Therapy Facility Research Articles

Passive SOBP generation from a static proton pencil beam using 3D-printed range modulators for FLASH experiments

The University Proton Therapy facility in Dresden (UPTD), Germany, is equipped with an experimental room with a beamline providing a static pencil beam. High proton beam currents can be achieved at this beamline which makes it suitable for FLASH experiments. However, the established experimental setup uses only the entrance channel of the proton Bragg curve. In this work, a set of 3D-printed range modulators designed to generate spread out Bragg peaks (SOBPs) for radiobiological experiments at ultra-high dose rate at this beamline is described. A new method to optimize range modulators specifically for the case of a static pencil beam based on the central depth dose profile is introduced. Modulators for two different irradiation setups were produced and characterized experimentally by measurements of lateral and depth dose distributions using different detectors. In addition, Monte Carlo simulations were performed to assess profiles of the dose averaged linear energy transfer (LETD) in water. These newly produced range modulators will allow future proton FLASH experiments in the SOBP at UPTD with two different experimental setups.

Demonstration of momentum cooling to enhance the potential of cancer treatment with proton therapy

In recent years, there has been a considerable push towards ultrahigh dose rates in proton therapy to effectively utilize motion mitigation strategies and potentially increase the sparing of healthy tissue through the so-called FLASH effect. However, in cyclotron-based proton therapy facilities, it is difficult to reach ultrahigh dose rates for low-energy beams. The main reason for this lies in the large momentum spread that such beams have after reducing their energy to levels required for proton therapy, incurring large losses in conventionally used momentum or energy selection slits. Here we propose momentum cooling by using a wedge in the energy selection system (instead of a slit) to reduce the momentum spread of the beam without introducing substantial beam losses. We demonstrate this concept in our eye treatment beamline and obtain a factor of two higher transmission, which could eventually halve the treatment delivery time. Furthermore, we show that with a gantry design incorporating this feature, we can achieve almost a factor of 100 higher transmission for a 70 MeV beam compared with conventional cyclotron-based facilities. This concept could enhance the potential of proton therapy by opening up possibilities of treating new indications and reducing the cost.

Pediatric Dysphonia and the Access to Voice Therapy: A Study in Speech-Language Patology Services Available in a Capital City in the Northeast of Brazil

Defining the laryngeal and vocal alterations in the pediatric group studied in private speech therapy facilities; and estimating the time period between the problem being identified by the parents and the access to the proper provided services. A cross-sectional analytical observational research with data collected from medical records by the speech therapist of each private facility. A written form was prepared and sent to the speech therapists of the 40 existing facilities. We received 124 of them from the pediatric group being assisted in 15 of the facilities. The form included questions about gender, age, vocal complaints; general degree of dysphonia; otorhinolaryngological diagnosis of vocal fold alterations; the age that the problem was identified by the parents and the beginning of speech therapy. The larynx was examined by videonasopharyngolaryngoscopy, and voice quality by auditory-perceptual assessment. The time period between the identification of the participant's dysphonia by the parents and the start of speech therapy was considered long (3.5years). The group showed variance in the proportion of nodule and cyst between genders. The highest prevalence of nodules occurred in boys; and the cyst in girls. Moderate general dysphonia occurred between 4 and 17years old, average age of 7years and 7months, with greater distribution between 5 and 10years of age. The average time delay until the start of speech therapy was 3.5years, more frequently in the 5-10years group and due to nodules in boys and cysts in girls.

Investigation on the proton range uncertainty with spectral CT-based virtual monoenergetic images.

