11/24/2013 CR kv V CR kv V DR D kv k DR D kv k DR D kv k DR D kv k 2

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1 Mastering Digital Radiography: CR and DR Exposures, Techniques and Doses The following slides show a hand phantom exposed from 50 to 100 kv to demonstrate the minute differences visualized on an image using higher kv and lower mas with both CR and DR. Dennis Bowman RT(R) Clinical Instructor/Staff Radiographer Community Hospital of the Monterey Peninsula (CHOMP) Cabrillo College Speaker/Consultant Digital Radiography Solutions (drs drs) CR 50 kv CR 60 kv CR 70 kv CR 80 kv 1

2 CR 90 kv CR 100 kv DR 50 kv DR 60 kv DR 70 kv DR 80 kv 2

3 DR 90 kv DR 100 kv Barry Burns the CR guru Barry Burns MS, RT(R), DABR Retired adjunct Professor of Radiologic Science, University of North Carolina School of Medicine in Chapel Hill, North Carolina, stipulated that when using CR everyone can increase kv from film/screen techniques (except Konica which is 5 10 kv). These are the new digital Optimum kvs as developed by Barry Burns DIGITAL OPTIMUM kv Body Part - Adult kv Chest (Bucky/Grid) Chest (Non-Grid) (105) Abdomen Extremities (Non-Grid) Extremities (Grid) Extremities (Bucky) AP Spines C-Spine Lateral T-Spine Lateral L-Spine Lateral Ribs Skull BE (Air Con) Abdomen (Iodine) Pediatric: Infant Extremities Pediatric Chest (Screen) Universal CR Technique Chart using 100% More mas UNIVERSAL CR TECHNIQUE CHART 100% More mas Part View Small Medium Large mas kv mas kv mas kv Abdomen AP (Grid) Ankle AP Ankle Obl Ankle Lat Chest -Adult AP (tt - 72") Chest -Adult Lat (tt - 72") Chest - Baby PA (72") Chest - Baby L at (72") Chest - Newborn AP (40") Chest - Newborn L at (40") C-Spine AP (Bucky - 72" ) C-Spine AP (Bucky - 40" ) C-Spine Odontoid (72") C-Spine Odon toid (40") C-Spine Lat (Bucky - 72") C-Spine Swimmers (40" ) C-Spine Trauma Obl. ( tt ) C-Spine AP (tt - 40") C-Spine Lat (tt - 72") Elbow AP Elbow Obl Elbow Lat Femur - Distal Lateral ( tt ) Fin ger All Views Foot AP Foot Obl Foot Lat Forearm AP Forearm Lat H and PA H and Obl H and Lat Size of the Patient The techniques are of a small, medium and large male Small = lbs. Medium = lbs. Large = lbs. Females would be approximately 10 lbs. lighter. 3

4 Page 2 Universal CR Technique Chart using 100% More mas UNIVERSAL CR TECHNIQUE CHART 100% More mas Hip AP ( tt ) Hip X-Table Lat (Grid) Humerus AP Knee AP (Bucky) Knee Obl (Bucky) Knee Lat (Bucky) Knee Sunrise ( tt ) Knee Non-Bucky L-Spine AP L-Spine X-Table Lat (Grid) Mandible Obl (40") Pelvis AP (Grid) Ribs Upper (72") Ribs Lower (40") Ribs Obl (72") Shoulder AP Shoulder Mercedes Shoulder Axillary Sinus Caldwell Sinus Waters Sinus Lateral Skull AP Skull Lat (Grid) Tib-Fib AP Tib-Fib Lat Toe All Views T-Spine AP T-Spine Lat (2 sec) Wrist PA Wrist Obl Wrist Lat Zygomatic Arch SMV view (tt - 30") If you have never seen these kind of techniques before They will be hard to believe and scary. Exposure Index numbers Dose Exposure, Exposure Index/Indicator numbers. (S, LgM, EI, EI_s, ReX, EXI, DEI) are how you tell if your technique was correct. The Exposure Index EI (what we will call it from now on) number is best if the centering and collimation are very good. EI ranges and corrupted numbers The concept of Agfa s CR LgM range, Fuji s CR S range, GE s (DR) range and Siemens DR range. Even with the range you should always be shooting for the best number in that range (which means the lowest dose). These EI numbers are easily corrupted (but only up to 100% in most cases). Lead shields or surgically implanted metal can definitely skew the EI #. Collimated fields using less than 33% of the IR. Centering, collimation and corrupting Exposure Index numbers Agfa CR Perfectly centered and collimated to 14x mas LgM is 2.04 or S# is 240 4

