Search Results (301)

This article presents a comprehensive overview of the current and emerging roles of cryogenics and superconductivity in medical diagnostics, imaging, and therapy. Beginning with the historical foundations of both fields and their technological maturation, this review emphasizes how cryogenic engineering and superconducting materials have become indispensable to modern medical systems. Cryogenic technologies are highlighted in applications such as cryosurgery, cryotherapy, cryostimulation, and cryopreservation, all of which rely on controlled exposure to extremely low temperatures for therapeutic or biological preservation purposes. This article outlines the operating principles of cryomedical devices, the refrigerants and cooling methods used, and the technological barriers. This paper reviews the latest applications of superconductivity phenomena in medicine and identifies those that could be used in the future. These include cryogenic therapy, radiotherapy (cyclotrons, particle accelerators, synchrotron radiation generation, isotope production, and proton and ion beam delivery), magnetic resonance imaging (MRI), nuclear magnetic resonance spectroscopy (NMR), positron emission tomography (PET), and ultra-sensitive magnetic signal transducers based on SQUIDs for detecting ultra-low bio-signals emitted by human body organs. CT, MRI/NMR, and PET features are compared using the operation principle, specific applications, safety, contraindications for patients, examination time, and additional valued peculiarities. This article outlines the prospects for the development of superconducting and cryogenic materials and technologies in medical applications. Advances in diagnostic imaging are reviewed, with particular attention on the progression from conventional MRI scanners to ultra-high-field (UHF) systems exceeding 7–10.5 T, culminating in the 11.7 T Iseult whole-body MRI magnet. Another important application area described in this article includes biofunctionalized magnetic nanoparticles and superconducting quantum interference devices (SQUIDs), which enable the ultrasensitive detection of biomagnetic fields and targeted cancer diagnostics. Finally, this article identifies future directions of development in superconducting and cryogenic technologies for medicine. Full article

Background/Objectives: Traditionally, proton therapy assumes a fixed relative biological effectiveness (RBE) value of 1.1, which can lead to inaccurate dose calculations in treatment planning. This study examines the effect of dynamic arc delivery and pencil beam scanning (PBS) linear energy transfer (LET) optimization on LET-dependent RBE dose escalation to nervous tissue structures in head and neck (H&N) cancer patients undergoing proton beam therapy, utilizing two RBE dose models. Methods: Fifteen head and neck cancer patients previously treated with PBS proton therapy at high risk of nervous tissue toxicity were retrospectively analyzed. Three plans were developed for each patient: PBS, dynamic arc, and PBS with LET optimization. RBE-weighted dose distributions were calculated and compared for all patient plans using a linear LET-weighted model and a tissue-specific α/β-dependent model. LET-dose (LET_d) constraints were systematically tested to determine optimal values for plan quality and efficacy in altering LET spatial distribution in regions of concern. LET-dependent RBE enhancement was calculated for the three different planning methods. Results: Dynamic arc plans increased RBE enhancement when compared to PBS, while LET optimization for PBS consistently reduced RBE-enhanced dose to nervous tissue compared to non-optimized plans for both RBE models. Patient-specific variability in optimization benefit was observed, with the most significant improvements in cases with greater initial RBE enhancement. A maximum LET_d constraint of 2.5 µm/keV above 80% of the maximum structure dose threshold was found to balance plan quality and RBE mitigation. Conclusions: Dynamic arc delivery increased RBE enhancement relative to static PBS. LET optimization successfully modified LET_d spatial distributions to minimize RBE enhancement to nervous tissue structures when compared to non-LET optimized PBS and dynamic arc plans. Patient-specific risk stratification should be used when clinically deploying LET optimization. Full article

Purpose: Peripapillary choroidal melanoma provides a unique challenge; proximity to visually important structures, such as the optic disc and fovea, confers a high risk for the development of maculopathy and optic neuropathy, leading to poorer visual outcomes with most forms of radiotherapy. Ocular proton therapy (OPT) requires an aperture to shape the beam to the tumour. An aperture ‘notch’ may minimise damage to the optic disc and/or the fovea. This study aims to explore if there are any additional advantages to incorporating a notch over the optic nerve beam area. Design: Retrospective audit (cohort study). Participants: Participants included eighty-three patients treated at Liverpool with proton beam therapy from January 2012 to March 2020 for their peripapillary choroidal melanoma. All had a minimum of two and a half years of follow-up vision data; this was to ensure there was enough visual acuity assessment data to perform sufficient analysis. Patients excluded had choroidal melanoma situated over 3 mm from the optic disc, as these were unlikely to have an aperture notch. Methods: A retrospective audit was undertaken in accordance with the Declaration of Helsinki, and registered with the Royal Liverpool Hospitals audit department (audit reference number: Ophth/SE/2024-25/25). Data was collated from the Liverpool Ocular Oncology database, clinic letters and the individual proton beam 3D plans. Robust statistical analysis using a mixed effects model was used to explore associations between notched beams and vision loss and complications. Main Outcome Measures: The primary outcome measure is visual acuity loss post-proton beam therapy. Secondary outcome measures were enucleation and other complication rates. Results: Analysis shows that at 10 years post-OPT, there would be an expected 0.058 (p = 0.077) logMAR of vision saved using a notch for the optic disc compared to no notch (normal apertures); this is considered clinically significant. This cohort also loses vision at a slower rate than other cases. No other predictors were found to be statistically significant for loss of vision, and notched beams showed no advantage in reducing rates of complications. Conclusions: There is some evidence of a trend that utilising a notch for optic disc does show long-term vision benefit; it demonstrates a clinically significant benefit in patients with peripapillary choroidal melanoma. Full article

