Radiation Protection Chapter 12

Other clinical manifestations also cause involuntary motion. These include:

-Chills -Tremors such as those experienced by patients with Parkinson's disease -Muscle spasms -Pain -Active withdrawal

To prevent repeat images, radiographers must, from the beginning:

-Correctly position the patient -Select the appropriate technical radiographic exposure factors that will ensure the production of optimal images for each initial examination

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

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

Good communication:

-Encourages reduction in anxiety and emotional stress -Enhances the professional image of the radiographer as a person who cares about the patient's well-being -Increases the chance for successful completion of the x-ray examination

Whether using screen-film or digital imaging, the radiographer must achieve a balance in technical radiographic exposure factors to:

-Ensure the presence of adequate information in the recorded image -Minimize patient dose

Four basic types of gonadal shielding devices used are:

-Flat contact shields -Shadow shields -Shaped contact shields -Clear lead shields

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

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

-Lens of the eyes -Breasts -Thyroid Gland -Reproductive organs

Neglecting to use standardized technique charts necessitates estimating the technical exposure factors, which may result in:

-Poor-quality images -Repeat examinations -Additional and unnecessary exposure of the patient

Analysis of the department's repeats rate:

-Provides valuable information for process improvement -Helps minimize patient exposure -Improves the overall performance of the department

Poorly processed radiographs offer inadequate diagnostic information, leading to:

-Repeat examinations -Unnecessary patient exposure

The repeat rate depends on:

-Technologist's skill in the operation of the fluoroscopic equipment -Communication between the technologist and the patient -Patient's cooperation -Patient's condition

Lack of such control may be attributed to:

-The patient's age -Breathing patterns or problems -General anxiety -Physical or mental discomfort -Excitability -Fear of the examination -Fear of unfavorable prognosis -Mental instability

Patient exposure can be substantially reduces by:

-Use of proper body or part immobilization -Motion reduction techniques -Appropriate beam limitation -Adequate filtration of the x-ray beam -Use of gonadal or other specific area shielding -Selections of suitable technical exposure factors -Elimination of repeat radiographic exposures

Two types of patient motion exist:

-Voluntary -Involuntary

For both digital and nondigital imaging, a high-quality image has:

-sufficient density or brightness to display anatomic structures -an appropriate level of subject contrast to differentiate among the anatomic structures -the maximum amount of spatial resolution -a minimal amount of distortion.

Essentially all diagnostic x-ray proc result in fetal exposures of less than _____ Gy. so the risk of abnormality is very small if irradiated during an unknown pregnancy.

0.01

studies of past groups of fetuses exposed to rad have shown that damage to newborn is unlikely for doses below _____ Gy.

0.2

Which of the following examinations are considered to be unnecessary radiologic procedures? 1. Chest x-ray study as a part of a reemployment physical 2. Screening mammography 3. Whole-body multislice 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, & 3

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

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

Exposure of patients to medical x-rays is commanding increasing attention in out society for two reasons:

1. Frequency of x-ray examinations, among all age groups, is growing annually. This increase indicates that physicians are relying more and more on radiographic examinations to assist them in patient care and diagnosis. 2. Concern among public health officials is increasing regarding the risk associated with medical x-ray exposure, especially the possibility of late effects.

Categories for Discarded Images:

1. Incorrect patient positioning 2. Incorrect centering of there radiographic beam 3. Patient motion during the radiographic exposure 4. Improper collimation of the radiographic beam 5. Presence of external foreign bodies 8. PostProcessing artifacts

Technical Exposure Factor Considerations

1. Mass per unit volume of tissue of the area of clinical interest 2. Effective atomic numbers and electron densities of the tissues involved 3. type of image receptor 4. SID 5. Type and quantity of filtration employed 6. Type of x-ray generator used (single phase, three phase, or high frequency) 7. Balance of radiographic density or brightness and contrast required

Unnecessary Radiologic Procedures

1. Preadmission chest x-ray examinations 2. CXR for preemployment physical 3. L spine x-ray for preemployment physical 4. X-rays for health checkups 5. CXR for TB screening 6. Whole-body CT screening

Some Benefits of a Repeat Analysis Program

1. The program increases awareness among staff and student radiographers of the need to produce optimal-quality recorded images. 2. Radiographers generally become more careful in producing their radiographic images because they are aware that the images are being reviewed. 3. When the repeat analysis program identifies problems or concerns, in-service education programs covering these specific topics may be designed for imaging personnel.

