Potential of [18F]-Fluoromisonidazole positron-emission tomography for radiotherapy planning in head and neck squamous cell carcinomas

B. Henriques de Figueiredo, T. Merlin, H. de Clermont-Gallerande, M. Hatt, D. Vimont, P. Fernandez, F. Lamare
Strahlenther Onkol. 2013-11-01; 189(12): 1015-1019
DOI: 10.1007/s00066-013-0454-7

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1. Strahlenther Onkol. 2013 Dec;189(12):1015-9. doi: 10.1007/s00066-013-0454-7. Epub
2013 Nov 1.

Potential of [18F]-fluoromisonidazole positron-emission tomography for
radiotherapy planning in head and neck squamous cell carcinomas.

Henriques de Figueiredo B(1), Merlin T, de Clermont-Gallerande H, Hatt M, Vimont
D, Fernandez P, Lamare F.

Author information:
(1)Department of Radiotherapy, Institut Bergonié, 229, cours de l’Argonne, 33076,
Bordeaux Cedex, France, .

BACKGROUND AND PURPOSE: Positron-emission tomography (PET) with
[(18)F]-fluoromisonidazole (FMISO) permits consideration of radiotherapy dose
escalation to hypoxic volumes in head and neck cancers (HNC). However, the
definition of FMISO volumes remains problematic. The aims of this study are to
confirm that delayed acquisition at 4 h is most appropriate for FMISO-PET imaging
and to assess different methods of volume segmentation.
PATIENTS AND METHODS: A total of 15 HNC patients underwent several
FMISO-PET/computed tomography (CT) acquisitions 2, 3 and 4 h after FMISO
injection. Three automatic methods of PET image segmentation were tested: fixed
threshold, adaptive threshold based on the ratio between tumour-derived and
background activities (R(T/B)) and the fuzzy locally adaptive Bayesian (FLAB)
method. The hypoxic fraction (HF), which is defined as the ratio between the
FMISO and CT volumes, was also calculated.
RESULTS: The R(T/B) for images acquired at 2, 3 and 4 h differed significantly,
with mean values of 2.5 (1.7-2.9), 3 (2-4.5) and 3.4 (2.3-6.1), respectively. The
mean tumour volume, as defined manually using CT images, was 39.1 ml (1.2-116
ml). After 4 h, the mean FMISO volumes were 18.9 (0.1-81), 9.5 (0.9-33.1) and
12.5 ml (0.9-38.4 ml) with fixed threshold, adaptive threshold and the FLAB
method, respectively; median HF values were 0.47 (0.1-1.93), 0.25 (0.11-0.75) and
0.35 (0.14-1.05), respectively. FMISO volumes were significantly different.
CONCLUSION: The best contrast is obtained at the 4-hour acquisition time. Large
discrepancies were found between the three tested methods of volume segmentation.

DOI: 10.1007/s00066-013-0454-7
PMID: 24173497 [Indexed for MEDLINE]

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