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Artificial Intelligence in Adaptive Radiation Therapy
CBCT or when propagating contours from one volumetric image to a new volumetric image. Registrations can be computationally demanding, requiring much time to perform, and lead to delays in the adaptive proton workow. AI can signicantly reduce the time required for performing the registrations [24]. Chapter 9 looks at the use of AI for deformable and rigid registration as it pertains to the general development of AI deformable registration tools. Specically to proton therapy, some groups have begun to develop tools to evaluate the robustness of the deformable registration, performed with or without AI assistance [2529], or used expert analysis to evaluate the contours propagated with the deformable registration [30].
18.2.3 Contour propagation
While AI tools have been developed and validated for initial contouring of patient anatomy and treatment targets (chapter 9), the same tools can be used for daily adaptive therapy. Since other AI contouring tools are designed to generate new contours without a patient specic prior, a recent study focused on adaptive proton therapy workows incorporated the planning CT contours and generated patient specic models for the daily adaptive workow [31, 32]. More work is needed to develop more robust, rapid, and reliable daily contouring tools for daily adaptive proton therapy, including rapid quality assurance reviews of the contours [25].
18.2.4 Dose calculations
The third computationally demanding step in the adaptive proton therapy workow is the dose calculation. While the pencil beam and, more recently, the Monte Carlo, dose calculations can be performed in less than 1 min [33], there are opportunities to use AI as a secondary dose check, rene the pencil beam dose calculation in the local scatter inaccuracies, or perform a full dose model [1, 3439]. There is signicant overlap between the dose calculation and plan optimization, given that each scenario of an analytic plan optimization requires at least an estimate of the dose distribution. The use of AI for proton dose calculations is at an early stage but multiple groups are developing AI tools to increase the speed of the dose calculations and potentially improve the nal plan through more optimal plan generation.
18.2.5 Plan optimization
Plan optimization for proton therapy can be a computationally demanding process, with some current commercial optimization algorithms requiring minutes to hours for the creation of multiple potential plans used for the calculation of Pareto optimal solutions. While there is extensive work ongoing to develop AI tools for rapid plan optimization, few studies have looked specically at the area of online proton plan optimization/reoptimization with AI algorithms [40]. The issue of rapid plan optimization for adaptive proton therapy has been addressed with other analytic tools (plan libraries) or approximations (limiting spots or using prior beam arrangements) [41]. The same AI tools being developed for general plan optimization in chapter 10 can be explored for online adaptive proton therapy.
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18.2.6 Other developments
There remain other issues in adaptive proton therapy for which AI will provide additional improvements. Currently, the use of CBCT has been extensively studied and validated for static anatomy. Motion artifacts are particularly challenging for CBCT imaging. As noted in chapter 8, AI can be a powerful tool to correct the motion artifacts in CBCT imaging [42, 43]. Such developments in the imaging of moving anatomy will be important for proton therapy workows.
Second, current imaging for proton therapy typically focused on the use of CT or CBCT which are not able to provide the same soft tissue or biological information of MRI or PET. Following the work described in chapter 8, the use of AI to provide synthetic MR or biological information in the context of CT based workows can potentially provide critical information to aid the adaptation or triaging of proton therapy workows [44, 45].

18.3 Implementation of adaptive proton therapy

As with any adaptive radiotherapy workow, the daily changes in the patient contours and, when required, the treatment plan must be reviewed with appropriate quality assurance. The need to verify any updated contours was discussed above and remains an area of research, in particular considering AI tools to increase the speed and accuracy of the contour reviews. In addition, there is need to perform secondary verication of the updated plan, as noted above with respect to secondary dose calculations.
There have been recent reports of quality assurance methods for adaptive proton therapy [3, 46, 47]. The current publications have not explicitly included AI tools in the online quality assurance checks but the need for rapid, robust, and reliable QA presents a strong case for incorporating AI tools in the implantation of adaptive proton therapy workows. Additionally, there are multiple groups deploying adaptive proton therapy workows including PSI in Switzerland and a collaboration between IBA, Raystation, UC Leuven, and UMCG (ProtonART). The collabo­rative model allows for the deployment of commercially developed tools in Raystation combined with vendor support from IBA and clinical experts.