Information Needed to Develop the Request for Patient Radiation Dose Form

1. The x-ray unit used for the study 2. The projections taken 3. The number of images associated with each projection 4. Each projection's technical exposure factors (kVp, mAs, image receptor size) 5. The SID for each projection 6. The patient's AP or lateral dimensions at the site of each projection 7. For fluoroscopic irradiation, the approximate kVp, mA, and especially the duration 8. For spot films, the number taken, the kVp and mA selected, and the approximate exposure time

For protection of the ovaries of a female patient, the shield should be placed approximately:

2.5 cm (1 inch) medial to each palpable anterior superior iliac spine.

Female reproductive organs receive about:

3x more exposure.

Gonadal shielding devices are used on patients during diagnostic x-ray procedures to protect the reproductive organs from exposure to the useful beam when these organs are in or within approximately:

5 cm of a properly collimated beam.

Primary beam exposure for male patients may be reduced as much as:

90% to 95% when the gonads are also covered with a contact shield.

Pediatric patients require special consideration and appropriate radiation protection procedures because they are more vulnerable to:

Both the late somatic effects and the genetic effects of radiation

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

Direct patient shielding is not typically used in:

CT

If a maximum of 500 people were inhabiting the earth and each person were to receive an equivalent dose (EqD) 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

The Alliance for Rad Safety in Pediatric Imaging created 2 well known initiatives to create awareness about methods to lower rad doses for pediatric and/or adult patients: What are they?

Image Gently Image Wisely

Shortening the length of exposure time with an appropriate increase in milliamperes (mA) to maintain sufficient milliampere-seconds (mAs) for useful radiographic density or brightness and using very-high-speed imaging receptors can compensate for:

Involuntary motion.

The sensing material in the TLD:

Lithium fluoride (LiF)

The use of the PA projection during a juvenile scoliosis radiographic examinations results in:

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

In which projections will a young female patient receive a significantly lower dose to her breast tissue during a chest x-ray study?

PA

Nonessential Radiologic Examinations

Radiographic examinations performed in the absence of definite medical indications

If magnification is not desired, a complementary increase in:

SID may be made.

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

T/F: If the rad procedure will cause pain and/or discomfort, the patient must be informed before the procedure begins.

True

T/F: Irradiating a known pregnant woman is performed only when a physician believes it is in the best interest of the patient to undergo the exam

True

Areas of breast tissue may be shielded by using:

a clear lead shadow shield.

The bone marrow dose is:

a dose of radiation delivered to that organ.

Shadow shields are made of:

a radiopaque material.

After an imaging study is completed and a woman discovers that she was pregnant at the time - what is the first step?

a request for patient radiation dose form should be completed to determine exposure level

Because blurred images have little or no diagnostic value, a repeat examination is necessary, even though it results in:

additional radiation exposure for the patient.

In high-kVp radiography that employs kVp settings of 90 or above,

air gap techniques are for themes part not as effective.

When x-rays are scattered through greater angles, such as occurs for radiographs produced at less than 90 kVp,

air gap techniques are more useful.

Some facilities that perform chest radiography by using kVp of 120 to 140 do successfully use:

air gap techniques.

Effective communication is a type of dialogue that:

alleviates the patient's uneasiness and increases the likelihood for cooperation and successful completion of the procedure.

Gonadal shielding should be a secondary protective measure, not a substitute for:

an adequately collimated beam.

The air gap technique is:

an alternative procedure to the use of a radiographic grid for reducing scattered radiation during certain examinations (cross-table lateral projection of the cervical spine, areas of chest radiography, and selected special procedures such as cerebral angiography in which some degree of magnification is acceptable).

Effective communication

an interaction that produces a satisfying result through an exchange of information

The ASRT recognizes that the routine use of fluoroscopy to ensure proper positioning for radiography prior to making an exposure is:

an unethical practice that increases patient dose unnecessarily and should never be used in place of appropriate skills required of the competent Radiologic Technologist.

A repeat image is:

any image that must be performed more than once because of human or mechanical error during the production of the initial image.

Whenever a female patient of childbearing age is to undergo an x-ray examination, it is essential that the radiographer carefully question the patient regarding:

any possibility of pregnancy.

The concept of genetically significant dose (GSD) is used to:

assess the impact of gonadal dose.

The potential for radiation exposure to the radiosensitive body organs or tissues of a patient requires the use of intelligent patient positioning and/or personal shielding (a device made of lead or lead-impregnated materials that will adequately attenuate ionizing radiation) to reduce or eliminate a radiation dose that would otherwise result in:

biologic damage.

