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X.M. Ma



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    P3.14 - Radiotherapy (ID 730)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Radiotherapy
    • Presentations: 1
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      P3.14-007 - A Functional Equivalent Uniform Dose Correlates with Radiation Pneumonities in Radiation Therapy (ID 9929)

      09:30 - 09:30  |  Author(s): X.M. Ma

      • Abstract
      • Slides

      Background:
      The literature on dose-volume parameters and pneumonitis is extensive, whose results are inconsistent, both for the best predictive metrics and significant comorbid factors. To develop an improved functional equivalent uniform dose (fEUD) with perfusion factors of single photon emission computed tomography (SPECT) images as predictors of radiation peneumonitis (RP) in patients undergoing curative radiotherapy (RT).

      Method:
      Figure 1Functional lung imaging was performed using single photon emission computed tomography (SPECT) for perfusion imaging. Perfusion factors were defined as the mean percentile perfusion levels of the four areas of the top to 75%, 75% to 50%, 50% to 25%, 25% to 0%, respectively. fEUD were calculated from perfusion factors in computed tomography (CT) and SPECT fused images and standard dose-volume parameters were extracted from radiotherapy treatment planning. Total lung (TL) volumes minus GTV, V5 and V20 (the percentage of normal lung tissue receiving more than 5Gy and 20Gy), fEUD (equivalent to 2Gy/fx, α/β=3.3, a=1), and mean dose of TL were analyzed to evaluate correlations between RP, which was evaluated using Common Terminology Criteria for Adverse Events (CTCAE) version 4.03. Statistical significance was defined as a P-values of <.05.



      Result:
      A total of 28 patients treated with intensity modulated RT or 3D conformable RT were analyzed, grades≥3 RP were observed in 6 patients. There was only a significant difference in fEUD between patients with RP and free (p=0.007). Insignificant tendency of difference was showed in the mean dose of TL (p = 0.052). V5 and V20 of whole lung were almost identical between the two groups (p=0.161 and 0.197), as the most values are below the recommended thresholds from published papers.

      Conclusion:
      SPECT-based equivalent uniform dose presented more significant to predict RP compared to standard dose–volume parameters and mean dose.

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