The stopping power ratio (SPR) prediction error will contribute to the range uncertainty of proton therapy. Spectral CT is promising in reducing the uncertainty in SPR estimation. The purpose of this research is to determine the optimal energy pairs of SPR prediction for each tissue and to evaluate the dose distribution and range difference between the spectral CT with the optimal energy pairs method and the single energy CT (SECT) method. A new method was proposed based on image segmentation to calculate the proton dose with spectral CT images for the head and body phantom. CT number of each organ region were converted to SPR with the optimal energy pairs of each organ. The CT images were segmented into different organ parts with thresholding method. Virtual monoenergetic (VM) images from 70keV to 140keV were investigated to determine the optimal energy pairs for each organ based on Gammex 1467 phantom. The beam data of Shanghai Advanced Proton Therapy facility (SAPT) was employed in matRad (an open-source software for radiation treatment planning) for the dose calculation. The optimal energy pairs were obtained for each tissue. The dose distribution of two tumor sites (brain and lung) were calculated with the aforementioned optimal energy pairs. The maximum dose deviation between spectral CT and SECT at the target region was 2.57% and 0.84% for the lung tumor and brain tumor respectively. The range difference between spectral and SECT was significant with 1.8411mm for the lung tumor. γ passing rate was 85.95% and 95.49% for the lung tumor and brain tumor with the criterion 2%/2mm. This work presents a way to determine the optimal energy pairs for each organ and to calculate the dose distribution based on the more accurate SPR prediction.

Systematic Review and Meta-analysis of the Association Between Radiation Therapy Treatment Volume and Patient Outcomes

Evidence of a volume-outcome association in cancer surgery has shaped the centralization of cancer services; however, it is unknown whether a similar association exists for radiation therapy.The objective of this study was to determine the association between radiation therapy treatment volume and patient outcomes. This systematic review and meta-analysis included studies that compared outcomes of patients who underwent definitive radiation therapy at high-volume radiation therapy facilities (HVRFs) versus low-volume facilities (LVRFs). The systematic review used Ovid MEDLINE and Embase. For the meta-analysis, a random effects model was used. Absolute effects and hazard ratios (HRs) were used to compare patient outcomes. The search identified 20 studies assessing the association between radiation therapy volume and patient outcomes. Seven of the studies looked at head and neck cancers (HNCs). The remaining studies covered cervical (4), prostate (4), bladder (3), lung (2), anal (2), esophageal (1), brain (2), liver (1), and pancreatic cancer (1). The meta-analysis demonstrated that HVRFs were associated with a lower chance of death compared with LVRFs (pooled HR, 0.90; 95% CI, 0.87- 0.94). HNCs had the strongest evidence of a volume-outcome association for both nasopharyngeal cancer (pooled HR, 0.74; 95% CI, 0.62-0.89) and nonnasopharyngeal HNC subsites (pooled HR, 0.80; 95% CI, 0.75-0.84), followed by prostate cancer (pooled HR, 0.92; 95% CI, 0.86-0.98). The remaining cancer types showed weak evidence of an association. The results also demonstrate that some centers defined as HVRFs are undertaking very few procedures per annum (<5 radiation therapy cases per year). An association between radiation therapy treatment volume and patient outcomes exists for most cancer types. Centralization of radiation therapy services should be considered for cancer types with the strongest volume-outcome association, but the effect on equitable access to services needs to be explicitly considered.

MONTE CARLO NEUTRON DOSE MEASUREMENT IN PROTON THERAPY FOR HEALTHCARE WORKER RADIATION SAFETY

Background: Proton therapy is an innovative and highly advanced external radiation therapy modality for cancer treatment that uses positively charged atomic particles. The usage of proton therapy facilities in Asia has been increasing and will be followed by Indonesia in the short-coming years. In line with its significant benefits, the application of proton therapy also requires radiation protection awareness due to its higher energy used by protons produces scattered photon and neutron radiation in proton interactions. Therefore, optimal verification is needed in the commissioning process for designing proton therapy shielding bunkers. Objective: This research aims to examine the effect of concrete density on proton shielding by calculating the equivalent dose H*(10) of neutrons in the treatment control room (TCR) and the door of the compact proton therapy facility (CPTC) using Particle and Heavy Ion Transport code System (PHITS) simulation software. Method: The proton facility modeled for this simulation uses a compact proton therapy type planned to be built at one of the radiotherapy facilities in Indonesia. The proton therapy bunker model consists of a synchrocyclotron accelerator room and an examination room with standard configurations, wall thicknesses, and modeling areas under compact proton therapy standards. The analysis is focused on assessing the suitability of concrete materials and wall thicknesses and determining the neutron exposure dose values in the TCR and CPTC doors. The geometry, radiation source, and type of concrete in the wall are simulated from a conservative assumption to a more realistic model. Result: At the designated points in the TCR and CPTC door, measurements are taken from the simulation, which indicates that the equivalent dose H*(10) value is below one mSv/year. Conclusion: This value indicates that the dose rate passing through the wall does not exceed the dose limit value already set at one mSv/year for the general public.

