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
Memory immune cells that screen intruders as they enter lymph nodes
Australian scientists have discovered a new population of 'memory' immune...
medicalxpress.com
India suspends plans for warnings on cigarette packets
India has suspended plans for bigger health warnings on cigarette...
medicalxpress.com
Face scans show how fast a person is aging
Every face tells a story, and that story apparently includes...
medicalxpress.com
HIV patients experience better kidney transplant outcomes than Hepatitis C patients
HIV (human immunodeficiency virus)-positive kidney transplant patients experienced superior outcomes...
medicalxpress.com
Moving upstream to promote a healthier nation
The Society for Public Health Education (SOPHE) proudly announces the...
medicalxpress.com
World first study reveals antibodies that may trigger psychosis in children
A world first study revealing the presence of two antibodies...
medicalxpress.com
Morning Break: Ebola Patient Improves, Feraheme Warning
(MedPage Today) -- Health news and commentary from around the...
medpagetoday.com
New resuscitation guidelines for severely hypothermic patients in cardiac arrest
The general rule for treatment of patients in cardiac arrest...
medicalxpress.com
Understanding fish oil benefits during pregnancy
A study by University of Western Australia has advanced understanding...
medicalxpress.com
Researchers find importance of regulatory T-cells generated early in life
(MedicalXpress)—Originating in the thymus, the autoimmune regulator (Aire) protein controls...
medicalxpress.com
Diet rich in methionine may promote memory loss
Memory loss has recently been associated with excessive silencing of...
medicalxpress.com
Study shows female mammalian phenotype results from repression of male-linked genes by methylation
(MedicalXpress)—A team of researchers with the University of Maryland and...
medicalxpress.com
Arizona governor signs abortion drug notification mandate
Gov. Doug Ducey signed a bill Monday that requires abortion...
medicalxpress.com
Southeast England ahead on genetic tests for inherited eye conditions
New research from The University of Manchester published in the...
medicalxpress.com
Teenagers more inclined to repeat 'risky' behaviour
School-age teenagers who have previously engaged in risky online behaviour...
medicalxpress.com
Symmetry leads to lack of attention
New research has found humans are likely to underestimate the...
medicalxpress.com
Smartphone app could change how depression is diagnosed
It's common to hear complaints about our near-constant connection to...
medicalxpress.com
Pulmonary embolism risk scoring could guide treatment, ease burden on EDs
An analysis led by University of Cincinnati (UC) emergency medicine...
medicalxpress.com
Why icing doesn't work to heal injuries
Applying ice to a muscle after injury is a commonly...
medicalxpress.com
Exposure to ultrafine particles influences cardiac function
The adverse health effects caused by fine particles have been...
medicalxpress.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 +