Optimization of breast tomosynthesis: Computer simulations of image acquisition and glandular dose
Optimering av brösttomosyntes : Datorsimuleringar av bildinsamling och bröstkörteldos
Författare
Summary, in English
Breast tomosynthesis (BT) is an X-ray imaging technique recently introduced as an alternative or complement to standard digital mammography (DM) in breast imaging and breast cancer screening. In BT, a set of projection images is acquired over a limited angular range and reconstructed into a volume of slice images. The method includes many possible combinations of acquisition parameters that have to be optimized for best possible clinical performance and outcome. The visibility of breast cancer lesions is important in this context. Compared to DM images, the reconstructed BT volume provides additional information on depth, reducing the superposition of breast tissue, which may hide true lesions or appear as false positive findings. Thus, the BT volume also contains information about the distribution of dense tissue within the breast, which is of interest when estimating the radiation dose from DM and BT exposure.
In this thesis, a simulation procedure was developed for the optimization of image acquisition and estimation of individual glandular dose in BT. The procedure was shown to be useful in generating BT images with realistic sharpness, though with higher image noise and contrast than experimentally acquired images (Paper I). The procedure was used to investigate the influence of angular range, distribution of projection images, and dose distribution on simulated microcalcifications in reconstructed BT volumes. Image acquisitions with very high central dose yielded significantly lower visibility than acquisitions with more uniform dose distributions, and the depth resolution increased with wider angular range (Paper II).
A method for localizing dense tissue from reconstructed BT volumes was verified using the simulation procedure (Paper III). A prototype software program was used for automatic and objective estimation of breast density in BT, with similar performance as DM (Paper IV). Using software breast phantoms recreated from reconstructed BT volumes, the glandular dose could be estimated with good overall accuracy for breast phantoms with different amounts and distributions of dense tissue (Paper V).
The developed simulation procedure has been a useful tool for optimizing acquisition parameters and estimating glandular dose in BT. The procedure could potentially be developed for further evaluation of the imaging chain and estimation of individual glandular dose in human cases.
In this thesis, a simulation procedure was developed for the optimization of image acquisition and estimation of individual glandular dose in BT. The procedure was shown to be useful in generating BT images with realistic sharpness, though with higher image noise and contrast than experimentally acquired images (Paper I). The procedure was used to investigate the influence of angular range, distribution of projection images, and dose distribution on simulated microcalcifications in reconstructed BT volumes. Image acquisitions with very high central dose yielded significantly lower visibility than acquisitions with more uniform dose distributions, and the depth resolution increased with wider angular range (Paper II).
A method for localizing dense tissue from reconstructed BT volumes was verified using the simulation procedure (Paper III). A prototype software program was used for automatic and objective estimation of breast density in BT, with similar performance as DM (Paper IV). Using software breast phantoms recreated from reconstructed BT volumes, the glandular dose could be estimated with good overall accuracy for breast phantoms with different amounts and distributions of dense tissue (Paper V).
The developed simulation procedure has been a useful tool for optimizing acquisition parameters and estimating glandular dose in BT. The procedure could potentially be developed for further evaluation of the imaging chain and estimation of individual glandular dose in human cases.
Avdelning/ar
- BioCARE: Biomarkers in Cancer Medicine improving Health Care, Education and Innovation
- Medicinsk strålningsfysik, Malmö
Publiceringsår
2018
Språk
Engelska
Publikation/Tidskrift/Serie
Lund University, Faculty of Medicine Doctoral Dissertation Series
Volym
2018
Issue
71
Fulltext
Dokumenttyp
Doktorsavhandling
Förlag
Lund University: Faculty of Medicine
Ämne
- Medical and Health Sciences
Nyckelord
- breast tomosynthesis
- Monte Carlo simulation
- acquisition parameters
- software breast phantom
- microcalcifications
- breast density
- glandular dose
- glandular distribution
Aktiv
Published
Projekt
- Optimization of breast tomosynthesis: Computer simulations of image acquisition and glandular dose
Forskningsgrupp
- Medical Radiation Physics, Malmö
ISBN/ISSN/Övrigt
- ISSN: 1652-8220
- ISBN: 978-91-7619-637-3
Försvarsdatum
5 juni 2018
Försvarstid
09:00
Försvarsplats
CRC, rum 93-09-002, Jan Waldenströms gata 35, Skånes Universitetssjukhus i Malmö
Opponent
- Susan Astley (PhD)