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Fluoroscopy Review

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Fluoroscopy Review

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    1. Fluoroscopy Review RT 255

    2. Basic “Imaging Chain”

    3. Conventional Fluoroscopic Unit Conventional fluoroscopy User viewed faint image on screen User in direct path of beam Very high dose to user and patient Excellent resolution No longer used

    4. Conventional Fluoroscopy

    5. Conventional Fluoroscopy

    6. Light Levels and Fluoroscopy

    7. Image Intensified Fluoroscopy Electronic conversion of screen image to light image that can be viewed on a monitor ? resolution ? dose

    8. The image intensifier (I.I.)

    9. Modern fluoroscopic system components

    10. Modern Fluoroscopic Unit

    11. Image intensifier systems

    12. Image Intensifier VACUUM TUBE ENCASED IN A LEAD HOUSING = 2MM PB (PRIMARY BARRIER)

    13. Functioning of Image Intensifier

    14. IMAGE INTENSIFIER INPUT PHOSPHOR – CESIUM IODIDE PHOTOCATHODE (LIGHT TO E’S) ELECTOSTATIC LENSES – FOCUSES AND ACCELERATES THE E INTENSIFIES LIGHT = BRIGHTNESS GAIN (BG) BG = MG X FG

    15. II Image Intensifier The input phosphor converts x-ray to light* Light from the input phosphor is sent to the photocathode made of cesium and antimony compounds* Photocathode turns light into electrons (called photoemission)* Now we have electrons that need to get to the anode

    16. Image Intensifier Tube Vacuum diode tube 1. Input phosphor (CsI) X-rays ? light 2. Photocathode Photoemission Light ? electron beam 3. Electrostatic lenses Maintain & minify e- 4. Anode Attracts e- in beam 5. Output phosphor (ZnS-CdS) e- ? light

    17. Multi-field II Units II that allows selection of input phosphor size 2 or 3 size selections 25/17 25/17/12 or 23/15/10 Smaller input magnifies output by moving focal point away from output Requires more x-rays to maintain brightness

    18. IMAGE INTENSIFIER CESIUM IODIDE – Input Phosphor ZINC CADMIUM SULFIDE – Output phosphor ELECTRON FOCUSING LENS + CURRENT ATTRACTS e TO ANODE 25 – 35 KVP POTIENTIAL ACROSS TUBE Output phosphor contains a thin al plate to prevent light returning to the photocathode

    19. The anode of the II The anode is about 20” away from these electrons so what will help move the E’s? Electrostatic lenses have a negative charge to repel the negative electrons and push them to the anode and focus them to a narrow beam* Anode has a hole in the middle of it allowing electrons to pass through and hit the output phosphor made of zinc cadmium sulfide* The electrons are carrying the latent image and when they hit the output phosphor they are turned into light again

    21. Image intensifier component Input screen: conversion of incident X Rays into light photons (CsI) 1 X Ray photon creates ? 3,000 light photons Photocathode: conversion of light photons into electrons only 10 to 20% of light photons are converted into photoelectrons Electrodes : focalization of electrons onto the output screen electrodes provide the electronic magnification Output screen: conversion of accelerated electrons into light photons

    22. Intensifier Brightness Gain (BG) BG = Minification Gain x Flux Gain Minification gain (MG): The ratio of the squares of the input and output phosphor diameters. This corresponds to “concentrating” the light into a smaller area, thus increasing brightness MG = (Input Diameter )2 (Output Diameter)2

    23. Minification Electrons had to be focused down to fit through the hole at the anode Input phosphor is much bigger than the anode opening Input phosphors are 10-35 cm in diameter* (6, 9 , 12 inches) Output phosphors are 2.5 to 5 cm (1 in) in diameter* Most fluoro tubes have the ability to operate in 2 sizes (just like small and large focal spot sizes) Bi focus - M=Newer units - tri focus

    24. Intensifier Flux Gain

    25. 1000 light photons at the photocathode from 1 x-ray photon photocathode decreased the # of ë’s so that they could fit through the anode Output phosphor = 3000 light photons (3 X more than at the input phosphor!) This increase is called the flux gain

    26. Flux gain The ratio of the number of light photons striking the output screen to the ratio of the number of x-ray photons striking the input screen is called fluxgain

    27. Brightness gain The II makes the image brighter because it minified it and more light photons. Multiply the flux gain times the minification gain.