18.4 Summary

Proton therapy might provide clinically superior dose distributions for some treat­ment locations as a result of the Bragg peak depth dose distribution which allows for sparing of distal tissues. Due to the sensitivity of the Bragg peak location in the patient, the precision of the dose distribution requires knowledge of the integral tissue composition, density, and magnitude. Daily set-up uncertainties, motion due to bowels or breathing, and weight or tumor changes can all contribute to variations in the proton Bragg peak locations resulting in dose delivery differences in the target as well as other organs in close proximity to the target. To maximize the advantages of the proton dose distribution, adaptive workows have been proposed to measure the changes of the integral tissues and adjust the position of the Bragg peak to stop
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at the intended position more precisely. The current adaptive proton therapy workows can require signicant time and computational resources to image, measure, adjust, and recalculate the optimal dose distribution for the current patient anatomy. Articial intelligence can provide dramatic reductions in time and improved image quality to detect the anatomic variations.

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IOP Publishing
Artificial Intelligence in Adaptive Radiation Therapy
Yi Wang and X. Sharon Qi
Chapter 19
Artificial intelligence in clinical trials
Sang Ho Lee, Huaizhi Geng and Ying Xiao
Articial intelligence (AI) is transforming clinical trials, making them more efcient,exible, and focused on patient needs. Clinical trials have always been essential to
medical progress, providing the strong evidence needed to ensure that new treat­ments, drugs, and medical devices are safe and effective. However, traditional trials can be costly, time-consuming, and sometimes difcult to organize, especially when it comes to nding and enrolling the right participants. AI offers new ways to address these challenges by making trials more adaptive and data-driven, allowing researchers to adjust plans based on patient-specic information and ongoing results. This chapter discusses the importance of clinical trials in healthcare, explains key trial methods, and explores how AI is changing the way trials are designed and run. From improving participant selection to using digital twin (DT) technology for personalized trial plans, AI is making trials more accurate and responsive. The chapter also covers important ethical and regulatory issues to consider when applying AI in clinical research. With these advances, AI has the potential to improve the speed, quality, and impact of clinical trials, leading to faster and more reliable medical discoveries.

