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.

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.