Suspended from above the radiographic beam-defining system, shadow shields hang over the area of clinical interest to:

cast a shadow in the primary beam over the patient's reproductive organs.

Flat contact shields can be placed:

directly over the patient's reproductive organs.

In digital imaging: the amt of exp (mAs) to the digital image receptor (does or does not) directly affect the amount of brightness produced -because of computer processing.

does not

Imaging personnel must reduce the risk to patient whenever possible by:

employing methods that produce high-quality images with lower radiation exposure.

Shaped contact shields, containing 1 mm of lead, are contoured to:

enclose the male reproductive organs.

The radiographer is responsible for consulting the technique chart before making each radiographic exposure, to:

ensure a diagnostic image with minimal patient dose.

Skin dose in general represents the absorbed dose to the most superficial layers of the skin. This region is called the:

epidermis.

Radiographers are the operators of complex imaging equipment and therefore are the individuals who may first recognize:

equipment malfunction.

By determining the number of repeats and the reasons for producing unacceptable radiographic images,

existing problems and conditions in an imaging department are identified.

When the gonadal dose is applied to the entire population, the dose becomes:

far more significant.

Adequate collimation of the radiographic beam, to include only the anatomy of interest must always be the:

first step in gonadal protection.

The automatic collimation system reduces the radiation field size to the dimensions of the image receptor, but because many pediatric patents are significantly smaller than the image receptor,

further manual adjustment of collimation is sometimes necessary.

To eliminate voluntary patient movement during radiography, the radiographer must:

gain the cooperation of the patient or adequately immobilize that individual during the radiographic exposure.

Patients with the potential to reproduce should be:

gonadally shielded during x-ray procedures whenever the diagnostic value of the examination is not compromised.

Part of this questioning involves asking the patient for the date of:

her last menstrual period (LMP).

In diagnostic radiology, the relatively low gonadal dose for a single human is considered:

insignificant / unimportant

Although each type of specification has significance in estimating the risk to the patient, ESE is the most frequently reported because:

it is the simplest to determine.

Gonadal shielding is used unless:

it will compromise the diagnostic value of the examination.

Flat contact shields are made of:

lead strips or lead-impregnated materials 1 mm thick.

A shield is recommended if the ovaries and uterus are:

less than 5 cm from any edge of the field.

In screen-film imaging, as kVp increases and mAs decreases, radiographic contrast is reduced; consequently, the amount of diagnostically useful information i the recorded image is:

less.

Because children have a greater life expectancy, they may easily survive long enough to develop:

leukemia induced by radiation or develop a radiogenic malignancy such as lung or thyroid cancer.

The female reproductive organs receive about three times more exposure during a given radiographic procedure involving the pelvic region than do the:

male reproductive organs.

Bone marrow dose may also be referred to as the:

mean marrow dose.

A rad exam of a pregnant woman should be performed with special efforts to ____ the dose to lower abdomen and pelvic regions.

minimize

With regard to the potential for biologic damage from exposure to ionizing radiation, children are:

much more vulnerable to both the late somatic effects and genetic effects of radiation than are adults.

Involuntary motion is caused by:

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

Flat contact shields are not suited for:

non recumbent positions or projections other than AP or PA.

The use of higher kVp and lower milliamperage and exposure time in seconds (mAs) reduces:

patient dose.

Radiation dose to the breast of a young patient may be further reduced by:

performing the scoliosis examination with the radiographic beam entering the posterior surface of the patient's body instead of the anterior surface.

Gonad shielding minimizes the number of:

potentially deleterious x-ray induced mutations expressed in future generations.

Image post processing digital images are essential to:

produce a high-quality diagnostic image in which artifacts are controlled.

Appropriate and consistent use of exposure technique charts, adequate peak kilovoltage (kVp), and a well-calibrated AEC are essential to:

producing quality diagnostic images consistently while minimizing patient radiation exposure.

What is the Image Wisely Campaign?

promotes lowering amt of rad used and eliminating unnecessary imaging procedures in adult imaging

What can a rad tech do to eliminate or minimize patient motion?

proper body or body part immobilization and motion reduction techniques

With the air gap technique, the removal of scatter radiation improves:

radiographic image contrast.

What is the Image Gently Campaign?

raises awareness about methods to lower rad dose during pediatric rad exams

For female patients, the use of a flat contact shield placed over the reproductive organs:

reduces exposure by approximately 50%.

In digital imaging, increasing kVp by 15% with a corresponding decrease in mAs:

reduces patient radiation exposure.