5 Perfectly centered now 17x mas LgM is 2.11 or S# is % change Centered 1 high mas LgM is 2.21 or S# is % change Centered 2 high mas LgM is 2.24 or S# is % change Shoulder phantom with 3 sheets of Polyethylene to make it the thickness of a large adult male. These experiments will show the difference in EXI and DEI numbers when the collimation is left more and more open. GE built in detector (DEI range ) 8 x8 DEI % change GE built in detector 9 x9 DEI % change 5

6 GE built in detector 10 x10 DEI % change GE built in detector 11 x11 DEI % change GE built in detector 12 x12 DEI % change GE built in detector 13 x13 DEI % change To summarize those 2 examples The technique always stayed the same. It was just the centering or collimation changes that corrupted the EI number. Even though the exposure index number (LgM, S and DEI) has been corrupted up to 60%, the image is still perfectly diagnostic/passable in any facility. If your EI number is above 100% over what is considered perfect it is not a corruption problem. This means you over exposed. What does mas do in the digital world? Not what it did in the film world, that s for sure!! To a large extent, mas does not really control brightness (density) any more. Brightness is almost completely controlled by processing algorithms. You just need enough mas or your image will have quantum noise or mottle. 6

7 Critiquing digital images The EI numbers are the number 1 way to critique your image. Some DR control panels do not have an EI number. You definitely need to use the magnification mode to check for noise and burn. You should always be able to Level and Window and make your image look well penetrated and contrasty. Critiquing digital images (continued) It is impossible to prove you used the correct technique if all you are using is what the finished image looks like as your gauge. Witness the awesome power of Automatic Rescaling Fuji 85 4 mas S# mas S# mas S# mas S# 6 7

8 mas S# 3 Carestream Portable Detector 85 2 mas EI mas EI mas EI mas EI mas EI

9 85 45 mas EI 2405 What are the differences between CR and DR? For all CR (except Agfa) you can use at least 50 times too much mas and have a perfectly diagnostic/passable image. For most DR you can use about 10 times too much mas. How can there be a Universal CR/DR technique chart? As we all well know, this would have been impossible in the film/screen processor days. All modern generators (25 years or newer) are high frequency and all tubes are the same on the inside. All CR/DR manufacturers set their systems up to have the perfect EI# appear when 1 mr hits the Image Receptor. Merrill s Atlas of Radiographic Positioning and Procedures In mid 2013 Bruce Long, First Author of Merrill s, hired me to create the first ever digital technique charts for the Merrill s Atlas. In it s 50+ year history they have always had film/screen techniques. In the 14 th edition which will be released in 2015, there will be almost 250 digital techniques included (half CR and half DR). Each technique will also have the ESE Dose. Is the EI range given by the vendor perfect for your facility? This hip had an LgM of The mag view shows that there is acceptable mottle. My colleague Ramiro and I discovered that we could use half the mas and still have a perfectly diagnostic image. Our rads loved the idea of cutting the radiation dose in half (though images had acceptable mottle) ) because we re an Image Gently facility. 9

10 This lateral C Spine also had an LgM of The mottle shown is also acceptable. Universal CR Technique Chart Least mas UNIVERSAL CR TECHNIQUE CHART LEAST mas Abdomen-(Most mas) AP (Grid) Ankle AP Ankle Obl Ankle Lat Chest -Adult AP (tt - 72") Chest -Adult Lat (tt - 72") Chest - Baby PA (72") Chest - Baby Lat (72") Chest - Newborn AP (40") Chest - Newborn Lat (40") C-Spine AP (Bucky - 72") C-Spine AP (Bucky - 40") C-Spine Odontoid (72") C-Spine Odontoid (40") C-Spine Lat (Bucky - 72") C-Spine Swimmers (40") C-Spine Trauma Obl. ( tt ) C-Spine AP (tt - 40") C-Spine Lat (tt - 72") Elbow AP Elbow Obl Elbow Lat Femur - Distal Lateral ( tt ) Finger All Views Foot AP Foot Obl Foot Lat Forearm AP Forearm Lat Hand PA Hand Obl Hand Lat Universal CR Technique Chart Least mas (Page 2) UNIVERSAL CR TECHNIQUE CHART LEAST mas Hip AP ( tt ) Hip X-Table Lat (Grid) Humerus AP ( tt ) Knee AP (Bucky) Knee Obl (Bucky) Knee Lat (Bucky) Knee Sunrise ( tt ) Knee Non-Bucky L-Spine AP L-Spine X-Table Lat (Grid) Mandible Obl (tt - 40") Pelvis AP (Grid) Ribs Upper (72") Ribs Lower (40") Ribs Obl (72") Shoulder AP Shoulder Mercedes Shoulder Axillary Sinus Caldwell Sinus Waters Sinus Lateral Skull AP Skull Lat (Grid) Tib-Fib AP Tib-Fib Lat Toe All Views T-Spine AP T-Spine Lat (2 sec) Wrist PA Wrist Obl Wrist Lat Zygomatic Arch SMV view (tt - 30") Differences of the Least mas to 100% More mas technique charts The Least mas chart uses the smallest mas of all the charts (least dose to patient, most chance of mottle). The 33% More mas chart uses 33% more mas/dose than the Least mas chart. The 66% More mas chart uses 66% more mas/dose than the Least mas chart. The 100% More mas chart uses 100% (double) more mas/dose than the Least mas chart. How to use these four charts Begin with the Most mas because this has the least chance of noise. If you have a diagnostic image and the EI numbers show you can use less mas, go to the 66% More mas chart. If again you have a diagnostic image and the EI numbers show you can use less mas, go to the 33% More mas chart. Finally, if you have a diagnostic image and the EI numbers show you can still drop the mas, go to the Least mas chart. This is the proof of how much dose you save your patient when you increase the kv and decrease the mas and/or decrease the EI #. Radiation Dose Saved SID kv mas Dose Radiation 50% EI Saved Decrease (mr) (%) (mas) 50% EI Dose (mr) Total Dose Reduction (%) 40" " % % 40" % % 40" % % 40" % % 10

