Open AccessDW‐MRI and 18 F‐FLT PET for early assessment of response to radiation therapy associated with hypoxia‐driven interventions. Preclinical studies using manipulation of oxygenation and/or dose escalation
Author(s) -
Tran LyBinhAn,
Bol Anne,
Labar Daniel,
Karroum Oussama,
Mignion Lionel,
Bol Vanesa,
Jordan Bénédicte F.,
Grégoire Vincent,
Gallez Bernard
Publication year - 2015
Publication title -
contrast media & molecular imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.714
H-Index - 50
eISSN - 1555-4317
pISSN - 1555-4309
DOI - 10.1002/cmmi.1670
Subject(s) - carbogen , medicine , nuclear medicine , radiation therapy , effective diffusion coefficient , glioma , hypoxia (environmental) , tumor hypoxia , standardized uptake value , magnetic resonance imaging , positron emission tomography , cancer research , chemistry , radiology , oxygen , organic chemistry
Early markers of treatment response may help in the management of patients by predicting the outcome of a specific therapeutic intervention. Here, we studied the potential value of diffusion‐weighted MRI (DW‐MRI) and 18 F‐fluorothymidine ( 18 F‐FLT), markers of cell death and cell proliferation respectively, to predict the response to irradiation. In addition, dose escalation and/or carbogen breathing were used to modulate the response to irradiation. The studies were performed on two hypoxic rat tumor models: rhabdomyosarcoma and 9L‐glioma. The rats were imaged using MRI and PET before and two days after the treatment. In both tumor models, changes in ADC (apparent diffusion coefficient) and 18 F‐FLT SUV (standardized uptake value) were significantly correlated with the tumor growth delay. For both tumor models, the ADC values increased in all irradiated groups two days after the treatment while they decreased in the untreated groups. At the same time, the uptake of 18 F‐FLT increased in the untreated groups and decreased in all treated groups. Yet, ADC values were not sensitive enough to predict the added value of dose escalation or carbogen breathing in either model. Change in 18 F‐FLT uptake was able to predict the higher tumor response when using increased dose of irradiation, but not when using a carbogen breathing challenge. Our results also emphasize that the magnitude of change in 18 F‐FLT uptake was strongly dependent on the tumor model. Copyright © 2015 John Wiley & Sons, Ltd.