Digital Breast Tomosynthesis from a first idea to clinical routine

Transcription

1 International Master Programm Biomedical Engineering Digital Breast Tomosynthesis from a first idea to clinical routine Historical background 2D imaging of 3D objects has important limitations Jörg Barkhausen Clinic for Radiology and Nuclearmedicine, University Hospital Schleswig Holstein Campus Lübeck Clinical Example Historical background 2D imaging of 3D objects has important limitations Request: to generate 3D information out of several 2D x ray images First ideas were published by Ziedes des Plantes in 1931 Planography Planography Basic idea: relative movement of the x ray tube, the image receptor and the patient Result: a single plane is displayed sharply, and all other structures are blurred Limitation: only one plane per scan, 3D coverage increases radiation dose 1

2 Digital Tomosynthesis Digital Tomosynthesis Basic idea by Miller et al. in 1971: production of an infinite number of planar slices from a finite number of radiographs Equipment: linear tomographic x ray machine, fluoroscope and TV system, video recorder, analog to digital converter and a computer Maravilla KR, AJR 1983 Several clinical applications including angiotomography Maravilla KR, AJR 1983 Digital Tomosynthesis Clinical background Level of the internal auditory canal Level of the orbits and facial structures Maravilla KR, AJR 1983 Breast cancer is the most common malignancy in women Worldwide, breast cancer comprises 10.4% of all cancer incidence among women Prognosis and survival rate varies greatly depending on staging Early detection is most crucial Mammography Mammography: Advantages Fast Non expensive Accurate Detects Microcalcification and Masses Allows for breast cancer screening 2

3 Mammography Typical findings: stellatelesion Typical findings: stellatelesion Calcifications solitary, large calcification with smooth margins benign clustered, irregular, small calcifications suspicious Reasons for Nondetection of Cancer Breast Ultrasound 335 US depicted cancers, 56% > 10 mm Review of mammograms by 5 radiologists 81% (272 / 335) of cancers were not seen at mammography even in retrospect 78% (263 / 335) of cancers were obscured by overlapping dense tissue Bae MS, Radiology

4 Breast MRI First idea: Digital Breast Tomosynthesis Niklason LT, Radiology 1997 Digital Breast Tomosynthesis Mastectomy specimen X rax tube moves in an arc Stationary breast tissue Stationary digital dector Low radiation dose images were acquired using step and expose method 2 phantoms and 4 mastectomy specimen Niklason LT, Radiology 1997 Mammography Digital Tomosynthesis Niklason LT, Radiology 1997 Digital Brust Tomosynthese (DBT) Digital Breast Tomosynthesis in Lübeck Mammomat Inspiration Digital Mammography Stereotactic Breast Biopsy Digital Breast Tomosynthesis (DBT) 25 projections 50 angle 4

5 Different DBT Systems Angular range System Detector type GE Essential indirect Hologic Selenia Dimension s direct IMS Giotto direct Philips Micro Dose Linear slit scan Planmed Nuance Excel DBT direct Siemens MAMMOMAT Inspiration direct Detector size 24 x 30 cm 24 x 29 cm 24 x 30 cm 21 Lines, 24 cm 24 x 30 cm 24x 30 cm Detector pixel size X ray tube motion Number of projectionen 100 µm 70 µm 85 µm 50 µm perpendicular to motion Step & Shoot Cont. Step & Shoot Cont. Cont. Cont Angular range Scan time 7 s 3,7 s 12 s 3 10 s 20 s 25 s Prerequisites for clinical routine Case 1 Robust and commercially available hardware (not too expensive) Some excellent clinical examples Enthusiastic physicians Courtesy I. Andersson Lesion visible only in one standard view Case 2: 8 mm invasive Carcinoma Case 2 Case 3 5

6 Case 3: no mass at DBT Case 3: additional MRI MRM, subtraction, 4 min after contrast Prerequisites for clinical routine Radiation exposure Robust and commercially available hardware (not too expensive) Some excellent images Enthusiastic physicians Low radiation Mammo cc Single Projektion DBT (25 Projections) Mammo mlo AGD 1,05 mgy AGD 0,06 mgy AGD 1,46 mgy AGD 1,28 mgy Radiation exposure Compressible water oil mixture phantoms digital mammography (FFDM) Digital breast tomosynthesis (DBT) Single craniocaudal view Mean glandular dose (MGD) for different breast of varying sizes and glandular compositions Feng SS, Radiology 2012 Radiation exposure FFDM MGD mgy DBT MGD mgy Compressed thickness 5 cm, 50 % glandular fraction FFDM 1.2 mgy DBT 1.3 mgy ( +8% ) Single view DTB reduces dose compared standard two view FFDM Feng SS, Radiology

7 Prerequisites for clinical routine Robust and commercially available hardware (not too expensive) Some excellent images Enthusiastic physicians Low radiation Data from large clinical trials Screening: DM versus DM + DBT 2011 to 2012, multicenter trial patients presented for Screening Mammography, received additional DBT Tumor detection rate DM 5,2 DM + DBT 5,7 Recall rate DM 12% DM + DBT 8,4 % Greatest reduction in recall rate occurred in women with dense breasts and those younger than 50 Haas BM, Radiology yo, screening 48 yo, screening ADH Cyst Head to head comparison Cancer or no cancer? In none of the available smaller studies DBT was inferior to digital mammography Detection of microcalcification with DBT!? Most studies suffer from a selection bias, only women with abnormal DM included Malmö Breast Tomosynthesis Screening Trial (MBTST) with subjects started in

8 Additional tomosynthesis Additional tomosynthesis Slice 13 Slice 21 Slice 32 Slice 46 Additional MRI Conclusion subtraction without contrast with contrast Digital breast tomosynthesis is technically ready for clinical use All published studies showed excellent results for digital breast tomosynthesis We need more clinical studies DBT will change our algorithm in breast imaging within the next 5 years 8