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					                           Jose Lopez,
                              PhD
                             Director

                     Sylvia Revel, RSO
                   Registration and Gamma
                             Knife


     Auditors:                            Badge Monitor:
Samantha Sorrells, Assistant RSO    Audrea Tamez, Safety Specialist
 Adis Umpierre, Safety Specialist




                  214-648-2250
   Texas is an Agreement State:
       Texas will meet or exceed regulations set by the NRC (Nuclear
        Regulatory Commission)

   The State of Texas, Department of State Health Services issues
    registrations for machines that produce radiation and licenses for
    the use of radioactive materials.

   UT Southwestern Environmental Health and Safety office and the
    radiation safety officer (RSO) provide oversight of all fluoroscopy
    machines on site.

   This training is required for all physicians requesting fluoroscopy
    privileges and that do not hold a current ABR certification.

   Fluoroscopy training is required every two years.
    We are surrounded by radiation in our daily lives at all times.
    Natural background radiation is about 350 mrem annually.
                        Conventional Consumer, 2.0%    Occupational, 0.1%
                        radiography /
                         fluoroscopy                    Industrial, 0.1%
                       (medical), 5.0%
      Interventional
       fluoroscopy
     (medical), 7.0%                                                           Radon and Thoron
                                                                              (background), 37.0%

Nuclear medicine
(medical), 12.0%




               Computed
              tomography
            (medical), 24.0%                                        Space (background),
                                                                            5.0%
                                               Terrestrial           Internal
                                           (background), 3.0%   (background), 5.0%

     The NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the
     United States, provides a complete review of all radiation exposures for 2006.
   Scatter is the greatest                           Tube
    source of exposure.           Primary
                                  Beam

   Does not linger in the
    room. It is only present
    when the x-ray beam is                            Scatter
    on.

   The patient is the main
    source of scatter.                      Patient


   Scatter radiation is weaker
    than the primary beam
               5,000 mrem – Whole Body
               50,000 mrem – Extremities
               100 mrem – General Public
               500 mrem – Minors/Fetus

                Patient Exposure
   No regulatory limit for dose to the patient
   Patient dose is at the discretion of the physician
    – taking into account risk vs. benefit
   Radiosensitivity - The relative susceptibility of
    cells, tissues, organs, organisms, or other
    substances to the injurious action of radiation.

   Cells are most sensitive to radiation when they
    are:
       Rapidly dividing
       Undifferentiated
       Have a long mitotic future

   Increasing Sensitivity to Radiation
         Lymphocytes
         Erythrocytes, Granulocytes
         Epithelial Cells
         Endothelial Cells
         Connective Tissue Cells
         Bone Cells
         Nerve Cells
         Brain Cells
         Muscle Cells
Radiation            Threshold to    Amount of       Amount of         Time to Effect
Effect               Produce (rad)   Fluoro to       Cine to produce
                                     produce @       @ 30R/min
                                     5R/min
Transient Erythema         200          42 minutes      6 minutes         24 hours


Epilation                  300            1 hour        12 minutes        3 weeks


Main Erythema              600           2 hours        18 minutes         10 days


Pericarditis               800          2.7 hours       24 minutes       >10 weeks


Dermal Necrosis           1800           6 hours          1 hour         >10 weeks




        Patient doses are controlled by the
                    physician
6 – 8 wks post            16 – 21 wks post          18 -21 months
procedure                 procedure                 post procedure

A 40 year-old male who underwent coronary angiography, coronary
angioplasty and a second angiography procedure due to
complications, followed by a coronary artery by-pass graft, all on
March 29, 1990.
   If fluoroscopy must be used on a pregnant
    patient, the physician must consult with a
    Board-Certified Radiologist.

   Alternate imaging techniques should be used if
    available.
Week of                  Possible effects to Fetus
Gestation
4 to 11 weeks                 Multiple severe abnormalities of many organs


11 to 15 weeks                    Mental retardation and microcephaly


After 20 weeks           Fetus is more radioresistant, however, functional defects
                                            may be observed.

Any prenatal radiation           Low incidence of leukemia (1 in 2000)


 Always follow the ten day rule when expose women to radiation
 Have the patient complete and sign a LMP (last menstrual period) form.
   Fluoroscopy is real time x-ray imaging captured on
    a TV monitor, while radiography is a single image
    captured with one exposure.

   Fluoroscopy beam-on times are usually less than 5
    minutes for most cases outside of Cardiac Cath
    and Interventional Radiology.

