Purpose Integrating multiple radiotherapy modalities, including photon and proton therapy, within a single clinical facility requires universal fiducial markers that perform reliably across all imaging and treatment systems. For computed tomography (CT) and image-guided radiotherapy (IGRT), fiducials should be large enough to ensure visibility without introducing significant image artifacts. In CyberKnife treatments, a fiducial diameter of at least 0.75 mm is necessary to maintain accurate tracking, particularly in the abdominal and pelvic regions. However, fiducials of this size are unsuitable for proton therapy due to the considerable beam perturbation they cause. This study investigates the design and implementation of customized fiducials that balance imaging visibility, tracking reliability, and proton beam perturbation, enabling their use across multiple radiotherapy modalities. Materials/Methods Customized coil-shaped platinum fiducials with a 0.75 mm diameter and variable coil gaps were developed to reduce the amount of metal in the proton beam path. For image visibility and trackability assessments, both standard fiducials (0.5 and 0.75 mm diameters with nominally zero coil gaps) and customized versions were inserted in an anthropomorphic phantom. Visibility was evaluated using cone-beam CT (CBCT) and kilovoltage (kV) imaging on both photon and proton treatment systems. Trackability was assessed in the CyberKnife system using an anthropomorphic phantom and a respiratory motion platform. Proton beam perturbation was measured using radiochromic films that were placed downstream of the fiducials and irradiated with a broad spread-out Bragg peak (SOBP) field. A triple-channel film dosimetry method was employed for analysis. Results Customized fiducials with increased coil gaps demonstrated visibility comparable to standard fiducials in IGRT for both photon and proton systems. In the CyberKnife system, these customized fiducials also provided reliable tracking performance under both static conditions and simulated respiratory motion. The film measurements revealed that the customized fiducials with coil gaps larger than 0.5 mm/coil could significantly reduce proton beam perturbation compared to both the standard 0.75 and 0.5 mm diameter fiducials. Conclusions This study demonstrates the feasibility of redesigning fiducial markers to maintain a large diameter for reliable imaging visibility and trackability while minimizing proton beam perturbation by increasing the coil gap. Adopting a universal fiducial marker design has the potential to streamline clinical workflows and support seamless integration across various radiotherapy modalities.

BACKGROUND:Quantum computing (QC) is emerging as a transformative tool for solving complex optimization problems across various fields, including biomedical applications. While classical optimization methods are well-established, they frequently face limitations when applied to complex and large-scale problems in radiotherapy planning. PURPOSE:This study aims to explore the implementation and evaluate the effectiveness of quantum optimization methods, specifically quantum annealing and the quantum approximate optimization algorithm (QAOA), in radiotherapy planning. In particular, we employ an Ising Hamiltonian formulation of the cost function, empirically implementing it on annealing-based quantum hardware and for the first time on circuit-based one. METHODS:We formulated a simplified radiotherapy optimization problem and solved it using quantum annealing on a D-Wave quantum annealer. Subsequently, we adapted this optimization problem for the QAOA framework and implemented it on IBM Quantum circuit-model hardware. Comparative analyses were conducted between classical and quantum methods and implementations, highlighting QC's potential advantages and limitations in specific optimization contexts. To demonstrate that the Hamiltonian formulation is valid and practically usable, we first tested it in simplified proof-of-principle examples and then extended it to a more clinically relevant bilateral prostate proton plan. In this new example, dose parameters were extracted directly from a commercial treatment planning system (RayStation) and incorporated into the Hamiltonian optimization workflow. Both one-qubit-per-voxel and two-qubits-per-voxel encodings were evaluated to illustrate scalability. Additionally, we discussed scalability considerations, practical challenges, and future research directions necessary for integrating quantum algorithms into routine clinical radiation therapy practices. RESULTS:To our knowledge, this study presents the first demonstration of using QC circuit-model hardware for radiotherapy planning optimization. The quantum annealing approach successfully determined the optimal solution. Convergence was achieved after 20 iterations on a quantum simulator (noise free) and after 100 iterations on actual quantum hardware (due to inherent hardware noise). In the bilateral prostate proton plan derived from realistic data, the Hamiltonian-based optimization assigned higher dose to the prostate relative to surrounding organs-at-risk, confirming the feasibility of applying QC optimization directly to clinically sourced parameters. CONCLUSIONS:Quantum optimization techniques demonstrate potential advantages over classical methods, particularly in complex optimization scenarios relevant to radiation therapy. The formulation of a Hamiltonian cost function, its validation on real quantum hardware, and its application to realistic data collectively represent a first concrete step toward QC-based treatment planning optimization in medical physics. Future research should focus on addressing scalability, overcoming practical implementation challenges, and advancing the development of scalable, fault-tolerant quantum systems suitable for clinical integration.

