CT- versus coregistered FDG-PET/CT-based radiation therapy plans for conformal radiotherapy in colorectal liver metastases: a dosimetric comparison

• Published in: Japanese journal of radiology Vol. 30; no. 8; pp. 628 - 634
• Main Authors: Parlak, Cem, Topkan, Erkan, Sonmez, Serhat, Onal, Cem, Reyhan, Mehmet
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.10.2012; Springer Nature B.V
• Subjects: Adult; Aged; Algorithms; Colorectal Neoplasms - pathology; Female; Fluorodeoxyglucose F18; Humans; Imaging; Liver Neoplasms - diagnostic imaging; Liver Neoplasms - radiotherapy; Liver Neoplasms - secondary; Male; Medicine; Medicine & Public Health; Middle Aged; Multimodal Imaging - methods; Nuclear Medicine; Original Article; Positron-Emission Tomography; Radiology; Radiopharmaceuticals; Radiotherapy; Radiotherapy Dosage; Radiotherapy, Conformal - methods; Tomography, X-Ray Computed - methods; Treatment Outcome; FDG-PET; Target-volume delineation; Colorectal liver metastases; Radiation therapy; Computed tomography
• ISSN: 1867-1071; 1867-108X
• DOI: 10.1007/s11604-012-0101-8

Purpose Our aim was to compare computed tomography (CT) and coregistered [ 18 F]-fluorodeoxyglucose positron emission tomography CT-(FDG-PET/CT) based delineation of gross tumor volume (GTV) in unresectable colorectal liver metastasis (CRLM). Materials and methods Fifty-four patients with unresectable CRLM were enrolled but 16 were excluded due to detection of additional hepatic metastases in ten on PET/CT scans, precluding radiotherapy because of transcendent critical organ doses beyond tolerable limits; and of extrahepatic metastases in six. For 38 eligible patients, both CT and PET/CT images were acquired, and two 3D conformal plans were made using the CT and FDG-PET/CT fusion data sets. Radiotherapy plans (RTP) and doses to critical organs were analyzed. Results Comparisons between two RTPs revealed need for change in GTV in 31 of 38 analyzable patients (81.6 %). In 25 (65.8 %) patients, GTV was significantly increased, with a median of 33.2 % ( p  < 0.001), whereas median 12.8 % decrease in six (15.8 %) ( p  < 0.001). There were no clinically meaningful differences in critical organ doses. Conclusion Coregistered FDG-PET/CT may improve delineation of GTV and theoretically reduce the likelihood of geographic misses in unresectable CRLM. Additionally, integration of FDG-PET/CT in the initial assessments of CRLM may spare almost one third of patients from potentially futile radical interventions.