Özet:

The aim of this study was to evaluate the effect of contrastenhanced computed tomography (CT) scans on the radiation dose calculations for lung cancer treatment planning with intensity modulated radiotherapy (IMRT). Material and Method: CT images used for radiotherapy (RT) planning of 10 patients with lung cancer were evaluated retrospectively. IMRT plans were used 5–7 coplanar beams according to tumor localization. The dose was 60 Gy. Contrast-enhanced and unenhanced doses of 50% (D50), 90% (D90) and 95% (D95) of planning target volume (PTV) were compared. Similarly, contrast-enhanced and unenhanced doses of spinal cord, which is one of critical normal structures, were compared. Contrast-enhanced and unenhanced percentages of volume of normal lung tissue, which is another of critical normal structures, received ≥20 Gy dose were also compared. Results: There was no significant difference between contrast-enhanced and unenhanced PTV D95, D90 and D50 doses (p >0.05). Similarly, there was no significant difference between contrastenhanced and unenhanced doses of spinal cord (p >0.05). There was also no significant difference between contrast-enhanced and unenhanced V20 percentages (p >0.05). Conclusion: Our findings suggest that use of contrast agent has not significant effect on the dose calculation for lung cancer treatment planning with IMRT.

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