Single proton LET characterization with the Timepix detector and artificial intelligence for advanced proton therapy treatment planning

Objective. Protons have advantageous dose distributions and are increasingly used in cancer therapy. At the depth of the Bragg peak range, protons produce a mixed radiation field consisting of low- and high-linear energy transfer (LET) components, the latter of which is characterized by an increased ionization density on the microscopic scale associated with increased biological effectiveness. Prediction of the yield and LET of primary and secondary charged particles at a certain depth in the patient is performed by Monte Carlo simulations but is difficult to verify experimentally. Approach. Here, the results of measurements performed with Timepix detector in the mixed radiation field produced by a therapeutic proton beam in water are presented and compared to Monte Carlo simulations. The unique capability of the detector to perform high-resolution single particle tracking and identification enhanced by artificial intelligence allowed to resolve the particle type and measure the deposited energy of each particle comprising the mixed radiation field. Based on the collected data, biologically important physics parameters, the LET of single protons and dose-averaged LET, were computed. Main results. An accuracy over 95% was achieved for proton recognition with a developed neural network model. For recognized protons, the measured LET spectra generally agree with the results of Monte Carlo simulations. The mean difference between dose-averaged LET values obtained from measurements and simulations is 17%. We observed a broad spectrum of LET values ranging from a fraction of keV μm−1 to about 10 keV μm−1 for most of the measurements performed in the mixed radiation fields. Significance. It has been demonstrated that the introduced measurement method provides experimental data for validation of LETD or LET spectra in any treatment planning system. The simplicity and accessibility of the presented methodology make it easy to be translated into a clinical routine in any proton therapy facility.

Neutron-Irradiation Testing of FPGA-Embedded Hadron Fluence Sensors

Hadron fluence monitors based on static random access memories (SRAMs) are being used at CERN and have been proposed for proton therapy facilities. Some of the limitations of the state of the art are related to the usage of separate components for sensing upsets and for reading them out, as these increase the power consumption, the board complexity and its size. Moreover, in some cases, due to radiation-tolerance requirements, the readout logic is fixed and it cannot be updated once the system has been implemented. In this work, we show how to overcome the mentioned limitations by using an SRAM-based field programmable gate array (FPGA) for implementing both the sensitive element (the configuration SRAM) and the readout logic (the firmware in the fabric). In fact, we describe the implementation of a compact, reprogrammable, low-power, actively self-reading hadron fluence sensor realized by means of a Xilinx Artix-7 FPGA. Moreover, we present the customized radiation-hardening-by-design techniques adopted for the readout logic. We irradiated two sensor prototypes at the Jožef Stefan Institute’s TRIGA Mark II research reactor, under different neutron spectra and flux conditions. We discuss our results, which include the measurements of the radiation tolerance, the single event upset cross section of the configuration SRAM, the sensitivity to thermal neutrons, and the failure cross section of the readout logic.

