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Knowing how number is used is key to controlling exposure.

Imaging in a radiology film environment is much like playing Goldilocks and the Three Bears. You take your image, hold it up to the viewbox and say: “This image is too light”; “This image is too dark”; or, “This image is just right!” If you underexpose your image, it will be too light, and if you overexpose the image, it will be too dark (See figure 1). The density and contrast of the image on film is controlled by the kV, mAs and other exposure factors.

However, with digital imaging devices, brightness and contrast are no longer linked to exposure factors. Digital systems produce images with consistent density and contrast regardless of the exposure factors (See figure 2). So how does a radiographer know if a digital image is over- or under-exposed?

The potential for gross overexposure is one issue we encounter when a radiology department or clinic changes to a digital image receptor. The reason for this increased risk is that we’ve lost the visual connection between the exposure and an image’s appearance. That’s why it’s so important for the radiographer to understand how to read and utilize the exposure indicators.

On digital imaging systems, an exposure indicator provides useful feedback to the radiographer about exposures delivered to the image receptor (ASRT, 2020). An over- or under-exposed image will deliver an incorrect exposure indicator; whereas a correct exposure will provide a corresponding exposure indicator. The indicator is a vendor-specific value that provides the radiographer with an indication of the accuracy of their exposure settings for a specific image (ASRT, 2020). The exposure indicator has as many different names as there are vendors in the market. The names include S-number, REG, IgM, ExI and Exposure Index.

Carestream’s computed radiography (CR) and digital radiography (DR) systems both reference their exposure indicator as the exposure index or EI. After an exposure is made, the resulting image appears on the monitor and displays a number in the Exposure Index field. The number is a representation of the average pixel value for the image in a predefined Region of Interest (ROI).

The exposure index allows the radiographer to match the exposure to the desired speed class of operation. The speed class is set in a given department by consulting with an interpreting radiologist. The radiologist’s feedback on sample images helps determine the level of image noise he or she can accept. It’s important to note that, as speed class increases, so does the amount of image noise. Once an acceptable noise level is established, a radiographer can identify the speed class of operation for the imaging system and the corresponding technique charts. It’s the responsibility of the radiographer to select a technique that provides enough exposure to reduce the amount of noise while also adhering to ALARA standards.

The exposure index is indirectly proportional to the speed class of operation. If you’re using the Carestream Exposure Index values, for every 300-exposure-index increase, the speed class is reduced by half. In other words, if the exposure index increases from 1400 to 1700, the speed class is reduced from a 400-speed class to a 200-speed class. The Carestream EI is not necessarily unique to the receptor type. However, CR systems typically operate at a lower speed class than DR systems.

IEC Exposure Index is international standard

Remember that each radiology imaging manufacturer has its own method of providing exposure indicators. This can be confusing to radiographers who have multiple vendors within their facility. Fortunately, there is a standard for exposure index for digital X-ray imaging systems. Developed concurrently by the International Electrotechnical Commission (IEC) and the American Association of Physicists in Medicine (AAPM), in cooperation with digital radiography system manufacturers, the index has been implemented as an international standard. It’s known as the IEC exposure index. Carestream systems are configurable for the user to display the Carestream EI, the IEC EI, or both.

The IEC exposure index is unique to the receptor type being used and to the exam performed. Three default Target Exposure Index (TEI) values are preloaded into the system. The three values represent the default Target EI for bucky, non-bucky and pediatric exams.

Once the operating speed class is determined, the key operator can adjust the Target EIs to correspond to the recommendations made by the facility’s physicist. After an exposure, the IEC EI will display, followed by the deviation index (DI) in parentheses. The deviation index quantifies the difference between the actual EI and the Target EI, and this feedback allows the radiographer to track and adjust his or her exposures. When the actual EI is equal to the Target EI, the DI will equal 0. A positive or negative DI indicates the amount of exposure greater or lesser than the target EI. It does not necessarily mean that an image needs to be

repeated. If the deviation is greater than +3, the exposure index displays in red to indicate a high/low exposure that might need further review.

