Proton beam therapy (PBT) is an emerging and advanced technique for high-precision radiation treatment of cancer patients. Its success is attributable to the fact that proton beams, in contrast to conventional radiation treatment with high-energy photon beams, have a finite range and deposit most of their dose at the end of range, allowing for dose reduction in healthy tissues surrounding the tumor. However, PBT is very sensititive to tissue morphology and anatomical variations that occur during the course of treatment. Hence, image guidance is mandatory to avoid tumor underdosage and normal-tissue overdosage.

Current standard-of-care image guidance techniques using X-ray and surface imaging cannot accurately localize the tumor and capture tumor motion during dose delivery due to poor soft-tissue contrast. Hence, the targeting accuracy of PBT for tumors in the thorax, abdomen, and pelvis that move during dose delivery due to respiration, peristalsis, and organ filling is compromised. This lack poses a fundamental barrier to exploiting the full potential of PBT as a tool for high-precision radiation treatment. 

To overcome this barrier, the scientists have developed the world’s first in-beam magnetic resonance imaging (MRI) prototype system and integrated it with PBT. Real-time in-beam MRI enables high-soft tissue contrast imaging and live organ motion tracking such that proton dose delivery can be synchronized with tumor motion, and the targeting accuracy can be increased up to its physical limit. The next step is to demonstrate the clinical feasibility of integrating real-time in-beam MRI into PBT through MR-integrated proton therapy (MRiPT) for the first time worldwide within the framework of clinical trials.

The aim of the TEMPO project is to fulfill the regulatory requirements as a prerequisite for the approval of the planned clinical trials. To this end, a regulatory concept will be developed and implemented through orientation and scientific consultation meetings with the approving authorities, such as the Federal Institute for Drugs and Medical Devices (BfArM).