitro release time can reach more than 6 h, and the drug release behaviors were lined with Higuchi equation. In vivo and in vitro studies showed that, the gastrointestinal bioadhesive and floating pellets prepared in this study have good bioadhesivity, floatability and good sustained release characteristics.

Application of small animal radiation research platform in radiotherapy / 中华放射肿瘤学杂志

Small Animal Radiation Research Platform (SARRP) is a highly efficient platform specifically designed for research in the fields of radiation oncology and radiobiology.This platform possesses precise radiometers with gantries capable of isocentric,coplanar,and non-coplanar contormal irradiation.Based on the three-dimensional images acquired by the cone-beam computed tomography,the platform can perform real time treatment planning and irradiation,which assures timeliness for precise irradiation and research on small animals.The wide application of SARRP not only accelerates the bench to bedside translation,but also facilitates the development of radiation oncology and radiobiology.

Design of artifact-free head holder for small animal imaging / 中国医学装备

Objective:To design a kind of head holder for small animal imaging without artifact. Methods: The head holder was designed for small animal imaging according to rodent head stereotaxic apparatus with lightweight and easy molding material (polymethyl methacrylate). The holder can be easily made with ordinary lathe and can be easily operated in small animal imaging device. Results:After the trial in small animal PET-CT, the holder can effectively solve the problems in small animal imaging such as the artifact caused by tiny displacement, tilt head position, deviating from the central field of view and respiratory depression. Conclusion: The small animal imaging device was designed in simple structure to overcome the shortcomings of the existing technology. The operation of the device is simple, which is worthy of popularization head holder of application.

Contribuição do contraste negativo na artrografia tomográfica do joelho normal de cães / Contribution of negative contrast in computed tomography arthrography of the normal canine stifle

A ruptura do ligamento cruzado cranial é uma das causas mais comuns de claudicação do membro pélvico de cães. A radiografia e a ultrassonografia são métodos de diagnóstico frequentemente utilizados na rotina clínica de pequenos animais, porém a tomografia computadorizada é uma modalidade de imagem ainda pouco estudada para avaliar a articulação do joelho de cães. O presente trabalho teve por objetivo avaliar a contribuição do contraste negativo na artrografia tomográfica do joelho normal de cães, para visibilizar as estruturas intra-articulares e padronizar o uso desse contraste na articulação. Foram utilizados 24 membros pélvicos de cães de raças variadas, selecionados pela ausência de histórico de doença articular prévia do joelho e por apresentarem exames radiográficos, ultrassonográficos e macroscópicos normais. O experimento foi delineado em dois grupos, sendo o grupo I constituído de animais com peso até 20 kg e grupo II acima de 20 kg. Foram feitos cortes tomográficos com o membro flexionado e estendido. A quantidade média de ar empregada para a distensão da cápsula articular foi de 49 ml para o Grupo I e de 81 ml para o Grupo II. Utilizou-se um tubo de látex na porção distal à articulação do joelho para reduzir o escape de ar pelo tendão extensor digital profundo, que possui comunicação intra-articular. Foi possível visibilizar pela imagem tomográfica, em todas as articulações, as seguintes estruturas: ligamento cruzado cranial e caudal, meniscos medial e lateral, ligamento patelar, ligamentos colaterais e cápsula articular. Desta forma, o contraste negativo se mostrou uma alternativa eficaz para auxiliar a identificação das estruturas anatômicas do joelho na artrografia tomográfica.

The cranial cruciate ligament rupture is one of the most common causes of canine hind limb lameness. The radiographic and ultrasonographic are methods of diagnosis frequently used in small animal clinics, but there are few studies of computed tomography to exam the stifle joint in dogs. The aim of this study was to evaluate the contribution of negative contrast in computed tomography arthrography of the normal stifle of dogs for the visualization of intra-joint structures, and to standardize the use of contrast in this joint. Twenty-four hind limbs from dogs of several breeds were used. They were selected based on history of absence of previous stifle joint disease and normal radiographic, ultrasonographic and macroscopic exams. The experiment was designed in two groups: Group I animals weighing up to 20 kg, and Group II animals weighing above 20 kg. Tomographic sections were done with the limb flexed and extended. The amount of air used for the joint capsule distension was approximately 49 ml for group I and 81 ml for group II. A latex tube was used on the distal portion of the stifle to reduce air escaping through the long digital extensor tendon, which has intra-joint communication. In all joints, the tomographic image allowed the visualization of the following structures: cranial and caudal cruciate ligament, medial and lateral menisci, patellar ligament, medial and lateral collateral ligament and joint capsule. Thus, the negative contrast (air) showed to be an effective alternative in the evaluation of the stifle anatomical structures by using tomography arthrography.