The DI chart below outlines how to use the deviation index. In the example above, the DI was calculated as 1.06. In the chart you’ll see that a DI of 1 means the resulting exposure was

26% higher than the Target EI. The initial DI was 1.06, so we can estimate that we are slightly higher, perhaps closer to 30%. Although it might be a good image, it is merely an indicator to the radiographer that he/she might be able to reduce the exposure factors the next time a particular exam is performed- reducing the dose to the patient while still acquiring an acceptable image.

Martin Pesce, RT, is Clinical Development Manager at Carestream

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Journal of Medical Imaging and Radiation Sciences

Abstract

This article describes the essential elements of the new standardized exposure indicator (EI) established by the International Electrotechnical Commission for digital radiography systems. First, a review of the limitations of the narrow exposure latitude of film screen radiography is presented followed by the brief description of two digital radiography systems, a computed radiography system and a flat-panel digital radiography system. These systems feature wide exposure latitude, variable speed class, and image processing to produce images that appear with the same density regardless of the exposure used and a characteristic EI displayed on images to provide the technologist with some indication of the exposure level to the digital detector. The third point described focussed on the major elements of the standardized EI of the IEC and described them with respect to standardization efforts, deviation index, and the target EI (EIT), responsibilities of both the manufacturers and users. This new standardized EI is now proportional to the detector exposure and requires the user to establish EIT values for all examinations in order to ensure optimization of the dose to the patient without compromising the image quality. The values (EI and EIT) can now be used to calculate the DI, which provides immediate feedback to the technologist as to whether the correct exposure was used for the examination. Finally, an insight into optimization research will be presented as a means of illustration of a dose-image quality optimization strategy that can be used to determine EIT values objectively.

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The author(s) have no financial disclosures or conflicts of interest to declare.

Ultrasound Biosafety Considerations for the Practicing Sonographer and Sonologist

Departments of Radiology and Bioengineering, University of California, San Diego, La Jolla, California USA

Address correspondence to Thomas R. Nelson, PhD, Department of Radiology, University of California, San Diego, Medical Teaching Facility, Room 113, 9500 Gilman Dr, La Jolla, CA 92093-0610 USA.Search for more papers by this author

Departments of Radiology and Bioengineering, University of Michigan, Ann Arbor, Michigan USA

Department of Obstetrics and Gynecology, Rush University, Chicago, Illinois USA

National Center for Physical Acoustics, University of Mississippi, University, Mississippi USA

Departments of Radiology and Bioengineering, University of California, San Diego, La Jolla, California USA

Address correspondence to Thomas R. Nelson, PhD, Department of Radiology, University of California, San Diego, Medical Teaching Facility, Room 113, 9500 Gilman Dr, La Jolla, CA 92093-0610 USA.Search for more papers by this author

Departments of Radiology and Bioengineering, University of Michigan, Ann Arbor, Michigan USA

Department of Obstetrics and Gynecology, Rush University, Chicago, Illinois USA

National Center for Physical Acoustics, University of Mississippi, University, Mississippi USA

Abstract

The purpose of this article is to present the practicing sonographer and sonologist with an overview of the biohazards of ultrasound and guidelines for safe use.

Abbreviations

Overview

Ultrasound is an imaging modality that has important diagnostic value. Although useful in a variety of applications, diagnostic ultrasound is particularly useful in prenatal diagnosis. To date, there is no evidence that diagnostic ultrasound produces harm in humans or the developing fetus when used properly.

There are, however, an increasing range of ultrasound studies being performed. Newer technologies can have higher acoustic output levels than earlier equipment. Also, subtle or transient effects of diagnostic ultrasound, such as changes in membrane permeability or neuronal migration, are not completely understood.

Therefore, diagnostic ultrasound should be used prudently with ultrasound examinations performed only by trained, competent personnel. To ensure continued safety, it is essential to maintain an awareness of the potential for bioeffects, especially with newer equipment and more sophisticated procedures.