    28. BRIGHTNESS CONTROL ABC ABS AEC ADC MAINTAINS THE BRIGHTNESS OF THE IMAGE – BY AUTOMATICALLY ADJUSTING THE EXPSOURE FACTORS (KVP &/OR MAS) FOR THICKER PARTS SLOW RESPONSE TIME - IIMAGE LAG

    29. BG = MG X FG FLUX GAIN – increase of light brightness due to the conversion efficiency of the output screen 1 electron = 50 light photons is 50 FG Can decrease as II ages Output phosphor almost always 1 inch Zinc cadnium phosphot Flux gain is almost always 50

    30. BG = MG X FG Brightness gain BG = MINIFICATION GAIN X FLUX GAIN (old Patterson B-2 fluoro –obsolete) Brightness gain is a measure of the conversion factor that is the ratio of the intensity of the output phosphor to the input phosphor conversion factor = intensity of OP Ř mR/sec

    31. Image Intensifier Terms Flux Gain (usually stated rather than calculated)

    32. Intensifier Performance Conversion factor is the ratio of output phosphor image luminance (candelas/m2) to x-ray exposure rate entering the image intensifier (mR/second). Very difficult to measure: no access to output phosphor No absolute performance criteria

    33. Intensifier Brightness Gain Flux Gain (FG): Produced by accelerating the photoelectrons across a high voltage (>20 keV), thus allowing each electron to produce many more light photons in the output phosphor than was required to eject them from the photcathode. Summary: Combining minification and flux gains:

    34. Intensifier Brightness Gain Example: Input Phosphor Diameter = 9” Output Phosphor Diameter = 1” Flux Gain = 75 (usually 50) BG = FG x MG = 75 x (9/1)2 = 6075 Typical values: a few thousand to >10,000 for modern image intensifiers

    35. Fluoroscopic Noise (Quantum Mottle) Fluoroscopic image noise can only be reduced by using more x-ray photons to produce image. Accomplished in 3 ways: Increase radiation dose (bad for patient dose) Frame-averaging: creates image using a longer effective time Can cause image lag (but modern methods good) Improve Absorption Efficiency of the input phosphor

    36. Cesium Iodide (CsI) Phosphor The column shaped Helps to direct the Light with Less blurring

    37. Intensifier Format and Modes

    39. Units of measurement INPUT PHOSPHOR – IS MEASURED IN _________________________________ OUTPUT PHOSPHOR IS MEASURED IN ______________________________

    40. Units of measurement INPUT PHOSPHOR – IS MEASURED IN Milliroentgens mR OUTPUT PHOSPHOR IS MEASURED IN CANDELAS (LIGHT) VIEWBOXES ARE MEASURED IN: lamberts (light)

    41. MAG MODE VS PT DOSE MAG USED TO ENLARGE SMALL STRUCTURE OR TO PENETRATE THROUGH LARGER PARTS PATIENT DOSE IS INCREASED IN THE MAG MODE – DEPENDANT ON SIZE OF INPUT PHOSPHOR

    42. MAG MODE FORMULA IP OLD SIZE IP NEW SIZE = %mag

    43. PT dose in MAG MODE IP OLD SIZE 2 IP NEW SIZE 2 = ? pt dose

    44. Minification gain - again BG = MINIFICATION GAIN X FLUX GAIN MINIFICATION GAIN – same # e at input condensed to output phosphor – ratio of surface area on input screen over surface area of output screen IP SIZE 2 OP SIZE 2

    45. ABC Automatic brightness control allows Radiologist to select brightness level on screen by ? kVp or ? mAs Automatic dose control Located just beyond the Output Phosphor Will adjust according to pt thickness

    46. Brightness Control Automatic brightness stabilization Automatic adjustments made to exposure factors by equipment Automatic gain control Amplifies video signal rather than adjusting exposure factors

    47. Automatic Brightness Control Monitoring Image Brightness Photocell viewing (portion of) output phosphor TV signal (voltage proportional to brightness) Brightness Control: Generator feedback loop kVp variable mA variable/kV override kV+mA variable Pulse width variable (cine and pulsed fluoro) less dose with pulsed vs continous fluoro

    48. Fluoroscopic Dose Rates

    49. Intensifier Format and Mag Modes

    50. Image Quality Contrast Resolution Distortion Quantum mottle

    51. Contrast Controlled by amplitude of video signal Affected by: Scattered ionizing radiation Penumbral light scatter

    52. Resolution Video viewing Limited by 525 line raster pattern of monitor Newer digital monitors 1024 - better resolution

