Faculty Collaboration Database

Treatment planning for MR-guided SBRT of pancreatic tumors on a 1.5 T MR-Linac: A global consensus protocol. Clin Transl Radiat Oncol 2024 Jul;47:100797

Date

06/04/2024

Pubmed ID

38831754

Pubmed Central ID

PMC11145226

DOI

10.1016/j.ctro.2024.100797

Scopus ID

2-s2.0-85193854752 (requires institutional sign-in at Scopus site)   3 Citations

Abstract

BACKGROUND AND PURPOSE: Treatment planning for MR-guided stereotactic body radiotherapy (SBRT) for pancreatic tumors can be challenging, leading to a wide variation of protocols and practices. This study aimed to harmonize treatment planning by developing a consensus planning protocol for MR-guided pancreas SBRT on a 1.5 T MR-Linac.

MATERIALS AND METHODS: A consortium was founded of thirteen centers that treat pancreatic tumors on a 1.5 T MR-Linac. A phased planning exercise was conducted in which centers iteratively created treatment plans for two cases of pancreatic cancer. Each phase was followed by a meeting where the instructions for the next phase were determined. After three phases, a consensus protocol was reached.

RESULTS: In the benchmarking phase (phase I), substantial variation between the SBRT protocols became apparent (for example, the gross tumor volume (GTV) D_99% ranged between 36.8 - 53.7 Gy for case 1, 22.6 - 35.5 Gy for case 2). The next phase involved planning according to the same basic dosimetric objectives, constraints, and planning margins (phase II), which led to a large degree of harmonization (GTV D_99% range: 47.9-53.6 Gy for case 1, 33.9-36.6 Gy for case 2). In phase III, the final consensus protocol was formulated in a treatment planning system template and again used for treatment planning. This not only resulted in further dosimetric harmonization (GTV D_99% range: 48.2-50.9 Gy for case 1, 33.5-36.0 Gy for case 2) but also in less variation of estimated treatment delivery times.

CONCLUSION: A global consensus protocol has been developed for treatment planning for MR-guided pancreatic SBRT on a 1.5 T MR-Linac. Aside from harmonizing the large variation in the current clinical practice, this protocol can provide a starting point for centers that are planning to treat pancreatic tumors on MR-Linac systems.

Author List

Grimbergen G, Eijkelenkamp H, Snoeren LMW, Bahij R, Bernchou U, van der Bijl E, Heerkens HD, Binda S, Ng SSW, Bouchart C, Paquier Z, Brown K, Khor R, Chuter R, Freear L, Dunlop A, Mitchell RA, Erickson BA, Hall WA, Godoy Scripes P, Tyagi N, de Leon J, Tran C, Oh S, Renz P, Shessel A, Taylor E, Intven MPW, Meijer GJ

Authors

Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of Wisconsin
William Adrian Hall MD Professor in the Radiation Oncology department at Medical College of Wisconsin