Language：Japanese   Publisher：(一社)日本コンピュータ外科学会  

著者らは、術者の被ばく量低減を目的として、遠隔操作型のCT透視ガイド下針穿刺ロボット(Zerobot)の研究開発を開始している。今回、動物実験のCT画像をもとに術者である医師がロボットを遠隔操作してブタの体内にある標的に対して穿刺を行う場合に、針と標的との位置関係によってどのように針の軌道修正の作業を行うのか調査した。Zerobotを用いて、X軸、Y軸、Z軸の三つの直動軸で三次元方向の並進運動を行い、針の位置を決定した。A軸、B軸の二つの回転軸で回転運動を行い、針の姿勢を決定した。調査に使用したデータはブタを用いた穿刺精度試験で得られたものであった。ロボットを医師が遠隔操作することによる穿刺において、針が標的に近づくにつれ修正回数は指数的に増加していることが分かった。なお、残りの穿刺深さが約10mmとなるのをピークに、それ以降はA軸とB軸の修正回数は減少し、一方で刺し直し回数が増加している様子が観察された。合計60回の穿刺のうち、A軸の修正は110回、B軸の修正は66回、刺し直しは37回であった。自動穿刺シミュレーションの結果、穿刺経路と針との距離と角度がゼロに収束しており、針先を三次元的な穿刺経路に追従させることができることを確認した。針が標的に近づくにしたがって穿刺速度が減速していることが示された。

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Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Computer Aided Surgery  

DOI： 10.5759/jscas.22.14

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RAD51 forms a complex with BRCA2 and plays a central role in the DNA damage response pathway that is associated with homologous recombination. The structures of RAD51 and its homologues are highly conserved from prokaryotes to higher eukaryotes. Although a large number of BRCA2 mutations have been reported, there are only a few reports on the mutations of RAD51, which have been shown in humans and dogs. However, several mutations of canine RAD51 were identified from mammary gland tumour tissues in a recent study. Some of these mutations seem to have an influence on the homo-oligomerization or interaction with "Partner and localizer of BRCA2" (PALB2). In this study, we cloned the canine PALB2 homologue and investigated the effect on its interaction with the RAD51 mutants to evaluate the alteration in the function of RAD51 mutants. The A209S and T225S mutants of RAD51 show an attenuation of the interaction between RAD51 and PALB2. These results indicate that the canine RAD51 mutations can potentially alter the homologous recombination pathways in response to DNA damage in dogs.

DOI： 10.1111/vco.12542

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/cas.14150

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/cas.14150

Language：English   Publishing type：Research paper (scientific journal)  

Bexarotene (1), a retinoid X receptor (RXR) agonist approved for the treatment of cutaneous T cell lymphoma (CTCL), was reported to migrate into baboon brain based on findings obtained by positron emission tomography (PET) with a 11C-labeled tracer. However, co-administration of non-radioactive 1 had no effect on the distribution of [11C]1, probably due to non-specific binding of 1 as a result of its high lipophilicity. Here, we report a fluorine-18 (18F)-labeled PET tracer [18F]6 derived from RXR partial agonist CBt-PMN (2), which has lower lipophilicity and weaker RXR-binding ability than [11C]1. The concomitant administration of 1 or 2 with [18F]6 with resulted in decreased accumulation of [18F]6 in liver, together with increased brain uptake and increased accumulation in kidney and muscle, as visualized by PET. A plausible explanation of these findings is the inhibition of [18F]6 uptake into the liver by concomitantly administered 1 or 2, leading to an increase in blood concentration of [18F]6 followed by increased accumulation in other tissues.