Background: skull base chordoma (Ch) and chondrosarcoma (ChSa) are rare neoplasms prone to local relapse. Alongside surgery, proton therapy (PT) is a well-established treatment for them. Given the relatively long patient survival expectancy, post-treatment quality of life (QoL) is crucial. This study prospectively assessed long-term QoL in this collective. Methods: seventy-seven adult patients (median age, 50 years; male n = 31; 40.3%) with skull base Ch/ChSa completed at least two EORTC-QLQ-C30 and BN20 questionnaires during and after PT. Oncological outcomes and therapy-related toxicities were recorded during follow-up. QoL was analyzed, with post-treatment scores compared to each patient’s baseline and correlated to oncological outcomes. Results: median follow-up was 51 months (range, 1–94), with 5-year overall survival (5yOS) and local control (5yLC) rates of 88.8% and 82.8%, respectively. The time to local or distant failure ranged from 8 to 58 (median, 22) months. QoL deteriorated directly at completion of PT and two to three years thereafter, especially in patients with local or distant failure. From the fifth year onward, QoL improved again. Complete resection before PT correlated to better QoL at all time points. Disease progression was associated with overall worse QoL, higher neurological symptoms already before PT, and higher symptom burden one year thereafter. Males reported better QoL before and one year after PT than females. Conclusions: PT achieves excellent OS and LC in patients with skull base Ch/ChSa. QoL declines directly after PT but remains close to reference population values. From the fifth year onward, QoL improves again. Gender, resection status, and disease progression significantly affect QoL in these patients. Full article

Background: Adolescents and young adults (15–39 years of age at time of diagnosis: AYA) with sarcoma are a unique patient population. The objective of this review is to examine the literature outlining the benefits of proton beam therapy (PBT) for treatment of AYA sarcoma patients, barriers to PBT, evaluation of AYA-specific considerations and challenges, and exploration of future opportunities for improvements in care. Methods: An electronic search was conducted using databases and online search engines, primarily PubMed. The search criteria included studies and reviews completed from 2015 to 2025. Results: 57 articles were reviewed and categorized into sections: PBT for the treatment of the AYA patient, barriers to PBT, AYA-specific considerations and challenges, and future directions for the care of an AYA patient. Conclusions: Through this review, PBT can be deemed necessary when treating AYA sarcoma patients with radiation therapy to decrease long-term therapy-related toxicities. Furthermore, considerations for caring for an AYA sarcoma patient must extend beyond evidence-based treatment plans and must embrace the patient as a whole person through acknowledgement of the challenging impact on physical, mental, and social well-being from symptoms to diagnosis, diagnosis to treatment, and treatment to survivorship. Full article

Accurate knowledge of a patient’s anatomy during every treatment fraction in proton therapy is an important prerequisite to ensure a correct dose deposition in the target volume. Adaptive proton therapy aims to detect those changes and adjust the treatment plan accordingly. One way to trigger a daily re-planning of the treatment is to take a proton radiograph from the beam’s-eye view before the treatment to check for possible changes in the water equivalent thickness (WET) along the path due to daily changes in the patient’s anatomy. In this paper, the Two-Plane Imaging System (TPIS) is presented, comprising two ATLAS IBL silicon pixel-detector modules developed for the tracking detector of the ATLAS experiment at CERN. The prototype of the TPIS is described in detail, and proof-of-principle WET images are presented, of two-step phantoms and more complex phantoms with bone-like inlays (WET 10 to 40 mm). This study shows the capability of the TPIS to measure WET images with high precision. In addition, the potential of the TPIS to accurately determine WET changes over time down to 1 mm between subsequently taken WET images of a changing phantom is shown. This demonstrates the possible application of the TPIS and ATLAS IBL pixel-detector module in adaptive proton therapy. Full article

