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.
What is Vapor Density? Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of
derive an expression for the variation of g with altitude or depth
An electric dipole is held in a uniform electric field. (1) Using suitable diagram, show that it does not undergo any translatory motion, and (2) derive an expression for the
Uniform motion When a body falls by a fluid, the pull of gravity is soon balanced by the frictional forces set up, and it continues to move at a constant velocity. If this is t
On the way to school, Jamal realizes that he left his physics homework at house. His car was initially heading north at 24.0 m/s. It takes him 35.5 s to turn his car around and hea
Question: An optimistic model for a battery is just an ideal seat of EMF. A further realistic model commonly used to model actual batteries is Answer: Note that the i
Current time base generator
Define the introduction about Schrödinger’s Atom. Introduction to the Schrödinger’s Atom: To describe the spectral line puzzle, Bohr came up along with a radical model of t
Speed of light (in vacuo); c The speed on which electromagnetic radiation propagates within a vacuum; it is described as 299 792 458 m/s.
Explain the Diagramming Waves? There are two ways that waves can be indicated in a two-dimensional diagram. Parallel lines can be drawn that are meant to show the position of
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