11 How Low Can You Go? This is my version of ALARA. With the new optimum kvs already in place, it s figuring out how low can we take the mas and get an image with no, or acceptable, mottle. I m hoping that everyone will make it a competition or goal to see what is the minimum dose needed for any given view. It doesn t take any skill to overexpose. Speaking of How Low We Can Go, we now have Cesium and Gadolinium based DR detectors. CsBr (Cesium Bromide) and CsI (Cesium Iodide) Needle Phosphor detectors are high efficiency compared to standard Gadolinium based detectors. Gadolinium detectors need 33% to 50+% more exposure than Cesium to produce a similar image. Here is the CESIUM DR UNIVERSAL TECHNIQUE CHART. CESIUM DR UNIVERSAL TECHNIQUE CHART Abdomen AP (Grid) 85 4 to to Ankle AP Ankle Obl Ankle Lat Chest -Adult AP (Grid) Chest -Adult AP (Non Grid) Chest (2-9 lb) AP (Non Grid - 45") Chest (2-9 lb) Lat (Non Grid - 45") Chest (10-20 lb)pa (Non Grid - 72") Chest (10-20 lb)lat (Non Grid - 72") Chest (21-35 lb)pa (Non Grid - 72") Chest (21-35 lb)lat (Non Grid - 72") C-Spine AP (Bucky - 72") C-Spine AP (Bucky - 40") C-Spine Odontoid (72") C-Spine Odontoid (40") C-Spine Lat (Bucky - 72") C-Spine Swimmers (40") Elbow AP Elbow Obl Elbow Lat Finger All Views Foot AP Foot Obl Foot Lat Forearm AP Forearm Lat Hand PA Hand Obl Hand Lat Page 2 of the CESIUM DR UNIVERSAL TECHNIQUE CHART. CESIUM DR UNIVERSAL TECHNIQUE CHART Hip AP 85 4 to Hip X-Table Lat (Grid) Humerus AP (Non Grid) Knee AP (Bucky) Knee Lat (Bucky) Knee Sunrise Knee Non-Bucky L-Spine AP L-Spine X-Table Lat (Grid) Mandible Obl (40") Pelvis AP (Grid) Ribs Upper AP (72") Ribs Upper Obl (72") Ribs Lower AP (45") Shoulder AP (Bucky) Shoulder Mercedes Shoulder X-T Axillary (N-Grid) Sinus Caldwell Sinus Waters Sinus Lateral Skull AP Skull Lat (Grid) Tib-Fib AP Tib-Fib Lat Toe All Views T-Spine AP to 12 T-Spine Lat Wrist PA Wrist Obl Wrist Lat Zygomatic Arch SMV view 70 5 to Here is the GADOLINIUM DR UNIVERSAL TECHNIQUE CHART. GADOLINIUM DR UNIVERSAL TECHNIQUE CHART Abdomen AP (Grid) 85 6 to to Ankle AP Ankle Obl Ankle Lat Chest -Adult AP (Grid) Chest -Adult AP (Non Grid) Chest (2-9 lb) AP (Non Grid - 45") Chest (2-9 lb) Lat (Non Grid - 45") Chest (10-20 lb)pa (Non Grid - 72") Chest (10-20 lb)lat (Non Grid - 72") Chest (21-35 lb)pa (Non Grid - 72") Chest (21-35 lb)lat (Non Grid - 72") C-Spine AP (Bucky - 72") C-Spine AP (Bucky - 40") C-Spine Odontoid (72") 85 8 to to to 18 C-Spine Odontoid (40") C-Spine Lat (Bucky - 72") C-Spine Swimmers (40") Elbow AP Elbow Obl Elbow Lat Finger All Views Foot AP Foot Obl Foot Lat Forearm AP Forearm Lat Hand PA Hand Obl Hand Lat Page 2 of the GADOLINIUM DR UNIVERSAL TECHNIQUE CHART. GADOLINIUM DR UNIVERSAL TECHNIQUE CHART Hip AP 85 5 to to to 16 Hip X-Table Lat (Grid) Humerus AP (Non Grid) Knee AP (Bucky) Knee Lat (Bucky) Knee Sunrise Knee Non-Bucky L-Spine AP L-Spine X-Table Lat (Grid) Mandible Obl (40") Pelvis AP (Grid) Ribs Upper AP (72") Ribs Upper Obl (72") Ribs Lower AP (45") Shoulder AP (Bucky) Shoulder Mercedes Shoulder X-T Axillary (N-Grid) Sinus Caldwell Sinus Waters Sinus Lateral Skull AP Skull Lat (Grid) Tib-Fib AP Tib-Fib Lat Toe All Views T-Spine AP Sixteen T-Spine Lat Wrist PA Wrist Obl Wrist Lat Zygomatic Arch SMV view 70 eight

12 Digital Radiography Solutions Maximizing Image Quality, Minimizing Patient Dose Dennis Bowman Website: digitalradiographysolutions.com Phone: like me on Facebook for a few monthly posts 12