The purpose of this article is to review ultrasound biosafety considerations for the practicing sonographer and sonologist as well as to provide references for more detailed discussion and guidance. There has been considerable debate within the ultrasound bioeffects community regarding setting specific values for the mechanical index (MI) and thermal index (TI) to limit bioeffects risk. There also has been some reluctance in the bioeffects community to help sonographers and sonologists make appropriate practical clinical biosafety decisions because of this debate.

This article should be viewed as the considered opinion of the authors and should not be taken as the position of any professional society or medical specialty board. This article is an effort on our part to start a discussion on what constitutes appropriate practical guidance to the sonographer and sonologist regarding acoustic output values consistent with obtaining diagnostic information while protecting patient welfare.

Ultrasound Acoustic Output and Bioeffects

Some tissues, such as those in the developing embryo and fetus, are particularly sensitive to energy deposition from many imaging modalities, including ultrasound. Up to 8 weeks after conception, organogenesis is taking place in the embryo. This is a period when cell damage might lead to anomalies or subtle developmental changes. Fetal effects also vary with the increasing mineralization of developing bone, raising the potential for heating of sensitive tissues such as brain and spinal cord, although the increasing fetal size in later gestation may provide some additional resistance to thermal insults. The brain and spinal cord continue to develop through to the neonatal period, so continued vigilance is necessary.

The presence of bone within the ultrasound beam greatly increases the likelihood of a temperature rise due to direct absorption in the bone itself and conduction of heat from bone to adjacent tissues. Generally, the temperature rise is greatest at bone surfaces and the adjacent soft tissues. As a result, it also is important to minimize eye exposures in the fetus and adult because of the relatively low perfusion in the eye, particularly in the lens, which has a reduced capability for heat dissipation.

Furthermore, because ultrasound is mechanical energy, the mechanical interaction of sound with cells and tissues has the potential to produce nonthermal bioeffects.

Limited information is available regarding possible subtle biological effects at diagnostic levels in fetal, pediatric, and adult patients. Therefore, one should limit acoustic output and exposure time commensurate with obtaining an acceptable diagnostic evaluation. At present, there is no reason to withhold diagnostic scanning, including during pregnancy, provided it is medically indicated and is used prudently by fully trained operators. 1 – 3 However, it also is important to keep in mind that the potential for bioeffects also exists with equipment that is not adjusted properly or used prudently.

Standard for Real‐time Display of Thermal and Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment

Before 1976, there were no limits to the permissible acoustic output from diagnostic ultrasound equipment. In 1976, the US Food and Drug Administration (FDA) began regulating medical devices, including ultrasound, and eventually developed 4 application‐specific exposure limits (peripheral vascular, 720 mW/cm 2 ; cardiac, 430 mW/cm 2 ; fetal and other, 94 mW/cm 2 ; and ophthalmic, 17 mW/cm 2 ). 4 , 5 This regulatory output level was established on the basis of the predicate devices in use in the market at that time and the apparent safety of ultrasound as understood at that time.

In 1992, at the request of manufacturers and end users interested in obtaining specific improvements in the diagnostic capabilities of ultrasound, the FDA changed this limit to 720 mW/cm 2 for all applications except eye scanning. Most prenatal epidemiologic studies on bioeffects have been based on ultrasound exposures occurring before 1992 with equipment regulated according to the pre‐1992 output limits of 94 mW/cm 2 . Along with the change in output limits, the FDA also mandated that machines capable of producing higher outputs be able to display to the diagnostician some indication of the relative potential for ultrasound‐induced bioeffects. This regulation is known as the Standard for Real‐Time Display of Thermal and Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment, more commonly known as the output display standard (ODS). 4 , 6

The original proposal for implementation of the ODS was to remove limits on machine output, placing full responsibility on the operator. Subsequently, it was decided to implement the ODS with the limits along with some indication of the acoustic output on the display. Since 1992, equipment is capable of operating with acoustic outputs of up to 720 mW/cm 2 with the specific acoustic output under the direct control of the operator and with the expectation that techniques that are as low as reasonably achievable (ALARA) will be used.