    53. Size Distortion Affected by same parameters as static radiography Primarily OID Can be combated by bringing image intensifier as close to patient as possible

    54. Shape Distortion Geometric problems in shape of input screen Concave shape helps reduce shape distortion, but does not remove it all Vignetting or pin cushion effect

    55. Image distortion

    56. Quantum Mottle Blotchy, grainy appearance Caused by too little exposure Most commonly remedied by increasing mA

    57. Beam splitting mirror Often a beam splitting mirror is interposed between the two lenses. The purpose of this mirror is to reflect part of the light produced by the image intensifier onto a 100 mm camera or cine camera. Typically, the mirror will reflect 90% of the incident light and transmit 10% onto the television camera.

    58. Viewing Fluoroscopic Images

    59. Recording the Fluoroscopic Image STATIC IMAGES Cassettes 105 mm chip film = 12 frames per second Digital fluoroscopy DYNAMIC VIEWING: Cine film Videotape

    60. TV camera connections several ways to connect the TV camera to the II. fiber optics bundle to allow light off the output phosphor to go to the TV camera – OLD UNITS - only recording device was??? lens coupling device that allows the light from the output phosphor to be split by a mirror so that a portion is sent to the TV camera and a portion is sent to the film camera.

    61. IMAGE RECORDING OLD II - ONLY FIBER OPTICS –NO LENS SPLITTER TO OTHER RECORDING DEVICES ONLY RECORED IMAGE ON SPOT CASSETTES (9X9 ONLY) NEWER - TAKES CASSETTES /105 PHOTOSPOT / VIDEO/ CINE

    62. Recording the Fluoroscopic Image Dynamic systems Cine film systems Videotape recording Static spot filming systems

    63. Image recording Cassette loaded spot film Where is the tube? How should you put the IR into the II slot? You can format the image, 2 on 1, 4 on 1 or 1 on 1 Cassette loaded spot film increases patient dose Photo spot camera will take the image right off the output phosphor This requires less patient dose

    64. Cassettes Standard size - 9” x 9” Stored in lead-lined compartment until ready for exposure When exposure is made, mA is raised to radiographic level Multiple image formats

    66. RECORDING IMAGES OLD (Smaller) II with fiber optic ONLY RECORDING WAS CASSETTE CASSETTE “SPOT” IMAGES TAKEN DURING FLUORO PROCEDURE VERY OLD 9X9 inch cassettes Later could take up to 14 x 14 inches

    67. Cine Film Systems Movie camera intercepts image 16 mm and 35 mm formats Record series of static exposures at high speed 30 – 60 frames per second Offer increased resolution At the cost of increased patient dose

    68. Fluoroscopy mA Low, continuous exposures .05 – 5 ma (usually ave 1 – 2 ma) Radiographic Exposure (for cassette spot films) mA increased to 100 – 200 mA

    69. CASSETTE SPOT FILMING vs PHOTOSPOT FILMING First type of recording used 9x9 cassettes then later up to 14x 14 9 on 1, 4 on 1, 2 on 1 Delay while filming (anatomy still moving) Radiographic mA - must boost up to 100 – 200 mA for filming And moving cassettes around inside tower Higher patient dose Replaced by Photospot (f/sec) filming

    70. CASSETTE SPOT FILMING vs PHOTOSPOT FILMING Photospot (f/sec) filming – Set at control panel from 1 f/sec – 12 f/sec Used for rapid sequence: Upper Esophogram Voiding Cystourethrograms (Peds) Lower patient dose

    73. RECORDING DEVICES RESOLUTION P 542 (3rd ed) OPTICAL MIRROR – BEST BUT NOT PERMANENT RECORDING MEDIUM SPOT FILM CASSETTES 6LP/MM PHOTO SPOT 105 / 70 CINE 35 MM / 16 MM DIGITAL (?) (VS FILM) VIDEO – VIEWING REALTIME VIDEO TAPE - PLAYBACK

    75. Other Recording From II - Light is split by lenses Beam splitter – is a partially reflective mirror. It allows about 80-90% is transmitted to the camera tube Remaining light directed to recording systems: ex: Cine

    78. Cinefluorgraphy aka CINE 35 or 16 mm roll film (movie film) 35 mm ? patient dose / 16 mm – higher quality images produced 30 f/sec in US – (60 frames / sec) THIS MODALITY = HIGHEST PATIENT DOSE (10X greater than fluoro) (VS SINGLE EX DOSE IS ?)

