Surface Guidance for Better Radiation Therapy Planning

Plans with lower organ-at-risk (OAR) dose, including non-coplanar VMAT plans, have historically been more difficult to plan and have taken longer to deliver than simple VMAT arcs. 

MapRT helps increase the therapeutic ratio of treatment plans, making advanced and non-coplanar planning simple and safe1-26:

    • Two lateral wide-field cameras in the CT simulation room capture a full 3D surface of patients and their accessories. This includes the key collision risk areas, such as elbows and knees. 
    • This 3D surface is then used to make a “virtual treatment room”, and calculate a clearance map: which beams are safe, for every couch/gantry angle combination. 

Published evidence shows that MapRT use can improve treatment plans in around 20% of cases27. Typical increases in treatment time for clinically meaningful OAR dose reductions are 30-50 seconds per fraction27,28.

Improved assessment of deliverability

A five-center planning study29 recently showed improved assessment of deliverability using MapRT:

Customization options to extend your MapRT system:

API Access in RayStation®

MapRT integrates directly with RayStation for collision checking and optimisation of non-coplanar beam angles.

API Access in Eclipse

MapRT clearance data can be accessed within Eclipse using the built-in Application Programming Interface (API).

Hear from users on their clinical experiences:


I would say 30 more seconds of treatment in exchange for 4% of lifetime coronary event risk [reduction], I will take it.”

Siqiu Wang, Medical Physics Resident, University of Texas Southwestern

“From day one, you can ensure that any plan that you have has a safe delivery, and you can reduce your need for physical collision checks.”

Adi Robinson, PhD, DABR, AdventHealth Celebration

Frequently Asked Questions

Clinically meaningful plan improvements have been shown with only 30 seconds increase in treatment time2. Capturing the entire patient and accessory surface during simulation typically takes 1-2 minutes. Many users find MapRT helps avoid the work of physical clearance checks, and the new API enables clinics to access clearance data within their TPS.

RayStation 2025 (Photon) has a native integration with MapRT, allowing dynamic clearance checking during plan construction.

Multiple Eclipse users have scripts to view clearance maps and beam clearances inside the TPS.

The published evidence is strong that non-coplanar VMAT treatment are superior to standard VMAT. MapRT specific evidence includes a 900-patient study showing plan improvements in 18.4% of cases1, and a multicenter trial showing improved dose conformity and compactness which would not have been considered without MapRT.

1. Smyth, G., et al. (2019). Recent developments in non-coplanar radiotherapy. The British Journal of Radiology, 92(1097), 20180908.

2. Fleckenstein, J., et al. (2018). Non-coplanar VMAT combined with non-uniform dose prescription markedly reduces lung dose in breath-hold lung SBRT. Strahlentherapie und Onkologie, 194(9), 815–823.

3. Fitzgerald et al. (2016). A comparison of three different VMAT techniques for the delivery of lung stereotactic ablative radiation therapy. J Med Radiat Sci. 2016 Mar;63(1):23-30.

4. Ma, M., et al. (2021). Dosimetric comparison of coplanar and non-coplanar beam arrangements for radiotherapy of patients with lung cancer: A meta-analysis. Journal of Applied Clinical Medical Physics, 22(4), 34–43.

5. Kim, S. T., et al. (2020). Non-coplanar VMAT plans for lung SABR to reduce dose to the heart: A planning study. The British Journal of Radiology, 93(1105), 20190596.

6. Lincoln, J. D., et al. (2023). Static couch non-coplanar arc selection optimization for lung SBRT treatment planning. Physics in Medicine and Biology, 68(15).

7. Chapet, O., et al. (2006). Potential benefits of using non-coplanar field and intensity modulated radiation therapy to preserve the heart in irradiation of lung tumors in the middle and lower lobes. Radiotherapy and Oncology, 80(3), 333–340.

8. Ye et al. (2024). Dosimetric investigation of couch rotation angles in non-coplanar VMAT plans for lung cancer SBRT. Front Oncol. 2024 Dec 24;14:1454676.

9. Frengen, J., et al. (2023). Locoregional breast radiotherapy including IMN: Optimizing the dose distribution using an automated non-coplanar VMAT technique. Acta Oncologica, 62(10).