The ODS consists of the MI and the TI. The MI is an on‐screen indicator of the relative potential for ultrasound to induce an adverse bioeffect by a nonthermal mechanism. The TI is an on‐screen indicator of the relative potential for a tissue temperature rise. The TI is a model‐based approach to determine where the maximum temperature and location in the acoustic field would be expected on the basis of the imaging parameters and the acoustic propagation model selected.

Although not perfect, TI and MI estimates represent the most practical approach to thermal and nonthermal risk estimation currently available. Nevertheless, for the acoustic indices to be meaningful, the diagnostician must be familiar with ultrasound safety issues and their implications for fetal and patient imaging studies. Implementation of the ODS puts much greater responsibility for patient safety on the ultrasound end user. Adherence to the ALARA principle also is recommended.

An additional major requirement for acceptance of the ODS by the FDA pertains to adequate education of end users. This requires information about the ODS be provided by the manufacturer, which is most commonly in the form of the publication Medical Ultrasound Safety 7 from the American Institute of Ultrasound in Medicine, which is provided with new ultrasound scanners. However, the broader goal for sonographers and sonologists should be an understanding of the potential for bioeffects through initial applications training by the vendor, ongoing continuing medical education courses, and vigilant daily awareness of acoustic output.

Acoustic Physics

Physical Properties of Ultrasound

Ultrasound is mechanical energy that propagates longitudinally through elastic media, such as tissues, creating alternating zones of compression and rarefaction. Ultrasound imaging typically uses short pulses (Figure 1) with acoustic energy reflected back toward the transducer from interfaces having different acoustic properties. Typical biomedical ultrasound imaging parameters are shown in Table . 8

The acoustic power is the rate of energy production. The Système International d’Unités unit of power is the watt (1 J/s). The acoustic intensity is the rate of energy flowing through a unit area 6 (watts per square centimeter). Acoustic output is measured for a variety of pulse conditions with the intensity relationships between the various measured parameters shown in Table and Figure 1.

The current FDA output limits for diagnostic ultrasound are a spatial‐peak temporal‐average intensity (ISPTA) less than 720 mW/cm 2 . The acoustic output depends on the output power, pulse repetition frequency, and scanner operating mode (eg, B‐mode, M‐mode, pulsed, or color or power Doppler imaging). 4 , 9

Acoustic pulses showing where and how acoustic output is measured and reported for a single scan line at the focus of a diagnostic medical ultrasound system.

Department of Health

Guide for Radiation Safety/Quality Assurance Programs

Introduction

This guide describes the type and extent of information and standards by which the New York State Department of Health will evaluate a facility’s Radiation Safety/Quality Assurance Program.

Our Department has implemented this program to reduce radiation exposure and optimize diagnostic x-ray image quality. It is our goal to assist facilities to be more actively involved and responsible for Quality Assurance in their operations. It is important to review the program as a whole and not to become enmeshed in the everyday quality control tests. Facilities may substitute quality control tests if the tests are deemed equivalent by the Department prior to their implementation.

References can be found in the bibliography to assist you with test procedures and to answer questions not addressed in this brief guide regarding Quality Control and Quality Assurance.

ALARA Principle (As Low As Reasonable Achievable)

The regulations in Part 16 and this guide have been established on the ALARA Principle to assure that the benefits of the use of ionizing radiation exceed the risks to the individual and the public health and safety.

Control Limits and Standards

The control limits and standards used in this guide have been taken from the Federal Performance Standard for Diagnostic X-ray Equipment, Part 16, and other references listed in the bibliography. Processor problems need to be addressed as they occur and before the limits are exceeded. Equipment problems should be corrected and documented expeditiously and shall be corrected with appropriate documentation within thirty (30) days of discovery. The RS/QA program for Computed Tomography equipment is contained in a separate document.

The statutory authority for these rules and regulations is found in the New York State Public Health Law, Section 225. The Radiation Safety/Quality Assurance requirements are outlined in Section 16.5 and 16.23 of Part 16 of Chapter 1 of Title 10 (Health) of the Official Compilation of Codes, Rules and Regulations. Please note that this program is in addition to and does not replace other sections of Part 16, which pertain to your operation.