Beam dynamics optimization in the LEBT of LLICTF

A Low Energy Beam Transport (LEBT) has been designed and optimized to inject both a 50[Formula: see text]keV/u, 50[Formula: see text]mA [Formula: see text] beam and a 20[Formula: see text]keV/u, 1[Formula: see text]mA [Formula: see text] beam into the downstream Radio Frequency Quadrupole (RFQ) at the Lanzhou Light Ion Cancer Therapy Facility (LLICTF). The overall aim is to increase the operation efficiency and simplify the complexity of the LLICTF. This dual-beam operation mode creates phase space distortions as a result of the intense space charge, and causes transverse asymmetry due to a mixture of solenoids and a dipole magnet. To mitigate the phase space distortions of the high-intensity proton beam, two beam scrapers have been placed at locations determined through careful analysis of the space charge forces and external focusing force of the beam. Additionally, the Particle Swarm Optimization (PSO) algorithm has been utilized to obtain an approximate solution for the dipole parameters, which helps maintain the symmetry of different symmetrical beams passing through it. Optics designs that implement these solutions are verified with multi-particle simulations.

Analysis of particle therapy registries based on a unified treatment policy for esophageal cancer.

This study aimed to evaluate the efficacy and safety of particle therapy (proton beam therapy and carbon-ion radiotherapy) for esophageal cancer by analyzing prospective nationwide registry data from particle therapy facilities throughout Japan. Patients diagnosed with esophageal cancer who received particle therapy between May 2016 and June 2018 were recruited from the registries of 12 particle therapy centers in Japan. Eventually, we enrolled 174 patients who met the inclusion criteria. Of the 174 patients, 137 (78.7%) were male, with a median age of 69years (range: 41-88years). Clinical stages included I (n = 55; 31.6%), II (n = 31; 17.8%), III (n = 82; 47.1%), IV (n = 3; 1.7%) and unknown (n = 3; 1.7%) (Union for International Cancer Control, seventh edition), and the median follow-up period was 908days (range: 76-1669days) for all patients. The 3-year overall survival (OS) rate, the 3-year progression-free survival (PFS) rate and the 3-year local control (LC) rates were 60.5, 53.2 and 72.7%, respectively. For each clinical stage, the 3-year OS rates were I, 84.8%; II, 60.3% and III, 42.9%; the 3-year PFS rates were I, 71.9%; II, 58.3% and III, 37.0% and the 3-year LC were I, 78.4%; II, 79.8% and III, 65.2%, respectively. Notably, four patients (2.3%) with ≥Grade 3 cardiopulmonary toxicities were observed (Common Terminology Criteria for Adverse Events, version 5.0). Our study showed that particle therapy for esophageal cancer has lower rates of adverse cardiopulmonary events than X-ray radiotherapy.

Neutron Capture Therapy: The Promise of Novel Agents and Medical Facility-Based Neutron Sources

Neutron Capture Therapy: The Promise of Novel Agents and Medical Facility-Based Neutron Sources

OPTIma: a tracking solution for proton computed tomography in high proton flux environments

Currently there is a large discrepancy between the currents that are used for treatments in proton beam therapy facilities and the ultra low beam currents required for many proton CT imaging systems. Here we provide details of the OPTIma silicon strip based tracking system, which has been designed for performing proton CT imaging in conditions closer to the high proton flux environments of modern spot scanning treatment facilities. Details on the physical design, sensor testing, modelling, and track reconstruction are provided along with Monte-Carlo simulation studies of the expected performance for proton beam currents of up to 50 pA at the nozzle when using a σ= ∼10 mm spot scanning cyclotron system. Using a detailed simulation of the proposed OPTIma system, a discrepancy of less than 1% on the Relative Stopping Power is found for various tissues when embedded within a 150 mm diameter Perspex sphere. It is found that by accepting up to 7 protons per bunch it is possible to operate at cyclotron beam currents up to 5 times higher than would be possible with a single proton based readout, significantly reducing the total beam time required to produce an image, while also reducing the discrepancy between the beam currents required for treatment and those used for proton CT.

NeuTHOR Station-A Novel Integrated Platform for Monitoring BNCT Clinical Treatment, Animal and Cell Irradiation Study at THOR.

