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
With e-cigarettes, tobacco isn’t the only danger
E-cigarettes are far from safe, Robert Jackler, MD, writes in...
scopeblog.stanford.edu
Study demonstrates potential of rapid whole-genome sequencing in critically ill infants
A study published today in The Lancet Respiratory Medicine and...
medicalxpress.com
Doc Compensation Up, as Is Dissatisfaction: HealthLeaders Media
(MedPage Today) -- Stubborn RN gender pay gap, inequality of...
medpagetoday.com
Family break-up linked to heightened risk of psychosomatic problems in teens
Parental separation or divorce is linked to a heightened risk...
medicalxpress.com
Disaster Planning: Making Communities Mentally Strong
(MedPage Today) -- Why resiliency matters when it comes to...
medpagetoday.com
Hospitals Increasingly Turn to Patients for Advice
(MedPage Today) -- New federal incentives are driving hospitals' interest...
medpagetoday.com
FDA: Medtronic must stop most sales of Synchromed drug pumps
The Food and Drug Administration says Medtronic must stop most...
medicalxpress.com
Antibiotic use in California neonatal intensive care units varies widely, study finds
California neonatal intensive care units have huge differences in their...
scopeblog.stanford.edu
Studies yield mixed findings on high-dose flu vaccine for elders
If you're age 65 or older and go to your...
medicalxpress.com
Use of Post-Op RT Waning in Prostate Cancer (CME/CE)
(MedPage Today) -- Overall rates low despite greater use in...
medpagetoday.com
Effective sleep apnea treatment lowers diabetes risk
Using a simple device for eight hours a night to...
medicalxpress.com
Children's eye injuries from nonpowder guns on the rise
Over 3000 children were treated in U.S. emergency departments in...
medicalxpress.com
New class of cholesterol drug proves safe and effective for patients with dyslipidemia
Treatment with PCSK9 antibodies reduces mortality and produces profound reductions...
medicalxpress.com
PCSK9 Inhibitors Appear to Lower Death Risk (CME/CE)
(MedPage Today) -- PCSK9 inhibitors appeared to reduce overall- and...
medpagetoday.com
A GLiMMER of Hope for Global Health?
(MedPage Today) -- Healthful eating and living is the core...
medpagetoday.com
HCV Drug Combo Succeeds in Advanced Disease (CME/CE)
(MedPage Today) -- Is treatment best option for all HCV...
medpagetoday.com
Stanford Medicine’s Lloyd Minor on re-conceiving medical education
Stanford Medicine is no stranger to pioneering changes in medical...
scopeblog.stanford.edu
Hearts Different for ART Kids?
(MedPage Today) -- Altered function persists at age 5 after...
medpagetoday.com
Physical exercise helps women with breast cancer to better tolerate chemotherapy
Women with breast cancer who follow a physical exercise program...
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 +