DOI： 10.1016/j.bmc.2019.05.045

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Language：English   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/acs.jmedchem.9b00617

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ireland Ltd  

Objective: To evaluate the accuracy of robotic insertion of various ablation needles at various locations under computed tomography (CT) guidance in swine. Materials and methods: The robot was used for CT-guided insertion of four ablation needles, namely a single internally cooled radiofrequency ablation (RFA) needle (Cool-tip), a multi-tined expandable RFA needle (LeVeen), a cryoablation needle (IceRod), and an internally cooled microwave ablation needle (Emprint). One author remotely operated the robot with the operation interface in order to orient and insert the needles under CT guidance. Five insertions of each type of ablation needle towards 1.0-mm targets in the liver, kidney, lung, and hip muscle were attempted on the plane of an axial CT image in six swine. Accuracy of needle insertion was evaluated as the three-dimensional length between the target centre and needle tip. The accuracy of needle insertion was compared according to the type of needle used and the location using one-way analysis of variance. Results: The overall mean accuracy of all four needles in all four locations was 2.8 mm. The mean accuracy of insertion of the Cool-tip needle, LeVeen needle, IceRod needle, and Emprint needle was 2.8 mm, 3.1 mm, 2.5 mm, and 2.7 mm, respectively. The mean accuracy of insertion into the liver, kidney, lung, and hip muscle was 2.7 mm, 2.9 mm, 2.9 mm, and 2.5 mm, respectively. There was no significant difference in insertion accuracy among the needles (P =.38) or the locations (P =.53). Conclusion: Robotic insertion of various ablation needles under CT guidance was accurate regardless of type of needle or location in swine.

DOI： 10.1016/j.ejrad.2018.06.006

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.berh.2019.01.007

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Language：English   Publishing type：Research paper (scientific journal)  

Mutations in the p53 gene are associated with more than half of all human cancers. These mutations often cause a disruption of the tumor-suppressor function of p53 and induce genomic instabilities. Wild‑type p53 requires tetramerization to function as an initiator of cell cycle arrest and apoptosis. Although alterations in p53 tetramerization caused by mutation have been well studied, there are few cell lines containing an endogenous mutation in the tetramerization domain of p53. Here, we report the discovery of a canine mammary gland tumor cell line CTB‑m2, which contains the Leu332Gln (L332Q) mutation corresponding to Leu344 in the tetramerization domain of human p53. Although CTB‑m2 cells are genetically heterozygous for the Leu332Gln mutation, the mutant mRNA was almost exclusively expressed. CTB‑m2 cells showed enhanced cell proliferation compared to wild‑type p53-expressing CTB‑m cells of the same lineage. A p53 tetramerization reporter assay showed that the ability of the p53 mutant to form tetramers was significantly lower than that of wild‑type p53. An immunoblot analysis of cross-linked p53 oligomerized forms demonstrated that the L332Q mutant lacked the ability to form tetramers but retained the ability to form dimers. These data suggest that the p53 mutant cell line CTB‑m2 could be a useful tool for analyzing the precise tetramerization mechanisms of p53 and verifying the effects of therapeutic agents against tumors expressing p53 mutants that lack the ability to tetramerize.

DOI： 10.3892/or.2018.6409

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：RADIOLOGICAL SOC NORTH AMERICA  

Purpose: To evaluate the accuracy of the remote-controlled robotic computed tomography (CT)-guided needle insertion in phantom and animal experiments.
Materials and Methods: In a phantom experiment, 18 robotic and manual insertions each were performed with 19-gauge needles by using CT fluoroscopic guidance for the evaluation of the equivalence of accuracy of insertion between the two groups with a 1.0-mm margin. Needle insertion time, CT fluoroscopy time, and radiation exposure were compared by using the Student t test. The animal experiments were approved by the institutional animal care and use committee. In the animal experiment, five robotic insertions each were attempted toward targets in the liver, kidneys, lungs, and hip muscle of three swine by using 19-gauge or 17-gauge needles and by using conventional CT guidance. The feasibility, safety, and accuracy of robotic insertion were evaluated.
Results: The mean accuracies of robotic and manual insertion in phantoms were 1.6 and 1.4 mm, respectively. The 95% confidence interval of the mean difference was 20.3 to 0.6 mm. There were no significant differences in needle insertion time, CT fluoroscopy time, or radiation exposure to the phantom between the two methods. Effective dose to the physician during robotic insertion was always 0 mSv, while that during manual insertion was 5.7 mSv on average (P<.001). Robotic insertion was feasible in the animals, with an overall mean accuracy of 3.2 mm and three minor procedure-related complications.
Conclusion: Robotic insertion exhibited equivalent accuracy as manual insertion in phantoms, without radiation exposure to the physician. It was also found to be accurate in an in vivo procedure in animals. (C) RSNA, 2017

