放化疗期间胶质母细胞瘤的变化是通过治疗前后的磁共振成像 (MRI) 推断出来的，但由于频繁的 MRI 工作，很少进行研究。使用组合 MRI-直线加速器 (MRI-linac)，我们评估了每日放化疗期间的变化。在放化疗期间，每天使用 0.35T MRI-linac 对胶质母细胞瘤患者进行前瞻性成像，并在 3 个时间点使用或不使用独立高场造影剂进行成像核磁共振成像。分析整个治疗过程中的肿瘤或水肿（病变）和切除腔动态，并与单独的 T1 对比后 (T1 C) 和 T2 体积进行比较。在本次分析中纳入的 36 名患者中，8 名仅具有腔，12 名仅具有病变，16 名两者都有空洞和病变。其中，64% 的患者在 MRI-linac 扫描治疗期间出现病变增长，46% 的患者出现空腔缩小。病变的平均 MRI-linac 迁移距离为 1.3 cm（范围，0-4.1 cm），空腔的平均迁移距离为 0.6 cm（范围，0.1-2.1 cm）。独立体积与 MRI-linac 体积与 R2 值密切相关：0.991（T2 与 MRI-linac 腔）、0.972（T1 C 与 MRI-linac 腔）和 0.973（T2 与 MRI-linac 病变）。尽管非造影 MRI-linac 无法将造影增强与周围非增强肿瘤和水肿区分开，但 T1 C 与 MRI-linac 病变之间存在中等相关性（R2 = 0.609）。从治疗前到治疗后，所有可用扫描 (n = 35) 的患者中，T1 C 和 MRI-linac 病变一起变化 - 缩小 (n = 6)、生长 (n = 12) 或不变 (n = 8) - 在 26 例中(74%) 患者。另外 9 名患者 (26%) 在 MRI-linac 上出现生长，但 T1 C 成分有所缩小。没有患者出现 T1 C 病灶生长而 MRI-linac 病灶缩小的情况。在整个放化疗过程中，每天在 MRI-linac 上成像的胶质母细胞瘤患者都可以看到解剖学变化。随着手术切除腔缩小，边缘可能会缩小以保存正常的大脑。病变未切除或正在生长的患者可能需要扩大切缘以覆盖变化。当在非对比 MRI-linac 上看到病变生长时，有限体积胶质母细胞瘤加强试验可以考虑触发钆造影剂给药来评估适应性放射治疗。版权所有 © 2024 Elsevier Inc. 保留所有权利。

Glioblastoma changes during chemoradiation therapy are inferred from magnetic resonance imaging (MRI) before and after treatment but are rarely investigated due to logistics of frequent MRI. Using a combination MRI-linear accelerator (MRI-linac), we evaluated changes during daily chemoradiation therapy.Patients with glioblastoma were prospectively imaged daily during chemoradiation therapy on 0.35T MRI-linac and at 3 timepoints with and without contrast on standalone high-field MRI. Tumor or edema (lesion) and resection cavity dynamics throughout treatment were analyzed and compared with standalone T1 postcontrast (T1+C) and T2 volumes.Of 36 patients included in this analysis, 8 had cavity only, 12 had lesion only, and 16 had both cavity and lesion. Of these, 64% had lesion growth and 46% had cavity shrinkage during treatment on MRI-linac scans. The average MRI-linac migration distance was 1.3 cm (range, 0-4.1 cm) for lesion and 0.6 cm (range, 0.1-2.1 cm) for cavity. Standalone versus MRI-linac volumes correlated strongly with R2 values: 0.991 (T2 vs MRI-linac cavity), 0.972 (T1+C vs MRI-linac cavity), and 0.973 (T2 vs MRI-linac lesion). There was a moderate correlation between T1+C and MRI-linac lesion (R2 = 0.609), despite noncontrast MRI-linac inability to separate contrast enhancement from surrounding nonenhancing tumor and edema. From pretreatment to posttreatment in patients with all available scans (n = 35), T1+C and MRI-linac lesions changed together-shrank (n = 6), grew (n = 12), or unchanged (n = 8)-in 26 (74%) patients. Another 9 patients (26%) had growth on MRI-linac, although the T1+C component shrank. In no patient did T1+C lesion grow while MRI-linac lesion shrank.Anatomic changes are seen in patients with glioblastoma imaged daily on MRI-linac throughout the chemoradiation therapy course. As surgical resection cavities shrink, margins may be reduced to save normal brain. Patients with unresected or growing lesions may require margin expansions to cover changes. Limited volume glioblastoma boost trials could consider triggered gadolinium contrast administration for evaluation of adaptive radiation therapy when lesion growth is seen on noncontrast MRI-linac.Copyright © 2024 Elsevier Inc. All rights reserved.