Dosimetry study of three-dimension conformal radiation therapy(3DCRT) in treating cervical cancer recurred in pelvis / 肿瘤研究与临床

ABSTRACT

Objective To eompare the dose distribution of three-dimension conformal radiation therapy(3DCRT) and common radiation therapy (CRT) of the planning target volume(PTV) and organ at risk (OAR) in recurred cervical cancer treatment planning. Methods Thirteen patients,who had cervical cancer recurred in pelvis treated with 3DCRT in Shanxi Cancer Hospital from May to August 2007, were selected. After CT simulation, the CT images were transferred into Topslane treatment system. The same physicist designed 3DCRT plan and common radiation therapy plan for every patient,total dose 50 Gy, 90 % is dose covered PTV, then compared the dose distribution of PTV and OAR.Results At the same prescribed dose of 50Gy,there were no significant differences on OAR maximum dose between 3DCRT plans and common radiation therapy plans(P >0.05), however, there was significant differences on PTV maximum dose(P <0.01). The difference of PTV uniformity were significant between 3DCRT plans and common radiation therapy plans (P <0.001). Compared the high dose region of OAR(V40), the difference was significant (P <0.001). Between 3DCRT plans and common radiation therapy plans, they showed 53.31 ml (90.69 %), 124.00 ml (79.47 %), 655.16 m1(92.22 %) median reduction in the V40 of rectum, bladder, intestine, respectively. Conclusion At the same PTV coverage of the prescribed dose, 3DCRT plans showed worse dose uniformity, however, the radiation volume to organs at risk in 3DCRT plans were smaller than common radiation therapy plans. So patients with cervical cancer recurred in pelvis received 3DCRT may be potentially diminish the Normal Tissue Complications Probability(NTCP).