DOI： 10.1148/radiol.2017162856

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CELL PRESS  

We evaluated the efficacy of a neutralizing anti-high mobility group box 1 (HMGB1) monoclonal antibody in MRL/lpr lupus-prone mice. The anti-HMGB1 monoclonal antibody (5 mg/kg weight) or class-matched control immunoglobulin G2a (IgG2a) was administered intravenously twice a week for 4-15 weeks. Urine albumin was monitored, and histological evaluation of the kidneys was conducted at 16 weeks. Lymphadenopathies were evaluated by 1-(2'-deoxy-2'-[F-18]fluoro-beta-D-arabinofuranosyl) cytosine ([F-18] FAC) positron emission tomography/computed tomography (PET/CT) at 12 weeks. Following 4-week treatment, [F-18]FAC-PET/CT showed similar accumulation in cervical and axillary lymph nodes at 12 weeks of age. However, anti-HMGB1 monoclonal antibody sufficiently inhibited the increase in albuminuria compared to an isotype control following 15-week treatment. Complement deposition was also improved; however, there were no significant differences in IgG deposition and renal pathological scores between the two groups. Anti-double-stranded DNA (dsDNA) antibody titers and cytokine and chemokine levels were also unaltered. Although there were no significant differences in glomerular macrophage infiltration, neutrophil infiltration was significantly decreased by the anti-HMGB1 monoclonal antibody. Antagonizing HMGB1 treatment suppressed HMGB1 translocation from nuclei in the kidney and suppressed neutrophil extracellular traps. The anti-HMGB1 monoclonal antibody demonstrated therapeutic potential against albuminuria in lupus nephritis by inhibiting neutrophil recruitment and neutrophil extracellular traps.

DOI： 10.1016/j.omtm.2017.05.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The retinoid X receptor (RXR) partial agonist 1-[(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)amino]benzotriazole-5-carboxylic acid (1; CBt-PMN, E-max = 75%, EC50 = 143 nM) is a candidate for treatment of central nervous system (CNS) diseases such as Alzheimers and Parkinsons diseases based on reports that RXR-full agonist 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (bexarotene) shows therapeutic effects on these disease in rodent models. Here, we synthesized carbon-11-labeled ([C-11]1) as a tracer for positron emission tomography (PET) and used it in a PET imaging study to examine the brain uptake and biodistribution of 1. We found that (CO2)-C-11 fixation after tinlithium exchange at -20 degrees C afforded [C-11]1. This methodology may also be useful for synthesizing (CO2H)-C-11-PET tracer derivatives of other compounds bearing pi-rich heterocyclic rings. A PET/CT imaging study of [C-11]1 in mice indicated 1 is distributed to the brain and is thus a candidate for treatment of CNS diseases.

DOI： 10.1021/acs.jmedchem.7b00817

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Background: Oxidized LDL (oxLDL) can exist as a complex with beta(2)-glycoprotein I (beta(2)GPI) in plasma/serum of patients with non-autoimmune atherosclerotic disease or antiphospholipid syndrome (APS). Nonetheless, direct in vivo evidence supporting the pathophysiological involvement of oxLDL/beta(2)GPI complexes and specific autoantibody against the complexes in developing atherothrombosis has yet been established. In the present study, we demonstrated in vivo distribution of single chain variable fragment of IgG anti-oxLDL/beta(2)GPI complexes (3H3-scFv) in Watanabe heritable hyperlipidemic (WHHL) rabbits by PET/CT imaging.
Methods: An antibody-based PET probe, Cu-64-3H3-scFv, was established, and WHHL rabbits were applied for a non-autoimmune atherosclerotic model to demonstrate in vivo distribution of the probe.
Results: 3H3-scFv has exhibits specificity towards beta(2)GPI complexed with oxLDL but neither a free form of beta(2)GPI nor oxLDL alone. Post-intravenous administration of Cu-64-3H3-scFv into WHHL rabbits has demonstrated a noninvasive approach for in vivo visualization of atherosderotic lesion. The imaging probe achieved ideal blood clearance and distribution for optimal imaging capacity in 24 h, significantly shorter than that of an intact IgG-based imaging probe. Cu-64-3H3-scFv targeted on atherosclerotic plaques in aortas of WHHL rabbits where extensive accumulation of lipid deposits was observed by lipid staining and autoradiography. The accumulation of Cu-64-3H3scFv in aortic segments of WHHL rabbits was 2.8-folds higher than that of controls (p = 0.0045).
Conclusions: The present in vivo evidence supports the pathophysiological involvement of oxLDL/beta(2)GPI complexes in atherosclerotic complications of WHHL rabbits. Cu-64-3H3-scFv represents a novel PET imaging probe for non-invasive pathophysiological assessment of oxLDL/beta(2)GPI complexes accumulated in atherosclerotic plaques. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.autrev.2016.12.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