PURPOSE:Incident learning in large, multi-site hospital systems faces challenges from resource constraints, diverse site cultures, and deviations from system-wide policies. This study introduces a novel, resource-efficient hybrid approach to facilitate cross-site learning and proactive risk management, ultimately enhancing patient safety. METHODS:A hybrid approach, integrating statistical, and root cause analyses was used to analyze safety events recorded from 2023 to 2024 at five sites. Events were categorized by time, site, type, and harm score with statistics tracking the event frequency per category. Failure modes (FMs) were identified with summative keywords. The frequency and cross-site correlation of keywords were innovatively displayed by word clouds. The hybrid approach was exemplified at a high-throughput satellite clinic, where treatments and incidents were tracked quarterly. A proactive model was also employed to predict the number of potentially affected patients at this site. RESULTS:An analysis of 228 reported events revealed that most incidents occurred within the treatment planning category, where the keywords "carepath" and "contour" were identified as the top two frequently reported FMs, repeated 13 and 10 times respectively. The keywords "contour" and "documentation" appeared across four sites, followed by "carepath" and "couch" which appeared across three sites. At the featured satellite clinic, a total of 18 FMs were identified from yearly 8,714 treatments. The proactive model showed an average risk priority number decreased from 106 to 77, and the estimated number of affected patients decreased from 27 to 20 at this site. CONCLUSIONS:We developed a comprehensive, system-wide approach that enhanced efficiency in incident learning across multi-site clinics. Site-specific shifts in safety culture were effectively benchmarked and cross-site learning was facilitated through measurable endpoints. A novel word cloud analysis was developed, enhancing visualization of cross-site root causes. Additionally, a proactive model was adopted to increase system-wide preparedness and improve patient safety outcomes.

Among the genetic algorithms generally used for optimization problems in the recent decades, quantum-inspired variants are known for fast and high-fitness convergence and small resource requirement. Here the application to the patient scheduling problem in proton therapy is reported. Quantum chromosomes are tailored to possess the superposed data of patient IDs and gantry statuses. Selection and repair strategies are also elaborated for reliable convergence to a clinically feasible schedule although the employed model is not complex. Clear advantage in population size is shown over the classical counterpart in our numerical results for both a medium-size test case and a large-size practical problem instance. It is, however, observed that program run time is rather long for the large-size practical case, which is due to the limitation of classical emulation and demands the forthcoming true quantum computation. Our results also revalidate the stability of the conventional classical genetic algorithm.

Purpose:This study presents an evaluation of the dosimetric performance of radiochromic EBT4 films for clinical proton therapy, benchmarked against the widely used EBT3 model. Key parameters assessed include dose-response behavior, energy dependence, sensitivity, reproducibility, temporal stability, and longitudinal and lateral linear energy transfer (LET) effects. Methods:EBT4 films from three independent batches and one batch of EBT3 films were irradiated using monoenergetic therapeutic clinical proton beams ranging from 70 to 225 MeV. Film irradiation was done at various depths in a solid water phantom, while doses from 0.25 to 20 Gy were delivered. Following scanning, the film responses were quantified as net optical density and calibrated with absolute dose measurements from a parallel plate ionization chamber. Temporal kinetics of net optical density were studied at various time points up to 120 hours post irradiation. Film dependency on LET of the proton beams was assessed through both lateral beam profiles and longitudinal depth-dependent analyses beyond pristine Bragg peaks. Results:EBT4 films exhibited a highly linear and reproducible dose-response (R² > 0.998), with minimal energy dependence (<3%) across 70 to 225 MeV proton energies. Compared to EBT3, EBT4 films showed an under-response of approximately 13%-20% at 10 Gy, depending on the batch, with a batch-to-batch variation of ∼8% observed between EBT4 films. Reproducibility between independent irradiations was within 1%, and sensitivity tests confirmed the ability to resolve dose variations as small as ±5% for doses as low as 0.5 Gy. The film's optical density stabilized within 24 hours post-irradiation. LET-dependent response was observed in high-LET regions for EBT4 films, similar to EBT3 films. Conclusions:While EBT4 films exhibit relatively lower sensitivity compared to EBT3 and LET corrections remain necessary in high-gradient dose regions, EBT4 films are a promising candidate for routine and high-resolution proton dose measurements, provided that batch-specific calibration is performed.

