Using Fluorodeoxyglucose Positron Emission Tomography to Assess Tumor Volume During Radiotherapy for Non-Small-Cell Lung Cancer and Its Potential Impact on Adaptive Dose Escalation and Normal Tissue Sparing

Journal Article · Sun Mar 15 04:00:00 EDT 2009 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2008.10.054· OSTI ID:21172688

Feng, Mary ^[1]; Kong, Feng-Ming ^[1]; Gross, Milton ^[2]; Fernando, Shaneli; Hayman, James A; Haken, Randall K. ten ^[1]

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1. Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States)
2. Department of Nuclear Medicine, University of Michigan, Ann Arbor, MI (United States)

Purpose: To quantify changes in fluorodeoxyglucose (FDG)-avid tumor volume on positron emission tomography/computed tomography (PET/CT) during the course of radiation therapy and examine its potential use in adaptive radiotherapy for tumor dose escalation or normal tissue sparing in patients with non-small-cell lung cancer (NSCLC). Methods and Materials: As part of a pilot study, patients with Stage I-III NSCLC underwent FDG-PET/CT before radiotherapy (RT) and in mid-RT (after 40-50 Gy). Gross tumor volumes were contoured on CT and PET scans obtained before and during RT. Three-dimensional conformal RT plans were generated for each patient, first using only pretreatment CT scans. Mid-RT PET volumes were then used to design boost fields. Results: Fourteen patients with FDG-avid tumors were assessed. Two patients had a complete metabolic response, and 2 patients had slightly increased FDG uptake in the adjacent lung tissue. Mid-RT PET scans were useful in the 10 remaining patients. Mean decreases in CT and PET tumor volumes were 26% (range, +15% to -75%) and 44% (range, +10% to -100%), respectively. Designing boosts based on mid-RT PET allowed for a meaningful dose escalation of 30-102 Gy (mean, 58 Gy) or a reduction in normal tissue complication probability (NTCP) of 0.4-3% (mean, 2%) in 5 of 6 patients with smaller yet residual tumor volumes. Conclusions: Tumor metabolic activity and volume can change significantly after 40-50 Gy of RT. Using mid-RT PET volumes, tumor dose can be significantly escalated or NTCP reduced. Clinical studies evaluating patient outcome after PET-based adaptive RT are ongoing.

• OSTI ID: 21172688
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 4 Vol. 73; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
FLUORODEOXYGLUCOSE
LUNGS
PATIENTS
POSITRON COMPUTED TOMOGRAPHY
RADIATION DOSES
RADIOTHERAPY
UPTAKE