Quantcast Maximum permissible dose - Fundamentals of X-Ray Physics

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
c. Radiation Equivalent Man (rem). The rem is the absorbed dose in rads
multiplied by various quality factors. Fortunately, in the energy range used for medical
radiography, 1 R = 1 rad = 1 rem. In other words for all practical purposes the rad and
rem will be the same as the R.
4-29. MAXIMUM PERMISSIBLE DOSE
Maximum permissible dose (MPD) is affected both by the size of each dose and
the rate at which these doses are received. For radiation workers or those individuals
whose occupation requires exposure to ionizing radiation on a regular basis (such as
the x-ray specialist), radiation protection guides recommend the following maximum
accumulated dose. For external exposure, from x- or gamma rays, to the whole body,
the maximum average dose rate should not exceed 5 rems per year. The same dose
rate applies to the head and trunk, active blood-forming organs, the gonads, and the
lens of the eye. When only a single portion of the body is exposed, as compared to the
whole body, the maximum permissible dose is sometimes higher. For example, it is
recommended that the average dose rate to the hands, forearms, feet, and ankles
should not exceed 75 rems per year.
a. No occupational dose is allowed persons under 18 years of age. Individuals
who are over 18 years of age, but who have not yet reached their 19th birthday, may be
occupationally exposed to ionizing radiation, provided they do not exceed 1.25 rems
dose equivalent to the whole-body in any calendar quarter, nor 3 rems in the 12
consecutive months prior to their 19th birthday. The accumulated dose at any
subsequent age should not exceed 5(N-18), where 5 is the maximum dose rate per
year, N is the age of the worker in years, and 18 is the age prior to which no
occupational dose is allowed. Following are two examples of calculating the maximum
permissible (accumulated) dose.
Age 20.
5(N-18) = 5(20-18) = 5(2) = 10 rems.
Age 31.
5(N-1B} = 5(31-1B} = 5(13} = 65 rems.
b. AR 40-14, Control and Recording Procedures for Occupational Exposure to
Ionizing Radiation, further delineates maximum exposure levels by stating that the
accumulated dose equivalent of radiation to the whole-body, head, and trunk, active
blood-forming organs, gonads, and lenses of the eye will not exceed 1.25 rem in any
calendar quarter nor 5 rems in anyone calendar year.
c. The maximum permissible dose for an individual in the general population
group (excluding radiation workers) is significantly lower than that of radiation workers.
Currently, it is recommended that the yearly radiation exposure to individuals in the
general population should be held to one-tenth that of the occupational limits. This does
not include exposure to natural radiation or medical and dental x-ray. Thus, for whole
MD0950
4-25



Medical News
ESC: Gout Drug Gets Thumbs Down in Heart Surgery
BARCELONA (MedPage Today) -- Findings from two trials suggested the...
medpagetoday.com
PodMed: A Medical News Roundup From Johns Hopkins (with audio)
(MedPage Today) -- This week's topics include treating adolescent depression,...
medpagetoday.com
Grand Roundup: Top posts for the week of Aug. 24
The five most-read stories this week on Scope were: “Sleep...
scopeblog.stanford.edu
Grand Roundup: Top posts for the week of Aug. 24
The five most-read stories this week on Scope were: “Sleep...
scopeblog.stanford.edu
To Pee or Not to Pee? That's Improbable!
(MedPage Today) -- That?s Improbable! is MedPage Today?s weekly roundup...
medpagetoday.com
ESC on SIGNIFY: No Comment
BARCELONA (MedPage Today) -- The results of SIGNIFY, a study...
medpagetoday.com
Firm Date for ICD-10 Switch Still Not Raising Urgency
WASHINGTON (MedPage Today) -- Although there is a firm date...
medpagetoday.com
ESC: Gout Drug Some Help in Heart Surgery (CME/CE)
BARCELONA (MedPage Today) -- Giving the gout drug colchicine perioperatively...
medpagetoday.com
ESC: Novel Heart Failure Drug a Game-Changer (CME/CE)
(MedPage Today) -- An investigational heart failure drug being developed...
medpagetoday.com
Tax forms could pose challenge for HealthCare.gov
If you got health coverage through President Barack Obama's law...
medicalxpress.com
Sudden death predictor identifies ICD candidates in new ESC Guidelines
Saturday 30 August 2014: A new sudden death predictor for...
medicalxpress.com
The early cost of HIV: Inflammatory response breaks down intestinal lining, but help may come from friendly bacteria
Researchers at UC Davis have made some surprising discoveries about...
medicalxpress.com
First expert consensus on ventricular arrhythmias published
The first expert consensus on ventricular arrhythmias is published today....
medicalxpress.com
First comprehensive ESC Guidelines on aortic diseases published
The first comprehensive ESC Guidelines on aortic diseases are published...
medicalxpress.com
First recommendations on all new oral anticoagulants in pulmonary embolism published
The first recommendations on the use of all new oral...
medicalxpress.com
First multidisciplinary recommendations on management of arrhythmias in ACS patients
The first multidisciplinary recommendations on the management of arrhythmias in...
medicalxpress.com
ESC/EACTS revascularization guidelines stress benefit of revascularization in stable CAD
The therapeutic benefit of revascularisation in coronary artery disease (CAD)...
medicalxpress.com
Study shows cavities have become the most common childhood disease
A Washington Post blog entry published earlier this week reports...
scopeblog.stanford.edu
Study shows cavities have become the most common childhood disease
A Washington Post blog entry published earlier this week reports...
scopeblog.stanford.edu
CMS Shuts Down Sunshine Act Database -- Again
WASHINGTON (MedPage Today) -- The Centers for Medicare and Medicaid...
medpagetoday.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +