1. Fluoroscopy Intro to EQUIPMENT
RT 244
FALL
Week 1
Wed- CONTINUED
Ref: Fluoroscopy – Bushong’s Ch. 24

2. Basic Componets of “old” Fluoroscopy “Imaging Chain”
Primary
Radiation
EXIT Radiation
Fluoro TUBE
PATIENT
105 Photospot
Fiber Optics OR
Image Intensifier
ABC
LENS
SPLIT
Cassette
Image Recording Devices
CINE
CONTROL
UNIT
VIDICON
Camera Tube TV

3. Conventional I I system

4. IMAGE INTENSIFIER

5. 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 5

6. Anode and Output Screen
Positively charged
25 kVp
Hole in center allows electrons to pass through to output screen
OUTPUT SCREEN
Usually 1 inch in diameter
Zinc cadnium sulfide coating
Changes electrons back to LIGHT

7. Image Intensifier PROPERTIES Image Quality
Contrast
Resolution
Distortion
Quantum mottle

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

9. reduce contrast of an image intensifier tube.
Veiling glare
Scatter in the form of x-rays, light & electrons can
reduce contrast of an image intensifier tube.

10. Resolution Video viewing Limited by 525 line raster pattern of monitor
Newer digital monitors better resolution
MORE ON THIS LATER IN THE LECTURE

11. Image distortion
PINCUSHION EFFECT

12. 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
Vignetting
FALL-OFF OF BRIGHTNESS AT PERIPHERY (EDGES) OF THE IMAGE

13. VIGNETTING…….
Darkness on edges (falloff of brightness)

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

15. ABC

16. Basic Componets of “old” Fluoroscopy “Imaging Chain”
Primary
Radiation
EXIT Radiation
Fluoro TUBE
PATIENT
105 Photospot
Fiber Optics OR
Image Intensifier
ABC
LENS
SPLIT
Cassette
Image Recording Devices
CINE
CONTROL
UNIT
VIDICON
Camera Tube TV

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

18. 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 - IMAGE LAG

19. 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

20. 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)

21. Quantum Mottle Blotchy, grainy appearance
Caused by too little exposure
Most commonly remedied by increasing Ma
Controlled by the ABC
Affected by too little technique
size of patient
distance of II to patient
size of collimation

22. 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

23. KEEP I.I. CLOSE TO PATIENT reduces beam on time

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

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

27. Fluoroscopic Imaging

28. Coupling I.I. to TV Monitor
2 Methods:
Fiber optics directly to T.V. camera.
Lens system which utilizes auxiliary imaging devices.

30. Directly to T.V.
Only cassettes can be used.

31. Beam splitting mirror

32. Basic Componets of “old” Fluoroscopy “Imaging Chain”
Primary
Radiation
EXIT Radiation
Fluoro TUBE
PATIENT
105 Photospot
Fiber Optics OR
Image Intensifier
ABC
LENS
SPLIT
Cassette
Image Recording Devices
CINE
CONTROL
UNIT
VIDICON
Camera Tube TV

34. 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 to other RECORDING DEVICES
and transmit 10% onto the television camera*.
*TV MONITOR is the weakest link (low resolution)

35. Viewing Fluoroscopic Images

37. Lenses / Mirrors Used to direct image to recording devices
Several mirrors in a series and angled - the last mirror is outside the II for the operator to view
Image decreases as it is projected from 1 mirror to the next
Only 1 person can view image

38. STATIC IMAGES DYNAMIC IMAGES
RECORDING THE IMAGE
STATIC IMAGES
DYNAMIC IMAGES

39. Basic Componets of “old” Fluoroscopy “Imaging Chain”
Primary
Radiation
EXIT Radiation
Fluoro TUBE
PATIENT
105 Photospot
Fiber Optics OR
Image Intensifier
ABC
LENS
SPLIT
Cassette
Image Recording Devices
CINE
CONTROL
UNIT
VIDICON
Camera Tube TV

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

41. Recording Fluoroscopic Images

42. 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 or uses /105 PHOTOSPOT / VIDEO/ CINE
NEWEST = USES DIGITAL !!!!!!!!!
(but the tests* still have all of it!)