   There is no radiation exposure from the machine
    unless fluoro is in use.

   Typical machine output
      Normal mode 5 R/min
      Boost mode >10 R/min
   Automatic Brightness
    Control (ABC)
       Controls generator output
        to assure constant
        brightness at display (TV)
       Compensates for changes
        in:
         Patient thickness
         Patient density
         X-ray output
         Technique
         Field size
         Magnification
   Image Intensifier (I I)
       Converts x-ray image   Tube
        into light image       Image
                               Intensifier

   Tube
       X-ray is produced
        when energized


                   Tube
   ALARA – As Low As Reasonably Achievable
       Radiation exposure for occupational workers is
        usually much less than the allowed annual radiation
        exposure because personnel follow ALARA
        guidelines. The basic guidelines are:
         Minimize your time near radiation sources
         Maximize your distance from radiation sources
         Use shielding devices when applicable
   Patient radiation exposure must also follow
    ALARA, this includes
       Collimation of the primary radiation beam
       Understanding the controls of the C-arm to lower
        patient dose when possible
   Short taps of the fluoroscopy beam-on foot pedal
    instead of standing continuously on the beam-on foot
    pedal. Prolonged exposure will not improve the image
    brightness or resolution.

   Use last image hold feature when needing to view a
    static image

   Reductions can be realized by:
       Using pulse fluoro in place of continuous fluoro
       Not exposing the patient while not viewing the TV image
       Pre-planning images – eliminate panning
       Avoid redundant views
       Be aware of the 5-minute time notifications
Distance
     When possible, increase
      your distance from the
      patient during fluoroscopy.


     Inverse square law :
                   Intensity = 1/d²
     This means two regular size
     steps back from the radiation
     source will decrease
     exposure by four.
   Position the X-ray tube
    under the patient.
   The largest amount of
    scatter radiation is
    produced where the
    beam enters the patient.
   By positioning the x-ray
    tube below the patient,
    you decrease the
    amount of scatter
    radiation to your vital
    organs.
ALWAYS stand closer to the
image intensifier
                                         Scatter radiation
                                          intensity is less on
                                          the image intensifier
                                          side as compared to
                                          the x-ray tube side.
                                         For lateral and
                                          oblique projections:
                                          position the x-ray
                                          tube on the opposite
                                          side of the patient
                                          from where you are
ALWAYS stand further from the x-ray       standing.
tube side
Note – The exposure decreases as the distance from the x-ray source increases
This is where you have the most
control. Types of shielding
include:
    •Lead Aprons
    •Thyroid Shields
    •Movable Shields
   Provides protection from
    scatter radiation
   Must be stored properly
       Hang aprons – see example to the
        right
       DO NOT fold aprons
   Always face the source of
    radiation
   Integrity must be checked
    annually
       Checks are performed by radiology
       Integrity can be verified visually,
        tactile or with fluoro
   Apron fit - A proper
   fitting apron should
   come up to the level of
   your collar bone.




Note: Apron at the level
      of the collar bone



                       Thyroid shield should extend
                       over the top edge of the apron

        Wrap around aprons should fully cover all
        of the velcro in the front. If a wrap around
        apron does not fully close, it is not providing
        optimum protection.
   At the time of apron checks, aprons are
     tagged. The tags are there to inform the
    employee wearing the apron that the apron was
    checked that year.

   Apron tagging is as follows:
    Checked in:   Checked in:   Checked in:
    2009          2010          2011
    2012          2013          2014
    2015          2016          2017
    2018 &        2019 &        2020 &
    So on         So on         So on



   If an apron is not tagged or if it has a color tag that is
    out of date, pull the apron from circulation and contact
    Radiology.
  Area                                      Lead Equivalence                                 Regulation
  Fluoro with shields/drapes in place                        0.25                               289.227(i)(4)(A)

  Fluoro with shields/drapes removed                         0.50                             289.227(m)(8)(B)(i)
  Angio, Cath Lab and OR                                     0.50                             289.227(m)(8)(B)(i)

  All other areas                                            0.25                               289.227(i)(4)(A)

 289.227(i)(4)(A) Protective devices shall be of no less than 0.25 millimeter (mm) lead equivalent material except as specified
       in subsections (i)(13) and (m)(8)(B)(i) of this section.
 289.227(m)(8)(B)(i) - (B) Where sterile fields or special procedures prohibit the use of normal protective barriers or drapes,
       all of the following conditions shall be met.
      (i) All persons, except the patient, in the room where fluoroscopy is performed shall wear protective aprons that
       provide a shielding equivalent of 0.5 mm of lead.