10. Xie, Y., et al. (2020). Postmastectomy radiotherapy for left-sided breast cancer patients: Comparison of advanced techniques. Medical Dosimetry, 45(1), 34–40.

11. Xu, Y., et al. (2021). Non-coplanar volumetric modulated arc therapy for locoregional radiotherapy of left-sided breast cancer including internal mammary nodes. Radiology and Oncology, 55(4), 499–507.

12. Bharati, A., et al. (2023). Dosimetric comparison of coplanar versus non-coplanar volumetric modulated arc therapy for treatment of bilateral breast cancers. Journal of Medical Physics, 48(3).

13. Biau, J., et al. (2022). Postoperative SBRT in the treatment of early-stage oropharyngeal and oral cavity cancers with high-risk margins: A dosimetric comparison of VMAT with or without non-coplanar arcs and acute toxicity outcomes. Clinical and Translational Radiation Oncology, 38, 169–174.

14. Woods, K. E., et al. (2022). A prospective phase II study of automated non-coplanar VMAT for recurrent head and neck cancer: Initial report of feasibility, safety, and patient-reported outcomes. Cancers, 14(4), 939.

15. Gayen, S., et al. (2020). Dosimetric comparison of coplanar and non-coplanar volumetric-modulated arc therapy in head and neck cancer treated with radiotherapy. Radiation Oncology Journal, 38(2), 138–147.

16. Subramanian, V. S., et al. (2017). Multi-isocentric 4π volumetric-modulated arc therapy approach for head and neck cancer. Journal of Applied Clinical Medical Physics, 18(5), 293–300.

17. Wild, E., et al. (2015). Non-coplanar VMAT for nasopharyngeal tumors: Plan quality versus treatment time. Medical Physics, 42(5), 2157–2168.

18. Orlandi, E., et al. (2014). Radiotherapy for unresectable sinonasal cancers: Dosimetric comparison of IMRT with coplanar and non-coplanar VMAT. Radiotherapy and Oncology, 113(2), 260–266.

19. Orlandi, E., et al. (2014). Radiotherapy for unresectable sinonasal cancers: Dosimetric comparison of IMRT with coplanar and non-coplanar VMAT. Radiotherapy and Oncology, 113(2), 260–266.

20. Rossi, L., et al. (2021). On the importance of individualized, non-coplanar beam configurations in mediastinal lymphoma radiotherapy, optimized with automated planning. Frontiers in Oncology, 11, 619929.

21. Chen, X., et al. (2012). Non-coplanar intensity-modulated radiation therapy for young female patients with mediastinal lymphoma. Journal of Applied Clinical Medical Physics, 13(6), 3769.

22. Yu, V. Y., et al. (2018). A prospective 4π radiation therapy clinical study in recurrent high-grade glioma patients. International Journal of Radiation Oncology, Biology, Physics, 101(1), 144–151.

23. Raut, S., et al. (2025). A dosimetric comparison of coplanar versus noncoplanar volumetric modulated arc therapy (VMAT) for high-grade glioma. Cureus, 17(10), e94324.

24. Gonod, M., et al. (2025). Benchmarking MapRT and first clinical experience: A novel solution for collision-free non-coplanar treatment planning. Journal of Applied Clinical Medical Physics.

25. Sheng, K., et al. (2024). Quantification of dosimetry improvement with or without patient surface guidance. Advances in Radiation Oncology, 9(9), 101570.

26. Hirotaki et al. (2025). Dosimetric Comparison of Noncoplanar VMAT Without Rotating the Patient Couch Versus Conventional Coplanar/Noncoplanar VMAT for Head and Neck Cancer: First Report of Dynamic Swing Arc. Adv Radiat Oncol. 2024 Dec 30;10(3):101706.

27. Gonod et al., (2025). Benchmarking MapRT and first clinical experience: A novel solution for collision‐free non‐coplanar treatment planning. Journal of Applied Clinical Medical Physics.

28. Siqiu Wang’s presentation at SGRT USA 2024 Meeting, “SGRT in Planning: Our Clinical Experience in Surface Guided Clearance Mapping”.

29. Ke Sheng’s presentation at SGRT USA 2022 Meeting, “Surface Guided Clearance Mapping: See More, Do More and Achieve More”.

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