19.1 Designing clinical trials with AI

19.1.1 The essential role of clinical trials
Clinical trials are research studies conducted to evaluate new medical treatments, drugs, or devices. Clinical trials are pivotal in advancing healthcare technology, serving as the foundation for evaluating new medical innovations. These trials are instrumental in assessing the safety, efcacy, and overall benet of emerging medical products, including drugs, devices, and health system interventions [13]. They offer a critical platform for understanding the mechanisms, therapeutic effects, and potential adverse impacts of new technologies, thus playing a key role in their development.
doi:10.1088/978-0-7503-6119-4ch19 19-1 ª IOP Publishing Ltd 2025. All rights,
including for text and data mining (TDM), artificial intelligence (AI) training, and similar technologies, are reserved.
Artificial Intelligence in Adaptive Radiation Therapy
Particularly in the eld o f medicine, clinical trials facilitate the testing and validation of novel technologies such as biomedical imaging, digital data management, and online software solutions [4–6]. These trials integrate patient engagement, data science, and technological advancements to forge innovative care pathways [7]. The incorporation of electronic health records, mobile appli­cations, and wearable devices is revolutionizing clinical trials, making them more efcient and pragmatic [8].
Furthermore, clinical trials are crucial for generating evidence that shapes clinical practices and drug development [9]. They enable the comparison of new advance­ments to conventional treatments using rigorous scientic methods [10], thereby establishing their value and efcacy. The evolving nature of clinical trials, inuenced by regulatory and technological advancements, continually refines their designs and capabilities [11].
Clinical trials contribute to the optimization of current clinical procedures and ensure that novel treatments meet the safety and efcacy standards required for FDA approval. Clinical trials are essential in developing and implementing new technologies in healthcare, providing critical evidence-based data to support their application in clinical practice.
19.1.2 Trial protocols and methodologies
Clinical trial design methodologies encompass a range of statistical and practical considerations. Chow [12] and Onken [13] both emphasized the importance of randomization, blinding, and sample size determination in ensuring the validity and reliability of trial results. Sverdlov [ 14] and Hee [15] further expanded on these principles, with Sverdlov focusing on optimal designs for different stages of drug development and Hee discussing the application of Bayesian decision theory in small trials and pilot studies. Collectively, these methodologies aimed to enhance the efciency and quality of clinical trials.
Clinical trial design methodologies include various approaches such as single­arm, placebo-controlled, crossover, factorial, noninferiority, and diagnostic device validation designs [16]. Bayesian clinical trial design methodology is used for evaluating the effect of an investigational product on both recurrent event and terminating event processes [17]. Another method involves enrolling patient candi­dates based on the predicted progression of a condition and analysing subsets of clinical trial data to generate measures of efcacy [ 18]. Optimal designs are used for different stages of clinical drug development, including phase I dose–toxicity studies, phase I/II studies, phase II dose–response studies, phase III randomized controlled multi-arm multi-objective clinical trials, and population pharmacokinetics –pharma­codynamics experiments [19]. Randomized and controlled clinical trials are consid­ered the gold standard, but the design should be tailored to the specic research question and objectives [20].
A good clinical trial protocol should include a clear research question, a detailed methodology, and a study schedule and costing [21,
22]. It should also address
potential bias through blinding and random allocation of subjects [13].
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Furthermore, it must adhere to ethical principles, such as respect for persons, benecence, and justice, as well as good clinical practice guidelines [23].
A good clinical trial protocol should include key elements such as a rationale for the study, a clear method description, measures to ensure subject safety, information about research funders and organizational details, and a plan for monitoring the trial [24]. Additionally, protocols should align with routine clinical techniques and standard clinical processes to increase the likelihood of successful execution [25]. They should also incorporate principles of good clinical practice (GCP) to ensure rigor, reproducibility, and transparency in scientic research [26]. Other important elements include predened analysis plans, standardization of procedures across sites, assurance of staff competence, transparent data coding and entry, regular quality assurance, and open publication of data [27]. Furthermore, guideline protocols should be prepared and published to clarify the purpose and scope of the guideline, facilitate the development process, ensure integrity and quality, and avoid duplication [28]. Overall, a good clinical trial protocol should be compre­hensive, transparent, and aligned with established standards and guidelines.
19.1.3 AI-driven clinical trial design and execution
AI has the potential to signicantly impact clinical trial design and execution. It can be used to reshape key steps of trial design, such as patient cohort selection and monitoring, leading to increased success rates [29]. AI can also accelerate clinical testing by automating tasks and optimizing patient selection [30]. The opportunities are signicant. AI can create efciencies in various aspects of clinical trials, such as reducing sample sizes, improving enrollment, and conducting faster and more optimized adaptive trials [3]. AI technologies such as deep learning, neural networks, and natural language processing have been applied in disease diagnosis, personal­ized treatment, drug discovery, and forecasting epidemics or pandemics [31]. AI-driven platforms can efciently identify potential trial patients by applying clinical trial criteria to real-world data, reducing patient recruitment timelines by months [32]. However, AI presents both challenges and opportunities in clinical trial design and execution. The challenges include ethical concerns, data availability, and lack of regulatory guidance, which hinder the acceptance of AI tools in drug development [33]. The implementation of AI in clinical practice is still at an early stage, and more research is needed to assess its benets and challenges [34]. However, as regulators provide more guidance, its scope of use is expected to broaden rapidly [35].
19.1.4 Incorporation of digital twins (DTs) in clinical trials
DT technology represents a transformative approach to enhancing clinical trials, offering a revolutionary means of understanding and predicting the outcomes of medical interventions. At its core, this technology involves creating a virtual replica of each patient, meticulously crafted using advanced AI methods. This DT integrates a comprehensive array of data, encompassing the patients real-world medical history, physiological and molecular characteristics, and baseline health
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information [36, 37]. Such an intricate synthesis allows for a deeper, more personalized analysis of clinical trials.
The application of DTs extends across various medical disciplines, with notable impacts in elds such as oncology and cardiology. In oncology, for instance, DTs facilitate the simulation of diverse dosing regimens. This enables researchers to delve into the nuances of dose–response relationships and uncover key determinants that inuence a patients response to treatment. Such detailed insights are invaluable in tailoring more effective, individualized treatment strategies.
Cardiac in silico clinical trials is an area where DTs are making signicant strides. By generating personalized cardiac models based on individual clinical data, these trials allow for the meticulous assessment of various therapies. This not only enhances the understanding of treatment efcacy but also paves the way for more customized therapeutic approaches [38].
A critical aspect of DT technology in clinical trials is the incorporation of blockchain technology. By embedding these advanced cryptographic systems, the integrity of trial data is signicantly bolstered, ensuring its authenticity and reliability. This integration also plays a crucial role in safeguarding participant safety, a paramount concern in any clinical trial [37].
Matched pair analysis emerges as a powerful tool in this context. Researchers can compare the outcomes of a patient undergoing a clinical trial with those predicted for their DT. This comparison allows for a more nuanced evaluation of the treatments effectiveness, providing a clearer picture of its benets and potential risks [39].
Moreover, the fusion of AI with in silico trialssimulated trials conducted digitallyis set to revolutionize clinical trial design. AIs capability to expand case group sizes, automate and optimize trial designs, and even predict success rates, heralds a new era of efciency and effectiveness in clinical research. The result is a more streamlined, accurate, and predictive trial process, potentially accelerating the development of new treatments and therapies [40].

