Diffusion tensor imaging: Possible implications for radiotherapy treatment planning of patients with high-grade glioma
Diffusion tensor imaging: Possible implications for radiotherapy treatment planning of patients with high-grade glioma
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DOI：
10.1016/j.clon.2005.04.012
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发表时间：
2005-12-01
影响因子：
3.4
通讯作者：
Burnet, NG
中科院分区：
文献类型：
--
作者：
Jena, R;Price, SJ;Burnet, NG
目的：高级别胶质瘤（HGG）的放疗计划因无法成像肿瘤周围白质浸润而受到阻碍。扩散张量成像（DTI）是一种成像技术，似乎可以显示由肿瘤浸润引起的白质异常，而传统的计算机断层扫描或磁共振成像（MRI）无法显示这种异常。我们提出了一个新的术语，基于图像的高危体积（IHV），这是不同于总肿瘤体积（GTV）的异常。对于基于DTL的IHV，我们使用术语IHVDTI。本研究评估了DTI对HGG患者放射治疗计划个体化的价值。方法：将7例活检证实的HGG患者纳入理论计划练习，比较标准计划技术和基于DTI的个性化计划。将2.5 cm临床靶体积（CTV）边缘加到GTV上生成标准计划。对于基于dti的方案，CTV是通过在IHVDTI上增加1cm的余量来生成的。计算正常组织并发症概率（NTCP）的估计值，并用于估计使用基于dti的计划可以实现的剂量递增水平。结果：DTI的使用导致非均匀边缘被添加到GTV以包含肿瘤累及的高风险区域，但是，在7例中的6例中，IHVDTI被标准CTV边缘包裹。在所有病例中，DTI可用于减少计划靶体积（PTV）的大小（平均35%，范围18-46%），导致剂量递增（平均67 Gy，范围64-74 Gy）， NTCP水平与常规治疗计划相匹配。结论：DTI可用于个体化放疗靶体积，CTV的降低允许适度的剂量增加而不增加NTCP。DTI也可能有助于根据白质浸润程度对患者进行分层。
Aims: Radiotherapy treatment planning for high-grade gliomas (HGG) is hampered by the inability to image peri-tumoural white-matter infiltration. Diffusion tensor imaging (DTI) is an imaging technique that seems to show white-matter abnormalities resulting from tumour infiltration that cannot be visualised by conventional computed tomography or magnetic resonance imaging (MRI). We propose a new term, the image-based high-risk volume (IHV) for such abnormalities, which are distinct from the gross-tumour volume (GTV). For IHV based on DTL we use the term IHVDTI. This study assesses the value of DTI for the individual isation of radiotherapy treatment planning for patients with HGG.Methods: Seven patients with biopsy-proven HGG were included in a theoretical planning exercise, comparing standard planning techniques with individualised plans based on DTI. Standard plans were generated using a 2.5 cm clinical target volume (CTV) margin added to the GTV. For DTI-based plans, the CTV was generated by adding a 1 cm margin to the IHVDTI. Estimates of normal tissue complication probability (NTCP) were calculated and used to estimate the level of dose escalation that could be achieved using the DTI-based plans.Results: The use of DTI resulted in non-uniform margins being added to the GTV to encompass areas at high risk of tumour involvement, but, in six out of seven cases, the IHVDTI was encapsulated by the standard CTV margin. In all cases, DTI could be used to reduce the size of the planning-target volume (PTV) (mean 35%, range 18-46%), resulting in escalated doses (mean 67 Gy, range 64-74 Gy), with NTCP levels that matched the conventional treatment plans.Conclusion: DTI can be used to individualise radiotherapy target volumes, and reduction in the CTV permits modest dose escalation without an increase in NTCP. DTI may also be helpful in stratifying patients according to the degree of white-matter infiltration.