# Bringing 4π radiation therapy to the clinic

> **NIH NIH R44** · CELESTIAL ONCOLOGY INC. · 2022 · $1,132,278

## Abstract

Significance/Innovation: Utilizing non-coplanar beams in radiotherapy can significantly improve dosimetry for
better normal organ sparing and tumor targeting. However, the optimality of such therapy requires extensive
and efficient utilization of non-coplanar beams that are incompatible with existing radiotherapy platforms. The
widely available C-arm gantry systems are collision prone, cumbersome, and require undesirable patient couch
motion to achieve the non-coplanar angles. The existing robotic system lacks posterior beams and a planning
system to integrally optimize beam orientation and fluence, making it extremely limited in achievable dosimetry,
target sizes, applicable disease sites, and throughput.
Motivated by these clinical and market needs UCLA and RadiaBeam are developing a new robotic
radiotherapy platform called Polaris that overcomes the limitations of existing radiotherapy systems, with the
following innovative advantages: 1. A super compact 6MV linear accelerator enables unobstructed access to
4π solid angle, including posterior beams. 2. A mathematical framework for integrated beam orientation,
source-to-tumor distance, and fluence map optimization, which can efficiently create substantially better plans
than the clinical state-of-the-art. 3. A 3D image guidance system will be implemented for the first time on a
robotic radiotherapy system without impeding the degrees of freedom in non-coplanar delivery. 4. The
combination of hardware and software allows superior dosimetry to be efficiently delivered to targets of all
sizes, making our system a superior replacement of all C-arm gantry systems and the existing robotic
radiotherapy system as a general-purpose radiotherapy machine.
During the SBIR project (NIH Phase II 5R44CA183390-04), Celestial Oncology Inc. was founded to bring the
Polaris system to market, and received a $6M series A investment in 2020. This NIH SBIR Phase IIB bridge
project will accelerate the completion of the last technical, regulatory, and clinical steps required to bring this
life-saving therapy to the clinic. We propose the following aims:
Aims: 1a: Mechanically synchronize the X-ray source and detector robots. 1b. Collect projections for circular
and helical trajectories for CBCT reconstruction. 1c. Integrate the imaging component for end-to-end IGRT
accuracy validation. 2a. Complete the design, manufacturing, verification, and validation of the clinical system.
2b. Submit for US market clearance. 2c. Establish and certify a Quality Management System. 3a. Installation
and acceptance tests of the 4π radiotherapy system at UCLA. 3b. Early phase clinical study.
Impact: Polaris will serve as a superior replacement of all general-purpose machines with advantages in dose
conformity, automation, and throughput. These advantages will drive rapid adoption. The success of this
project will clear the last hurdles between the current level of technical development and what is needed to be
commercially and clinically...

## Key facts

- **NIH application ID:** 10464360
- **Project number:** 2R44CA183390-05
- **Recipient organization:** CELESTIAL ONCOLOGY INC.
- **Principal Investigator:** Ke Sheng
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $1,132,278
- **Award type:** 2
- **Project period:** 2022-05-06 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10464360

## Citation

> US National Institutes of Health, RePORTER application 10464360, Bringing 4π radiation therapy to the clinic (2R44CA183390-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10464360. Licensed CC0.

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