Comparative analysis of target volume coverage and liver exposure in high-dose-rate interstitial brachytherapy and in silico MR LINAC-based stereotactic body radiotherapy plans for colorectal liver metastases

Mansoorian, Sina; Hering, Svenja; Hofmaier, Jan; Xiong, Yuqing; Weingandt, Helmut; Rottler, Maya; Walter, Franziska; Rogowski, Paul; Seidensticker, Max; Ricke, Jens; Belka, Claus; Corradini, Stefanie; Eze, Chukwuka (2026): Comparative analysis of target volume coverage and liver exposure in high-dose-rate interstitial brachytherapy and in silico MR LINAC-based stereotactic body radiotherapy plans for colorectal liver metastases. Clinical and Translational Radiation Oncology, 56: 101030. ISSN 24056308

Abstract

Background

This study compared the plan quality and dosimetric parameters of single-fraction (SF) MR-LINAC (MRL)-based stereotactic body radiotherapy (SBRT) with delivered high-dose-rate interstitial brachytherapy (HDR-iBT) for colorectal liver metastases (CRLM).

Methods

Between August 2017 and March 2019, 26 patients with a total of 45 CRLM were treated in 28 sessions using HDR-iBT with 1 × 25 Gy and were retrospectively included in this study. For each patient, an in silico MRL-based SBRT plan was generated using the corresponding iBT CT dataset. In the iBT plans, a single fraction of 25 Gy was prescribed to the periphery of the gross tumor volumes (GTVs), while in the SBRT plans, the same dose was prescribed to the 80% isodose line covering the planning target volumes (PTVs). We compared the dosimetric properties of the delivered HDR-iBT and MRL-based SBRT plans.

Results

Median GTV was 3.83 cc (range: 0.13–92.58 cc) and median PTVSBRT was 15.47 cc (range: 2.68–164.17 cc). Both HDR-iBT and SBRT demonstrated excellent GTV coverage, with no statistically significant differences in GTV D98% (28.82 ± 2.57 Gy vs. 28.92 ± 0.88 Gy, p = 0.9). HDR-iBT achieved superior GTV D95% (31.62 ± 3.20 Gy vs. 29.22 ± 0.74 Gy, p < 0.01) and GTV D50% (64.71 ± 12.78 Gy vs. 30.22 ± 0.52 Gy, p < 0.01). Uninvolved liver dose metrics were higher in the SBRT plans compared to iBT, with a median relative difference in V5Gy of 5.29% (range: −13.69% to + 17.89%, p < 0.01) and a smaller relative difference in V10Gy of 1.5% (range: −7.74% to + 11.26%, p < 0.01).

Conclusion

Our comparison indicates MRL-based SBRT to liver lesions is feasible, achieving adequate target volume coverage without clinically relevant violations of organ-at-risk (OAR) constraints.

• Dokumententyp: Artikel (Klinikum der LMU)
• Organisationseinheit (Fakultäten): 07 Medizin > Klinikum der LMU München > Klinik und Poliklinik für Strahlentherapie und Radioonkologie
• DFG-Fachsystematik der Wissenschaftsbereiche: Lebenswissenschaften
• DFG: Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 491502892