(1) Background: A well-established Boron Neutron Capture Therapy (BNCT) facility includes many essential systems, which are the epithermal neutron beam system, on-line monitoring system (OMS), QA/QC (quality assurance or quality control) system, boron concentration (BC) measurement system, and treatment planning system (TPS). Accurate data transmission, monitoring, and deposition among these systems are of vital importance before, during, and after clinical, animal, and cell BNCT irradiation. This work developed a novel integrated platform NeuTHOR Station (NeuTHORS) for BNCT at Tsing Hua Open-pool Reactor (THOR). Apart from the data of the OMS and QA/QC system, the data of BC and TPS can be loaded on NeuTHORS before BNCT clinical, animal, and cell irradiation. (2) Methods: A multi-paradigm computer programming language c# (c sharp) was used to develop the integrated platform NeuTHORS. The design of NeuTHORS is based on the standard procedures of BNCT treatment or experiment at THOR. Moreover, parallel testing with OMS-BNCT (the former OMS) and QA/QC of THOR was also performed for more than 70 times to verify the validation of NeuTHORS. (3) Results: According to the comparisons of the output, NeuTHORS and OMS-BNCT and QA/QC of THOR show very good consistency. NeuTHORS is now installed on an industrial PC (IPC) and successfully performs the monitoring of BNCT Treatment at THOR. Patients' f BC and TPS data are also input into NeuTHORS and stored on IPC through an internal network from BC measurement room and TPS physicist. Therefore, the treatment data of each patient can be instantaneously established after each BNCT treatment for further study on BNCT. NeuTHORS can also be applied on data acquisition for a BNCT-related study, especially for animal or cell irradiation experiments. (4) Conclusions: A novel integrated platform NeuTHOR Station for monitoring BNCT clinical treatment and animal and cell irradiation study has been successfully established at THOR. With this platform, BNCT radiobiology investigations will be efficiently performed and a thorough data storage and analysis system of BNCT treatments or experiments can thus be systematically built up for the further investigation of BNCT at THOR.

Predictable and robust performance of a Bi-2223 superconducting coil for compact isochronous cyclotrons

The development of ever smaller medical particle accelerators is motivated by a desire to make proton therapy accessible to more patients. Reducing the footprint of particle accelerators and subsequently proton therapy facilities allows for cheaper and broader usage of proton therapy. By employing superconducting technologies for field shaping, the size of particle accelerators can be reduced further below what is possible with saturated iron. This article discusses experiments on a first-of-its-kind double pancake (DP), and an assembly of six DP coils, designed to be used as a so-called ‘flutter coil’ for a compact isochronous cyclotron for proton therapy, fabricated from high-temperature superconducting (HTS) BiPb x Sr2Ca2Cu3O y (Bi-2223) tape. The coils were mounted under pre-stress within a stainless-steel structure to maintain mechanical stability during the experiments. The critical current as a function of the temperature of both coils was measured in a conduction-cooled setup. A model describing the coils, based on tape data, was created and revealed that the measurements were in excellent agreement with the predictions. Additional experiments were performed to study the quench and thermal runaway behaviour of the HTS coils, determining whether such coils can be protected against fault scenarios, using realistic quench-detection levels and discharge extraction-rates. These experiments demonstrate that the coils are very robust and can be well protected against quenches and thermal-runaway events using common quench-protection measures with realistic parameters.

Measuring Global Inequity in Radiation Therapy: Resource Deficits in Low- and Middle-Income Countries Without Radiation Therapy Facilities

