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TU‐F‐12A‐03: Using 18F‐FDG‐PET‐CT and Deformable Registration During Head‐And‐Neck Cancer (HNC) Intensity Modulated Radiotherapy (IMRT) to Predict Treatment Response
Author(s) -
Vergalasova I,
Mowery Y,
Yoo D,
Brizel D,
Das S
Publication year - 2014
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4889358
Subject(s) - nuclear medicine , medicine , image registration , head and neck cancer , radiation therapy , standardized uptake value , pet ct , head and neck , lymph node , positron emission tomography , radiology , pathology , surgery , artificial intelligence , computer science , image (mathematics)
Purpose: To evaluate the effect of deformable vs. rigid registration of pre‐treatment 18F‐FDG‐PET‐CT to intra‐treatment 18F‐FDG‐PET‐CT on different standardized uptake value (SUV) parameters and investigate which parameters correlate best with post‐treatment response in patients undergoing IMRT for HNC. Methods: Pre‐treatment and intra‐treatment PET‐CT (after 20Gy) scans were acquired, in addition to a 12 week post‐treatment PET‐CT to assess treatment response. Primary and lymph node gross tumor volumes (GTV_PRI and GTV_LN) were contoured on the pre‐treatment CT. These contours were then mapped to intra‐treatment PET images via rigid and deformable registration. Absolute changes from pre‐ to intra‐treatment scans for rigid and deformable registration were extracted for the following parameters: SUV_MAX, SUV_MEAN, SUV_20%, SUV_40%, and SUV_60% (SUV_X% is the minimum SUV to the highest‐intensity X% volume). Results: Thirty‐eight patients were evaluated, with 27 available for classification as complete or incomplete response (CR/ICR). The pre‐treatment average tumor volumes for the patients were 24.05cm 3 for GTV_PRI and 23.4cm 3 for GTV_LN. For GTV_PRI, there was no statistically significant difference between rigid vs. deformable registration across all ΔSUV parameters. For GTV_LN contours, all parameters were significantly different except for ΔSUV_MAX. For deformably‐registered GTV_PRI, changes in the following metrics were significantly different for CR vs. ICR: SUV_MEAN(p=0.003), SUV_20%(p=0.02), SUV_40%(p=0.02), and SUV_60%(p=0.008). The following cutoff values separated CR from ICR with high sensitivity and specificity: ΔSUV_MEAN=1.49, ΔSUV_20%=2.39, ΔSUV_40%=1.80 and ΔSUV_60%=1.31. Corresponding areas under the Receiver Operating Characteristics curve were 0.90, 0.81, 0.81, and 0.85, respectively. Conclusion: Rigidly and deformably registered contours yielded statistically similar SUV parameters for GTV_PRI, but not GTV_LN. This implies that neither registration should be solely relied upon for nodal GTVs. Of the four SUV parameters found to be predictive of CR vs. ICR, SUV_MEAN was the strongest. Preliminary results show promise for using intra‐treatment 18F‐FDG‐PET‐CT with deformable registration to predict treatment response.