Dosimetric study on conventional mantle-field irradiation and intensity-modulated radiotherapy for Hodgkin's lymphoma

Abstract

Objective To compare the dose distribution of mantle-field radiotherapy using conven-tional radiotherapy(CRT) and four intensity-modulated radiotherapy(IMRT) techniques in stage Ⅰ and Ⅱ Hodgkin's lymphoma(HL). Methods Ten patients with patholocally proved early stage HL underwent CT simulation. Then both CRT and IMRT planning performed using ECLIPS treatment planning system(TPS). The dosimetric parameters of different irradiation plans were analyzed, including conformal index (CI), homo-geneity index (HI), D_(95) and V_(95) of planning target volume (PTV), D_(max),D_(mean),D_(min),V_5,V_(10),V_(20) and V_(30) of the lung, as well as Dmax of the spinal cord. Results The isodose distribution and homogeneity of PTV were better in IMRT plans when compared with CRT plans. Target coverage, target dose conformity and homogene-ity were similar among all the four IMRT techniques. The V_(30) of the lung using IMRT was lower than using CRT,but the low-dose volume of the lung was higher. Among the four IMRT technique plans,the lung V_(20) and V_(30) were lower in plans with more-field technique,but the V_5 and V_(10) were higher. The D_(max) of the spinal cord using IMRT was all lower than that using CRT. Conclusions IMRT is better than CRT in target cov-erage, conformity, homogeneity and normal tissue sparing, especially in protecting the spinal cord and decrea-sing high-dose lung volume,though the low-dose lung volume is higher. Seven-field IMRT technique for man-de-field radiotherapy is recommanded. Key words: Lymphoma/conventional radiotherapy; Lymphoma/intensity modulated radiothera-py; Treatment planning system; Dosimetry