Radiat Oncol J.  2020 Mar;38(1):52-59. 10.3857/roj.2020.00101.

Magnetic resonance image-based tomotherapy planning for prostate cancer

• Jung SH
• Kim J
• Chung Y
• Keserci B
• Pyo H
• Park HC
• Park W

• KMID: 2501453
• DOI: http://doi.org/10.3857/roj.2020.00101

Abstract

Purpose
To evaluate and compare the feasibilities of magnetic resonance (MR) image-based planning using synthetic computed tomography (sCT) versus CT (pCT)-based planning in helical tomotherapy for prostate cancer.
Materials and Methods
A retrospective evaluation was performed in 16 patients with prostate cancer who had been treated with helical tomotherapy. MR images were acquired using a dedicated therapy sequence; sCT images were generated using magnetic resonance for calculating attenuation (MRCAT). The three-dimensional dose distribution according to sCT was recalculated using a previously optimized plan and was compared with the doses calculated using pCT.
Results
The mean planning target volume doses calculated by sCT and pCT differed by 0.65% ± 1.11% (p = 0.03). Three-dimensional gamma analysis at a 2%/2 mm dose difference/distance to agreement yielded a pass rate of 0.976 (range, 0.658 to 0.986).
Conclusion
The dose distribution results obtained using tomotherapy from MR-only simulations were in good agreement with the dose distribution results from simulation CT, with mean dose differences of less than 1% for target volume and normal organs in patients with prostate cancer.

Keyword

Magnetic resonance imaging; Prostate cancer; Synthetic computed tomography; Helical tomotherapy