Although radiation therapy (RT) is an effective and inexpensive pillar of multidisciplinary cancer care, access to RT facilities remains highly inequitable globally. Numerous studies have documented this resource gap, yet many countries continue facing their raging cancer epidemics ill-equipped. In this study, we present an estimation of resource deficits in low- and middle-income countries (LMICs) without any RT facilities at all. This study builds on publicly available data on country classification, population, cancer incidence, and RT requirements provided by the World Bank Group, the World Health Organization, and the International Atomic Energy Agency. Leveraging these data, we developed a capacity-planning model to estimate the current deficit of fundamental RT resources for LMICs with more than 1 million inhabitants and no active RT facilities. There were 23 LMICs with a population of more than 1 million inhabitants and without any active RT facilities, 78% of which were located in sub-Saharan Africa. The aggregate population of these countries was 197.3 million people. The largest countries without RT facilities were Afghanistan and Malawi, with a population of 38.0 million and 18.6 million inhabitants, respectively. Estimated cancer incidence for all countries under study totaled at 134,783 new cases per year, 84,239 (62.5%) of which would have required RT. There was an aggregate deficit of 188 megavoltage machines and 85 brachytherapy afterloaders, along with simulation equipment and human capital in the magnitude of approximately 3363 trained radiation oncology staff. Hundreds of thousands of patients with cancer in LMICs continue to live in countries without access to RT in their own country. This extreme form of global health inequity requires urgent and decisive action, the success of which depends on the integration of international and local efforts.

Proton Radiosurgery: Current Concepts and Limitations for CNS Radiosurgery.

Stereotactic radiosurgery (SRS) is highly conformal, high-dose radiation therapy delivered in 1-5 fractions, and is considered the standard of care for several central nervous system (CNS) indications. Particle therapies, such as protons, have physical and dosimetric advantageous properties compared to photons. However, proton SRS (PSRS) is not widely performed given the few particle therapy facilities, high-cost, and limited outcomes research as a sole modality and in comparative studies. The data available differs from each pathology. For AVMs, especially those with deep or eloquent locations, PSRS obliteration rates outcomes appear favorable and superior. For meningiomas, PSRS has been used for grade 1 alone, and for higher grades a PSRS boost has been considered. For vestibular schwannoma, PSRS seems to have favorable control rates with modest toxicity outcomes. For pituitary tumors, data shows excellent results with PSRS for functional and non-functioning adenomas. For brain metastasis, moderate doses of PSRS achieves high local control rates with low rates of radiation necrosis. For uveal melanoma, dedicated eyeline PSRS (4-5 fractions) are associated with very high tumor control and eye retention rates. PSRS is effective and safe for various intracranial pathologies. Limited data, usually retrospective and single institution series exist. There are numerous advantages of protons over photons, so it is important to understand limitations with further studies. Published clinical outcomes and widespread adoption of proton therapy will be key to unlocking the potential benefits of PSRS.

A Study on Residents’ Perception towards the Importance of Forest Therapy in the Central Region of China: Based on the Cases in Korea

Background and objective: Recently, forest therapy has received strong support from the Chinese government and gradually embarked on the road of development. However, compared with South Korea, forest therapy started late in China. And it is still in the exploration stage of theoretical research and industrial practice. To study the development of forest therapy in China, we review the legal system and development of forest therapy in Korea. This study uses online surveys to help us understand the level of awareness of the importance of forest therapy in central China. And it also provides a reference for the further development of forest therapy in China.Methods: The methods used for this analysis were Chi-square test, one-way Analysis of Variance (ANOVA), principal component analysis (PCA), and one-way Multivariate Analysis of Variance (MANOVA) .Results: Our findings showed that the perception about forest therapy was significantly different among people with different educational level (χ² = 25.526, &lt;i&gt;p&lt;/i&gt; &lt; .001). The cognition of forest therapy is significantly different from the cognition of the importance of natural healing projects (&lt;i&gt;p&lt;/i&gt; &lt; .001) and pro-environmental projects (&lt;i&gt;p&lt;/i&gt; &lt; .001). Moreover, there was a significant difference in the perception towards the importance of 18 forest therapy facilities and 9 industrial development influencing factors with or without forest therapy awareness.Conclusion: The conclusion is that our participants have low awareness of forest therapy, but they have great expectations of forest therapy. In addition, the forest environment and emergency medical facilities reflect the recognition of the importance, including treatment programs, treatment facilities and factors affecting industrial development. Therefore, considering the successful experience of forest therapy in Korea, this study proposes practical measures to strengthen publicity, facility construction and treatment program development.

