Comparison between Monte Carlo simulation and measurement with a 3D polymer gel dosimeter for dose distributions in biological samples.

In this research, we used a 135 MeV/nucleon carbon-ion beam to irradiate a biological sample composed of fresh chicken meat and bones, which was placed in front of a PAGAT gel dosimeter, and compared the measured and simulated transverse-relaxation-rate (R2) distributions in the gel dosimeter. We experimentally measured the three-dimensional R2 distribution, which records the dose induced by particles penetrating the sample, by using magnetic resonance imaging. The obtained R2 distribution reflected the heterogeneity of the biological sample. We also conducted Monte Carlo simulations using the PHITS code by reconstructing the elemental composition of the biological sample from its computed tomography images while taking into account the dependence of the gel response on the linear energy transfer. The simulation reproduced the experimental distal edge structure of the R2 distribution with an accuracy under about 2 mm, which is approximately the same as the voxel size currently used in treatment planning.

Population of follicles and luteal structures during the oestrous cycle of mares detected by three-dimensional internal structure microscopy.

The structure of the equine ovary is different from that of other mammals in its extremely large size, the presence of ovarian fossa and the inverted location of its cortex and medulla. A three-dimensional internal structure microscopy (3D-ISM), which consists of a computer-controlled slicer, a CCD camera, a laser disc recorder and a PC, is very useful for the observation of the internal structures in equine ovaries. In addition, the three-dimensional images of follicles and corpus luteum (CL) reconstructed by the segmentation technique can clarify the spatial arrangement in the equine ovary. In this study, to understand the changes in the ovarian internal structures of the mare during the oestrous cycle, the size and numbers of follicles and luteal structures were analysed by 3D-ISM in addition to the concentrations of progesterone (P(4)) and oestradiol-17beta. As a result, many small follicles (<10 mm in diameter) were detected. It was recognized that the luteal structures were distinguished into three types, such as the corpus haemorragicum (CH), which is formed by blood elements at the cavity after ovulation, CL and corpus albican (CA). There were some CHs and CL in the group, which had the concentration of P(4) > 1 ng/ml. CHs were also observed in the group, which had low level of P(4) (P(4) < 1 ng/ml). CAs were found regardless of the P(4) level. In conclusion, 3D-ISM enabled the internal observation of the ovarian structures in detail, and estimation of the stage of the ovarian cycle with complementary physiological information. The findings by 3D-ISM provide basic information for clinical applications.

Biomechanical characterization of ventricular-arterial coupling during aging: a multi-scale model study.

Left ventricular-arterial (VA) coupling has been recognized to be of great significance in understanding both the global and local mechanical performance of the circulatory system. In this study, a closed-loop multi-scale model of the human cardiovascular system is established for the purpose of studying the coupled VA hemodynamic changes during aging. Obtained results show that age-associated changes in arterial properties have some negative but relatively small influences on left ventricular (LV) mechanical performance, whereas they progressively increase LV and aortic systolic pressures, and aortic pulse pressure during aging. Wave analysis reveals that increased aortic characteristic impedance and premature wave reflection induced by arterial stiffening are two coexistent factors responsible for aortic systolic hypertension and increased aortic pulse pressure at old age. In contrast, aortic dilatation can partly counteract the negative influences of arterial stiffening. Coupled LV-systolic and arterial stiffening (a constant VA coupling index) well preserves LV mechanical performance given normal LV diastolic function during aging, but with a concomitant further elevation of LV and aortic systolic pressures. Furthermore, it is found that the states of arterial, LV-systolic and diastolic stiffness can be distinguished by investigating the sensitivity of LV-systolic pressure to various cardiac indices.

Three-dimensional reconstruction of the equine ovary.

The equine ovary has a very unique structure in terms of its extreme large size, the presence of the ovulation fossa and the inverted location of its cortex and medulla. In the previous study, it was recognized that the application of three-dimensional internal structure microscopy (3D-ISM) to observe the mare ovary is very effective. Three-dimensional reconstruction of serially sliced images made by 3D-ISM was successful in this study with the aid of the sophisticated image processing technique. The rotation of the reconstructed ovary has been carried out with and without the application of the transparency technique in the ovarian stromal region. The spatial localization of follicles and corpus luteum was clearly visualized by rotating the reconstructed image of the ovary. The extraction of the images of follicles and corpus luteum was also available and gave a quantifiable understanding of their structure.

Computational fluid dynamics for brain circulation and aneurysm with therapeutic devices.

SUMMARY: We analysed fluid dynamics at brain arteries having multiple inflow and out flow like Willis ring based on clinical imaging modalities. In addition, we analysed fluid dynamics with therapeutic devices like coils and stents to simulate their influences to blood flow. 3D CTA and MRA obtained three-dimensional structures of the brain vessels. The centreline was obtained from the three dimensional structure. Diameter of the blood vessels was measured by 3D CTA/MRA then smooth surfaced blood vessel models were created. For the fluid analysis, we developed a home brew software which can display parameters such as streamline, etc. In addition, our CFD (computational fluid dynamics) software can work in collaboration with a CAD (computer aided design) software which we also developed (VCAD: Volume CAD). So, therapeutic devices such as coils, balloons and stents could be placed in the models and CFD analysis could be performed placing devices in the models. The flow pattern in the complicated vascular structure could be calculated such as Willis ring which has multiple inputs like ICA, VA and multiple outlets like MCA and PCA with communicating arteries. CFD with therapeutic devices could also analysed with our system. CFD including communicating arteries will assist the simulation of parent artery occlusion. CFD with therapeutic devices is helpful not only for simulation for embolization, but will help us to design therapeutic devices under computer simulation.

