Radt: 2033 Chapter 12

The formula for (mGya/mAs) at skin surface is:

(mGya/mAs) at 100 cm x (100/[100-8-T])^2

The formula for ESEd is:

(mGya/mAs) at skin surface x mAs used

Repeat rates for previously film-based radiology departments were documented to be in the range of ____ to _____, and their leading cause was attributed to the use of incorrect __________

- 10% to 15% - technical factors

To perform the air gap technique, the image receptor is placed _______ from the patient and the X-ray tube is positioned approximately ___________ away from the image receptor

- 10-15 cm (4 to 6 inches) - 300 to 366 cm ( 10 to 12 feet)

A high-quality image has sufficient ___ to display anatomic structures, an appropriate level of _________ to differentiate among such structures, the maximal amount of _______, and minimal amount of distortion

- brightness - subject contrast -spatial resolution

Other clinical manifestations that cause involuntary motion include:

- chills - tremors - muscle spasms - pain - active withdrawal

The radiographer should, from the beginning of the exam:

- correctly position the patient - select the appropriate technical radiographic exposure factors that will ensure the production of optimal quality images

Words and actions must demonstrate understanding and respect for _____ and _______

- human dignity - individuality

Inability to exercise control may be attributed to:

- the patients age - breathing problems or irregularities - increased anxiety - physical discomfort - fear or the examination - fear of unfavorable prognosis - mental instability

Patient exposure can be substantially reduced by:

- use of proper body or body part immobilization and other motion reduction techniques - proper X-ray beam limitation devices - adequate filtration of the X-ray beam - use of specific area shielding - selection of suitable technical exposure factors used in conjunction with computer-generated digital images - use of appropriate digital image processing - elimination of repeat radiographic exposures

Radiographers must limit the patient's exposure to ionizing radiation by:

-Employing appropriate radiation reduction techniques -Using protective devices that minimize radiation exposure

the use of _____ kVp and _____ mAs reduces patient dose

-Higher -lower

Even though the ASRT does not condone FGP, some imaging facilities continue to allow RTs to use fluoroscopy as a positioning aid because they believe that it:

-Is faster than having a repeat exposure -Reduces the number of repeat exposures -Provides less radiation exposure to the patient

No diagnostic procedure using ionizing radiation should be conducted unless its ______________ outweigh its _________

-benefits - risks

Decreasing the exposure time with an appropriate increase in mA to Mai rain sufficient mAs for useful radiographic _____ and using a very-high-speed ___ can compensate for involuntary motion.

-brightness -IR

Each encounter with a patient during a diagnostic X-ray procedure should begin with __ and ____ instructions

-clear -concise

The radiographer must always seek to achieve a balance in technical radiographic exposure factors to:

-ensure the presence of adequate information in the acquired image - minimize patient dose

Air gap technique works by using an ____ OID. Less scatter radiation at the detector _____ image blurring and thereby improves radiographic contrast.

-increased -decreases

Adequate penetration of the anatomic part is needed to create the difference in X-ray _____ exiting the part relative to adjacent structures to produce the desired level of _____

-intensities -contrast

Some reasons for unacceptable images are:

-patient mispositioning -incorrect centering -patient motion during the exposure -incorrect collimation -presence of external foreign bodies -post processing artifacts

QC program's documentation should include step-by-step procedures for:

-performance -monitoring -continuing quality control

An analysis of a departments repeat rate:

-provides valuable information for process improvement -helps minimize patient exposure - improves overall performance do the department

When irradiating a known pregnant patient, to minimize dose you can:

-select the smallest technical factors that will yield a diagnostic Lu acceptable image -precisely collimating the radiographic beam to include only the anatomic area of interest

Where FGP is permitted, the repeat rate depends on the:

-technologists skills in the operation of fluoroscopic equipment -communication between the technologist and the patient -patients cooperation -patients condition

According to the US Public Health Service, the estimated GSD for the population of the United States is approximately ________