Radiation Safety/Quality Assurance Programs

  1. Radiation Safety/Quality Assurance Responsibility

Each facility shall establish a committee of individuals to be responsible for the Radiation Safety/Quality Assurance program. Hospitals will include those departments, which use xrays for diagnostic purposes. This committee should be composed of a minimum of one radiologist, the Chief Technologist, the QC Technologist(s), and a Medical Physicist and a member of the in-house x-ray service or engineering group, if available. Individuals such as hospital administrators and representatives of contracted service companies may also be valuable. The committee in a non-hospital facility might be composed of a physician, radiologic technologist, office manager and service representative.

This oversight committee shall convene on a frequency adequate to meet their responsibilities, with a minimum of one meeting annually. More frequent meetings will probably be important in the initial stages of this program. The minutes of these meetings shall be kept for a minimum of three years.

It is the responsibility of this committee to provide direction to the program, assure that proper documentation and testing is maintained, review the program’s effectiveness and determine any changes which should be made.

The committee shall assign Quality Control responsibilities in writing. Specific assignments shall be recorded in the manual. The responsible individuals shall be properly instructed. Evidence of continuing education shall be available for those individuals actively engaged in the Quality Control testing and evaluation process.

Each facility will establish a manual that includes the following items:

  1. a list of the individuals responsible for testing supervising and repairing/or servicing the equipment;
  2. a list of the tests to be performed and the frequency of performance;
  3. the acceptability limits for each test;
  4. a brief description of the procedures to be used for each test (Appendix C-1 contains an example of a manual item on light field/x-ray field alignment);
  5. a list of the equipment to be tested;
  6. protocol for correction;
  7. reference materials and their location;
  8. a list of the equipment to be used for testing
  9. sample forms to be used for each test; and
  10. the committee organization and duties.
  • Equipment Records

    Records shall be maintained for each x-ray room and mobile x-ray unit and include:

    1. the initial test results (acceptance testing and radiation safety survey as appropriate);
    2. the current year;
    3. one set of test results from each intervening year to show changes over time.

    Records of repairs and other pertinent data shall also be available. It is not essential that the records be stored in the room with the x-ray equipment tested but must be easily accessible to anyone who needs to use them.

    Radiation Output and Exposure Rate Measurements for Selected X-ray Examinations

    The facility shall have available the radiation output measurements for common radiographic examinations they perform for patient and staff information for each x-ray unit. These measurements shall be repeated whenever changes are made to the system, which would impact the output. Appendix G is available for reference. Fluoroscopic exposure rates for the patient phantoms specified in Section 16.58(a)(9) of Part 16 for the most common examinations shall be posted so that they are conspicuous to the operator of each fluoroscopic unit.

    Processor and Sensitometer Logs

    Control charts of sensitometry shall be maintained and used to regulate processing.

    Processor maintenance logs shall include preventive maintenance, corrective maintenance and cleaning (Appendix H). Each action shall be dated and initialed.

    Processor charting of speed, contrast, and base + fog shall be graphed daily and posted as close as possible to the individual processor from which the data is derived. The graphs for each processor shall be kept for review for a period of time at least equal to the facility’s inspection interval.

    Facilities using dry image processing devices must evaluate those devices according to the manufacturer’s recommended test procedures and test frequencies. The results of the evaluation must be compared to the manufacturer’s published specifications for that type of device. The results of those evaluations and any corrective actions taken must be retained for a period of time equal to at least the facility’s inspection interval.

    QC Records for Test Equipment

    Records shall be maintained and available for review for QC test equipment, which requires calibration.

    Radiation Safety Policies and Procedures

    The written policy and procedures must be available for the holding of patients, use of gonad and scoliosis (if performed) shielding, pregnant patients and operators, personnel monitoring, x-ray screening and repeat, reject analysis. (Guidelines for information to be included can be found in Appendix F).

    Each facility shall make or have made the following tests, at the frequency specified, and maintain records of the data. The type of tests and the frequency of the tests may be modified at the discretion of the Department if the facility can show documented proof that alternative tests or schedules will ensure good diagnostic image quality.

