Evolution of dosimetric treatment planning for pediatric total lymphoid irradiation (TLI): a single-institution experience.

Autor: Ferrer C; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain., Huertas C; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain., Ocanto A; Radiation Oncology Department, H.U. La Paz, Madrid, Spain., García D; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain., Plaza R; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain., Mínguez C; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain., de la Monja P; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain., Escribano A; Radiation Oncology Department, H.U. La Paz, Madrid, Spain., Pérez A; Pediatric Hemato-Oncology Department, H.U. La Paz, Madrid, Spain., Sáez M; Medical Physics and Radiation Protection Department, H.U. La Paz, Madrid, Spain.
Jazyk: angličtina
Zdroj: Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology [Rep Pract Oncol Radiother] 2024 Feb 16; Vol. 28 (6), pp. 772-783. Date of Electronic Publication: 2024 Feb 16 (Print Publication: 2023).
DOI: 10.5603/rpor.98734
Abstrakt: Background: Total lymphoid irradiation (TLI) is a conditioning regimen in allogeneic hematopoietic stem cell transplantation (allo-HSCT) which may reduce long-term toxicities attributed to other techniques, such as total body irradiation (TBI). At our institution, TLI treatments were first planned with the three-dimensional conformal radiation therapy (3D-CRT) technique and later with volumetric modulated arc therapy (VMAT). With the recent availability of a basic helical tomotherapy (HT), the possible dosimetric gain of the latter for TLI is studied.
Materials and Methods: 22 pediatric patients were planned for VMAT and HT, prescribed to 8 Gy in 4 fractions. VMAT was planned with template based on a single cost function, using the Monaco treatment planning system (TPS). HT plans were planned using Accuray Precision TPS for a basic HT without the dynamic jaws feature or VOLO-Ultra algorithm. Plan quality was analyzed based on four quality indices, mean and maximum doses to planning target volume (PTV) and organs at risk (OARs), dose gradient and integral doses. Differences were analyzed with Wilcoxon signed-rank test.
Results: HT plans resulted in improved conformity (CI) and homogeneity indices (HI) (p < 0.05) but less steep dose gradient (p = 0.181). VMAT plans created larger areas with high doses within the PTV, while comparable doses to OARs, except mainly for the spinal marrow, for which a reduction of 37.7% in D 2% was obtained (p < 0.05). Integral dose for non-tumor tissue was 11.3% lower with the VMAT template (p < 0.05).
Conclusion: HT achieves better conformity and homogeneity even without its more advanced features. Nevertheless, the VMAT template achieves dosimetric results close to those of HT, both with similar clinical outcome.
Competing Interests: Conflict of interest: Authors declare no conflicts of interest.
(© 2023 Greater Poland Cancer Centre.)
Databáze: MEDLINE
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