0.20 millisievert (20 mrem)

If in the course of performing a specific radiographic procedure 75% of the active bone marrow were in the useful beam and received an average absorbed dose of 0.4 mGy the mean marrow dose would be:

0.3 mGy

Inability of a patient to exercise control of voluntary motion may result as a consequence of: 1. Breathing problems or irregularities 2. Physical discomfort 3. Muscle spasms

1 and 2 only

Which of the following examinations are considered unnecessary radiologic procedures? 1. Chest X-ray study as part of a preemployment physical 2. Screening mammography 3. Whole-body multi slice spiral CT screening

1 and 3 only

A woman who is 3 months pregnant has been in a motor vehicle accident. The emergency room physician suspects there is injury to her cervical spine and thus feels justified in ordering an x-ray examination to aid in determining the extent of the patient's injury. Because the patient is pregnant, the radiographer should: 1. Select the smallest technical exposure factors that will produce a diagnostically useful image. 2. Adequately and precisely collimate the radiographic beam to include only the anatomic area of interest. 3. Shield the patient's lower abdomen and pelvic region with a suitable protective contact shield.

1, 2, and 3

Analysis of an imaging department's repeats rate 1. provides valuable information for process improvement. 2. helps minimize patient exposure. 3. improves overall performance of the department.

1, 2, and 3

Effective communication between the radiographer and the patient does which of the following? 1. Encourages reduction in anxiety and emotional stress 2. Enhances the professional image of the radiographer as a person who cares about the patients well being 3. Increases the chance for successful completion of the examination

1, 2, and 3

Some clinical manifestations that can cause involuntary motion during a radiographic procedure include: 1. chills 2. tremors 3. muscle spasms 4. pain

1,2,3,4

The amount of radiation received by a patient from diagnostic imaging procedures may be presented in three ways:

1. Entrance skin exposure (ESE)- includes skin and glandular 2. Bone marrow dose 3. Gonadal dose

When using the air gap technique, the image receptor is moved ___ to ___ cm away from the patient, this distance allows low energy scattered x-rays to be absorbed in the air before reaching the image receptor

10 to 15 cm

As long as the part I'd adequately penetrated, increasing the kVp by __% with a corresponding decrease in mAs reduces patient exposure significantly while yielding satisfactory image quality

15%

The chance of malformations in a fetus is significantly increased above control levels only at doses beyond _______

15cGy

Which of the following are technical exposure factor considerations? 1. Patient mispositioning and incorrect collimation of the beam 2. Type of IR and SID used 3. Type of X-ray generator used and type and quantity of filtration employed

2 and 3 only

This risk is considered negligible at a fetal absorbed dose of ____ or less when compared with other risks during pregnancy

5 cGy

A series of research studies have reported repeat rates in many digital departments at approximately ____ and some at the same rate as for earlier film-screen systems departments

5%

Women older than ____ are primarily affected by bone density loss

50

The use of an air gap technique requires the selection of technical exposure factors that are comparable to those used with an ______ ratio grid.

8:1

The skin and gonads of the patient receive a "double dose" of x radiation whenever:

A repeat radiograph is necessary, as a consequence of human or mechanical error

Using appropriate technical exposure factors and an 8:1 ratio grid, an optimal quality cross-table lateral projection of the cervical spine was obtained. If another radiograph is obtained, using an air gap technique and technical exposure factors that are comparable to those used with the 8:1 ratio grid, the patient dose will be:

About the same

In fluoroscopy, how is the amount of radiation that a patient receives usually estimated?

