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Title: Ventilation/Perfusion Positron Emission Tomography—Based Assessment of Radiation Injury to Lung

Purpose: To investigate {sup 68}Ga-ventilation/perfusion (V/Q) positron emission tomography (PET)/computed tomography (CT) as a novel imaging modality for assessment of perfusion, ventilation, and lung density changes in the context of radiation therapy (RT). Methods and Materials: In a prospective clinical trial, 20 patients underwent 4-dimensional (4D)-V/Q PET/CT before, midway through, and 3 months after definitive lung RT. Eligible patients were prescribed 60 Gy in 30 fractions with or without concurrent chemotherapy. Functional images were registered to the RT planning 4D-CT, and isodose volumes were averaged into 10-Gy bins. Within each dose bin, relative loss in standardized uptake value (SUV) was recorded for ventilation and perfusion, and loss in air-filled fraction was recorded to assess RT-induced lung fibrosis. A dose-effect relationship was described using both linear and 2-parameter logistic fit models, and goodness of fit was assessed with Akaike Information Criterion (AIC). Results: A total of 179 imaging datasets were available for analysis (1 scan was unrecoverable). An almost perfectly linear negative dose-response relationship was observed for perfusion and air-filled fraction (r{sup 2}=0.99, P<.01), with ventilation strongly negatively linear (r{sup 2}=0.95, P<.01). Logistic models did not provide a better fit as evaluated by AIC. Perfusion, ventilation, and the air-filled fraction decreased 0.75 ± 0.03%, 0.71 ± 0.06%, and 0.49 ± 0.02%/Gy,more » respectively. Within high-dose regions, higher baseline perfusion SUV was associated with greater rate of loss. At 50 Gy and 60 Gy, the rate of loss was 1.35% (P=.07) and 1.73% (P=.05) per SUV, respectively. Of 8/20 patients with peritumoral reperfusion/reventilation during treatment, 7/8 did not sustain this effect after treatment. Conclusions: Radiation-induced regional lung functional deficits occur in a dose-dependent manner and can be estimated by simple linear models with 4D-V/Q PET/CT imaging. These findings may inform future studies of functional lung avoidance using V/Q PET/CT.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [4] ;  [5] ; ; ;  [1] ;  [5] ;  [2] ;  [6] ;  [2] ;  [1] ;  [5] ;  [2]
  1. Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne (Australia)
  2. (Australia)
  3. Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne (Australia)
  4. Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne (Australia)
  5. Centre for Molecular Imaging, Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia)
  6. Department of Medicine, University of Melbourne, Parkville (Australia)
Publication Date:
OSTI Identifier:
22458789
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 93; Journal Issue: 2; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BIOMEDICAL RADIOGRAPHY; CHEMOTHERAPY; CLINICAL TRIALS; DATASETS; DENSITY; DOSE-RESPONSE RELATIONSHIPS; FIBROSIS; GALLIUM 68; LOSSES; LUNGS; PATIENTS; PLANNING; POSITRON COMPUTED TOMOGRAPHY; RADIATION DOSES; RADIATION INJURIES; RADIOTHERAPY; UPTAKE; VENTILATION