FDG PET/CT for rectal carcinoma radiotherapy treatment planning: comparison of functional volume delineation algorithms and clinical challenges

The best option for treatment of anal cancer is chemoirradiation. FDG-PET detects the primary tumor and metastatic involved lymph nodes better and more frequently than CT only. During last decade, fusion of different imaging modalities became important factor in radiotherapy treatment planning. Patient was diagnosed for squamous cell carcinoma by colonoscopy and FDG/PET followed by histopathological confirmation. A precise determination of target volume is very important in radiotherapy. In recent years higher utilization of FDG-PET CT fusion in radiotherapy treatment planning of anal cancer is recorded. Image registration and fusion between CT for radiotherapy treatment planning and FDG PET can help better visualization and especially in the determination of boost target volume. We observed much better detection of affected lymphatics by the data obtained by image co-registration of PET and CT data. This fact allowed us to increase dose prescribed to tumor and affected lymph nodes. PET is very important imaging modality for patients with anal canal cancer. FDG-PET has proved to be important tool for the radiotherapy treatment planning of anal canal carcinoma

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FDG-PET/CT imaging for staging and definition of tumor volumes in radiation treatment planning in non-small cell lung cancer

Journal of Clinical Oncology ◽

10.1200/jco.2009.27.15_suppl.7574 ◽

2009 ◽

Vol 27 (15_suppl) ◽

pp. 7574-7574 ◽

Cited By ~ 1

Author(s):

Y. Xu ◽

S. Ma ◽

D. Yu ◽

J. Wang ◽

L. Zhang ◽

...

Keyword(s):

Treatment Planning ◽

Fdg Pet ◽

Radiation Treatment ◽

Target Volume ◽

Ct Images ◽

Planning System ◽

Treatment Planning System ◽

Volume Delineation ◽

Pet Ct ◽

Fdg Pet Ct

7574 Background: 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) /computed tomography (CT) has a potential improvement for staging and radiation treatment (RT) planning of various tumor sites. But from a clinical standpoint, the open questions are essentially the following: to what extent does PET/CT change the target volume? Can PET/CT reduce inter-observer variability in target volume delineation? We analyzed the use of FDG-PET/ CT images for staging and evaluated the impact of FDG- PET/CT on the radiotherapy volume delineation compared with CT in patients with non-small cell lung cancer (NSCLC) candidates for radiotherapy. Intraobserver variation in delineating tumor volumes was also observed. Methods: Twenty-three patients with stage I-III NSCLC were enrolled in this pilot study and were treated with fractionated RT based therapy with or without chemotherapy. FDG-PET/CT scans were acquired within 2 weeks prior to RT. PET and CT data sets were sent to the treatment planning system Pinnacle through compact disc. The CT and PET images were subsequently fused by means of a dedicated radiation treatment planning system. Gross Tumor Volume (GTV) was contoured by four radiation oncologists respectively on CT (CT-GTV) and PET/CT images (PET/CT-GTV). The resulting volumes were analyzed and compared. Results: For the first phase, two radiation oncologists outlined together the contours achieving a final consensus. Based on PET/CT, changes in TNM categories occurred in 8/23 cases (35%). Radiation targeting with fused FDG-PET and CT images resulted in alterations in radiation therapy planning in 12/20 patients (60%) by comparison with CT targeting. The most prominent changes in GTV have been observed in cases with atelectasis. For the second phase was four intraobserver variation in delineating tumor volumes. The mean ratio of largest to smallest CT-based GTV was 2.31 (range 1.01–5.96). The addition of the PET data reduced the mean ratio to 1.46 (range 1.12–2.27). Conclusions: PET/CT fusion images could have a potential impact on both tumor staging and treatment planning. Implementing matched PET/CT reduced observer variation in delineating tumor volumes significantly with respect to CT only. [Table: see text]

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