chapter 11 (module 10) rad sci

effective communication can

encourage reduction in anxiety and emotional stress, enhance image, complete x-ray examination successfully

the radiographer should reveal any negative possibilities, including discomfort, pain, but do not ___

over-emphasize

the radiographer must gain the patient’s cooperation. if not, use immobilization devices like the ___ for pediatric immobilization

Pigg-O-Stat

what are examples of involuntary motion?

heart, digestive organs, chills, tremors (parkinson’s)

what are examples of voluntary motion?

patient’s age, breathing patterns, anxiety, physical discomfort, mental discomfort, excitability, fear of the exam, fear of an unfavorable outcome

how can you compensate for motion?

decrease exposure time and increase mA. this maintains sufficient mAs to achieve the desired radiograph

what are radiosensitive organs that need special attention?

lens of the eye, breasts, reproductive organs (gonads)

shielding should be used as a secondary protective measure, not a substitute for a properly ___ beam

collimated

when gonads are not in the primary beam- precise collimation ___ gonadal exposure

reduces

female reproductive organs receive _ more exposure than males

3

when should protective shielding be used?

when it will not obscure necessary clinical information

a flat contact shield may reduce gonadal dose by up to _ % for females and up to _% for males

females 50%; males 95%

AEC provides ___ exposure to the IR

consistent

what technique reduces patient dose and decreases image contrast?

high kVp and low mAs

radiographer should select the highest practical __ and the lowest __ that will yield sufficient information for each exam

kVp; mAs

what’s the difference between chest and rib images?

chest uses a high kVp and low mAs; rib images use lower kVp and higher mAs

_____ prevent artifacts caused by IR, software, or patient related problems

digital artifacts

the ___ was designed to standardize the way an image is processed in the department

QC program

the air gap technique ___ scatter; which makes it alternative to using a ___

removes; grid

for the air gap technique, the IR is placed ___ from the patient. an increase SID is used to decrease ___

6-10 inches; magnification

the air gap technique is more effective with kVp of __ or lower. this means you would need to increase __ to compensate for distance, which increases dose

90; mAs

you would be better of using PA instead of AP to ___ breast dose in scoliosis and eyes in skull procedures

decrease

what is the largest contributor to unnecessary dose?

repeat x-rays

digital imaging reduces repeats due to:

wider exposure latitude, and images can be manipulated to see the full dynamic range

in the ____ program, a designated person reviews repeats and establishes patterns or areas of weakness that needs to be conveyed to the technologists

repeat analysis program

what exams have little to no benefit?

hospital pre-admission chest x-ray, pre-employment physical, part of a routine health check up, CXR for mass TB screening, whole body CT

frequency of x-ray procedures is increasing at the rate of __ % per year in the US

18%

patient dose from diagnostic x-rays is typically reported in one of three ways:

entrance skin exposure, gonadal dose, bone marrow dose

according to physicists, the true patient dose is very difficult to ___

measure

ESE is typically measured with

TLD’s (thermoluminesccent dosimeters)

most frequently used dose measurement (reported) does ___ tell the specific organ dose

NOT

physicist will estimate ESE by using exposure to ___

air; Gya

ESE can be converted to ___ by using well-documented conversion numbers.

it is typically measured at a SID of __ inches

40

which procedures have the highest gonadal dose?

lower GI series, ct pelvis and hips

mean marrow dose ___ be measured directly

cannot!!!! it is only estimated.

__ % of bone marrow is in useful beam.

received average absorbed dose is __ mGy

mean marrow dose is __ mGy

25% ; 0.8 mGy ; 0.2 mGy

the average radiation dose to the entire active bone marrow in the U.S is approximately __ Gy/yr

.001 Gy/yr

the average annual gonadal EqD to members of a population who are of childbearing age in the US is

20 mrad

most hospitals use between the ages of ___ as the child-bearing age range

12-55

the most dangerous time is when most women ____

do not know they are pregnant

major organogenesis occurs during weeks __ of pregnancy

2-10

early in organogenesis, radiation can cause ___ abnormalities such as skeletal deformities.

later in organogenesis, neurological effects are more common.

congential

spontaneous abortion can occur within the first __ weeks at radiation doses of less than __ Gyt

2 ; 0.25

at an in-utero dose of _ Gyt, deformities and congenital effects are most likely to occur

2

what happens if patient is irradiated and later finds out that she pregnant?

fetal dose must be estimated by a physicist, and test objects are used to determine fetal dose. the radiologist and the referring physician should discuss how far into the gestation the exam was performed

what are the two options for a woman who was unknowingly irradiated and later finds out she is pregnant?

continue the pregnancy to term or terminate the pregnancy

if the fetus received less than __ Gyt, a therapeutic abortion is NOT indicated

0.10 Gyt

between __ and __ Gyt, the physician should consult the patient’s emotional and physical needs and allow the patient to decide once she is fully aware of all facts.

0.10 and 0.25

if the fetus received more than __ Gyt, a therapeutic abortion may be indicated due to risks of congenital abnormalities

0.25

during an unknown pregnancy, relay information to RSO and ordering physician. the RSO determined EqD to the embryo-fetus. then:

patient’s physician will be given an estimated dose to the fetus. determines ESE and uses predetermined factors to come up with fetal dose.

you should prevent radiation exposure for unknown pregnancy. wait if the ER has done a pregnancy test. if a patient was irradiated with an unknown pregnancy,

the patient’s OB will request fetal dose estimate, which is done by the physicist. RT provides as much detail as possible

CT beam is usually __ collimated

tightly

___ is an awareness program of the American college of radiology, the radiological society of north america, the american association of physicists in medicine, and the american society of radiologic technologists

image wisely

what is image gently?

the alliance for radiation safety in pediatric imaging

what does image gently focuses on:

parent education, exam record card, parent pamphlets in 14 languages