By measuring the radiation exposure rate at tabletop and multiplying this by the fluoroscopy time

Repeat analysis is particularly critical in:

CR and DR

Noninvasive cray procedure that can quantitatively predict the risk of bone fractures

DEXA

In digital imaging, the amount of exposure reaching the digital image ___________ affect the amount of brightness produced, because of computer processing

Does not affect

The most widely used test to determine the degree of bone loss by measuring bone mineral density is:

Dual Energy X-ray Absorptiometry (DEXA)

___ is the most frequently reported because it is the simplest to determine.

ESE

Holistic patient care begins with __________ between the radiographer and the patient

Effective communication

The equivalent dose (EqD) to the reproductive organs that, if received by every human in a large population group, would be expected to bring about an identical gross genetic injury to that total population, as does the sun of the actual doses received by exposed individual members of a population

GSD

As part of the Image Gently Campaign, radiographers and imaging facilities can pledge to:

Image gently

the goal of this campaign is to change long-established practice by raising awareness about methods for lowering radiation dose during pediatric medical imaging examinations

Image gently campaign

Promotes lowering the amount of radiation used in medically necessary imaging procedures and eliminating unnecessary procedures in adult medical imaging

Image wisely Campaign

Areas of the body that should be shielded from the useful beam whenever possible are the:

Lens of the eye, breasts, thyroid gland, and reproductive organs

The use of the PA projection during a juvenile scoliosis radiographic examination results in which of the following?

Lower entrance exposure dose to the anterior body surface, thereby significantly reducing the dose to the breast

I'm which of the following projections will a young female patient receive a significantly lower dose to her breast tissue during a chest X-ray ?

PA

If magnification is not desired, a corresponding increase in ________ may be made.

SID

The recorded detail in a radiographic image is termed:

Spatial resolution

Which of the following are used to assess skin doses?

TLD

When a lead shield is placed incorrectly within the collimated X-ray beam and automatic exposure control is used:

The lead shield may obscure anatomic information or interfere with the automatic exposure control system

I'm fluoroscopy, the amount of radiation that a patient receives at the entrance surface of the skin is usually estimated by measuring:

The radiation exposure rate at the tabletop and then multiplying by the fluoroscopy time

The use of which of the following results in an increase in the patient dose?

Use of the lowest possible kVP with the highest possible mAs for each exam

Some traditional radiographic examinations are very often casually performed in the:

absence of definite medical indication

This air gap method effectively provides an:

adequate grid-type scatter clean-up effect

Is an alternative procedure to use in place of a radiographic grid for reducing scattered radiation during specific examinations

air gap technique

FGP is an unethical practice that increases patient dose unnecessarily and should never be used in place of:

appropriate skills required of a competent radiologic technologist

The GSD is the average annual gonadal EqD to members of the population who:

are of childbearing age

According to the national council of radiation protection and measurements, the chance of malformations from fetal radiation exposure is significantly increased above control levels only at doses:

beyond 15 cGy

____ positioning provides the lowest patient ESE.

blind

What is obtained and presented by the medical physicist, radiologist, or radiation safety officer to the patients physician is a ______ of the approximate EqD to the embryo-fetus due to the X-ray examination.

calculated estimate

What is obtained and presented by the medical physicists, radiologist, or radiation safety officer to the patients physician is a ________ of the approximate EqD to the embryo-fetus due to the X-ray examination

calculated estimate

Because multiple bony areas span the entire body, the radiation dose absorbed by the organ called bone marrow:

cannot be measured accurately by a direct method- it can only be ESTIMATED

As a result of increased numbers of people in the United States being required to and subsequently undergoing diagnostic imaging procedures each year, concern about the ____ of radiation exposure from these procedures continues to grow

collective risk

everyone within the imaging department should always behave as this type of professional

compassionate

Shields for the lens of the eye are the contact type and are positioned:

directly on the patient

When, using the air gap technique, ______ must be increased to overcome magnification

distance

The NCRP recommendation states that abdominal examinations should be performed:

during the first few days after the onset of menses to minimize the possibility of irradiating an embryo

"An interaction that produces a satisfying result through an exchange of information" and can be accomplished through verbal messages, body language, and clear and concise instructions

effective communication

_____ may be converted to patient skin dose by using well-documented multiplication factors.

entrance skin exposure (ESE)

