Developing oxygen-enhanced magnetic resonance imaging as a prognostic biomarker of radiation response.
Oxygen-Enhanced Magnetic Resonance Imaging (OE-MRI) techniques were evaluated as potential non-invasive predictive biomarkers of radiation response. Semi quantitative blood-oxygen level dependent (BOLD) and tissue oxygen level dependent (TOLD) contrast, and quantitative responses of relaxation rates (ΔR1 and ΔR2*) to an oxygen breathing challenge during hypofractionated radiotherapy were applied. OE-MRI was performed on subcutaneous Dunning R3327-AT1 rat prostate tumors (n=25) at 4.7 T prior to each irradiation (2F × 15 Gy) to the gross tumor volume. Response to radiation, while inhaling air or oxygen, was assessed by tumor growth delay measured up to four times the initial irradiated tumor volume (VQT). Radiation-induced hypoxia changes were confirmed using a double hypoxia marker assay. Inhaling oxygen during hypofractionated radiotherapy significantly improved radiation response. A correlation was observed between the difference in the 2nd and 1st ΔR1 (ΔΔR1) and VQT for air breathing rats. The TOLD response before the 2nd fraction showed a moderate correlation with VQT for oxygen breathing rats. The correlations indicate useful prognostic factors to predict tumor response to hypofractionation and could readily be applied for patient stratification and personalized radiotherapy treatment planning.
Department of Radiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Bioengineering, University of Texas at Arlington, Arlington, Texas 76019, USA.
Derek A
DA
White
Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Zhang
Z
Zhang
Department of Radiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Li
L
Li
Department of Radiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Jeni
J
Gerberich
Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
Strahinja
S
Stojadinovic
German Cancer Center, Heidelberg, Germany.
Peter
P
Peschke
Department of Radiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA. Electronic address: Ralph.Mason@UTSouthwestern.edu.
Ralph P
RP
Mason
D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D000069473:Radiation Dose Hypofractionation; D051381:Rats; D013997:Time Factors; D047368:Tumor Burden / Q000528:radiation effects; D000072258:Tumor Hypoxia; D059016:Tumor Microenvironment
D014408:Biomarkers, Tumor; D010100:Oxygen
Hypoxia; Magnetic resonance imaging; Oxygen; Radiation response; Reoxygenation; Stereotactic body radiation therapy (SBRT)