Article title: Hi’CT: a pixel sensor-based device for ion tomography
DOI: 10.1007/s41365-023-01251-x
One sentence summary:
The Hi'CT system, leveraging the silicon pixel sensor technology, aims to revolutionize cancer treatment by enhancing the accuracy and safety of heavy-ion radiotherapy.
Keywords:
Heavy-Ion Imaging, Computed Tomography, Silicon Pixel Detectors, Monte Carlo, Phantoms, Radiotherapy, Image-guided, Tracking
The Novelty
This study conceptually designed and evaluated a compact full digital Heavy-Ion Computed Tomography (Hi’CT) system in a Geant4 based simulated environment. Utilizing an in-situ computational model, the Hi’CT system employs silicon pixel sensors within a micron level pixel pitch size to record and reconstruct the individual paths of carbon ions. The results achieve less than 1% deviation in Relative Stopping Power (RSP) and better image quality of CATPHAN phantoms. Furthermore, the tracking algorithm is developed as part of this system, which achieved a 20% modulation transfer function (MTF) normalization value of CTP528 imaging results at 5 lp/cm. The Hi'CT system also proposes a rapid imaging algorithm that does not require tracking process, shortening the image reconstruction time. Fast acquisition of carbon ion CT images facilitates fast patient positioning verification. By applying two dedicated algorithms, this system was tested with CATPHAN 600-series phantoms. The results fulfill the clinical requirements of distance-to-agreement (DTA) <1% in proton or heavy-ion therapy, and the density resolution can be down to 10.5%.
In the future, by directly utilizing the clinical beam for imaging and employing a compact fully digital design, Hi’CT can be integrated into compact treatment room. The real-time imaging capability reduces target deviations caused by organ or respiratory movement, achieving optimized treatment effectiveness and improved quality of life for patients.
The Background
Particle therapy, involving heavy-ion and proton therapies, has become a progressively advanced, safe, and promising avenue in cancer treatment. Despite the fact that heavy-ions have the advantage of higher relative biological effectiveness, accurately predicting the range of ions in tissues has been a long-standing challenge. This is crucial for precise dose delivery in heavy-ion radiotherapy. Current methods of making treatment plan, relying on converting X-ray Computed Tomography (CT) HU value into Relative Stopping Power (RSP) of heavy ions, which led to inevitable range uncertainties. These uncertainties necessitate the use of "safety margins" in treatment planning and this potentially exposes normal tissues to excessive radiation doses. Therefore, this study proposed a novel method, the Heavy-Ion Computed Tomography (Hi’CT) system, to resolve this problem. By using silicon pixel sensors to track the path of individual carbon ions, this technological breakthrough has the potential to significantly improve the accuracy and safety of particle therapy (heavy-ion radiotherapy), reducing the risks associated with irradiation to normal tissues.
The SDG impact
According to the published data of World Health Organization (WHO), cancer is the second leading cause of death globally, accounting for nearly 10 million deaths in 2020. The introduction of the Hi’CT system can be part of the solution which directly addresses this global health crisis by enhancing the effectiveness of cancer treatments and reducing unwanted side effects. This research is in alignment with the United Nations' Sustainable Development Goal (SDG) 3: "Good Health and Well-being", particularly targeting Indicator 3.4.1 - reducing premature mortality from non-communicable diseases through prevention and treatment. Furthermore, the development and implementation of the Hi’CT system also cater to SDG 9: "Industry, Innovation and Infrastructure", fostering technological advancements in the medical field.
Graphical Abstract
