M.V. Colaço

Application of the SR-PhC-μCT technique with phase retrieval for the characterization of internal and external structures of Rhodnius prolixus

The present work is the second one of a two- part publication on the use of Synchrotron Radiation Phase Contrast microtomography (SR-PhC-μCT) for the study of Rhodnius prolixus morphology. In previous paper the visualization of various detailed features were highlighted thanks to the edge enhancement effects typical of the phase contrast technique, but the contrast between foreground and background remained poor. In this study the same data set have been re-visited with application of a single distance phase retrieval algorithm. The resulting slices showed very high quality images that enable a better visualization of important muscles and neurohemal organs of the central nervous system within the head of Rhodnius prolixus.

Analysis of femur head microstructure in ovariectomized rats

It is well accepted that rat ovariectomy (OVX) is a model of estrogen deficiency. OVX played a very important role in the initiating and developing of osteoporosis and it has been shown to be a major risk factor for the development of postmenopausal osteoporosis in women. In this work we used synchrotron radiation computed microtomography to investigate the skeletal effects in femoral head of female Wistar rats after bilateral ovariectomy surgery. The CT system was set up at the SYRMEP beamline in the synchrotron radiation facility ELETTRA (Trieste, Italy). Micro-CT images provided 3D information on precise trabecular microstructure by the reconstruction of multiple 2D images with almost 2 μm resolution. Our aim was to use histomorphometric analysis to reveal the effect of OVX on the three-dimensional (3D) trabecular bone microarchitecture. Evaluated morphometric parameters were trabecular bone volume-tissue volume ratio (BV/TV), trabecular number (Tb.N), trabecular separation (Tb.Sp) and trabecular thickness (Tb.Th). OVX group presented noticeable reduction in the Tb.N and Tb.Th when compared with control group (P 0.05). Our data may help to gain more insight into the potential mechanism of osteoporotic femoral head fractures.

Synchrotron microtomography to evaluate effects of different polychemotherapy drugs on cortical bone structure

Abstract Purpose: To determine the effects of different polychemotherapy drugs on cortical bone structure, the femur diaphysis of rats were treated with two different chemotherapy drugs, AC (doxorubicin + cyclophosphamide) and TC (docetaxel + cyclophosphamide), and evaluated by 3D morphological analysis using synchrotron radiation microtomography. Materials and methods: Wistar rats were classified into three groups. One group received doses of docetaxel and cyclophosphamide (G1) – TC regimen; a second group received doses of doxorubicin and cyclophosphamide (G2) – AC regimen; while a control group (G0) received no further treatment. 3D tomographic images of the rats’ femurs were obtained at the SYRMEP (Synchrotron Radiation for Medical Physics) beamline at the ELETTRA Synchrotron Laboratory in Trieste, Italy, using monochromatic X-rays with resolution of 9 μm. Results: It could be shown that the treatment caused significant differences in morphological parameters measured from the 3D images of femur diaphysis of rats, among the studied groups, complementing a previous study using stereological methods, biochemistry and electron microscopy. Conclusions: Our results indicate that the same process of osteoporosis caused by advancing age might occur in young women treated with docetaxel + cyclophosphamide (TC) and doxorubicin + cyclophosphamide (AC). 3D microtomography was shown to be an outstanding technique for bone analysis.

Synchrotron radiation X-ray microtomography and histomorphometry for evaluation of chemotherapy effects in trabecular bone structure

Three-dimensional microtomography has the potential to examine complete bones of small laboratory animals with very high resolution in a non-invasive way. One of the side effects caused by some chemotherapy drugs is the induction of amenorrhea, temporary or not, in premenopausal women, with a consequent decrease in estrogen production, which can lead to bone changes. In the present work, the femur heads of rats treated with chemotherapy drugs were evaluated by 3D histomorphometry using synchrotron radiation microcomputed tomography. Control animals were also evaluated for comparison. The 3D tomographic images were obtained at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at the Elettra Synchrotron Laboratory in Trieste, Italy. Results showed significant differences in morphometric parameters measured from the 3D images of femur heads of rats in both analyzed groups.