Objective. We aim to characterize kinetics of radiation-induced optical density in newly released EBT4 radiochromic films exposed to clinical x-rays. Several film models and batches were evaluated for the film sensitivity, optical signal increasing with time, relative film noise, and minimum detectable limits (MDL).Approach. Radiochromic film pieces from a single batch of EBT3 and three batches of EBT4 were exposed to doses of 77.38 cGy, 386.92 cGy, and 773.84 cGy using a 6 MV x-ray beam. The films were scanned with a flatbed scanner at specific time intervals up to 120 h. The time-series net optical density of red, green and blue colors was corrected for response of the scanner with time and studied to establish the saturation characteristics of film polymerization process. Dose-response from 3.86 cGy to 1935 cGy was also determined for each color. MDL of the films was quantitatively defined as the dose that would double the net optical density of red color above the standard deviation of the residual signal at zero dose. The relative noise characteristics of EBT3 versus EBT4 were studied as a function of time, dose and scanner resolution.Main Results. For doses ≥ 100 cGy, analysis revealed a stability of optical density beyond 48 h post-exposure for EBT3 and EBT4 films. EBT3 films attained 80%-90% of their net optical density at 48 h within minutes of irradiation, compared to 72%-88% for EBT4 films. The rate of growth was slowest for blue color, fastest for red, while green was in between the two. The MDL for EBT4 averaged 15 cGy for three batches, whereas EBT3 films reliably detected doses as low as 8.5 cGy.Significance. Several batches of the new EBT4 film showed slightly lower response compared to its predecessor over 3.86 cGy to 1935 Gy range. For all practical purposes, the post-irradiation growth of polymers ceases between 48 to 60 h for both EBT films. Overall, the EBT4 film exhibited noise characteristics similar to EBT3, except for lower doses where the noise was observed to be higher than its predecessor.

Dear Editor With the expansion of proton therapy, made possible by advances such as compact beam delivery systems, sophisticated treatment planning concepts and innovative patient positioning, access to this cutting-edge treatment has increased significantly. While this growth is undoubtedly beneficial to a greater number of cancer patients, it also comes with unique challenges, especially for smaller or newly established proton centers. These centers often lack the extensive resources, established workflows and experienced staff found in larger facilities. This is where our initiative comes into play. To address these challenges, we created the GCPP to support all proton therapy centers in their mutual interest, regardless of their size, experience, or resources. The goal of the GCPP is to provide optimized, practical guidelines, technical documentation, and white papers that are essential for daily clinical operations to ensure that every patient receives the highest standard of treatment quality in proton therapy. GCPP can be defined as a set of practices motivated by Good Clinical Practice (GCP), an internationally recognized framework of standards in the field of clinical trials applied inter alia in radiotherapy, without focusing on ethics guidelines. Applied to the field of proton and particle therapy, this means that GCPP is based exclusively on scientific criteria designed to guarantee safe, effective, and efficient treatment for patients. In doing so, GCPP focuses on comprehensive quality assurance, standardized operating procedures and established irradiation conditions, paying particular attention to the contribution of medical physics experts. Consistent or comparable quality standards: Just as clinical trials are designed to provide scientifically valid and comparable results regardless of study site by applying the rigorous technical GCP criteria, GCPP aims to focus on practicable and interoperable medical physics practice standards in clinical applications of proton therapy that ensure a comparable high-quality level of treatment for every patient. Standardized operating procedures (SOPs): The greatest possible consistency or comparability of processes is critical to reducing variability in patient treatment and expanding the reproducibility of clinical outcomes. Involvement of medical physics experts: Interdisciplinary collaboration is the only way to ensure that the complex medical physics and technical aspects of proton therapy are appropriately translated into clinically successful patient treatments while maintaining the highest scientific standards. Distribution of resources: GCPP aims to focus on making medical physics knowledge that is clinically relevant, easily accessible through concise, application-oriented resources, without focusing on extensive theoretical discourses or complex guidelines. Sharing knowledge: By promoting an efficient flow of information between clinical centers, GCPP aims to contribute to the effective dissemination of relevant knowledge, best practices, and innovations. This collaborative approach will enable the sharing of experiences and solutions to common challenges in proton therapy and enable quality of care regardless of the proton center's mission or stage of development. Engagement and feedback: Through initiatives such as questionnaires that accompany our guidelines, GCPP aims to actively solicit feedback from the community to ensure that resources are practical and based on real-world applications. The nature of GCPP publications: GCPP publications aim to be concise, practical, and directly applicable to clinical workflows, making them an ideal reference tool for everyday practice. This intended practical focus, with the active solicitation of feedback from the community, will ensure that GCPP resources remain relevant and useful to all proton therapy centers. Address standardization challenges: GCPP aims to focus on supporting the current challenges associated with broader applications of proton and particle therapy treatments by promoting adherence to GCP scientific standards within and between proton centers. At the same time, this should create the conditions for successful clinical proton therapy trials to establish this innovative radiation method. By promoting standardized, high-quality proton therapy through the GCPP initiative, we aim to ensure that this sophisticated treatment modality could serve its full potential in cancer treatment. We invite the community to participate in GCPP and support the initiative to contribute to the collective effort to combine scientific rigor with practical application, which could serve to ensure long-term positive patient outcomes in proton therapy. The Journal of Applied Clinical Medical Physics (JACMP) seems to us to be the ideal platform for realizing our goals regarding distribution of important resources due to its large readership among clinical medical physicists and its focus on practical, clinically oriented publications. Because of its commitment to advancing the field through accessible and applicable research, the JACMP seems to us to be particularly well suited for the dissemination of the GCPP projects. The authors have nothing to report. The authors declare no conflicts of interest.

