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1 MAMMOGRAPHY MAMMO QC – covered in week 8 Rev. Spring 2014 Equipment – Lecture #1 Bushong Ch. 23.

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Presentation on theme: "1 MAMMOGRAPHY MAMMO QC – covered in week 8 Rev. Spring 2014 Equipment – Lecture #1 Bushong Ch. 23."— Presentation transcript:

1 1 MAMMOGRAPHY MAMMO QC – covered in week 8 Rev. Spring 2014 Equipment – Lecture #1 Bushong Ch. 23

2 2 2 PHANTOM IMAGES WEEKLY - to assure film density, contrast, uniformity and image quality are optimum – Using the SAME cassette and technical factors each time WEEKLY - to assure film density, contrast, uniformity and image quality are optimum – Using the SAME cassette and technical factors each time 4/5 masses 4/5 masses 3/4specks 3/4specks 4/6 fibers 4/6 fibers should be seen should be seen (see pg 500 review book) (see pg 500 review book)

3 3 Mammography Equipment Bushong – Ch. 23 FILM SCREEN & DIGITAL When the x-ray tube is tilted in its housing, the effective focal spot is small, the x-ray intensity is more uniform, and tissue against the chest is imaged.

4 4 4 EQUIPMENT DIFFERENCES TARGET MATERIAL – TARGET MATERIAL – MOLYBDENUM MOLYBDENUM MO/RHODIUM MO/RHODIUM SMALLER FOCAL SPOTS SMALLER FOCAL SPOTS SHORTER SID SHORTER SID KVP RANGES LOW ~ 24 – – 28 (Bushong) (type of target used) MAS PHOTOCELLS

5 5 5 Mammography Imaging System High frequency generators High frequency generators TARGET MATERIAL: TARGET MATERIAL: Tungsten (W), (z = ____?) 74 Tungsten (W), (z = ____?) 74 Molybdenum (Mo), (z = ___ ?) 42 Molybdenum (Mo), (z = ___ ?) 42 or rhodium (Rh) target (z = ___ ?) 45 or rhodium (Rh) target (z = ___ ?) 45 Focal spot sizes 0.3/0.1 mm (Bushong) Focal spot sizes 0.3/0.1 mm (Bushong) with tilted tube with tilted tube Maximum 600 mAs limit Maximum 600 mAs limit

6 6 6 Mammography Imaging System Inherent filtration 0.1 Al equivalent Inherent filtration 0.1 Al equivalent Heel effect used to advantage Heel effect used to advantage Compression reduces motion, improves spatial resolution, lowers patient dose Compression reduces motion, improves spatial resolution, lowers patient dose High-transmission cellular grid High-transmission cellular grid Automatic exposure control Automatic exposure control

7 7 7 A high-transmission cellular grid designed specifically for mammography. 4:1 or 5:1 grid ratio 40 line/cm frequency 4:1 grid doubles pt dose – but improves contrast significantly p 327 Correct way to load mammography film and position the cassette. Spatial resolution improves when the x-ray film is placed closest to the breast and between the x-ray tube and the radiographic intensifying screen.

8 8 8 DEDICATED MAMMOGRAPIC EQUIPMENT  KVP RANGE : 23 – 28 kvp (BUSHONG)  TARGETS: Molybdenum / Rhodium (vs. Tungsten)  FOCAL SPOTS  (can range from 0.1 – 0.6)  SID 60 –70 cm (vs. 100cm)  Compression Paddle  Heel Effect (fat/cat)  GRIDS : 4:1 or 5:1 (vs 8 to16:1) What does “DEDICATED” Mean in the above title?

9 9 9 Anode Heel Effect – Which portion should Be under the cathode Side of the TUBE? The heel effect can be used to advantage in mammography by positioning the cathode toward the chest wall to produce

10 10 DIGITAL MAMMO DIGITAL has a resolution of approximately DIGITAL has a resolution of approximately 5 lp/mm – but also has MORE CONTRAST 5 lp/mm – but also has MORE CONTRAST  CONVENTIONAL FILM/SCREEN: resolution of approximately 12 lp/mm No need for an additional exposure to the patient

11 11 MAMMOGRAPHIC IMAGES The BREAST has a low subject contrast – little differences in density = soft tissue radiography

12 12 Compression in mammography has three principal advantages: improved spatial resolution, improved contrast resolution, and lower patient dose. Compression in mammography has three principal advantages: improved spatial resolution, improved contrast resolution, and lower patient dose. Can affect: kVp & mAs ranges

13 13 MAX 25 PSI - how is this measured?

14 14

15 15 Position of AEC over breast tissue Most MAMMOS ARE NOW DIGITAL – NOT FILM SCREEN PROCESSING

16 16 Remove all ambient light when possible – for better images

17 17 Other Imaging of the Breast

18 18 Breast Ultrasound 18 What is best seen? Why is US chosen over X-Ray?

19 19

20 20 CT Breast Scanner Detect lesions 5mm in size 1/10 of the radiation 2-3 times higher spatial resolution

21 21 3d Mammo ? 21

22 22 Breast MRI 22

23 23

24 24 Mammo Images & Procedures in Lecture # 2 24

25 25 Digital vs Film Image 25

26 26


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