Proton beam radiotherapy for cancer takes advantage of the fact that the rate of energy deposition increases as the protons slow down, as the inverse of the velocity. A typical treatment may address a cancer that lies under 150 mm of healthy tissue. 160 MeV protons will penetrate the healthy tissue depositing little energy and doing little damage. Then they come to a halt in the next 20 mm depositing the bulk of their energy there and doing enough damage to kill the cancer. If the protons lose half their kinetic energy in the cancer, and a sufficient dose is three Grays, calculate: i) The required power incident on the cancer to perform the treatment of a 20 mm cancer in five minutes. ii) The required beam current.

Proton beam radiotherapy for cancer takes advantage of the fact that the rate of energy deposition increases as the protons slow down, as the inverse of the velocity. A typical treatment may address a cancer that lies under 150 mm of healthy tissue. 160 MeV protons will penetrate the healthy tissue depositing little energy and doing little damage. Then they come to a halt in the next 20 mm depositing the bulk of their energy there and doing enough damage to kill the cancer. If the protons lose half their kinetic energy in the cancer, and a sufficient dose is three Grays, calculate: i) The required power incident on the cancer to perform the treatment of a 20 mm cancer in five minutes. ii) The required beam current.

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter1: Atomic Structure

Section: Chapter Questions

Problem 6RQ: How many valence electrons are generally contained in materials used for insulators?

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