To ensure standardization in the processing of both film and digital images, it is absolutely essential that every imaging department establish a quality control program that includes:

regular monitoring and maintenance of all processing and imaging display equipment in the facility.

Air gap technique

removes scatter radiation by using an increased OID.

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

repeat analysis program.

A small, relatively thin pack of TLDs is:

secured to the patient's skin in the middle of the clinical area of interest and exposed during a radiographic procedure.

Technical exposure factors that minimize the radiation dose to the patient should be:

selected whenever possible.

The use of the PA projection results in a much lower radiation dose to the anterior body surface, thereby:

significantly reducing the dose to the patient's breasts.

____ ____ is the term used in rad safety to refer to the dose to the epidermis (the most superficial layers of skin)

skin dose

In general, (smaller / larger) doses of rad are sufficient to obtain useful images in pediatric imaging compared to adults.

smaller

Irradiating a pregnant woman should be done by selecting the _____ technical factors with precise collimation and lead contact shielding of abdomen area.

smallest

When AEC is not used, to ensure uniform selection of technical x-ray exposure factors, efficient imaging departments use:

standardized technique charts for each x-ray unit.

The radiographer should always select the highest practical kVp within the optimal range for the position and part, coupled with the lowest mAs that will yield:

sufficient information for each radiographic examination.

In making this decision, the physician must determine whether the benefit to the patient, sufficiently justifies subjecting the patient to the risk of:

the absorbed radiation resulting from the procedure.

Mean marrow dose:

the average radiation dose to the entire active bone marrow

A quality control radiographer, or other designated person, reviews discarded film images with co-workers to determine:

the causes of various repeats.

Shields for the lens of the eye are always of:

the contact type and are positioned directly on the patient.

What is the most significant factor used in determining the estimated fetal dose to a pregnant woman?

the correction to the measured rad output at a given kVp as a result of the patient's thickness and the distance from the image receptor to the tabletop.

With gonadal shielding in pediatric studies, If the gonadal tissue is more than 2 cm from the edge of the field of view (assuming good collimation), the use of a gonadal shield does not significantly affect the gonadal dose because in that case:

the dose is caused mainly by internal scatter.

Fluoroscopically guided positioning (FGP)

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

Quality Control Program ensures:

the production of optimal-quality images.

To minimize patient motion in pediatric radiography,

the radiographer must employ very short exposure times by selecting a high-mA station and also using effective immobilization techniques.

Repeat exposures is permissible when recommended by:

the radiologist for the purpose of obtaining additional diagnostic information.

The responsibility for ordering a radiologic examination lies with:

the referring physician.

Thermoluminescent Dosimeters (TLDs)

the sensing devices most often used to measure skin dose directly.

Shaped contact shields are not recommended for PA projections because:

the shield covers only the anterior and lateral surfaces of the productive organs.

GSD is the equivalent dose (EqD) to the reproductive organs, that, if received by every human, would be expected to bring about an identical gross genetic injury to the total population, as does:

the sum of the actual doses received by exposed individual members of the population.

If the flat contact shield is used during a typical fluoroscopic examination, it must be place under the patient to be effective because:

the x-ray tube is located under the radiographic table.

Nonessential Radiologic Examinations unnecessarily exposes the patient to radiation because:

there is virtually no benefit to the patient in terms of useful information gained from the procedure.

Flat shields are most effective when:

they are used as protective devices for patients having anteroposterior (AP) or posteroanterior (PA) radiographs while in a recumbent position.

Clear lead shields are made of:

transparent lead-acrylic material impregnated with approximately 30% lead by weight.

T/F: The argument for using FGP does not hold true with current repeat rates of 7-8% because it would not be ethical to overexpose 90% of patients to attempt to lower the repeat rate

true

According to studies published by Beebe and others in 1978, the risk of a radiation-induced leukemia in children after a substantial dose of ionizing radiation is approximately:

two times that of adults.

Because radiation dose to bone marrow may be responsible for radiation-induced leukemia, the dose to this organ becomes:

very significant.

Motion controlled by will is classified as:

voluntary motion.

Entrance Skin Exposure (ESE) may be converted to patient skin dose by using:

well-documented multiplicative factors.

A digital image receptor is capable of responding to a large variance in x-ray intensities exiting the patient. As a result, the digital image receptor is said to have a:

wide dynamic range.

Use external landmarks to guide placement of a testicular or ovarian shield:

▬Male pt: the symphysis pubis can be used to guide shield placement over the testes ▬Female pt: placed ~ 1 inch medial to ASIS to protect the ovaries