When using Fluoro without drapes 0.50 lead equivalence must be
used.
Check the lead equivalence of the apron you are using
     Check the tag on the inside of the apron, the lead equivalence is marked either 0.25,
     0.35 or 0.50.
     If the apron is less than 0.50,
           Do not wear that apron
           Remove apron from circulation
           Report the deficiency to Radiology
   Excessive light can
    decrease the ability
    of the eye to resolve
    detail.

   Eliminate
    extraneous light that
    can interfere with
    the fluoro exam.

   Room lighting
    should be dim.
   Spacers help maintain a safe tube
    to patient distance.

   If the tube is to close – can cause
    high skin dose rates to the patient

   Most machines have a spacer

   Some machines have a removable
    spacer – note if spacer is removed
    be aware of the increase risk to the
    patient.
                                                         Image
                                                         Intensifier

   Air gap – the amount
    of space between the
    patient and the
    Image Intensifier (I I).

                                                 Reduce Air Gap


   The presence of an air gap will always increase
    patient/operator radiation exposure and decrease
    image quality.

   Reducing air gap – reduces image blur

   Large air gap = large picture = large blur
   Collimation reduces
    unnecessary tissue
    exposure

   Reduces image noise
    caused by scatter
    radiation

   Reduces scatter
    radiation to the
    operator
   Collimation
    decreases the x-
    ray field size to
    the object of
    interest and
    decreases
    exposure to the
    patient and
    employees.

   Increases the x-
    ray field size


   Decreases the x-
    ray field size
   Increase in magnification = increase in dose

   Reduce the amount of magnification used
       Use last image hold and then magnify that image

       Magnification modes should be employed only
        when the increased resolution of fine detail is
        necessary
                                    Magnification
                                    control




 Norm – non magnified image.
        Should be default setting
 Mag 1 – magnified image, larger
          patient dose
 Mag 2 – more magnified, more
         patient dose
   Most modern C-arms have different
    operational dose modes available to the
    operator.
   The “Low Dose” mode uses fewer x-ray
    photons, this lowers patient dose.
   For larger patients and images that do not have
    a lot of contrast this mode may not provide
    adequate image quality.
   The “Low Dose” mode should be used when
    possible to achieve ALARA goals.
   C-arms also offer pulsed fluoro to the operator.

   Pulsed fluoroscopy utilizes a pulsed beam in
    place of a continuous beam of radiation.

   Can help decrease the patient dose.
   Pushing this
    button turns
    on the
    fluoroscopy
    low dose
    mode.

   Push this
    button to
    activate Pulse
    Fluoro.
                     The LED beside
                     the button will
                     light when
                     activated.
                     Foot Pedals
The normal fluoroscopy foot       The digital acquisition beam-
                                  on foot pedal uses a larger
pedal will not have a plus sign
                                  patient dose and should only
next to the eye. This foot        be used for recording special
pedal should be used for most     digital images that will require
applications.                     digital processing.
   Control the movement of the machine.

   Always have the brakes set before any other
    movement made.

   Activate one lock at a time. DO NOT activate
    all locks at once.

   C-arm locks are used for small movements.
                             AP to Lat
                                         Telescope (in-out)




    Tilt




                                            Side to side




Vertical (buttons to push)
                                         Brakes
Reporting Patient Exposure
   Each C-arm must have a fluoro log, and all
    procedures MUST BE RECORDED.

   The fluoro log is required by an internal policy
    and aids Medical Physics with calculating
    fluoro dose in cases of possible overexposure.

   At a minimum the following information must
    be documented for each patient
         Patient name and identifier
         Type of study
         Total fluoro time
         Physician name
Fluoro time




 Fluoro alarm reset
   In 2006 The Joint Commission defined the
    delivery of a cumulative dose of 1500 rad to a
    single field during a procedure to be a sentinel
    event.
         Cumulative dose equals a six month total


   Policy:
       If total fluoro time exceeds 150 minutes or 6000 mGy,
        notify the Radiation Safety Officer 214-648-2250.

       If an overexposure occurs at University Hospital
        Zale Lipshy or University Hospital St. Paul, the
        occurrence must be reported in the Event Reporting
        System.
   Measures the amount of radiation that reaches
    the patient’s skin.