Very-high-energy electron (VHEE) beams, ranging from 50 to 300 or 400 MeV, are the subject of intense research investigation, with considerable interest concerning applications in radiation therapy due to their accurate energy deposition into large and deep-seated tissues, sharp beam edges, high sparing properties, and minimal radiation effects on normal tissues. The very-high-energy electron beam, which ranges from 50 to 400 MeV, and Ultra-High-Energy Electron beams up to 1–2 GeV, are considered extremely effective for human tumor therapy while avoiding the spatial requirements and cost of proton and heavy ion facilities. Many research laboratories have developed advanced testing infrastructures with VHEE beams in Europe, the USA, Japan, and other countries. These facilities aim to accelerate the transition to clinical application, following extensive simulations for beam transport that support preclinical trials and imminent clinical deployment. However, the clinical implementation of VHEE for FLASH radiation therapy requires advances in several areas, including the development of compact, stable, and efficient accelerators; the definition of sophisticated treatment plans; and the establishment of clinically validated protocols. In addition, the perspective of VHEE for accessing ultra-high dose rate (UHDR) dosimetry presents a promising procedure for the practical integration of FLASH radiotherapy for deep tumors, enhancing normal tissue sparing while maintaining the inherent dosimetry advantages. However, it has been proven that a strong effort is necessary to improve the main operational accelerator conditions, ensuring a stable beam over time and across space, as well as compact infrastructure to support the clinical implementation of VHEE for FLASH cancer treatment. VHEE-accessing ultra-high dose rate (UHDR) perspective dosimetry is integrated with FLASH radiotherapy and well-prepared cancer treatment tools that provide an advantage in modern oncology regimes. This study explores technological progress and the evolution of electron accelerator beam energy technology, as simulated by the ASTRA code, for developing VHEE and UHEE beams aimed at medical applications. FLUKA code simulations of electron beam provide dose distribution plots and the range for various energies inside the phantom of PMMA. Full article

Experimental measurement of dose distributions is a pivotal step in the quality assurance of radiotherapy treatments, especially for those relying on high delivery accuracy such as hadron therapy. This study investigated the response of a polymer gel dosimeter to determine its suitability in performing geometric beam characterizations for hadron therapy under high-quenching conditions. Different extraction energies of proton and carbon ion beams were considered. Gel dose–response linearity and long-term stability were confirmed through optical measurements. Gel phantoms were irradiated with pencil beams and analyzed via magnetic resonance imaging. A multi-echo T₂-weighted sequence was used to reconstruct depth–dose profiles and transversal distributions acquired by the gels, which were benchmarked against reference data. As expected, a response-quenching effect in the Bragg peak region was noted. Nonetheless, the studied gel formulation proved reliable in acquiring the geometric characteristics of the beams, even without correcting for the quenching effect. Indeed, depth–dose distributions acquired by the gels showed an excellent agreement with measured particle range with respect to reference values, with mean discrepancies of 0.5 ± 0.2 mm. Single-spot transverse FWHM values at increasing depths also presented an average agreement within 1 mm with values determined with radiochromic films, thus supporting the excellent spatial resolving capabilities of the dosimetric gel. Full article

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults, associated with a high tendency for metastasis to the liver. Proton beam therapy (PBT) is the preferred external radiotherapy treatment for primary UM of certain sizes and locations in the eye, due to its efficacy and good local tumour control, as well as its precision to spare surrounding ocular structures. PBT is an effective alternative to surgical enucleation and other non-precision-targeted radiotherapies. Despite this, the radiobiology of UM in response to PBT is still not fully understood. This enhanced knowledge would help to further optimise UM treatment and improve patient outcomes through reducing radiation dosage to ocular structures, treating larger tumours that would otherwise require enucleation, or even offering a treatment strategy for the otherwise fatal liver metastases. In this review, we explore current knowledge of the treatment of UM with PBT, evaluating the biological responses to the therapy. Molecular factors, such as tumour size, oxygen tension levels, DNA damage proficiency, and autophagy, are known to influence the cellular response to radiotherapy, and these will be discussed. Furthermore, we examine innovative strategies to enhance radiotherapy outcomes, such as combination therapies with DNA damage repair and autophagy modulators, as well as advancements in PBT planning and delivery. By integrating current research and emerging technologies, we aim to provide opportunities to improve the therapeutic effectiveness of PBT in UM management. Full article

