CHAPTER 39 - PATIENT RADIATION DOSE MANAGEMENT

,late effects

The possible ________ of diagnostic x-ray exposure are of concern; therefore, attention must be given to good radiation control practices.

digital mammography and digital mammographic tomosynthesis.

Screen-film mammography has largely been replaced with __________ and ______________.

mammography

An entrance skin exposure (ESE) of approximately 8 mGya/view (800 mR/view) is normal in ___________

4:1 and 5:1

Radiographic grids are used in many mammography examinations. Grid ratios of ______ and ______ are most popular

two times

Patient radiation dose is increased by approximately _______ with the use of such grids compared with the nongrid technique.

Glandular dose (Dg)

______ varies in a complicated way, with variations noted in x-ray beam quality and quantity.

15%

Glandular dose is approximately_____ of the ESE.

8 mGya (800 mR)

Consider an examination that consists of craniocaudad and mediolateral oblique views, each of which produces an ESE of __________

Total D_g

_______ an be estimated by approximating that the contribution from each view will be 15% of the ESE

1 mGyt/view

Glandular dose should not exceed _________ with contact mammography and 3 mGyt/view with a grid

3 mGyt/view

Glandular dose should not exceed 1 mGyt/view with contact mammography and ________ with a grid.

Extremity radiography

__________ is a special x-ray examination but it is not one high on the list of patient radiation dose concerns.

Unnecessary patient radiation dose

____________________ is defined as any radiation dose that is not required for the patient’s well-being or for proper management and care.

radiologist’s or the clinician’s

The radiologic technologist has practically no control over what some consider the largest source of unnecessary patient radiation dose, that is, the unnecessary x-ray examination. This is almost exclusively the ____________ responsibility.

medical indication

Routine x-ray examinations should not be performed when there is no precise___________.

hospital admission

Chest x-ray examinations should not be performed for routine ____________ when no clinical indication of chest disease is found.

preemployment physical examination

Chest and lower back x-ray examinations as part of a _________________are not justified because the knowledge gained about previous injury or disease through this approach is nil.

Emergency Department

CT has passed radiography as the first line of diagnostic imaging. This overutilization, especially in the ________, must be controlled because of the rapidly rising population effective dose

5%

In the typical busy hospital facility the rate of repeat of screen-film examinations should not normally exceed______

Infrequent Errors

____________ that contribute to repeat examinations include dirty screens, use of improperly loaded cassettes, light leaks, chemical fog, artifacts caused by a dirty processor, wrong projection, improper patient preparation, grid errors, and multiple exposures.

Motion and improper collimation

________ and ________ are responsible for some repeats.

digitally mask

Postprocessing software allows an unprincipled radiographer to __________ an image to hide the lack of primary beam collimation.

lower patient

Digital radiography can be conducted at higher kVp, resulting in _______ radiation dose.

Proper collimation

__________ is essential to good radiographic technique.

Positive beam limitation

____________ does not prevent the radiologic technologist from reducing field size still further through collimation.

speed–screen-film combination

The fastest _____________ consistent with the nature of the examination should be used.

Digital radiographic (DR)

_________ image receptors are inherently faster than screen-film.

Digital Radiography

Patient dose should be lower with the use of ______ because of increased speed and increased kVp accompanied by reduced mAs.

proper beam collimation and the use of specific area shielding

The partial-body nature of the x-ray examination is controlled by ______________ and _____________

• the contact shield

• the shadow shield.

Two types of specific area shielding devices are used:

Lens Shield

__________ are always of the contact shield type.

contact or shadow shield type.

Gonadal shields, on the other hand, can be of the _________ or ________.

Shadow shields

_________ are particularly useful during surgery for which sterile procedure is required.

before birth

the period most sensitive to radiation exposure occurs ___________

early

the fetus is more sensitive _____ in pregnancy .

major organogenesis.

The time from approximately the 2nd week to the 10th week of pregnancy is called the period of _____________.

250 mGyt (25 rad).

No such responses occur at less than ________

25% to 50% range.

The incidence of spontaneous abortion in the absence of radiation exposure is estimated to be in the _________________.

relative risk estimate

The best approach to assessing risk of childhood malignancy is to use a ______________.

institute elective booking.

The most direct way to ensure against the irradiation of an unsuspected pregnancy is to ______________

elective booking

The most direct way to ensure against the irradiation of an unsuspected pregnancy is to institute _____________. This requires that the clinician, radiologist, or radiologic technologist determine the time of the patient’s previous menstrual cycle.

menstrual cycle

An alternative procedure is to have the patient herself indicate her _____________.

posting signs

We meet our responsibility to the pregnant patient by ___________ in the waiting room.

never indicated

Recommendation for abortion after diagnostic x-ray exposure essentially is _____________.