PURPOSE:The treatment of brain tumors in pregnant patients poses challenges, as the out-of-field dose exposure to the fetus can potentially be harmful. A pregnant patient with prior radiation treatment was presented with a brain tumor at our clinic. This work reports on our pre-treatment study that compared fetal dose exposure between intensity-modulated proton therapy (IMPT) using pencil beam scanning (PBS) and conventional photon 3D conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT), and the subsequent pregnant patient's radiation treatment. MATERIALS AND METHODS:Pre-treatment measurements of clinical plans, 3DCRT, VMAT, and IMPT, were conducted on a phantom. Measurements were performed using a device capable of neutron detections, closely following AAPM guidelines, TG158. For photon measurements, fetus shielding was utilized. On patient treatment days, which was determined to be proton treatment, shielding was used only during daily imaging for patient setup. Additionally, an in vivo measurement was conducted on the patient. RESULTS:Measurements showed that IMPT delivered the lowest fetal dose, considering both photon and neutron out-of-field doses to the fetus, even when shielding was implemented for photon measurements. Additionally, the proton plans demonstrated superior treatment for the mother, a reirradiation case. CONCLUSION:The patient was treated with proton therapy, and the baby was subsequently delivered at full term with no complications. This case study supports previous clinical findings and advocates for the expanded use of proton therapy in this patient population.

Purpose The lunar design of a Venezia ovoid makes commissioning of the applicator very challenging with traditional autoradiography. In this study, we propose a novel solution to ovoid commissioning and a quality assurance (QA) workflow to effectively assess the entire source path. Methods and materials A two-step commissioning process, using electron radiation and radiochromic films, was developed to verify the most distal source position. The ovoid was first attached to a film and was irradiated with a 12 MeV linac beam. This process was repeated on a separate, unexposed film, followed by irradiating it with a HDR source at the most distal position. Two lengths, including the ovoid thickness and the distance between the irradiated spot and the ovoid's outer surface, were obtained from the films’ intensity maps. The offset value was calculated from the subtraction of the two measured lengths. Besides acquiring the offset, a source positional simulator (SPS) and a series of planar x-rays from two orthogonal orientations were used to characterize source movement within the ovoid. Results Compared to x-ray-based autoradiography, the electron exposure significantly improved the ovoid's visibility on film. Our approach did not use surrogate, which further improved measurement outcomes by decreasing inherent uncertainties. The SPS results suggested the source movement was complex within the cervicovaginal area, but it was predictable with the proposed QA workflow. Conclusion We introduced a novel, surrogate-free method to commission the Venezia ovoid, which facilitated a manual applicator reconstruction. Additionally, we recommended QA multiple source positions to safely use the ovoid in clinical settings.

