radprooo

• The occupational radiation exposure of radiologic

  personnel engaged in general x-ray activity normally will

  not exceed - 1 mSv/yr
• Radiologists usually receive slightly higher exposures

  than radiologic technologists because the radiologist receives most of their exposure during fluoroscopy and is usually closer

  to the radiation source (the patient) during such

  procedures.
• The highest occupational exposure of diagnostic

  x-ray personnel occurs during fluoroscopy and

  mobile radiography
• During radiography, the radiologist is rarely

  present and the radiologic technologist is behind

  the console protective barrier
• When fixed protective barriers are not available, such as

  during mobile examination, the mobile x-ray imaging

  system is equipped with an exposure cord long enough to

  allow the technologist to leave the immediate examination

  area
• The radiologic technologist should wear a protective

  apron for each such mobile examination
• Scatter radiation from the patient is the source of occupational

  radiation exposure during fluoroscopy
• Personnel exposure, however, is related directly to the x-ray

  beam-on time
• Average whole body dose of (ORE) occupational Radiation Exposure- 0.7 msv/yr
• ORE of the receiving less than the minimum detectable dose - 53%
• value of ORE of those receiving less than 1 mSv/yr - 88%
• value of ORE of those receiving greater than 50 mSv/yr - 0.05%
• Remote fluoroscopy - results in low personnel exposures because

  personnel are not in the x-ray examination room with the

  patient
• Fluoroscopes with the xray tube over the table and the image receptor under the table results in better quality but higher personnel exposure. TRUE or FALSE?

  TRUE
• It is best to position the x-ray tube under the

  patient during C-arm fluoroscopy
• Personnel engaged in interventional radiology procedures

  often receive higher exposures than do those in general radiologic practice because of longer fluoroscopic x-ray beam-

  on time
• The frequent absence of a protective curtain on the image-

  intensifier tower and the use of cineradiography also contribute to higher personnel exposure.
• Extremity exposure during interventional radiology

  procedures may be significant
• Even with protective gloves, exposure of the forearm

  can approach the recommended dose limit of 500

  mSv/yr if care is not taken
• Without protective gloves, excessive hand exposures are possible.
• Personnel exposures associated with mammography

  are low because the low kVp of the operation results

  in less scatter radiation from the patient
• Usually, a long exposure cord and a conventional wall

  or window wall are sufficient to provide adequate

  protection during mammography
• Dedicated mammography x-ray units have

  personnel protective barriers made of lead glass,

  lead acrylic, and even plate glass as an integral

  component. Usually, such barriers are totally

  adequate
• Rarely does a room that is used strictly for

  mammography require protective lead shielding
• Personnel exposures in computed tomography (CT)

  facilities are low.

  Because the CT x-ray beam is finely collimated and

  only secondary radiation is present.
• Nursing personnel and others working in the operating room and in

  intensive care units are sometimes exposed to radiation from mobile

  x-ray imaging systems and C-arm fluoroscopes
• Although these personnel are often anxious about such exposures,

  many studies have shown that their occupational exposure is near

  zero and certainly is no cause for concern.
• It usually is not necessary to provide occupational radiation monitors

  for such personnel - nursing personnel
• Personnel who regularly operate or are in the immediate

  vicinity of a C-arm fluoroscope should wear an

  occupational radiation monitor, in addition to protective

  apparel
• In smaller hospitals, emergency centers, and private clinics,

  occupational exposures rarely exceed 5 mSv/yr
• Maximum Permissible Dose (MPD)

  -the dose of radiation that would be expected to

  produce no significant radiation effects
• At radiation doses below the MPD, no responses should

  occur. At the level of the MPD, the risk is not zero, but it

  is small.
• The concept of MPD is now obsolete and has

  been replaced by recommended dose limits (DLs)
• BEIR- Biologic effects of ionizing radiation committee
• The value 1 in 10,000 represents the approximate risk of

  death for those working in safe industries.
• The DL is specified only for occupational exposure
• dose limit - should not be confused with medical x-ray

  exposure received as a patient.
• The first DL, 500 mSv/wk was

  recommended in 1902
• The current DL is 1 mSv/wk . Through the

  years, a downward revision of the DL has

  occurred
• Today, the DL is specified not only for whole-body exposure

  but also for partial-body exposure, organ exposure, and

  exposure of the general population