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
Kids who lack sympathy more likely to share with virtuous friends
Children who sometimes lack sympathy for others are more likely...
medicalxpress.com
Watson, the narcoleptic Chihuahua, demonstrates symptoms on-air
What’s black and white (with just a few splotches of...
scopeblog.stanford.edu
Moderate coffee consumption lessens risk of clogged arteries and heart attacks
People who drink a moderate amount of coffee daily are...
medicalxpress.com
Risks of taking paracetamol long-term may have been underestimated by clinicians
Doctors may have underestimated the risks for patients who take...
medicalxpress.com
AS Patients Have Elevated Adipokine Levels (CME/CE)
(MedPage Today) -- Higher levels of visfatin in particular predict...
medpagetoday.com
Actemra Reduces Duration of QTc Interval in RA Patients (CME/CE)
(MedPage Today) -- Treatment has antiarrhythmic potential that may have...
medpagetoday.com
High prevalence of HCV in baby boomers presenting to ER
(HealthDay)—The prevalence of unrecognized chronic hepatitis C virus (HCV) is...
medicalxpress.com
How to Choose Best Opoid Addiction Treatment
(MedPage Today) -- The pros and cons of methadone and...
medpagetoday.com
Cannabis linked to increased risk of cerebrovascular events
(HealthDay)—Cannabis seems to be linked to cerebrovascular events, according to...
medicalxpress.com
Earlier surgery tied to greater benefit in cervical radiculopathy
(HealthDay)—For patients with painful degenerative disc disease and radiculopathy, undergoing...
medicalxpress.com
Successful cognitive behavioral therapy in youth equals decreased thinking about suicide
Penn Medicine researchers found that patients who did not respond...
medicalxpress.com
ACP releases new guidelines for preventing and treating bedsores
The American College of Physicians (ACP) today published two evidence-based...
medicalxpress.com
The NNT: An Overhyped and Confusing Statistic
(MedPage Today) -- Some pitfalls of summing up evidence with...
medpagetoday.com
Suicidal ideation prevalent in patients with fibromyalgia
(HealthDay)—Suicidal ideation is prevalent among patients with fibromyalgia and is...
medicalxpress.com
US spends more on cancer care, saves fewer lives than Western Europe
Despite sharp increases in spending on cancer treatment, cancer mortality...
medicalxpress.com
Standardization and simplification is key to helping NICU babies feed and grow
A new standardized approach for feeding infants in the neonatal...
medicalxpress.com
The hidden burden of dengue fever in West Africa
Misdiagnosis of febrile illnesses as malaria is a continuing problem...
medicalxpress.com
Teenager with stroke symptoms actually had Lyme disease
A Swiss teenager, recently returned home from a discotheque, came...
medicalxpress.com
A telephone lifeline for moms with postpartum depression
I’m currently pregnant and due in less than two weeks....
scopeblog.stanford.edu
Growing Role for Locum Tenens Docs: HealthLeaders Media
(MedPage Today) -- Can the EHR paper monster be tamed?...
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 +