High-energy X-rays leave a trace of destruction in bone collagen | 高能X射線在骨膠原中留下破壞痕跡

中文版谷歌中文翻譯(90% 準確率) | English translation
Buy/Sell Your Domains Here。在這裡購買/出售您的域名
Contact Dr. Lu for information about cancer treatments。聯繫盧博士,獲取有關癌症治療資訊。
Damage to bone marrow is another severe damage which leads eventually to leukemia.  That is why cancer patients receiving radiotherapy tend to develop leukemia within three years of treatments as a secondary cancer.
對骨髓的損害是另一種嚴重的損害,它最終會導致白血病。 這就是為什麼接受放射治療的癌症患者往往會在治療後三年內發展為繼發性癌症的白血病。
News Release

Peer-Reviewed Publication

Helmholtz-Zentrum Berlin für Materialien und Energie

xray on pike bones
image: The images (b) show the collagen distribution in pike bones before (left) and after (right) a μCT experiment and (c) before (left) and after (right) an X-ray diffraction μCT experiment at the mySpot beamline, BESSY. Also (d) before (left) and after (right) a 2D mapping XRD mySpot experiment. The damaged areas appear dark marked with yellow arrows. Arrows in pink show the x-rays. view more 

Credit: Charité Berlin/HZB

It has long been known that beyond a certain dose, X-rays damage living tissue, so there are clear medical indications for X-rays to keep radiation exposure to a minimum. In basic research on the properties and characteristics of mineralised tissue samples such as bone, researchers rely on increasingly powerful X-ray sources.

Bones from fish and mammals

“Until now, the motto has actually been: more flux and higher energy is better, because you can achieve greater depth of field and higher resolution with more intense X-rays,” says Dr. Paul Zaslansky from Charité-Universitätsmedizin. Zaslansky and his team have now analysed bone samples from fish and mammals at the MySpot beamline at BESSY II.

BESSY II generates a well characterized broad-range of X-rays, precisely focused in an intermediate energy range which allows insights into the finest structures and even chemical and physical processes in materials. “Thanks to sensitive detectors and rather mild irradiation conditions in BESSY II as compared with harder X-ray synchrotron sources, we were able to demonstrate on our various bone samples that collagen fibres become damaged by the irradiation absorption in the mineral nanocrystals,” Zaslansky summarises the results of the study.

Imaging the protein fibers

“We examined the samples under Second-Harmonic Generation laser-scanning microscopy for the imaging the protein fibers” explains first author Katrein Sauer, who is doing her doctorate in Zaslansky’s team. Together with HZB expert Dr. Ivo Zizak, she irradiated bone samples from pike fish, pigs, cattle and mice with precisely calibrated X-ray light.

Trail of destruction

The beams left a trail of destruction that is clearly visible in the confocal and electron microscopy images. “The high-energy photons from the X-ray light trigger a cascade of electron excitations. Ionisaton of calcium and phosphorus in the mineral then damages proteins like collagen in bone,” Sauer says. Break-down of collagen increases with the duration of the irradiation, but also shows up even with short irradiation at high flux.

Minimal doses for research on living materials

“X-ray methods are considered non-destructive in materials research, but at least for research on bone tissues this is not true,” says Zaslansky. “We have to be more careful in basic medical research that we don’t damage the very structures we actually want to analyse.” So, as everywhere in medicine, and even when there are no living tissues and DNA to damage, it comes down to using a minimal dose to get the insights that reflect the material condition without causing damage.

 

Note:

The X-rays produced at BESSY II are about ten thousand times more intense than X-rays used for medical examinations (for X-rays of a broken leg, the German Federal Office for Radiation Protection gives a dose of 0.01 millisievert). X-ray methods are extremely useful for medical examinations.


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