    79. Framing frequency Number of frames per second Cine – division of 60 (7.5, 15,30,90,120) Organ if interest determines f/s rate Patient exposu

    80. OVERFRAMING vs Exact Framing

    81. Monitoring The output phosphor of the II is connected directly to a TV camera tube when the viewing is done through a television monitor. The most commonly used camera tube - vidicon Inside the glass envelope that surrounds the TV camera tube is a cathode, an electron gun, grids and a target. Past the target is a signal plate that sends the signal from the camera tube to the external video device

    82. VIDEO/CAMERA TUBE PLUMICON, VIDICON, ORTHOCON, CCD’s TRANSFERS IMAGE FROM OUTPUT PHOSPHOR TO TV MONITOR CONNECTED BY FIBER OPTICS or Optical Lens VIDICON- MOST COMMOM PLUMICON – BETTER RESOLUTION CCD – Charged Coupling Devices ORTHOCON – VERY $$$$

    83. VIDEO/CAMERA TUBE VIDICON MOST COMMOM – good resolution with moderate lag – ok for organs Uses ANTIMONY TRISULFATE PLUMICON (a modification of Vidicon) – BETTER RESOLUTION / (? dose) Better for moving part like the heart –faster response time High performance, lag may improve, but ?quantum mottle Uses LEAD OZIDE ORTHOCON – VERY $$$$ - Larger (Not used) BEST RESOLUTION WITH NO LAG Functions as both II and pick up tube CCD – smaller & longer life, very little image lag

    84. Type of TV camera VIDICON TV camera – most commonly used in diagnostic improvement of contrast improvement of signal to noise ratio high image lag PLUMBICON TV camera (suitable for cardiology) lower image lag (follow up of organ motions) higher quantum noise level ??LOWER PT DOSE than Vidicon – but more Quantum M. CCD TV camera (digital fluoroscopy) digital fluoroscopy spot films are limited in resolution, since they depend on the TV camera (no better than about 2 lp/mm) for a 1000 line TV system

    85. TV camera and video signal (II) Older fluoroscopy equipment will have a television system using a camera tube. The camera tube has a glass envelope containing a thin conductive layer coated onto the inside surface of the glass envelope. In a PLUMBICON tube, this material is made out of lead oxide, whereas antimony trisulphide is used in a VIDICON tube.

    86. Vidicon (tube) TV Camera

    88. camera tube have a diameter of approximately 1 inch and a length of 6 inches.

    89. Vidicon Target Assembly

    90. Viewing Systems Video camera charge-coupled device (CCD) Video monitor Digital

    91. Video Viewing System Closed circuit television Video camera coupled to output screen and monitor Video cameras Vidicon or Plumbicon tube CCD

    93. Video Field Interlacing

    94. TV Monitor

    95. TV MONITOR CRT – Cathode Ray Tube Much larger than camera tube – but similar function The electrons are synchronized by the control unit – so they are of the same intensity and location as the electrons generated by the pick up (camera) tube.

    96. Different types of scanning

    97. Synchronization (Sync Signals)

    98. TV RESOLUTION-Vertical Conventional TV: 525 TV lines to represent entire image. Example: 9” intensifier (9” FOV) 9” = 229 mm 525 TV lines/229 mm = 2.3 lines/mm Need 2 TV lines per test pattern line-pair (2.3 lines/mm) /2 lines/line-pair = 1.15 lp/mm Actual resolution less because test pattern bars don’t line up with TV lines. Effective resolution obtained by applying a Kell Factor of 0.7. Example: 1.15 x 0.7 Kell Factor = 0.8 lp/mm

    99. KELL FACTOR VERTICAL RESOLUTION ABILITY TO RESOLVE OBJECTS SPACED APART IN A VERTICAL DIRECTION MORE DOTS(GLOBULES) = MORE SCAN LINES = MORE/BETTER RESOLUTION RATIO OF VERTICAL RESOLUITON # OF SCAN LINES KELL FACTOR FOR 525 LINE SYSTEM IS 0.7