Purpose: Smit sleeves are used to facilitate insertion of the intrauterine tandem during brachytherapy for cervical cancer. When a tandem and ovoids system is used the base of the Smit sleeve displaces the ovoids distally. The dosimetric impact of this displacement is not known. Herein we performed a dosimetric analysis to quantify this impact on the integral dose and dose delivered to the organs at risk (OARs). Material and methods: Eleven high-dose-rate brachytherapy plans in which a Smit sleeve was used with a tandem and ovoids were reviewed. A second set of plans was generated modifying the position of the ovoids to simulate absence of the Smit sleeve. The high-risk clinical tumor volume (HR-CTV) dose coverage was maintained the same for both sets of plans by appropriately rescaling the dwell times of the simulated plan. The mean integral dose, D-2cc to the OARs (bladder, bowel, sigmoid and rectum) and the ICRU rectum point dose were compared between the original and modified plans using a paired two-sample t-test. Results: Simulating removal of the Smit sleeve was associated with an average reduction in the mean integral dose of 6.1% (p < 0.001) and an average reduction of 10.9% (p = 0.004) to the rectal D-2cc. Doses to the remaining OARs decreased to a lesser magnitude with only that of the sigmoid being statistically significant. Conclusions: The use of a Smit sleeve with a tandem and ovoids system could lead to the delivery of a higher mean integral dose to achieve similar HR-CTV coverage. In addition, it could increase the dose to surrounding OARs, primarily the rectum. The clinical significance of these findings is unknown, but the potential dosimetric impact of using a Smit sleeve should be taken into consideration during the planning when this device is used.

We show that by adding a workspace qubit to Ahmed Younes, et al. algorithm (Younes et al. AIP Conf. Proc. 734:171, 2004, 2008), and applying newly defined partial diffusion operators on subsystems, the algorithm’s performance is improved. We consider an unstructured list of N items and M matches, 1 ≤ M ≤ N.

A crucial issue with in vivo biological/medical EPR is its low signal-to-noise ratio, giving rise to the low spectroscopic resolution. We propose quantum hyperpolarization techniques based on 'Heat Bath Algorithmic Cooling', allowing possible approaches for improving the resolution in magnetic resonance spectroscopy and imaging.

We study superdense coding with uniformly accelerated particle in single mode approximation and beyond single mode approximation. We use four different functions, the capacity of superdense coding, negativity, discord and the probability of success for evaluating the final results. In single mode approximation, all the four functions behave as expected, however in beyond single mode approximation, except the probability of success, the other three functions represent peculiar behaviors at least for special ranges where the beyond single mode approximation is strong.

The non-vanishing residual entanglement, between the fermionic modes in the infinite acceleration limit, does not violate CHSH inequality, therefore it is not non-local. In this paper, we study the usefulness of the residual fermionic entanglement in single mode approximation and beyond single mode approximation. It is shown that there are some cases where the CHSH inequality is not violated by the residual entanglement, but the state is useful for quantum teleportation. Conditions for the violation of the CHSH inequality in terms of the “presence probability” of the particle in different Rindler regions are given for the state to be useful for teleportation and superdense coding.

Spin systems controlled and probed by magnetic resonance have been valuable for testing the ideas of quantum control and quantum error correction. This paper introduces an X-band pulsed electron spin resonance spectrometer designed for high-fidelity coherent control of electron spins, including a loop-gap resonator for sub-millimeter sized samples with a control bandwidth ~ 40 MHz. Universal control is achieved by a single-sideband upconversion technique with an I-Q modulator and a 1.2 GS/s arbitrary waveform generator. A single qubit randomized benchmarking protocol quantifies the average errors of Clifford gates implemented by simple Gaussian pulses, using a sample of gamma-irradiated quartz. Improvements in unitary gate fidelity are achieved through phase transient correction and hardware optimization. A preparation pulse sequence that selects spin packets in a narrowed distribution of static fields confirms that inhomogeneous dephasing (1/T2*) is the dominant source of gate error. The best average fidelity over the Clifford gates obtained here is 99.2%, which serves as a benchmark to compare with other technologies.