43. Basic Componets of “old” Fluoroscopy “Imaging Chain”
Primary
Radiation
EXIT Radiation
Fluoro TUBE
PATIENT
105 Photospot
Image Intensifier
Fiber Optics
ABC
LENS
SPLIT
Cassette
Image Recording Devices
CINE
CONTROL
UNIT
VIDICON
Camera Tube TV

44. Radiographic Exposure for cassette spot films
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

45. 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

46. Cassettes Standard size - 9” x 9” (old) NOW CAN TAKE UP TO 14X14
Stored in lead-lined compartment until ready for exposure
When exposure is made, mA is raised to radiographic level
Multiple image formats

49. 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 49

51. Basic Componets of “old” Fluoroscopy “Imaging Chain”
Primary
Radiation
EXIT Radiation
Fluoro TUBE
PATIENT
105 Photospot
Fiber Optics OR
Image Intensifier
ABC
LENS
SPLIT
Cassette
Image Recording Devices
CINE
CONTROL
UNIT
VIDICON
Camera Tube TV

53. 70 & 105 PHOTOSPOT (CAMERA)
Photo spot camera will take the image right off the output phosphor
This requires less patient dose
70 & 105 mm roll film

54. 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

56. 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

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

58. TV camera and video signal & Recording the image
The output phosphor of the image intensifier is optically coupled to a television camera system.
Beam splitter – is a partially reflective mirror.
A pair of lenses focuses the output image onto the input surface of the television camera.
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 105 mm PHOTOSPOT camera or cine camera.

59. GENERAL SCHEME OF FLUOROSCOPY
VIDICON
FILM PM
REFERENCE kV
CONTROLLER
X Ray TUBE
GENERAL SCHEME OF FLUOROSCOPY
CINE - USED FOR CARDIAC CATH

60. 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

61. 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 ↓)

62. Cine
Cinefluorography is used most often in cardiology and neuroradiology.
The procedure uses a movie camera to record the image from the image intensifier.
These units cause the greatest patient doses of all diagnostic radiographic procedures, although they provide very high image quality.
The high patient dose results from the length of the procedure and relatively high inherent dose rate.
For this reason special care must be taken to ensure that patients are exposed at minimum acceptable levels.
Patient exposure can be minimized in a number of ways. The most obvious means of limiting exposure is to limit the time the beam is on.
CINE - 2mR per frame (60f/sec)
400 mr per “look”

63. More on Cine Synchronization Framing frequency
F-number of the optical system
Framing and patient dose

64. Synchronization
Camera shutters and x-ray pulsed fluoro happen at the same time
Only exposes pt when shutter is open to record image
Patient radiation dose ↑ as #/f/sec ↑
(filming a TV show – pattern seen)

65. F-number of the optical system
Speed of any given camera system
The amount of light made available to the lens

66. 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

67. OVERFRAMING vs Exact Framing
Also related to Radiation Safety………………

68. 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

69. More on Safety later….

70. 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

72. Line pair gauges

73. Line pair gauges
GOOD RESOLUTION POOR RESOLUTION

74. Video disc This technique is referred to as electronic radiography.
Fluoroscopic radiation continues only long enough to build up a useful image on the display monitor.
The image is stored as a single television frame on the video disc recorder.
There is about a 95% reduction in patient dose.

75. Video tape Utilizes VHS or high-resolution tapes.
Patient’s exposure to radiation is not increased.
Used for barium swallows.

76. Image Quality - Review Terms that are necessary to know:
Vignetting is the loss of brightness at the periphery of the II due to the concave surface
Pincushion effect is the drop off at the edges of the II due to the curved surface
Quantum mottle is the grainy appearance on the image due to statistical fluctuations
The center of the II will always have the best resolution.
Lag is the blurry image from moving the II too fast

77. OVERFRAMING vs Exact Framing

78. 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 78

79. VIDEO/CAMERA TUBE PLUMICON, VIDICON, ORTHOCON VIDICON MOST COMMOM
ORTHOCON – VERY $$$$
PLUMICON – BETTER RESOLUTION
TRANSFERS IMAGE FROM OUTPUT PHOSPHOR TO TV MONITOR
CONNECTED BY FIBER OPTICS

80. 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 $$$$

81. 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

82. Type of TV camera VIDICON TV camera
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
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

83. 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.

84. Vidicon (tube) TV Camera

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

88. Parts of the camera tube
Glass envelope
Electron gun (Cathode)
Control grid
Electrostatic grids
Target

89. Camera Tube steps Light is received by the camera tube.
The light from the II is received at the face plate of the target assembly.
Electrons are formed into an electron beam (by the control grid) at the electron gun.
Electrons are burned off by thermionic emission then focused and accelerated to the target. (made of antimony trisulfide)

90. Target of the Camera Tube

91. The electrons scan the signal plate similar to reading a page.
Starting in the upper left across to the right, then back to the left to right.
This is called an active trace.
The movement of the electron beam produces a RASTER pattern.
The same pattern occurs in the TV monitor.

92. The signal plate sends the electrical video signal to the control unit which amplifies the signal and synchronizes the pulses between the camera tube and the TV monitor.
This synchronization

93. Vidicon Target Assembly

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

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

96. Synchronization (Sync Signals)

97. TV camera and video signal (V)
On most fluoroscopy units, the resolution of the system is governed by the number of lines of the television system.
Thus, it is possible to improve the high contrast resolution by increasing the number of television lines.
Some systems have 1,000 lines and prototype systems with 2,000 lines are being developed.