    100. TV RESOLUTION-Horizontal Along a TV line, resolution is limited by how fast the camera electronic signal and monitor’s electron beam intensity can change from minimum to maximum. This is bandwidth. For similar horiz and vertical resolution, need 525 changes (262 full cycles) per line. Example (at 30 frames/second): 262 cycles/line x 525 lines/frame x 30 frames/second = 4.2 million cycles/second or 4.2 Megahertz (MHz)

    101. TV SYSTEMS Images are displayed on the monitor as individual frames – which tricks the eye into thinking the image is in motion (motion integration) 15 f/sec – eye can still see previous image Weakest Link - 2 lp /mm resolution Real Time

    103. Digital Fluoroscopy Use CCD to generate electronic signal Signal is sent to ADC Allows for post processing and electronic storage and distribution

    105. Video Camera Charged Coupled Devices (CCD) Operate at lower voltages than video tubes More durable than video tubes Semiconducting device Emits electrons in proportion to amount of light striking photoelectric cathode Fast discharge eliminates lag

    106. Newer Digital Fluoroscopy Image intensifier output screen coupled to TFTs TFT photodiodes are connected to each pixel element Resolution limited in favor of radiation exposure concerns

    107. DIGITAL Fluoro System

    108. DIGITAL FLUORO

    109. ADC – ANALOG TO DIGITAL CONVERTER TAKE THE ANALOG ELECTRIC SIGNAL CHANGES IT TO A DIGITAL SIGNAL TO MONITOR – BETTER RESOLUTION WITH DIGITAL UNITS

    112. DSA & POSTPROCESSING

    113. Fluro & Rad Protecion

    114. Regulatory Requirements 1. Regarding the operation of fluoroscopy units 2. Regarding personnel protection 3. Regarding patient protection shielding for image intensifier cumulative timer dead-man switch shielding for image intensifier cumulative timer dead-man switch

    115. Fluoroscopic Positioning Previewing Radiographers are trained in positioning Unnecessary radiation exposure to patient is unethical Fluoroscopic equipment should not be used to preview patient’s position

    116. Patient Protection Tabletop exposure rate Maximum 10 R/min Typically 1 – 3 R/min Some books ave is 4 R/min **

    117. Patient Protection Minimum source-to-skin distance 12” for mobile equipment 15” for stationary systems Audible alarm at 5 mins. Same rules for collimation

    118. Patient Protection Typical exposure rates Cinefluorography 7.2 R/min Cassettes 30 mR/exposure 105 mm film 10 mR/exposure

    119. Protection of Radiographer and Radiologist Single step away from the table decreases exposure exponentially Bucky slot cover Lead rubber drape Radiologist as shielding

    120. Protection of Others Radiographer’s responsibility to inform others in the room to wear lead apron Do not initiate fluoroscopy until all persons have complied

    121. PUBLIC EXPOSURE 10 % OF OCCUPATIONAL NON MEDICAL EXPOSURE .5 RAD OR 500 MRAD UNDER AGE 18 AND STUDENT .1 rem 1 mSv

    122. COLLIMATION (X-RAY TUBE) The PATIENT’S SKIN SURFACE SHOULD NOT BE CLOSER THAN ___________ CM BELOW THE COLLIMATOR? ____________ INCHES?

    123. Protection Lots to remember in the summer, for right now: Tube in never closer to the patient than 15” in stationary tubes and 12” with a C arm As II moves away from the patient the tube is being brought closer Bucky tray is connected to a lead shield called the Bucky slot cover. It must be 0.25 mm Pb There should be a protective apron of at least 0.25 mm Pb that hangs down from the II Every machine is required to have an audible timer that signals 5 minutes of fluoroscopy time Exposure switch must be a “dead man” type

    124. Regulations about the operation Fluoroscopic tubes operate at currents that range from0.5 to 5 mA with 3 the most common AEC rate controls: equipment built after 1974 with AEC shall not expose in excess of 10 R/min; equipment after 1974 without AEC shall not expose in excess of 5 R/min

    125. Other regulations Must have a dead man switch Must have audible 5 min. exposure timer Must have an interlock to prevent exposure without II in place Tube potential must be tested (monitored)weekly Brightness/contrast must be tested annually Beam alignment and resolution must be tested monthly Leakage cannot exceed 100mR/hr/meter

    126. Fluoroscopy exposure rate For radiation protection purposes the fluroscopic table top exposure rate must not exceed 10 mR/min. The table top intensity should not exceed 2.2 R/min for each mA of current at 80 kVp

