Abstract:
:Quantifying the retention or washout of (99m)Tc-Sestamibi (MIBI) in breast tumours in vivo may provide a basis for predicting the chemotherapy response. The aim of this study is to investigate the variations and limitations of the different methods used to quantify these parameters. A phantom was developed that allowed the modelling of MIBI pharmacokinetics in both the breast tumour and normal breast tissue. Washout and retention were calculated from tumour uptake values based on (1) background corrected counts or (2) total counts in the tumour region of interest (ROI), or (3) tumour to background ratios (TBR), or (4) normalized TBR (nTBR). Method 1 was the most accurate method of quantification whilst method 3 was the most inaccurate. The accuracy of method 1 was independent of the times at which images were acquired, but three sources of error are identified involving incorrect background selection, ROI reproducibility and inconsistent temporal separation of images. In conclusion, background subtracted tumour counts should be used in the calculation of MIBI retention or washout. Accurate results are dependent on selecting the appropriate background, drawing consistent ROIs and using reproducible time intervals between images.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Marshall C,Griffiths PAdoi
10.1088/0031-9155/50/9/013subject
Has Abstractpub_date
2005-05-07 00:00:00pages
2113-26issue
9eissn
0031-9155issn
1361-6560pii
S0031-9155(05)82308-5journal_volume
50pub_type
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