Magnetic resonance imaging system for three-dimensional conformal radiotherapy and its impact on gross tumor volume delineation of central nervous system tumors
H. Aoyama et al., Magnetic resonance imaging system for three-dimensional conformal radiotherapy and its impact on gross tumor volume delineation of central nervous system tumors, INT J RAD O, 50(3), 2001, pp. 821-827
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Onconogenesis & Cancer Research
Journal title
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS
Purpose: We developed an MRI system for three-dimensional planning in radio
therapy. Its contribution on gross tumor volume (GTV) delineation of centra
l nervous system (CNS) diseases was evaluated. Methods and Materials: The M
RI system, with corrected distortion, was registered on computed tomography
(CT) by means of fiducial/anatomic landmarks. In 41 consecutive patients w
ith various CNS diseases, GTVs determined by MRI/CT registration (MR/CT-GTV
) and CT alone (CT-GTV) were compared. Hard copies of diagnostic MRI were s
hown to doctors when CT-GTV was determined to simulate a conventional plann
ing situation. Multi-observer volumetric analysis was conducted, assessing
interobserver deviations among four radiation oncologists and intermethodol
ogical deviations between MR/CT-GTV and CT-GTV, Results: Overall, the mean
of geometric distortion was significantly reduced from 1.08 mm to 0.3 mm by
distortion correction (p < 0.0001), The contribution of the correction was
apparent at > 12.0 cm radius from the center of the magnetic field. Intero
bserver deviation was significantly reduced by MR/CT registration (p 0.005)
, The improvement was significant for acoustic neurinoma (p = 0.038), astro
cytomas (p = 0.043), and lesions at the cerebellum/brainstem (p = 0.008), T
he regression coefficient between MR/CT-GTV and CT-GTV was <0.9 for cerebel
lum/brainstem lesions, suggesting that MRI/CT-GTV was smaller than CT-GTV,
Conclusions: This system is feasible for three-dimensional planning and was
shown to reduce interobserver deviations in GTV delineation for CNS diseas
es. (C) 2001 Elsevier Science Inc.