98. TV Monitor

99. 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.

100. TV Monitor
The TV monitor contains the picture tube called cathode ray tube (CRT).
It works like the camera tube.
With an electron gun and control grids the electron beam is fired toward the anode.
The TV screen contains small fluorescent crystals

101. Video Field Interlacing

102. Different types of scanning11 1
INTERLACED
SCANNING 13 12 3 2 15 14 5
625 lines in 40 ms
i.e. : 25 frames/s 4 17 16 7 6 19 18 9 8 21 20 10 1 2 3 4 5 6 7
PROGRESSIVE
SCANNING 8 9 10 11 12 13 14 15 16 17 18

103. Line pair gauges GOOD RESOLUTION POOR RESOLUTION
6 LP/MM AT SPOT CASSETTE LP/MM AT TV

104. Two fields = a frame (525 lines)
It take 1/30 of a second.
To prevent flicker, two fields are interlaced to form on television frame.
There are 60 fields and 30 frames per second.
The eye cannot detect flickering above 20 frames/sec.

106. RASTER Pattern
The electron beam moves in the same raster pattern as in the camera tube.
The signal consists of many individual pulses corresponding to the individual location on the camera tube target.
The varying voltage pulses are later reassembled into a visible in by the TV monitor.

107. 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

108. Kell Factor
The ability to resolve objects spaced apart in a vertical direction.
More dots = more scan lines = more/better resolution
Kell factor for 525 line system is 0.7

109. KELL FACTOR VERTICAL RESOLUTION RATIO OF VERTICAL RESOLUITON
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

110. 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)

111. Bandpass/Horizantal Resolution
Horizontal resolution is determined by the bandpass.
Bandpass is expressed in frequency (Hz) and describes the number of times per second the electron beam can be modulated.
The higher the bandpass, the better the resolution

112. 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

114. Final Image
The result of hundreds of thousands of tiny dots of varying degrees of brightness.
These dots are arranged in a specific patterns along horizontal scan lines.
Usually 525 scan lines.
The electron gun within the picture tube scans from top to bottom in 1/60 of a second, (262 1/2 lines) called a field.

117. TABLE MOVEMENT horizonatal to upright ~ 30 sec

118. End of Week 1 Day 2

119. Digital Fluoro

120. DIGITAL FLUORO

122. DIGITAL Fluoro System

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

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

125. 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

126. CCD’s

127. Modern Digital Fluoro System under table tubes

128. Remote – over the table tube

129. Remote – over the table tube

130. 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

131. Digital – CCD using cesium iodide
Exit x-rays interact with CsI scintillation phosphor to produce light
The light interact with the a-Si to produce a signal
The TFT stores the signal until readout, one pixel at a time

132. CsI phosphor light detected by the AMA of silicon photodiodes

135. Digital Uses Progressive Scan
1024 x 1024
Higher spatial resolution
As compared to 525
8 images/sec
(compared to 30 in 525 system)

136. DSA & POSTPROCESSING

137. DSA

139. Mobile C-arm Fluoroscopy

141. Fluoro & Rad Protection INTRO RHB

142. 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

143. 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

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

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

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

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

148. 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

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

150. COLLIMATION The PATIENT’S SKIN SURFACE SHOULD NOT BE CLOSER THAN
___________ CM BELOW THE COLLIMATOR?
____________ INCHES?
15 cm / 6.5 inches

151. 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
151

152. 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

153. 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

154. 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

155. Patient Protection
A 2 minute UGI results in an exposure of approximately 5 R!!
After 5 minutes of fluoro time the exposure is 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

156. 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

158. 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

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

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

162. 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

163. ♀ receive 3x more dose than ♂ for pelvic x-rays
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 % ♂

165. KEEP I.I. CLOSE TO PATIENT

166. Over vs under the table fluoro tubes

167. 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

168. 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

169. 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

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

171. 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%

172. BUCKY SLOT COVER
.25 MM LEAD

173. Bucky Slot Cover

174. ISOEXPOSURE CURVES

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

176. TOWER CURTAIN
.25 MM LEAD EQ

177. Lead curtain & dose reduction

178. Pulsed Fluoro
Some fluoroscopic equipment is designed for pulsed-mode operation. With the pulsed mode, it can be set to produce less than the conventional 25 or 30 images per second. This reduces the exposure rate.
Collimation of the X ray beam to the smallest practical size and keeping the distance between the patient and image receptor as short as possible contribute to good exposure management.

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

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

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

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

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

186. 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 REMS

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

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

189. 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

190. 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

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

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

193. 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)

194. FLUOROSCOPY End of wk 1 RT 244 2008