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|Title: ||Studying the effects of alpha particles on zebrafish embryos with the help of CR-39 nuclear track detectors|
|Authors: ||Choi, Wing Yan (蔡詠恩)|
|Department: ||Department of Physics and Materials Science|
|Issue Date: ||2008|
|Course: ||AP4209 Project|
|Programme: ||BSc (Hons) in Applied Physics|
|Instructor: ||Prof. Peter K. N. Yu|
|Subjects: ||Alpha rays -- Physiological effect|
Zebra danio -- Embryos -- Physiology
Nuclear track detectors
|Abstract: ||Alpha particles from inhaled radon progeny are the most common source of
irradiation of the human respiratory tract. Not only the human respiratory tract may be
affected, radon may dissolve into the blood and enter other organ through the blood
circulatory system. Radon progeny in the blood of a pregnant woman may affect the
embryo through the exchange of nutrient at the placenta. It is therefore important to
estimate the effect caused by alpha particles to the embryo by using zebrafish embryo
as a vertebrate model.
Study has been shown that alpha particle would cause morphologic abnormalities in
48 hpf zebrafish embryo. In this project, we want to further study the relationship
between occurrence of malformation and the absorbed dose of the zebrafish embryo.
CR-39 solid-state nuclear track detectors with a thickness of 16 μm are used as
support substrates for holding the zebrafish embryos during irradiation. It can also
help to record the alpha particle incident position so that the number of alpha particle
actually going into the embryo cells can be found, thus, it can enable the calculation
of absorbed dose of the embryo cells.
In this study, planar 241Am source with an activity of 0.1151μCi and main alpha
energy equal to 5.49 MeV was employed. Five sets of experiments with irradiation
times of 2, 4, 6 and 8 min were conducted. Observations were made when the
irradiated embryos were developed to 48 hpf to determine whether malformation had
occured or not.
Among 112 irradiated zebrafish embryos, 21 of them showed morphologic
abnormalities. The smallest value of absorbed dose that caused malformation in this
study was 0.51 mGy and the largest value was 2.2 mGy. These correspond to 5.17 and
22 mSv equivalent doses in human, respectively.|
|Appears in Collections:||OAPS - Dept. of Physics & Materials Science|
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