Intact beta 2-glycoprotein I (i beta 2GPI) is a glycoprotein that regulates coagulation and fibrinolysis. Nicked beta 2GPI (n beta 2GPI) possesses an angiogenic property at a relatively low concentration, and an anti-angiogenic property at a high concentration. Here we investigated the functions of i beta 2GPI and n beta 2GPI in vascular endothelial growth factor (VEGF)-A-induced endothelial cell proliferation and tube formation. We used noninvasive PET imaging to analyze the in vivo distribution of intravenously injected beta 2GPI variants in tumor lesions in mice. i beta 2GPI was incubated with plasmin to obtain n beta 2GPI, and its N-terminal sequence was analyzed. n beta 2GPI had at least one other cleavage site upstream of the beta 2GPFs domain V, whereas the former plasmin-cleavage site locates between K-317 and T-318. Both of intact and nicked beta 2GPI significantly inhibited the VEGF-A-induced cell proliferation and the tube formation of human umbilical vein endothelial cells (HUVECs). PET imaging visualized considerably distributed intensities of all tested beta 2GPI variants in tumor lesions of pancreatic tumor cell-xenografts. These results indicate that beta 2GPI may be physiologically and pathophysiologically important in the regulation of not only coagulation and fibrinolysis, but also angiogenesis.

DOI： 10.18926/AMO/53999

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

RXR partial agonist NEt-41B (2a, 6-[ethyl-(4-isobutoxy-3-isopropylphenyl)amino]pyridine-3-carboxylic acid: EC50 = 169 nM, E-max = 55%) showed a blood concentration higher than its Emax after single oral administration at 30 mg/kg to mice, and repeated oral administration at 10 mg/kg/day to KK-A(y) mice afforded antitype 2 diabetes activity without the side effects caused by RXR full agonists. However, RXR full agonist NEt-3IB (la), in which the isobutoxy and isopropyl groups of 2a are interchanged, gave a much lower blood concentration than 2a. Here we used positron emission tomography (PET) with tracers [C-11] la, [C-11]2a and fluorinated derivatives [F-18] lb, [F-18]2b, which have longer half-lives, to examine the reason why la and 2a exhibited significantly different blood concentrations. As a result, the reason for the high blood concentration of 2a after oral administration was found to be linked to higher intestinal absorbability together with lower biliary excretion, compared with la.

DOI： 10.1021/ml500511m

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：HINDAWI PUBLISHING CORPORATION  

Mesothelin (MSLN) is a 40-kDa cell differentiation-associated glycoprotein appearing with carcinogenesis and is highly expressed in many human cancers, including the majority of pancreatic adenocarcinomas, ovarian cancers, and mesotheliomas, while its expression in normal tissue is limited to mesothelial cells lining the pleura, pericardium, and peritoneum. Clone 11-25 is a murine hybridoma secretingmonoclonal antibody (mAb) against human MSLN. In this study, we applied the 11-25 mAb to in vivo imaging to detect MSLN-expressing tumors. In in vitro and ex vivo immunochemical studies, we demonstrated specificity of 11-25 mAb to membranous MSLN expressed on several pancreatic cancer cells. We showed the accumulation of Alexa Fluor 750-labeled 11-25 mAb in MSLN-expressing tumor xenografts in athymic nude mice. Then, 11-25 mAb was labeled with Cu-64 via a chelating agent DOTA and was used in both in vitro cell binding assay and in vivo positron emission tomography (PET) imaging in the tumorbearing mice. We confirmed that Cu-64-labeled 11-25 mAb highly accumulated in MSLN-expressing tumors as compared to MSLN negative ones. The Cu-64-labeled 11-25 mAb is potentially useful as a PET probe capable of being used for wide range of tumors, rather than F-18-FDG that occasionally provides nonspecific accumulation into the inflammatory lesions.