The practice of using fluoroscopy to determine the exact location of the central ray before taking a radiographic exposure

fluoroscopic guided positioning (FGP)

Used to assess the overall impact of gonadal dose on a populace

genetically significant dose (GSD)

During a diagnostic X-ray procedure a _______ approach to patient care is essential.

holistic

If a maximum of 500 people inhabited an island and each person were to receive an equivalent dose of 0.005 Sv gonadal radiation, the gross genetic effect would be ________ the effect occurring if 50 individual inhabitants were each to receive 0.05 Sv of gonadal radiation and no equivalent dose were received by other inhabitants

identical to

It is the _______ task to determine the absorbed EqD to the patients embryo

individual's

__________________ motion, caused by muscle groups such as those associated with the digestive organs or the heart, cannot be willfully controlled.

involuntary

Children are much more vulnerable to the ___ effects of radiation than are adults.

late

Pediatric patients require special consideration and appropriate radiation protection procedures because they are much more vulnerable to which of the following?

late effects of radiation

The concept of GSD implies, that the genetic consequences of substantial absorbed doses of gonadal radiation received by a small number of individuals becomes significantly _____ when averaged over an entire population rather than applied to just a few of its members.

less

The first step in the process of getting a report of the irradiation of an unknown pregnancy is to:

list the specifics of the X-ray examination in as much detail as possibel

When X-rays are scattered through greater angles, such as for images produced at less than 90 kVp, air gap techniques are:

more successful

To maintain ALARA and follow the ASRT position statement and the ARRT code of ethics technologists:

must not use FGP positioning on patients

In high-kVp radiography that employs kVp settings of 90 or above, air gap techniques are:

not as effective

A systematic metabolic bone disorder

osteoporosis

Digital imaging significantly changed the cause of repeated images, shifting from exposure related to ____________

positioning errors

____ is especially significant in pediatric studies because of the increased possibility of late tissue effects occurring in these young patients

precise collimation

DEXA scanning does not require ______________ for the technologist or patients undergoing this procedure

protective shielding

_____ includes regular monitoring and maintenance of all processing and image display equipment

quality control program

When using the air gap technique it results in improved contrast which does what to scatter?

removes scatter

Health care facilities can gain significantly by implementing and maintaining a:

repeat analysis program

Various suitable _________ are available to immobilize the whole body or the individual body part to be imaged

retraining devices

The selection of ________ __________ technical exposure factors for each X-ray examination is essential to ensure a useful diagnostic image with minimal patient dose

scientifically correct

Used in radiation safety terminology to refer to the dose to the epidermis, the most superficial layers of the skin.

skin dose

Problems that occur in digital imaging tend to be ______ which can affect the quality of every image and the degree of radiation exposure of every patient until these problems are identified and corrected

systematic

The radiographer is responsible for consulting an available standardized __________ before making each radiographic exposure

technique chart

If irradiation happens to an unknown pregnancy the patients obstetrician will send a request for:

the amount of radiation dose that the patients embryo-fetus received from the X-ray study

Bone marrow dose may also be described in terms of the mean marrow dose, which is defined as:

the average radiation dose to the entire active bone marrow

It is the responsibility of _________ to determine the absorbed EqD to the patients embryo-fetus

the individual who exposed the pregnant patient

What are the sensing devices most often used to determine skin dose directly?

thermoluminescent dosimeters (TLDs)

As a consequence of their anatomic location, the female reproductive organs receive about __________ exposure during a given radiographic procedure involving the pelvic region than do the male reproductive organs.

three times more

According to studies published in 1978, the risk of radiation-induced leukemia in children after substantial dose of ionizing radiation is approximately __________ that of adults

two times

To reduce motion with pediatric patients, the radiographer must employ:

very short exposure times by selecting a high mA station and using immobilization devices

________ motion would, under normal circumstances, be expected to be controlled by the patient

voluntary

Exposure of the fetus to radiation arising from diagnostic procedures:

would rarely be cause, by itself, for terminating a pregnancy