    127. Patient Protection A 2 minute UGI results in an exposure of approximately 5 R!! After 5 minutes of fluoro time the exposure is 10-30 R Use of pulsed fluoro is best (means no matter how long you are on pedal there is only a short burst of radiation) ESE must not be more than 5 rads/min

    128. Rad Protection Always keep the II as close to the patient as possible to decrease dose Highest patient exposure happens from the photoelectric effect (absorption) Boost control increases tube current and tube potential above normal limits Must have continuous audible warning Must have continuous manual activation

    130. ESE FOR FLUORO TLD PLACED AT SKIN ENTRACE POINT 1 – 5 R/MINUTE AVE IS 4 R/MIN INTERGRAL DOSE – 100 ERGS OF TISSUE = 1 RAD EXPOSURE OR 1 GM RAD = 100 ERGS

    131. SSD – TUBE TO SKIN DISTANCE FIXED UNITS 18” PREFERRED 15 “ MINIMUM MOBILE UNITS ( C-ARMS) 12’ MINIMUM

    132. PATIENT PROTECTION LIMIT SIZE OF BEAM BEAM ON TIME DISTANCE OF SOURCE TO SKIN PBL FILTRATION (2.5 mm Al eq) @ 70 SHEILDING SCREEN/FILM COMBO

    134. GONAD SHIELDING MUST BE . 5 MM OF LEAD MUST BE USED WHEN GONADS WILL LIE WITHING 5 CM OF THE COLLIMATED AREA (RHB) KUB. Lumbar Spine Pelvis male vs female shielding

    135. Gonad shielding & dose ? receive 3x more dose than ? for pelvic x-rays 1 mm lead will reduce exposure (primary) by about 50% ? by about 90 – 95 % ?

    136. KEEP I.I. CLOSE TO PATIENT

    137. Over vs under the table fluoro tubes

    138. Framing and patient dose syll = Pg 31 The use of the available film area to control the image as seen from the output phosphor. Underframing Exact Framing, (58 % lost film surface) Overframing,(part of image is lost) Total overframing

    139. EXPOSURE RATES FLUORO MA IS 0.5 MA TO 5 MA PER MIN AVE DOSE IS 4 R / MIN IF MACHINE OUTPUT IS 2 R/MA/MIN = WHAT IS PT DOSE AT 1.5 MA FOR 5 MIN STUDY? 15R

    140. EXPOSURE RATES FOR FLUORO CURRENT STANDARD 10 R/MIN (INTENSIFIED UNITS) HLC: BOOST MODE 20 R/MIN OLD (1974) NO ABC NON IMAGE INTES 5 R/MIN

    141. DOSE REGULATIONS BEFORE 1974 - AT TABLETOP 5R/MIN (WITHOUT AEC) 5R/MIN (WITHOUT AEC) – BOOST MODE After 1974 with AEC 10 R/MIN 20R/MIN BOOST

    142. RADIATION PROTECTION The Patient is the largest scattering object Lower at a 90 DEGREE ANGLE from the patient + PRIMARY BEAM AT 1 METER DISTANCE - 1/1000 OF INTENSITY PRIMARY XRAY or 0.1%

    143. BUCKY SLOT COVER .25 MM LEAD

    144. ISOEXPOSURE CURVES

    145. PERSONNEL PROTECTION SCATTER FROM THE PATIENT TABLE TOP, COLLIMATOR, TUBE HOUSING, BUCKY STRAY RADIATION – LEAKAGE OR SCATTER RADIATION

    146. TOWER CURTAIN .25 MM LEAD EQ

    147. PERSONNEL PROTECTION STANDING BEHIND A PROTECTIVE PRIMARY (1/16TH pb) BARRIER: PRIMARY RADIATION EXPOSURE – 99.87% REDUCED PORTABLE BARRIER = 99 % REDUCTION

    148. PERSONNEL PROTECTION PROTECTIVE APRONS – 0.25 PB = 97% ? TO SCATTER 0.5 PB = 99.9% ? TO SCATTER THYROID SHEILDS (0.25 & 0.5) GLOVES (0.25 & 0.5)

