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Questions and Answers
The x-ray beam may be on for a relatively short time during C-arm fluoroscopy.
The x-ray beam may be on for a relatively short time during C-arm fluoroscopy.
False
Radiologic personnel should always exceed 50 mSv/yr (5000 mrem/yr) of radiation exposure per year.
Radiologic personnel should always exceed 50 mSv/yr (5000 mrem/yr) of radiation exposure per year.
False
Average exposures in most facilities are less than 1 mSv/yr (100 mrem/yr).
Average exposures in most facilities are less than 1 mSv/yr (100 mrem/yr).
False
The maximum permissible dose (MPD) was the dose of radiation that would be expected to produce significant radiation effects.
The maximum permissible dose (MPD) was the dose of radiation that would be expected to produce significant radiation effects.
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The dose limit (DL) is only specified for whole-body exposure.
The dose limit (DL) is only specified for whole-body exposure.
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The whole-body DL of 20 mSv/yr (2000 mrem/yr) is an effective dose.
The whole-body DL of 20 mSv/yr (2000 mrem/yr) is an effective dose.
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The DL for the skin is 500 mSv/yr (50 rem/yr) and it is less than the whole-body DL.
The DL for the skin is 500 mSv/yr (50 rem/yr) and it is less than the whole-body DL.
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Some organs of the body have a lower DL than the whole-body DL.
Some organs of the body have a lower DL than the whole-body DL.
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Radiologic personnel engaged in general x-ray activity typically receive occupational radiation exposures exceeding 5 mSv/yr.
Radiologic personnel engaged in general x-ray activity typically receive occupational radiation exposures exceeding 5 mSv/yr.
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Radiologists typically receive lower radiation exposures than radiologic technologists during fluoroscopy.
Radiologists typically receive lower radiation exposures than radiologic technologists during fluoroscopy.
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Fixed protective barriers are always available during mobile radiography.
Fixed protective barriers are always available during mobile radiography.
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Radiologic technologists are not required to wear protective aprons during mobile examinations.
Radiologic technologists are not required to wear protective aprons during mobile examinations.
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Personnel exposure during fluoroscopy is directly related to the x-ray beam-off time.
Personnel exposure during fluoroscopy is directly related to the x-ray beam-off time.
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Remote fluoroscopy results in high personnel exposures because personnel are in the x-ray examination room with the patient.
Remote fluoroscopy results in high personnel exposures because personnel are in the x-ray examination room with the patient.
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In C-arm fluoroscopy, it is recommended to position the x-ray tube over the patient.
In C-arm fluoroscopy, it is recommended to position the x-ray tube over the patient.
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Personnel engaged in interventional radiology procedures typically receive lower exposures than those in general radiologic practice.
Personnel engaged in interventional radiology procedures typically receive lower exposures than those in general radiologic practice.
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The recommended dose limit for radiologic personnel is 1 mSv/yr.
The recommended dose limit for radiologic personnel is 1 mSv/yr.
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Protective gloves used in interventional radiology procedures can eliminate forearm exposure.
Protective gloves used in interventional radiology procedures can eliminate forearm exposure.
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The goal of radiation dose reduction strategies is to keep personnel exposures as high as reasonably achievable.
The goal of radiation dose reduction strategies is to keep personnel exposures as high as reasonably achievable.
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Mammography personnel exposures are high due to scatter radiation from the patient.
Mammography personnel exposures are high due to scatter radiation from the patient.
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Dedicated mammography x-ray units do not have personnel protective barriers.
Dedicated mammography x-ray units do not have personnel protective barriers.
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Personnel exposures in computed tomography (CT) facilities are high due to uncollimated x-ray beams.
Personnel exposures in computed tomography (CT) facilities are high due to uncollimated x-ray beams.
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Interventional radiology procedures often involve the use of protective curtains on the image-intensifier tower.
Interventional radiology procedures often involve the use of protective curtains on the image-intensifier tower.
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Radiation dose reduction strategies are not necessary in fluoroscopy procedures.
Radiation dose reduction strategies are not necessary in fluoroscopy procedures.
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Study Notes
CT Imaging and Radiation Exposure
- Figure 40-2 shows isoexposure profiles for horizontal and vertical planes of a multislice helical CT imaging system.
Radiation Dose Limits
- The maximum permissible dose (MPD) was specified to be the dose of radiation that would produce no significant radiation effects.
- Today, dose limits (DLs) are specified not only for whole-body exposure but also for partial-body exposure, organ exposure, and exposure of the general population.
- The whole-body DL is 50 mSv/yr (5000 mrem/yr), which takes into account the weighted average to various tissues and organs.
Occupational Radiation Dose Management
- The recommended dose limit for radiologic personnel is 50 mSv/yr (5000 mrem/yr), but experience has shown that considerably lower exposures than this are routine.
- Occupational radiation exposure of radiologic personnel engaged in general x-ray activity normally will not exceed 1 mSv/yr (100 mrem/yr).
- Radiologists usually receive slightly higher exposures than radiologic technologists due to their proximity to the radiation source during fluoroscopy.
Fluoroscopy
- Fluoroscopy and mobile radiography result in the highest occupational exposure of diagnostic x-ray personnel.
- Personnel exposure is related directly to the x-ray beam-on time, but with care, personnel exposures can be kept as low as reasonably achievable (ALARA).
- Remote fluoroscopy results in low personnel exposures because personnel are not in the x-ray examination room with the patient.
Interventional Radiology
- Personnel engaged in interventional radiology procedures often receive higher exposures than those in general radiologic practice due to 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, and protective gloves can help reduce exposure.
Mammography
- Personnel exposures associated with mammography are low because the low kVp operation results in less scatter radiation from the patient.
- Rarely does a room that is used strictly for mammography require protective lead shielding.
Computed Tomography
- Personnel exposures in computed tomography (CT) facilities are low due to the finely collimated x-ray beam and low secondary radiation levels in the examination room.
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Description
Quiz on radiology and radiation oncology physics, including CT imaging systems and radiation safety guidelines.
