fill the blanks - 15
Nuclear radiation refers to those particles or waves which emanate from ....
atomic nucleus
In 1911 Sir Ernest Rutherford bombarded thin metal foils with .....particles.
alpha
Alpha particles are helium atoms stripped of their ....
two electrons
The nuclear fusion process makes use of cheap and abundant fuel and produces no......
radioactive waste product
The name of the unit rem is an acronym for......
röntgen-equivalent
Boron interacts with neutrons much ..... than ordinary tissue.
more strongly
This emission of particles or electromagnetic waves from a nucleus is referred to as .......
radiation or radioactive decay
Artificially produced radioisotopes are formed by bombarding normal atoms with ..... obtained from nuclear reactors, cyclotrons, ect.
energetic particles
The stability of many nuclei demonstrates the existence of a third force, a powerful.... force which holds the protons and neutrons together irrespective the electric repulsion forces.
attractive
Alpha radiation is not appropriate for radiation therapy since its....... is less than one-tenth millimeter inside the body.
penetration / range
Mass must be considered to be a form of energy according to the.... relation.
Einstein
Uranium-238 decays by alpha emission into thorium-234. The sum of the masses of the a particle and thorium atom is .....than the mass of the original uranium atom.
slightly less
An important parameter in radioactive decay is ....., the time for one half of the nuclei to decay, regardless of the original number.
the half life
The radioactive decay process may be presented by a „.....curve“
decay
The internally administered radioisotopes are selected according to the type and energy of the radiation emitted, the ....and the rapidity and completeness of their..... from the body.
half-life ; excretion
Ionization chambers, proportional counters, and Geiger-Muller counters differ mainly in terms of the.... applied to the electrodes in the ionizable gas.
voltage
Ionization chambers can be used to identify the... of radiation and radiation.....
type; energy
....and .....rays are used to trat cancer. The disadvantage is that there is no way to irradiate the cancerous tissue without damaging the normal tissue surrounding it.
x-rays; gamma
The ratio of cancer cells killed to normal cells killed is called the .....
therapeutic ratio
It is important to make the therapeutic ratio as..... as possible.
high
The „oxygen effect“ is a significant factor connected with the tissue radiation sensitivity (....... production).
free radical
Radioiodine, 131I, is a unique therapeutic agent since it is selectively taken up by the..... gland.
thyroid
Molecules having radioisotopes in their structure can follow the normal metabolic pathways and can „.....“ those pathways by the fact that some of the radioisotope nuclei decay and emit radiation, which can be detected outside the body.
trace
Nuclear processes may be used for long term generation of power in implanted devices such as ......
cardiac pacemaker
If heavy nuclei split to form two intermediate nuclei, the total mass is .... and energy is released.
reduced
if light nuclei are combined to form intermediate nuclei, the total mass is ........ and energy is ......
reduced; released
an example of charge conservation occurs when an electron e- and its antiparticle, the ..... unfergo an annihilation in which they change into two gamma rays
positron
the conversion of 1kilogram of mass yields ...... J of energy
9* 10^16
when a positron encounters an electron, the annihilate with the production of ......
two gamma ray photons
the plasma volume can be found by intravenous injection of a few uCi of......
131I serum albumin