Dei Damiano, Lambri Nicola, Sopranzi Claudia, Galdieri Carmela, Franzese Ciro, Scorsetti Marta, Mancosu Pietro
Radiotherapy and Radiosurgery Department, IRCCS Humanitas Research Hospital, via Manzoni 56, 20089, Rozzano, Milan, Italy.
Department of Biomedical Sciences, Humanitas University, via Rita Levi Montalcini 4, 20072, Pieve Emanuele, Milan, Italy.
Strahlenther Onkol. 2025 Jun 13. doi: 10.1007/s00066-025-02415-x.
Total marrow (lymph-node) irradiation (TMI/TMLI) is designed to minimize toxicities of conventional total body irradiation in hematopoietic stem cell transplant conditioning. Planning typically relies on a computed tomography (CT) scan acquired many days before treatment (e.g. 15 days; CT-15) to allow time for plan optimization. However, anatomical changes during this interval, influenced by patient condition and concurrent therapies, can compromise dosimetric accuracy. This study evaluates the impact of shortening the CT-to-treatment timeframe to 4 days (CT-4) on dosimetric and positioning accuracy in TMI/TMLI.
Eighteen patients were enrolled in this prospective study (ClinicalTrials.gov: NCT04976205). Treatment plans, optimized with a multi-isocenter volumetric modulated arc therapy on CT-15, were recalculated on CT‑4 to assess changes in planning target volume (PTV) dose coverage (PTV_D98%). Image matching quality between CT-15/CT‑4 and cone-beam CT acquisitions was assessed with a scale of 1 to 5. Wilcoxon signed-rank test with significance set at p < 0.05 was considered.
A significant reduction in median PTV_D98% was found between CT-15 (98.0%, minimum/maximum [98.0, 98.0]%) and CT‑4 (92.2%, [62.9, 98.9]%). Image matching quality improved in 72% of patients using CT‑4 compared to CT-15. In 11% of cases, relevant discrepancies required re-optimization using CT‑4.
These findings underscore the benefits of a shorter CT-to-treatment timeframe for improving dosimetric and positioning accuracy in TMI/TMLI. Automated planning tools may further enhance TMI/TMLI workflows, particularly for patients undergoing intensive conditioning protocols.
全骨髓（淋巴结）照射（TMI/TMLI）旨在将造血干细胞移植预处理中传统全身照射的毒性降至最低。计划制定通常依赖于在治疗前数天（如15天；CT-15）获取的计算机断层扫描（CT），以便有时间进行计划优化。然而，在此期间受患者病情和同步治疗影响的解剖结构变化可能会损害剂量测定的准确性。本研究评估将CT扫描至治疗的时间缩短至4天（CT-4）对TMI/TMLI中剂量测定和定位准确性的影响。
18名患者参与了这项前瞻性研究（ClinicalTrials.gov：NCT04976205）。在CT-15上使用多中心容积调强弧形放疗优化的治疗计划在CT-4上重新计算，以评估计划靶体积（PTV）剂量覆盖（PTV_D98%）的变化。使用1至5分制评估CT-15/CT-4与锥形束CT采集之间的图像匹配质量。采用Wilcoxon符号秩检验，显著性设定为p<0.05。
在CT-15（98.0%，最小值/最大值[98.0,98.0]%）和CT-4（92.2%，[62.9,98.9]%）之间发现PTV_D98%的中位数显著降低。与CT-15相比，72%使用CT-4的患者图像匹配质量有所改善。在11%的病例中，相关差异需要使用CT-4重新优化。
这些发现强调了缩短CT扫描至治疗时间框架对提高TMI/TMLI中剂量测定和定位准确性的益处。自动化计划工具可能会进一步优化TMI/TMLI工作流程，特别是对于接受强化预处理方案的患者。
