| ZHANG Gui-fang,LU Jie,WANG Chuan-dong,et al.Dosimetric comparison of two intensity modulated radiotherapy modes for breast cancer after radical mastectomy[J].Chinese Journal of Radiological Medicine and Protection,2011,31(4):456-459 |
| Dosimetric comparison of two intensity modulated radiotherapy modes for breast cancer after radical mastectomy |
| Received:July 12, 2010 |
| DOI：10.3760/cma.j.issn.0254-5098.2011.04.021 |
| KeyWords:Breast cancer Radical mastectomy Intensity modulated radiotherapy Dose distribution |
| FundProject:山东省自然科学基金(ZR2010HM071) |
| Author Name | Affiliation | E-mail | | ZHANG Gui-fang | Department of Radiation Physics, Shandong Tumor Hospital, Shandong Academy of Medical Sciences, Jinan 250117, China | | | LU Jie | Department of Radiation Physics, Shandong Tumor Hospital, Shandong Academy of Medical Sciences, Jinan 250117, China | | | WANG Chuan-dong | 山东省安丘市人民医院放射科 | | | YIN Yong | Department of Radiation Physics, Shandong Tumor Hospital, Shandong Academy of Medical Sciences, Jinan 250117, China | yinyongsd@yahoo.com.cn | | BAI Tong | Department of Radiation Physics, Shandong Tumor Hospital, Shandong Academy of Medical Sciences, Jinan 250117, China | | | SUN Tao | Department of Radiation Physics, Shandong Tumor Hospital, Shandong Academy of Medical Sciences, Jinan 250117, China | | | LIU Bo | Department of Radiation Physics, Shandong Tumor Hospital, Shandong Academy of Medical Sciences, Jinan 250117, China | | | WANG Ruo-zheng | 新疆医科大学附属肿瘤医院放射科 | |
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| Abstract:: |
| Objective To evaluate the dose distribution of target volume and normal tissues in forward intensity modulated radiotherapy (fIMRT) and inverse intensity modulated radiotherapy (iIMRT) modes for breast cancer after radical mastectomy. Methods Both fIMRT and iIMRT plans were developed for 10 patients with breast cancer after radical mastectomy. On each patient's CT images the supraclavicular area, chest wall, and internal mammary area were delineated. The prescription dose was 50 Gy in 25 fractions. In the fIMRT plan X-ray irradiation at the dose of 6 MV was adopted for the supraclavicular and the chest wall areas and electron irradiation at the dose of 9-12 MeV was adopted for the internal mammary area, and the doses of cold and hot spots were adjusted according to the fitting doses of these 3 regions. In the iIMRT plan the supraclavicular area, chest wall, and internal mammary area were taken as a whole target, 6 MV X-rays was used, and inverse optimal design was performed. The dose distribution of target volume and normal tissues, conformal index (CI ), and heterogeneous index ( HI ), and accelerator monitor unit (MU) were analyzed using dose-volume histogram(DVH)for the two intensity modulated modes. Results The maximum dose of PTV of the iIMRT plan was significantly lower than that of the fIMRT plan(t=-3.23,P<0.05), the minimum dose and V 95% of PTV of the iIMRT were significantly higher than those of the fIMRT plan(t= 4.08,-2.69, bothP<0.05). The CI level of the iIMRT plan was significantly higher than that of the fIMRT plan and the HI level of the iIMRT plan was significantly lower than that of the fIMRT plan (t=-3.13, 2.74, bothP<0.05). There were not significant differences in V 10, V 20, V 25, V 30, and D mean of the ipsilateral lung between these 2 groups. However, the V 15 of ipsilateral lung of the iIMRT group was significantly lower by 4.2% than that of the fIMRT group (t= 3.2,P<0.05). There were not significant differences in the mean dose ( D mean) and V 30 of heart, and D mean of contralateral lung and contralateral breast between these 2 groups. Conclusions Compared with fIMRT, the iIMRT plan results in more PTV coverage, higher conformity index, and more homogeneous dose distribution, with lower dose upon the lung at the affected side, and better protection of the contralateral lung, heart, and breast. |
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