Estimation of Internal Motion for Quantitative Improvement of Lung Tumor in Small Animal / 의학물리

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was 1.59x2.50 mm. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

A clinical gamma camera-based pinhole collimated system for high resolution small animal SPECT imaging

The main objective of the present study was to upgrade a clinical gamma camera to obtain high resolution tomographic images of small animal organs. The system is based on a clinical gamma camera to which we have adapted a special-purpose pinhole collimator and a device for positioning and rotating the target based on a computer-controlled step motor. We developed a software tool to reconstruct the target’s three-dimensional distribution of emission from a set of planar projections, based on the maximum likelihood algorithm. We present details on the hardware and software implementation. We imaged phantoms and heart and kidneys of rats. When using pinhole collimators, the spatial resolution and sensitivity of the imaging system depend on parameters such as the detector-to-collimator and detector-to-target distances and pinhole diameter. In this study, we reached an object voxel size of 0.6 mm and spatial resolution better than 2.4 and 1.7 mm full width at half maximum when 1.5- and 1.0-mm diameter pinholes were used, respectively. Appropriate sensitivity to study the target of interest was attained in both cases. Additionally, we show that as few as 12 projections are sufficient to attain good quality reconstructions, a result that implies a significant reduction of acquisition time and opens the possibility for radiotracer dynamic studies. In conclusion, a high resolution single photon emission computed tomography (SPECT) system was developed using a commercial clinical gamma camera, allowing the acquisition of detailed volumetric images of small animal organs. This type of system has important implications for research areas such as Cardiology, Neurology or Oncology.

Performance Measurement of Siemens Inveon PET Scanner for Small Animal Imaging / 의학물리

Inveon PET is a recently developed preclinical PET system for small animal. This study was conducted to measure the performance of Inveon PET as recommended by the NEMA NU 4-2008. We measured the spatial resolution, the sensitivity, the scatter fraction and the NECR using a F-18 source. A 3.432 ns coincidence window was used. A 1 mm3 sized F-18 point source was used for the measurement of spatial resolution within an energy window of 350~625 keV. PET acquisition was performed to obtain the spatial resolution from the center to the 5 cm offset toward the edge of the transverse FOV. Sensitivity, scatter fraction, and NECR were measured within an energy window of 350~750 keV. For measuring the sensitivity, a F-18 line source (length: 12.7 cm) was used with concentric 5 aluminum tubes. For the acquisition of the scatter fraction and the NECR, two NEMA scatter phantoms (rat: 50 mm in diameter, 150 mm in length; mouse: 25 mm in diameter, 70 mm in length) were used and the data for 14 half-lives (25.6 hr) was obtained using the F-18 line source (rat: 316 MBq, mouse: 206 MBq). The spatial resolution of the F-18 point source was 1.53, 1.50 and 2.33 mm in the radial, tangential and axial directions, respectively. The volumetric resolution was 5.43 mm3 in the center. The absolute sensitivity was 6.61%. The peak NECR was 486 kcps @121 MBq (rat phantom), and 1056 kcps @128 MBq (mouse phantom). The values of the scatter fraction were 20.59% and 7.93% in the rat and mouse phantoms, respectively. The performances of the Inveon animal PET scanner were measured in this study. This scanner will be useful for animal imaging.

Imaging Studies in Mouse Brain Using Clinical 3T MRI Scanner / 의학물리

The purpose of this study was to explore the potentials of a clinical 3T MRI in mouse brains and technical adaptation and optimization. T1-weighted images (T1WI), T2-weighted images (T2WI), FLAIR (Fluid Attenuated Inversion Recovery) images, Gadolinium enhanced T1-weighted images (Gd-T1WI), Diffusion weighted images (DWI) were acquired in brain of 2 mice (weight 20~25 g) with cerebral infarction by occlusion of right middle cerebral artery, 1 hour, 24 hours, 72 hours after infarction and 1 normal mouse brain using clinical 3T MRI scanner. We analyzed differentiation of striatum, ventricle, cerebral cortex, and possibility of detection of acute cerebral infarction. We could differentiate the striatum, ventricle, cerebral cortex on T2WI and on DWI, FLAIR, T1WI, the differentiation of each anatomy of brain was not definite, but acute cerebral infarction was detected on DWI of 1 hour, 24 hours, 72 hours after infarction and on T2WI, FLAIR of 24 hours, 72 hours after infarction. Clinical 3T MRI can be used in differentiation of anatomy of mouse brains and DWI can be helpul in detection of acute cerebral infarction in acute phase. With technical adaptation and optimization clinical 3T MRI can be useful tool for provide preclinical and clinical small animal studies.