    149. PERSONNEL PROTECTION MONITORING FILM BADGE TLD POSL POCKET DOSIMETER RING BADGE

    150. PERSONNEL PROTECTION MONITORING DOSE LIMITS WHOLE BODY EYES EXTREMITIES (BELOW ELBOW/KNEES)

    152. Report at least every quarter Preserved for a minimum of 3 years

    153. RHB NOTIFICATION (EXP IN 24 HOURS) (RP Syllabus – pg 68) IMMEDIATE reporting – WITHIN 24 HOURS TOTAL DOSE OF 25 rems Eye dose – 75 rem Extremity – 250 RADS OVEREXPOSURE – received w/in 24 hrs Must be ReportedWITHIN 30 DAYS TOTAL DOSE OF 5 rems Eye dose – 15 rem Extremity - 50 REMS

    154. LICENSE RENEWAL WITHIN 30 DAYS OF EXPRIATION NOTIFICATION OF CHANGE OF ADDRESS

    155. 100 mRem ( 0.1 rem / (1 msV) @ 30 cm from the source of radiaton RADIAITON AREA – RHB: 5 mRem ( 0.005 rem / (.05 msV) @ 30 cm from the source of radiation PUBLIC 2 mrem per week* (STAT) HIGH RADIAITON AREA –

    156. A “controlled area” is defined as one that is occupied by people trained in radiologic safety that is occupied by people who wear radiation monitors whose occupancy factor is 1

    157. RHB “RULES” RHB RP PG61 LICENTIATES OF THE HEALING ARTS (MD, DO, DC, DPM) MUST HAVE A RADIOLOGY SUPERVISOR & OPERATORS PERMIT & CERTIFICATE TO OPERATE OR SUPERVISE THE USE OF X-RAYS ON HUMANS SUPEVISORS MUST POST THEIR LICENSES

    158. RHB “RULES” RHB RP PG62 ALL XRAYS MUST BE ORDERED BY A PHYSICIAN VERBAL OR WRITTEN PRESCRIPTION See Section C – “Technologist Restrictions”

    159. Declared Pregnant Worker Must declare pregnancy – 2 badges provided 1 worn at collar (Mother’s exposure) 1 worn inside apron at waist level Under 5 rad – negligible risk Risk increases above 15 rad Recommend abortion (spontaneous) 25 rad (“Baby exposure” approx 1/1000 of ESE) www.ntc.gov/NRC/RG/08/08-013.html

    160. DOSE CINE - 2mR per frame (60f/sec) 400 mr per “look”

    161. FLUORO RAD PROTECTION REVIEW QUESTIONS

    162. If at ˝ foot from the radiation source the intensity of exposure is 240 mR per hour and you remain at this location for 10 minutes, you then moved 2 feet away from the radiation source and remained there for 20 minutes? What is your total exposure?

    163. If at ˝ foot from the radiation source the intensity of exposure is 240 mR per hour and you remain at this location for 10 minutes, you then moved 2 feet away from the radiation source and remained there for 20 minutes? What is your total exposure? 45 mR

    164. The greatest contribution of unnecessary radiation exposure to the patient comes from the x-ray operator’s failure to

    165. The greatest contribution of unnecessary radiation exposure to the patient comes from the x-ray operator’s failure to COLLIMATE

    166. All of the following must be posted in areas where x-ray production machines are utilized except: each x-ray supervisor and operator permit each certified radiologic technologist certificate and technologist fluoroscopy permit Radiologic Health Department Form RH-2364, “Notice to Employee” each physician’s license for the healing arts

    167. All of the following must be posted in areas where x-ray production machines are utilized except: each physician’s license for the healing arts

    168. During a 2 minute (fluoroscopy exposure time) routine upper GI series examination; a typical x-ray exposure to the patient is:

    169. During a 2 minute (fluoroscopy exposure time) routine upper GI series examination; a typical x-ray exposure to the patient is: 5 – 8 R (ave 4 R/ min)

    170. For a fluoroscopic system equipped with and automatic brightness control (automatic exposure control) mechanism and where the x-ray tube is fixed below the table, moving the image intensifier way from the patient will:

    171. For a fluoroscopic system equipped with and automatic brightness control (automatic exposure control) mechanism and where the x-ray tube is fixed below the table, moving the image intensifier way from the patient will: INCREASE EXPOSURE

    172. If at one foot from the radiation source the intensity of exposure is 240(mR) per hour And you remain at this location for 10 minutes you will receive and exposure of ______? What dose if you remained there for 20 minutes?