19.2 Implementation of AI in ongoing clinical trials

19.2.1 Integration with existing clinical trial frameworks
The key components of a clinical trial infrastructure (gure 9.1) include the performance site, which can be academic medical centers, multi-specialty groups, or clinical trial companies, and the staff involved such as investigators, coordinators, raters/neuropsychologists, and managers. Other important elements are access to study participants for enrollment, appropriate training of staff, regulatory oversight through investigational review boards, and ancillary services. Different types of studies, such as therapeutic, longitudinal observational, and imaging, have varying requirements for staff and infrastructure. Efcient trial development and participant accrual can be facilitated by parallel processing of trial approval steps, a physician­led research team, and regular meetings to foster research accountability. Centralizing resources and expertise, providing training for clinical research staff,
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Figure 19.1. Clinical trial infrastructure overview, illustrating core components: performance sites, staff roles, key elements, study types, and management and operations, each detailing essential elements for trial support.
developing common data elements, and evaluating effectiveness are recommended strategies to strengthen clinical trial infrastructure [24].
Additional key components of clinical trial infrastructure include strong hospital administrative support, clinical research staff, site-specic tumor boards, patient care navigators, and integration of translational research infrastructure and capa­bilities, which is crucial in cancer trials. Financial and organizational management, new trial feasibility assessment, standardization of procedures, compliance and safety monitoring, pharmacy support, patient recruitment, effective marketing, institutional support, building diverse teams, clinician engagement, and continuing professional education are also essential for the success of clinical trials. Information technology infrastructure and human coordinating processes facilitate sponsor/CRO collaboration on international trials. Developing this infrastructure functions as a quality improvement intervention, particularly in low- and middle-income countries, and increasing efciency in trial development is crucial [41].
The fundamental principles of trial design are also key components, summarized from the previous section, including a priori formulation of a specic research question, precise description of the study population, and limitation of potential bias. Randomization and blinding of investigators and participants are critical techniques to reduce bias, and the structure of modern trials, designed to protect patient safety while generating safety and efcacy data, is shaped by regulations and international standards [23].
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