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Sci‐Sat AM(2): Brachy‐07: Tomosynthesis‐based seed reconstruction in LDR prostate brachytherapy: A clinical study
Author(s) -
BrunetBenkhoucha M,
Verhaegen F,
Lassalle S,
BéliveauNadeau D,
Reniers B,
Donath D,
Taussky D,
Carrier JF
Publication year - 2008
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2965999
Subject(s) - brachytherapy , prostate cancer , medicine , tomosynthesis , nuclear medicine , medical physics , radiology , radiation therapy , cancer , mammography , breast cancer
To develop a tomosynthesis‐based dose assessment procedure that can be performed after an I‐125 prostate seed implantation, while the patient is still under anaesthesia on the treatment table. Our seed detection procedure involves the reconstruction of a volume of interest based on the backprojection of 7 seed‐only binary images acquired over an angle of 60° with an isocentric imaging system. A binary seed‐only volume is generated by a simple thresholding of the volume of interest. Seeds positions are extracted from this volume with a 3D connected component analysis and a statistical classifier that determines the number of seeds in each cluster of connected voxels. A graphical user interface (GUI) allows to visualize the result and to introduce corrections, if needed. A phantom and a clinical study (24 patients) were carried out to validate the technique. A phantom study demonstrated a very good localization accuracy of (0.4+/−0.4) mm when compared to CT‐based reconstruction. This leads to dosimetric error on D90 and V100 of respectively 0.5% and 0.1%. In a patient study with an average of 56 seeds per implant, the automatic tomosynthesis‐based reconstruction yields a detection rate of 96% of the seeds and less than 1.5% of false‐positives. With the help of the GUI, the user can achieve a 100% detection rate in an average of 3 minutes. This technique would allow to identify possible underdosage and to correct it by potentially reimplanting additional seeds. A more uniform dose coverage could then be achieved in LDR prostate brachytherapy.