Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Megavoltage therapy:
Kerst developed the betatron which accelerates electrons to high energy .It open a new radiation therapy era-the supervoltage or megavoltage era.Another development in the radiation therapy is the application of man made radioactive source .
One of the radioactive sources:
Cobalt 60: it emits penetrating gamma rays of about 1.25 Mev energy.60Co units (also called cobalt teletherapy and cobalt bomb units)
-The high energy gamma rays emitted by 60Co are absorbed by tissue and produce high energy electrons .- Most of electrons move in the same direction as the original beam .- As the gamma ray beam penetrates the first few mm beneath the skin ,the no. of electrons increases and the energy deposited by them increases.- The dose maximum occurs about 5 mm below the skin .-The relatively low dose at the skin from high energy x-rays of gamma rays is referred to as the skin –sparing effect.-The radiation from 60Co teletherapy unit is emitted continuously ,the unit is turned on by rotating the source wheel until the source is over the beam port in the large lead shield .It is turn off by rotating the source wheel until the source shielded by the wheel fig (1).
Mega voltage therapy has three major advantages :
- The maximum dose occurs below the skin and the skin sparing effect greatly reduces the pain from the treatment.- The high energy is almost completely in the Compton effect region and doses not give a large doses to the bone .- The greater penetrating ability permits better treatment of tumors deep inside the body.
Write down a short note on the discovery of neutron. Show the uses of radioisotopes.
a boy throws a ball of mass 20 kg vertically upwards.it raises to a maximum height of 100 m.at what height will the kinetic energy be reduced to 70%
It is an instrument used to detect small current passing by it by showing deflection. Galvanometers are of dissimilar types e.g. moving coil galvanometer, moving magnet galvanomete
two blocks of mass 2kg and 4 kg are held together by a string force of 10N is applied on 2kg and 20N on 4kg find the tension in the string connected between two blocks
Q. Why does the sky appear blue in colour? As-per to the Rayleigh's scattering law the shorter wavelengths are scattered much more than the longer wavelengths. The blue look o
How High Will It Go? The motion of the sledder within the animation below is same to the motion of a roller coaster car on a roller coaster track. The similarity of the two mot
Moment of Disk or Solid Cylinder about Axis We presume the axis of rotation is perpendicular to the disk and through its center and coincident with the axis of the cylinder. Co
who is first law of motion?
Diamagnetism is a basic property of all matter, though it is generally very weak. It is due to the no cooperative behaviour of oepenrbiting electrons when exposed to an applied mag
Define about the Graphite Structure Graphite is the allotropic form of carbon. In case of graphite the carbon atoms are arranged in regular hexagons in flat parallel layers a
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd