Rusthoven Kyle E, Carter Dennis L, Howell Kathryn, Kercher Jane M, Henkenberns Phyllis, Hunter Kari L, Leonard Charles E
Department of Radiation Oncology, University of Colorado Health Sciences Center, Denver, CO, USA.
Int J Radiat Oncol Biol Phys. 2008 Jan 1;70(1):296-302. doi: 10.1016/j.ijrobp.2007.08.047.
To compare dose distribution and normal tissue sparing in partial-breast treatment using three-dimensional conformal radiotherapy (3D-CRT) vs. intensity-modulated radiotherapy (IMRT).
Sixty-three patients with Tis-1N0M0 breast cancer were treated on a Phase II prospective accelerated partial-breast IMRT protocol at two facilities between April 2004 and January 2006. Fifty-six patients had data sets sufficient to adequately contour all structures. These cases were subsequently replanned with 3D-CRT techniques using the same contours, to compare the dose distribution patterns of 3D-CRT vs. IMRT.
The average planning target volume (PTV) to ipsilateral breast (IB) ratio was 24% (range, 7-58%). The average volume of IB receiving 25%, 50%, 75%, and 100% of the prescribed dose was 4.0%, 5.0%, 5.5%, and 10.5% less with IMRT than with 3D (p < 0.01). The dose reduction to normal breast was further improved in the subset of patients whose PTV to IB ratio was >25%, and in patients with contoured breast volume <750 cm(3). No difference was detected in delivery to the lumpectomy cavity or clinical target volume. The PTV volume receiving 95% of the dose was higher in the 3D conformal plans (p < 0.01), but no significant difference was observed in the PTV volume receiving 90% (p = 0.17). The irradiated heart and lung volumes were small with both techniques but also favored IMRT.
In T1N0 patients treated with external beam partial-breast radiotherapy, IMRT improves normal tissue sparing in the ipsilateral breast compared with 3DRT, without compromising dose delivery to the lumpectomy cavity and clinical target volume.
比较三维适形放疗（3D-CRT）与调强放疗（IMRT）在部分乳腺治疗中的剂量分布及正常组织保护情况。
2004年4月至2006年1月期间，63例Tis-1N0M0乳腺癌患者在两家机构接受了II期前瞻性加速部分乳腺IMRT方案治疗。56例患者有足够的数据集来充分勾画所有结构。随后使用相同的轮廓，用3D-CRT技术对这些病例重新进行计划，以比较3D-CRT与IMRT的剂量分布模式。
同侧乳腺（IB）的平均计划靶体积（PTV）比值为24%（范围为7%-58%）。IMRT时，接受25%、50%、75%和100%处方剂量的IB平均体积比3D-CRT分别减少了4.0%、5.0%、5.5%和10.5%（p<0.01）。在PTV与IB比值>25%的患者亚组以及勾画的乳腺体积<750 cm³的患者中，对正常乳腺的剂量降低情况进一步改善。在向肿块切除腔或临床靶体积的剂量输送方面未检测到差异。3D适形计划中接受95%剂量的PTV体积更高（p<0.01），但在接受90%剂量的PTV体积方面未观察到显著差异（p = 0.17）。两种技术照射的心脏和肺体积都较小，但IMRT更具优势。
在接受外照射部分乳腺放疗的T1N0患者中，与3DRT相比，IMRT可改善同侧乳腺的正常组织保护，且不影响向肿块切除腔和临床靶体积的剂量输送。
