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The Study of Geometry and Dosimetry Change for the Target of Lung Cancer On Two CT Images Using Rigid Registration

C Ma*, Shandong Cancer Hospital Affiliated to Shandong University, Jinan, 37


(Sunday, 7/14/2019)  

Room: ePoster Forums

Purpose: To analyze the target motion during the lung carcinoma radiotherapy and discuss thedosimetry change.

Methods: Ten patients with primary lung carcinoma were selected retrospectively.Each patient received two CT scanning and declining GTV1 and GTV2 during the radiotherapy.The two CT images were rigid deformed.Physicist designed plans both in GTV1 and GTV2 and campared the target motion and dosimetry variation.

Results: The targets of new CT(GTV2) were significantly smaller than those of old CT (GTV1).On thesame transverse the maximal difference of x-axis,y-axis was 4mm and 2.3mm. The avaragevolume of GTV1 and GTV2 which achieved the prescription dose was 99.45%±0.73% and97.19%±2.37% respctively.There were no statistical diffetence for the maximal dose,mean doseand the minimal dose of the target. The new plan for the mean dose of heart,left lung,total lungand the maximum dose of spinal-cord were smaller than those of the old plan with no significantdierrence.But there was statistically difference for the mean dose of right lung(t=3.172,P=0.025).

Conclusion: The target volume change and anatomic position displacement of lung carcinoma shouldnot be neglected in clinics.These changes would cause underdose in target and overdose innormal tissue.Therefore,it is necessary to have another CT scanning and replan during thelung carcinoma radiotherapy.


Not Applicable / None Entered.


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