Fine Structure of Detached Coils Observed by Micro-CT.

SUMMARY: Detached GDC was observed by high resolutional industrial microCT, whose resolution was higher than 0.1 mm. Unexpected destruction of the coils (kinking) was detected and unraveling also clearly visualized. Much higher resolution can improve safe and effectivity of GDC procedure.

A 3D unsteady flow analysis in a doubly constricted arterial vessel.

The aim of this study is to examine the interaction between two mild atherosclerotic proliferations spaced apart by a distance S by analyzing their influence on flow structure, pressure drop and stress field in an arterial vessel under pulsatile flow conditions. This has been achieved numerically by employing a time accurate, cell centered finite volume method in solving the Navier-Stokes equations governing the 3D unsteady flow dynamics in a conceptual model of an multiply constricted arterial vessel. In comparison to the pressure drop across a single stenosis, nearly a 50% increase in the late systolic and early diastolic pressure drops has been observed across the two mild constrictions when they are spaced within a distance of S

Remote Manipulation of Guidewire using a Virtual Reality Device.

SUMMARY: A trial of remote manipulation for micro guidewire is reported. The system had masterslave style. When an operator manipulated the virtual torque device at the master side, a machine at the distant slave side reproduced the manipulation. At the same time, the operator could feel the force feedback from the manipulation at the slave. We could experimentally realize this remote manipulating system using a virtual reality device.

[Statistical investigation on orthodontic patients who received treatment at Fukuoka Dental College during 15 years].

It has been fifteen years since the Department of Orthodontics started in 1973, and this report concerns mainly the results of clinical observations during these period. The results were as follows: 1) Three thousand four hundred and three patients visited during a fifteen years period and 2,065 (61%) of them received orthodontic treatment. This statistical investigation was performed on 2,065 patients. 2) The numbers of treated patients increased from 1973 to 1983 without 1980 but have almost unchanged with about 180 patients from 1984 to 1987. 3) The male patients were less than the female by the ratio of 1:1.67. As to age, the patients from 6 to 12 years old accounted for 72% of all the treated. 4) Analyzed by dental age categories, patients at the stage of III A and III B comprised 54% of all the treated. 5) Analyzed by month, the patients visited on March, July and August in spring and summer vacations. 6) Most of the patients (92%) lived in Fukuoka Prefecture and 38% of them lived in Sawara-ku, where lay in the south-western part of Fukuoka city. 7) Fifty six per cent of all patients were introduced by doctors and dentists. 8) As to malocclutions, the number of mandibular protrusion was the largest, crowding case was next, and maxillary protrusion was third. The total sum of these three cases accounted for 78% of all the treated. 9) In the initial orthodontic appliances, the use of the multi-brackets appliances was first, the chin cap appliances was second and plate appliances was third. The total sum of these three appliances accounted for about 73%. 10) Analyzing to age and initial orthodontic appliances, plate, chin cap, F. K. O. and I. M. A. appliances were used at the age from 7 to 8. Lingual arch appliances were also used at the age of 8. The multi-brackets appliances increased remarkably during the recent five year period and were used at the age of 10 to 11 and over 20 years.

Endocrine studies on ovarian androblastomas (Sertoli-Leydig tumors).

Endocrine studies were made on 4 women with ovarian Sertoli-Leydig cell tumors of varying degrees of differentiation. Clinically, all 4 patients showed evidence of increased androgen production, manifested by either hirsutism or virilization. The calculated ratios of steroid hormones between the affected ovarian venous values and peripheral values for testosterone (T), androstenedione (A), and dehydroepiandrosterone (DHEA) in 3 patients, were 1.4-18.6, 4.2-24.4, and 3.7-10.0, respectively. The peripheral levels of the hormones before salpingo-oophorectomy in all the patients were T: 0.97-45.0 ng/ml; A: 2.92-114.0 ng/ml; and DHEA: 13.0-20.9 ng/ml. In the 3 juvenile patients, elevated basal levels of LH and normal or subnormal levels of FSH (high LH:FSH ratio) were found. In a 12-year-old patient with 1,900 g tumor composed predominantly of Sertoli cells with lipid storage, the peripheral serum levels of T and estradiol (E2) were 114 ng/ml and 1890 pg/ml, respectively. The present data suggest that: 1) androblastomas have a biosynthetic capacity for androgen, estrogen, or both in which both the delta 5 and delta 4 pathways are involved, and 2) little correlation exists between the endocrine function and cellular composition of the tumors or their degree of differentiation.

Rupture of the pectoralis major. Report of 2 cases.

Two cases of rupture of the pectoralis major are reported, one caused by excessive tension and direct violence, while the other was a result of direct violence alone. The site of the rupture was at the lateral third portion of the pectoralis major in one and at the musculotendinous junction in the other. Both patients were treated surgically, and regained full function of their shoulders. Review of the literature suggests that surgical repair is generally advisable and more gratifying than conservative management.