• Int. J. Radiat. Oncol. Biol. Phys. · Nov 2010

    18F-FDG PET definition of gross tumor volume for radiotherapy of lung cancer: is the tumor uptake value-based approach appropriate for lymph node delineation?

    • Núria Rodríguez, Xavier Sanz, Carlos Trampal, Palmira Foro, Anna Reig, Martí Lacruz, Ismael Membrive, Joan Lozano, Jaime Quera, and Manuel Algara.
    • Department of Radiation Oncology, Hospitales de la Esperanza y del Mar, Barcelona, Spain. nrodriguez@imas.imim.es
    • Int. J. Radiat. Oncol. Biol. Phys. 2010 Nov 1; 78 (3): 659-66.

    PurposePositron emission tomography (PET) with the glucose analogue [18F] fluoro-2-deoxy-D-glucose ((18)F-FDG-PET) has been used in radiation treatment planning for non-small-cell carcinoma. To date, lymph nodes have been contoured according to the uptake of the tumor. This prospective study was performed to evaluate if nodal volume delineates according to FDG uptake within the primary tumor (PET-GTVnt) is suitable for nodal target volume delineation or if individualized nodal FDG uptake measure (PET-GTVnn) is necessary to better nodal target definition.Methods And MaterialsForty cases, who underwent a diagnostic (18)F-FDG PET/computed tomography (CT) scan, were included. Two PET-based GTVs for each lymph node were contoured and compared. First, we used an isocontour of 40% of the maximum tumor uptake (PET-GTVnt). Second, an isocontour of 40% of the maximum uptake of each node (PET-GTVnn) was employed. To avoid interobserver variability, this was carried out by the same radiation oncologist. Afterwards, the difference between both lymph node volumes was plotted against the ratio of the maximum uptakes (I(n)/I(t)) in a linear regression analysis.ResultsCompared with CT-based lymph node volume (CT-GTVn), the intraclass correlation coefficient of PET-GTVnn was higher than the coefficient of PET-GTVnt (p < 0.001). All cases could be divided into four groups: undetected (17.5%), detected but overestimated (10%), detected but underestimated (35%), and correctly detected (37.5%).ConclusionsIf a method of automatic delineation shall be applied, this method must be applied to every lesion separately. However, to facilitate the delineation in daily practice, when I(n)/I(t) is ≤25%, lymph nodes could be delineated in accordance with tumor uptake, keeping an absolute difference in radii <5 mm.Copyright © 2010 Elsevier Inc. All rights reserved.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…