DOI： 10.1155/2015/268172

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It is well known that many tumor tissues show lower apparent diffusion coefficient (ADC) values, and that several factors are involved in the reduction of ADC values. The aim of this study was to clarify how much each factor contributes to decreases in ADC values. We investigate the roles of cell density, extracellular space, intracellular factors, apoptosis and necrosis in ADC values using bio-phantoms. The ADC values of bio-phantoms, in which Jurkat cells were encapsulated by gellan gum, were measured by a 1.5-Tesla magnetic resonance imaging device with constant diffusion time of 30 sec. Heating at 42° C was used to induce apoptosis while heating at 48°C was used to induce necrosis. Cell death after heating was evaluated by flow cytometric analysis and electron microscopy. The ADC values of bio-phantoms including non-heated cells decreased linearly with increases in cell density, and showed a steep decline when the distance between cells became less than 3/um. The analysis of ADC values of cells after destruction of cellular structures by sonication suggested that approximately two-thirds of the ADC values of cells originate from their cellular structures. The ADC values of bio-phantoms including necrotic cells increased while those including apoptotic cells decreased. This study quantitatively clarified the role of the cellular factors and the extracellular space in determining the ADC values produced by tumor cells. The intermediate diffusion time of 30 msec might be optimal to distinguish between apoptosis and necrosis.

DOI： 10.18926/AMO/52009

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Ion exchange is a simple and efficient method for separating no-carrier-added 64Cu from an irradiated Ni target. We developed a semi-automated two-round 64Cu separation system equipped with a strong-base anion exchange resin column. We first verified the efficiency of the system using a non-radioactive substitute consisting of 25 mg of Ni and 127 ng of Cu, and confirmed that Cu was completely eluted at the second round of the separation step. After the bombardment, separation of 64Cu from the Ni target was achieved with high radiochemical purity. 64Cu produced and separated in this study had an extremely low level of Ni impurity. It could be used for labeling monoclonal antibodies for antibody positron emission tomography imaging and synthesizing radiopharmaceuticals. © 2012 The Author(s).

DOI： 10.1007/s10967-012-2340-7

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

The roles of cell density, extracellular space, intracellular factors, and apoptosis induced by the molecularly targeted drug rituximab on the apparent diffusion coefficient (ADC) values were investigated using bio-phantoms. In these bio-phantoms, Ramos cells (a human Burkitt's lymphoma cell line) were encapsulated in gellan gum. The ADC values decreased linearly with the increase in cell density, and declined steeply when the extracellular space became less than 4 gm. The analysis of ADC values after destruction of the cellular membrane by sonication indicated that approximately 65% of the ADC values of normal cells originate from the cell structures made of membranes and that the remaining 35% originate from intracellular components. Microparticles, defined as particles smaller than the normal cells, increased in number after rituximab treatments, migrated to the extracellular space and significantly decreased the ADC values of bio-phantoms during apoptosis. An in vitro study using bio-phantoms was conducted to quantitatively clarify the roles of cellular factors and of extracellular space in determining the ADC values yielded by tumor cells and the mechanism by which apoptosis changes those values.

DOI： 10.18926/AMO/48566

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DOI： 10.2327/jvas.42.7

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Veterinary Medical Association  

DOI： 10.12935/jvma.64.640

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Other Link： http://search.jamas.or.jp/link/ui/2011302179

Language：Japanese   Publisher：獣医麻酔外科学会  

DOI： 10.2327/jvas.42.21

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The diagnosis and surgical treatment of spinal epidural empyema (SEE) in a 2-year-old neutered male domestic shorthaired cat is described. SEE was diagnosed by computed tomographic myelography (CT myelography) and surgical exploration. The lesion was missed on both non-enhanced CT and conventional myelography. SEE should be considered in the differential diagnosis of progressive myelopathy in cats, and CT myelography should be undertaken when magnetic resonance imaging (MRI) cannot be performed. (C) 2010 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jfms.2010.01.015