    173. If at one foot from the radiation source theintensity of exposure is 240(mR) per hour And you remain at this location for 10 minutes you will receive and exposure of ______? What dose if you remained there for 20 minutes? 40(mR) 80 mR

    174. When the target to panel (tube to patient) distance is increased from 12 to 18 inches the ESE to patient is approximately: a. Increased by 45 % c. Decreased by 100 % b. Increased by 25 % d. Decreased by 45%

    175. When the target to panel (tube to patient) distance is increased from 12 to 18 inches the ESE to patient is approximately: Decreased by 45%

    176. At 1 foot from a source the output intensity is 300 mR/hr and you were there for 20 minutes. What is the intensity total if you moved 2 feet away and remained for an additional 40 minutes? __________________ ?

    177. At 1 foot from a source the output intensity is 300 mR/hr and you were there for 20 minutes. What is the intensity total if you moved 2 feet away and remained for an additional 40 minutes? 150 mr

    178. Fluoro equipment made after 1974 with AEC shall not produce an exposure rate to the patient in excess of : a. 1 R/ min c. 5 R/min b. 10 R/min d. 20 R/min

    179. Fluoro equipment made after 1974 with AEC shall not produce an exposure rate to the patient in excess of : 10 R/min - regular mode 20 R/min - boost (mag) mode

    180. Kilovolt peak (kvp) the intensity of the x-ray beam at table top should not exceed how many roentgens per minute for each milliampere (ma) of current? 0.2 roentgens per minute 1.0 roentgens per minute 2.2 roentgens per minute 5.0 roentgens per minute

    181. Kilovolt peak (kvp) the intensity of the x-ray beam at table top should not exceed how many roentgens per minute for each milliampere (ma) of current? 2.2 roentgens per minute

    182. The NCRP states that: the risk (to the embryo/fetus) is considered to be negligible at 5 rads or less when compared to the other risks of pregnancy , and the risk of malformation is significantly increased above control levels only at doses above how many rads: a. 7 b.10 c.15 d. 25

    183. The NCRP states that: the risk (to the embryo/fetus) is considered to be negligible at 5 rads or less when compared to the other risks of pregnancy ,and the risk of malformation is significantly increased above control levels only at doses above how many rads: 15 rads RHB (Stat 10 -20 50 rads = spontaneous abortion

    184. A “high radiation” area is any area , accessible to individuals, in which there exists radiation at such levels that an individual could receive in any one hour a dose to the whole body in excess of how many millirems ? a.5 b. 10 c. 50 d. 100

    185. A “high radiation” area is any area , accessible to individuals, in which there exists radiation at such levels that an individual could receive in any one hour a dose to the whole body in excess of how many millirems ? 100

    186. The exposure rate to a tech at 4 feet from the source is 240 m R/hr. What distance would be necessary to reduced the rate below 60 mR/hr? A. 1 foot B. 6 feet C. 2 feet D. 9 feet

    187. The exposure rate to a tech at 4 feet from the source is 240 m R/hr. What distance would be necessary to reduced the rate below 60 mR/hr? 9 feet

    188. If 85 kvp, 400ma 0.12s = 150mR - what is the mr/mas? A. 0.32 B. 3.1 C. 33.1 D. 17.6

    189. If 85 kvp, 400ma 0.12s = 150mR - what is the mr/mas? 3.125

    190. Each time an x-ray beam scatters, its intensity at 1 meter from the scattering object is what fraction of its original intensity? A. 1/10 B. 1/100 C. 1/500 D. 1/1000

    191. Each time an x-ray beam scatters, its intensity at 1 meter from the scattering object is what fraction of its original intensity? 1/1000 or .1%

    192. Which of the following gives the least patient exposure? a. mirror optical system b. vidicon TV camera c plumicon TV camera d. image orthicon

    193. Which of the following gives the least patient exposure? PLUMBICON TV camera

    194. During a CINE exam in which 35 mm film and a frame rate of 30 frames per second are utilized, what is the approximate skin exposure in roentgens/minutes? a. 1 (given 2mr/frame) b. 2 – 5 c. 5 – 10 d. over 10

    195. During a CINE exam in which 35 mm film and a frame rate of 30 frames per second are utilized, what is the approximate skin exposure in roentgens/minute? (given 2mr/frame) 2 – 5 R 30f x 60 sec = 1800 f x 2 mr = 3600 mr 3.6R

    196. FLUOROSCOPY REVIEW RT 255

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