We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Article |

Alpha Particle and Proton Beams in Therapy

John H. Lawrence, MD, DSc; Cornelius A. Tobias, PhD; James L. Born, MD; Alexander Gottschalk, MD; John A. Linfoot, MD; Robert P. Kling, MD
JAMA. 1963;186(3):236-245. doi:10.1001/jama.1963.63710030018011.
Text Size: A A A
Published online


HEAVY PARTICLES, either charged or uncharged, are called "heavy" because they actually are very heavy when compared with the weight of the electron. The neutron is approximately 1,800 times the weight of the electron and, in the case of other heavy particles, such as alpha particles, carbon nuclei, and other elements higher in the periodic table, they are proportionately heavier according to the number of protons and neutrons within their nuclei. These heavy particles have many interesting physical characteristics— For editorial comment, see page 254. especially their ability to produce dense ionization in tissue. In 1935, when these particles became available for experimental studies in the field of radiobiology, this known physical quality led us to investigate their biological effects on normal tissue.1,2 We found that per unit of ionization produced in tissue they were several times as destructive as equal doses of conventional x-rays. This led to setting


Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

First Page Preview

View Large
First page PDF preview




Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.