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPANDIDOS PUBL LTD  

In recent years, magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has seen wide clinical use, such as for early detection of cerebrovascular diseases and whole body screening for tumors. The apparent diffusion coefficient (ADC) standard phantom, which mimics the ADC values of several lesions in the body, is indispensable for the development of new pulse sequences for DWI, such as diffusion-weighted whole-body imaging with background body-signal suppression (DWIBS). However, information on the ADC values of the previously reported ADC standard phantoms is limited, because these phantoms were made using only a few different materials at a limited range of concentrations, and the ADC values were measured only at certain temperatures. It has been considered difficult, if not impossible, to create a phantom that provides arbitrary ADC values, because it is difficult to calculate the concentrations of the materials and the temperature at ADC measurement. In this study, we used polyethylene glycol (PEG) as a phantom material, and developed an empirical formula to calculate the PEG concentration at any measurement temperature to obtain arbitrary ADC values of the phantom. DWI images of phantoms made using seven different PEG concentrations were taken under heating from 17 to 46 degrees C at 1 degrees C intervals. Using ADC values calculated from these DWI images, we developed two empirical formulas: i) an empirical formula to calculate the ADC values of phantoms made using any PEG concentration at any measurement temperature; and ii) an empirical formula to calculate PEG concentrations to obtain arbitrary ADC values at any measurement temperature. We inspected the accuracy of these empirical formulas by newly made PEG phantoms. A comparison between the ADC values calculated with the empirical formulas and the measured ADC values confirmed the high accuracy of these formulas. PEG phantoms are safe, inexpensive and easy to make, compared with the previously reported ADC standard phantoms. Our empirical formulas enable us to calculate PEG concentrations that provide arbitrary ADC values at any measurement temperature. The empirical formulas could be used within a range of ADC values from 0.37x10(-3) to 3.67x10(-3) mm(2)/s, PEG concentrations from 0 to 120 mM, and measurement temperatures from IS to 45 degrees C. Using these formulas, it would be possible to make standard phantoms that mimic the ADC values of any clinical lesions. The PEG phantom might thus be an excellent new ADC standard phantom for MRI with DWI.

DOI： 10.3892/ijo_00000404

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPANDIDOS PUBL LTD  

Diffusion-weighted magnetic resonance imaging (MRI) is frequently used clinically, and is available for the whole-body screening for tumors. The exact mechanism by which the apparent diffusion coefficient (ADC) value decreases in tumorous tissue remains unclear, although various theories have been proposed, including intracellular and extracellular factor theories. It is impossible to distinguish each factor in the intracellular and extracellular spaces as the source of MR signal generation by means of conventional comparison between MR images and pathological specimens. Other factors which have been reported to affect ADC include cellularity and cellular edema of human tissues, and temperature of phantoms at the time of measurement. We employed a new technique that enables cellular MR imaging using a newly developed bio-phantom containing a living culture tumor cell line, Jurkat-N1. We investigated possible reasons for observed decreases in ADC values for tumors, and we considered the contribution of both the intracellular and extracellular space to such a decrease. The ADC values of the bio-phantom increased with increasing heat exposure from 27 to 45 degrees C. ADC values also increased after the destruction by sonication of tumor cell membranes. ADC values decreased as cellularity increased in the bio-phantorn. ADC values decreased due to cellular edema caused by a low salt concentration in the bio-phantom. Changes in pressure in the bio-phantom had no effect on the observed ADC values. We calculated both the intracellular ADC and extracellular ADC values using the ADC values, cellularity, and cellular volume of Jurkat-N1 cells in the bio-phantom. The extracellular ADC values in the bio-phantom were estimated to be lower than the ADC value of distilled water. These results indicate that not only intracellular ADC values, but also extracellular ADC values contribute to the determination of the ADC values of bio-phantoms. This is the first report to have examined the contribution of intracellular and extracellular space on the ADC values of bio-phantoms containing cultured tumor cells.

DOI： 10.3892/or_00000484

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER CHEMICAL SOC  

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Language：Japanese   Publisher：(公社)日本ビタミン学会  

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Language：Japanese   Publisher：(公社)日本薬学会  

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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