    This guide describes a basic Radiation Safety/Quality Assurance Program and represents only a portion of the Quality Control tests your facility may choose to perform as part of an individualized program.

    A chart of tests and frequencies can be found in Appendix A.

      Test frequency – Each day of operation

    Equipment functioning: Each day during the x-ray generator warm-up, and before xraying the first patient, the operator should check for indicator dial malfunction and also the mechanical and electrical safety of the x-ray system. Malfunctions and unsafe conditions shall be corrected promptly. Suggestions for visual and manual checks are in Appendix H.

    Film processing: For each day of operation, the processing system must operate as close to the film manufacturer’s temperature and speed recommendations of the product as possible. It is very important that corrective action be made when limits are exceeded or a pattern develops indicating a degradation of the system.

    Parameters to be included in processing checks:

    1. Speed Index or Medium Density:
      Control limits +/-0.15 Optical Density O.D.
    2. Contrast Index or Density Difference:
      Control limits +/-0.15 O.D.
    3. Base + Fog: Maximum density shall not exceed the established control limit by more than 0.03 O.D.

    Solution temperatures and replenishment rates should be checked when troubleshooting speed and contrast problems.

  • Test frequency – Quarterly
    1. Collimators
      1. Light field/X-ray Field alignment (App. C-1)
        The misalignment in either dimension of the edges of the light field versus the x-ray field shall not exceed 2% of the Source-Image-Distance (SID).
      2. Positive Beam Limitation (PBL) (App. C-2)
        The x-ray beam size shall not differ from the image receptor size by more than 3% of the SID in any one dimension or by a total of more than 4% of the SID in both dimensions.
      3. X-ray Field/Image Receptor alignment (App.C-3)
        The misalignment of the center of the x-ray field as compared to the center of the image receptor shall not exceed 2% of the SID.
    2. Collimators – Fluorographic

      This requirement applies to spot film and fluoroscopic beam size in worst case conditions.

      1. Image Receptor/X-ray Field alignment
        1. For image intensified equipment, the x-ray beam shall not exceed the visible area of the image receptor by more than 3% of the SID in one dimension or by a total of more than 4% of the SID in both directions.
        2. For non-certified image intensified equipment, the x-ray beam shall not exceed the visible area of the one/one spot film.
        3. For non-image intensified equipment, the x-ray field size shall not extend beyond the visible area of the image receptor.
  • Test Frequency – Semiannually
    1. Radiographic Timer (includes Automatic Exposure Control)
      1. Reproducibility of the Output

        Radiographic units or spot film devices are in compliance, if in field testing, it can be shown that for four exposures at a specific time:

        Xmax – Xmin/Xavg ≤ 10%

        where X is an exposure measurement in mR.

        The most commonly used exposure time settings should be selected for testing. If the results of the four exposures are not compliant, make six additional exposures and calculate the coefficient of variation. The coefficient of variation of the exposure measurements shall be no greater than 0.05 and shall be determined by the equation:

        where X is the average of the exposure measurements and S is the standard deviation of the exposure measurements.

        Certified equipment shall meet the manufacturers‘ specifications.

        Unless otherwise specified in the manufacturer’s written specifications, all equipment shall meet:

        ±2 kVp of the indicated for 100 kVp.

        For certified equipment, the average ratios of exposure to the indicated milliampere-seconds product (mR/mAs) obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum.

        That is (X1-X2) 1 Fetus 2.6 2.6 0 to 4 2.6 2.5 5 to 9 2.7 2.5 10 to 14 2.7 2.6 15 to 19 2.7 2.6 20 to 24 2.6 2.2 25 to 29 2.0 1.4 30 to 34 1.1 .6 35 to 39 .5 .2 40 to 44 .2 .04 45 to 49 .07 0 50 to 54 .03 0 55 to 64 .01 0 Over 65 0 0 1 Derived from data published by the National Center for Health Statistics, „Final Natality Statistics 1970,„ HRA 74-1120, vol. 22, No. 12, Mar. 20, 1974.
        [41 FR 30328, July 23, 1976; 41 FR 31812, July 30, 1976]

        Appendix F-4: Policy and Procedure Regarding the Use of Shielding for Scoliosis Patients

        The facility shall include the following information in its Policy and Procedures manual when a patient has films taken to evaluate scoliosis:

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        1. Methods to provide shielding of the gonads for all patients;
        2. Methods to provide shielding of the breast for female patients;
        3. Availability of compensating filters to decrease chest exposure; and
        4. Use of dedicated cassettes with film/screen combinations decreasing patient exposure.