Quasi-Alvarez drift-tube linac structures for heavy ion therapy accelerator facilities

Next generation heavy ion therapy and research facilities require efficient accelerating structures. Particularly, at low beam energies, right after the standard scheme of the ion source, low-energy beam transfer, and radio-frequency quadrupole (RFQ), several options for accelerating structures are available including the classic drift-tube linac (DTL), the interdigital H-mode DTL (IH-DTL), and superconducting quarter-wave resonators. These structures need to integrate the beam acceleration with the focusing channel, nowadays typically provided by permanent-magnet quadrupoles (PMQs). The frequency of operation needs to be in line with that of the RFQ structure, and it has been chosen at 750 MHz for practical considerations for the Next Ion Medical Machine Study (NIMMS) that is the application focus of this manuscript. While classic DTL structures at low ion beam energies do not provide enough space for PMQs at that frequency within a single $\ensuremath{\beta}\ensuremath{\lambda}$ period, IH-DTL structures do not provide the regular focusing channel with consequences on the beam quality. For these reasons, quasi-Alvarez drift-tube linac (QA-DTL) structures are reevaluated in this manuscript as they might fill this gap. They have not received much attention in the literature so far and therefore their design is described in detail. The design procedure presented here may serve as a blueprint for DTL design in general. In addition to the overall rf design, axial field stabilization with a new technique and multiphysics studies of the rf structure are described. A cost estimation completes the NIMMS QA-DTL study.

Introduction of Research Work on Laser Proton Acceleration and Its Application Carried out on Compact Laser–Plasma Accelerator at Peking University

Laser plasma acceleration has made remarkable progress in the last few decades, but it also faces many challenges. Although the high gradient is a great potential advantage, the beam quality of the laser accelerator has a certain gap, or it is different from that of traditional accelerators. Therefore, it is important to explore and utilize its own features. In this article, some recent research progress on laser proton acceleration and its irradiation application, which was carried out on the compact laser plasma accelerator (CLAPA) platform at Peking University, have been introduced. By combining a TW laser accelerator and a monoenergetic beamline, proton beams with energies of less than 10 MeV, an energy spread of less than 1%, and with several to tens of pC charge, have been stably produced and transported in CLAPA. The beamline is an object–image point analyzing system, which ensures the transmission efficiency and the energy selection accuracy for proton beams with large initial divergence angle and energy spread. A spread-out Bragg peak (SOBP) is produced with high precision beam control, which preliminarily proved the feasibility of the laser accelerator for radiotherapy. Some application experiments based on laser-accelerated proton beams have also been carried out, such as proton radiograph, preparation of graphene on SiC, ultra-high dose FLASH radiation of cancer cells, and ion-beam trace probes for plasma diagnosis. The above applications take advantage of the unique characteristics of laser-driven protons, such as a micron scale point source, an ultra-short pulse duration, a wide energy spectrum, etc. A new laser-driven proton therapy facility (CLAPA II) is being designed and is under construction at Peking University. The 100 MeV proton beams will be produced via laser–plasma interaction by using a 2-PW laser, which may promote the real-world applications of laser accelerators in malignant tumor treatment soon.

Implementation of Sphinx/Lynx as daily QA equipment for scanned proton and carbon ion beams.

Reporting on the first implementation of a proton dedicated commercial device (IBA Sphinx/Lynx) for daily Quality Assurance (QA) of scanned proton and carbon ion beams. Daily QA trendlines over more than 3 years for protons and more than 2 years for carbon ions have been acquired. Key daily QA parameters were reviewed, namely the spot size and position, beam range, Bragg peak width, coincidence (between beam and imaging system isocenters), homogeneity and dose. The performance of the QA equipment for protons and carbon ions was evaluated. Daily QA trendlines allowed us to detect machine performance drifts and changes. The definition of tolerances and action levels is provided and compared with levels used in the literature. The device has been successfully implemented for routine daily QA activities in a dual particle therapy facility for more than 2 years. It improved the efficiency of daily QA and provides a comprehensive QA process.