   Unreliable results for estimating exposures

   DAP shows the same dose for the following
    two situations
       Use of a low technique with the collimator open
       Use of a high technique with tight collimation
   Dose-area product (DAP): air karma multiplied
    by x-ray beam cross-sectional area, commonly
    measured in mGy × cm2.




   x-ray tube is just as great as dose-area for 100 cm or 200 cm, because the size of the
    measuring device increases with greater distance to the X-ray tube. But the dose
    itself decreases with greater distance to the tube. Thus the dose-area product is the
    same at each position if the size of the measuring device enables it to detect all of
    the radiation.
   More useful for determining the radiation
    effects on the patient.

   Calculates the cumulative dose based on the
    dose to a given point from the focal spot.

   Problems – dose is not correct if:
       The patient was not at the same distance as the
        measurement from the tube.
       If the exposure was not taken in the same location
        for the entire case.
   Anyone likely to receive more than 10% (500
    mrem) of the limit

    Individuals working with x-ray equipment or
    radioisotopes in clinical settings, radiotherapy,
    nuclear medicine, radiation physics, radiology

   “Declared pregnant ” individuals
       Contact EH&S dosimetry for more information on
        pregnancy
 Collar   badge – worn outside of apron.
                   Monitors dose to eyes and skin.

 Waist Badge – worn under apron. Monitors
                dose to organs.

 Fetal Badge – worn under apron. Monitors
               dose to fetus.

 Ring Badges – worn mainly when handling
                radioactive materials. Wear
                the badge on the hand most
                used.

Area Monitors – Posted in general public areas
                 to monitor dose.
   EH&S office MUST send used badges to
    Landauer for processing by 10th of the month.
   New badges are sent to the department badge
    monitor a week before the new wear date.
   Badges returned late incur a cost of $4.50 per
    badge
   If a badge is lost, you must submit a lost badge
    report (form is located on the EH&S website)
   Badges are to be worn facing front
   Area badges monitor the amount of radiation
    dose to general public areas
   Reports show the exposure to the
    radiation badge in mrem (exposure is
    tissue equivalent)

   Dose reports are provided and posted in
    departments for individuals who use
    dosimetry badges.

   Persons DOB and SS # are removed for
    protection.
Reports are divided into four sections:
  - for this wear period     - for this quarter - for this year; and   - lifetime dose
Each section, in turn, is broken down into three parts:
- Deep dose - Eye dose and - Shallow dose (also used for ring
                                                   badges)
A reading of “M” means minimal or <1 mrem of exposure
   It is very important that the radiation badges be worn properly
    and in the proper location.

   Erroneously high doses can be assigned if the badges are worn
    incorrectly; such as the collar badge on the waist or the waist
    badge on the collar.

   If you wear two badges, Landauer calculates an assigned total
    dose based on the exposures to both of your badges. Once a dose
    has been assigned, it becomes a permanent record. Therefore, it is
    important that the radiation badges be worn correctly to register
    accurate exposures.
                                 ESTIMATED DOSE CALCULATION
                                            e
                             One badge – H = 0.3c
                                                e
                             Two badges – H = 0.04c + 1.5w

                             c = collar badge
                             w = waist badge
EDE1 calculations applied; note the differences in assigned dose. All three
employees worked in the same environments with the same equipment.

  These persons wore their badges in CORRECT locations. This is known
  because the collar doses are higher than the waist doses. See how low the
  assigned dose is because of the EDE1 calculation.




This person wore badges in the INCORRECT locations; this is assumed because
the collar dose is lower than the waist dose. See how high the assigned dose is
because of the EDE1 calculation.
 Level Type                        Level 1     Level 2

 Whole Body Deep (D)               125 mrem    375 mrem

 Whole Body Shallow (S)            1250 mrem   3750 mrem

 Lens of Eye (L)                   375 mrem    1125 mrem

 Extremity (E)                     1250 mrem   3750 mrem


Level 1 – Procedural reminder
Level 2 – Notification with a questionnaire
   Think about radiation protection at all times

   As the machine operator, you have the most control
    over radiation safety

   Utilize time, distance, shielding

   Familiarize yourself with the equipment that you will
    be using.

   Wear lead aprons that fit

   Wear dosimetry badges in correct locations and return
    to the badge monitor on time
   As collimation increases, dose decreases

   As magnification increases, dose increases

   As air gap decreases, dose decreases

   Use pulsed fluoro to decrease dose

				
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