        Appendix F-5: Policy and Procedures for Pregnant Patients

        The facility shall include the following information in its Policy and Procedures manual item regarding pregnant and potentially pregnant patients:

        1. Method of establishing which patients may be pregnant;
        2. Policy for determining need for x-ray examination in pregnant patients;
        3. X-ray techniques for minimizing fetal exposure;
        4. Method of determining exposure to fetus; and
        5. Procedures to be followed in advising the woman and her practitioner of the exposure received by the fetus.

        Appendix F-6: Policy and Procedures of Personnel Monitoring

        The facility using personnel monitoring shall include the following information in its Policy and Procedures manual:

        1. The name of the person responsible for distribution, collection and records of badges;
        2. The location of controls;
        3. A prohibition against intentionally exposing the control or personnel badge; and
        4. The location of records and policy regarding notification of personnel of exposures.

        Appendix G: Radiation Output Measurements

        200 Speed 400 Speed
        Projection Aver. Max. Aver. Max.
        A/P LS (40″) – 23 cm 450 540 350 420
        P/A Chest (72″) – 23 cm Grid 25 30 15 18
        Nongrid 15 18 5 6
        Abd (KUB) (40″) – 23 cm 490 588 300 360
        Full Spine (72″) – 23 cm 260 312 145 174
        Cerv. Spine (40″) – 13 cm 135 162 95 114
        Lat. Skull (40″) – 15 cm 145 174 70 84

        Procedure for Chest or Spine

        1. Center the x-ray tube to the tabletop or vertical cassette holder. Check that the proper SID has been selected.
        2. For procedures done on the x-ray table, place the ionization chamber on the table. Center the chamber 23 cm from the top of the table.
        3. For procedures using an upright cassette holder, the chamber is centered vertically to the cassette holder. Measure the distance from the front of the upright cassette holder to the center of the ionization chamber. The measurement must be 23 cm.
        4. Check the light field from the collimator to make sure that the ionization chamber is completely covered. Collimate the beam to the field size used for the projection.
        5. Select the technical factors that would be used to image a medium size patient who measures 23 cm thick.
        6. Make an exposure and record the result. Record the values of three exposures and average these numbers.
        7. The resulting number is the radiation output for the exam you have selected. Compare with the above chart. Radiation outputs may not exceed twice the average for the projection. Chest output measurements may not exceed 50 mR. This number should be recorded along with the technical factors and distances used and posted for reference.

        Appendix H: Forms

        From: „Quality Control in Diagnostic Imaging“ Gray, Winkler, Stears and Frank, Aspen Publishers, 1983

        From: „Quality Control in Diagnostic Imaging“ Gray, Winkler, Stears and Frank

        Location ______________________________
        From _______________ To ______________

        Cause Number of Films Percentage Of Rejects Percentage Of Repeats
        1. Positioning
        2. Patient Motion
        3. Light Films
        4. Dark Films
        5. Clear Film X X
        6. Black Film
        7. Tomo Scouts X
        8. Static
        9. Fog – Darkroom
        10. Fog – Cassettes
        11. Mechanical
        12. Q.C. X X
        13. Miscellaneous (?) X
        14. Good Films
        Total Waste (1-4) ________ % X X
        Total Rejects (All except 5 and 12) X
        Total Repeats (1-4, 6, 8-11, 14) X
        Total Film Used ________

        From: „Quality Control in Diagnostic Imaging“ Gray, Winkler, Stears and Frank

        Visual and Manual
        Quality Control Checks

        Building: ___________________ Section:________________ Room #: ___________ Tube: _________

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