Cutaneous malignancies represent the most common cancers worldwide and pose a growing public health burden. While surgical excision remains the primary curative modality, radiotherapy offers an effective adjuvant therapy for high-risk histopathologic features and an established, organ-preserving alternative for patients with inoperable disease or lesions in cosmetically or functionally sensitive sites. Advances in radiotherapeutic techniques, including brachytherapy and proton therapy, have expanded the therapeutic armamentarium, allowing tailored treatment based on tumor depth, extent, and anatomical location. Contemporary evidence highlights favorable local control and toxicity outcomes with modern radiation therapy approaches, yet data remain fragmented, with most studies limited by small cohorts, heterogeneous methodologies, and limited follow-up durations. Furthermore, the role of radiotherapy in complex scenarios, such as perineural invasion, recurrent disease, and previously irradiated fields, continues to evolve. This review synthesizes the current literature on radiotherapeutic management of skin cancer, critically evaluates dosimetric and clinical outcomes across modalities, and identifies key gaps in evidence. Emphasis is placed on the need for prospective, multicenter investigations to better define comparative effectiveness, optimize dose-fractionation regimens, and integrate emerging technologies into clinical practice. Radiotherapy remains an indispensable modality in dermatological oncology, offering curative potential with preservation of cosmesis and function, yet its optimal utilization demands further high-quality research to refine patient selection and therapeutic strategies. Full article

Background: Proton beam therapy (PBT) provides excellent tumor control with minimal hepatic toxicity in patients with unresectable hepatocellular carcinoma (HCC), by minimizing radiation exposure to non-cancerous liver tissue. Progressive skeletal muscle loss, often seen in cirrhosis and HCC, can negatively impact treatment outcomes and survival. This study compared the efficacy and safety of PBT with transarterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) in patients with unresectable HCC. Methods: A total of 91 patients (PBT/TACE+RFA, n = 41/50) ineligible for surgery or RFA alone were retrospectively analyzed, with propensity score matching applied to adjust for differences in baseline characteristics, resulting in matched groups of 33 patients each. The cross-sectional area of the psoas muscle at the third lumbar vertebra was assessed using computed tomography. Results: PBT resulted in longer overall survival (OS) and fewer hepatic and systemic adverse events compared to TACE+RFA, with no grade 3 or higher toxicities observed in the PBT group. Importantly, psoas muscle size remained stable after PBT, even in patients with tumors ≥ 3 cm, whereas TACE+RFA led to significant muscle loss regardless of tumor size, which was associated with poorer prognosis. These findings suggest that, for patients with unresectable HCC not adequately controlled by RFA alone, PBT may improve OS and help preserve muscle mass, while offering lower toxicity and more favorable clinical outcomes than TACE+RFA. Conclusions: Overall, PBT may represent an effective strategy for managing unresectable HCC. Full article

Because hepatocellular carcinoma (HCC) is a radiosensitive cancer, radiation therapy has been used for the treatment of HCC; however, external beam therapies are currently not described in most of the guidelines for the treatment of HCC. External beam therapies include photon beam therapies and particle beam therapies, which are composed of X-rays or gamma rays and beams of carbon ions or protons, respectively. The focus of this narrative review is carbon-ion radiotherapy (C-ion RT). C-ion RT is well tolerated by elderly patients with HCC and/or sarcopenic patients. In general, a single HCC greater than 30 mm is a good indication for C-ion RT in patients with Child Grade A/B or ALBI Grade 1/2. The local control rates and overall survival rates at 5 years after C-ion RT for HCCs larger than 30 mm are excellent, with fewer adverse events, such as radiation-induced liver damage. Advanced HCC with portal vein tumor thrombus is also an indication for C-ion RT in certain selected patients. C-ion RT is a promising therapeutic option for patients with HCC. Full article

This paper presents the development of two mobile brain Positron Emission Tomography (PET) scanners under the PETITION project, designed for Intensive Care Units (ICUs) and Proton Beam Therapy (PBT) applications. The ICU scanner facilitates bedside imaging for critically ill patients, while the PBT scanner enables undisturbed proton beam irradiation during imaging. Key aspects of the hardware design, including modular detectors and electromagnetic interference considerations, are discussed along with preliminary performance evaluations. Operational testing, employing a ²²Na source and a hot-rod phantom, was conducted to determine the timing resolution (548 $\mathrm{p}$$\mathrm{s}$), energy resolution (11.4%) and a qualitative spatial resolution (around 2.2 $\mathrm{m}$$\mathrm{m}$). Our study presents findings on the ICU PET scanner’s electromagnetic emissions measured in a controlled EMC testing facility, where all the emissions tests performed comply with the standard EN 60601-1-2 (radiated emissions 15 dB below regulatory limits in the frequency range of 30 $\mathrm{M}$$\mathrm{Hz}$ to 1 G$\mathrm{Hz}$). Full article

Background: RMS is the most common soft tissue sarcoma in children. Pencil beam scanning proton therapy (PBS PT) enables highly conformal dose delivery with reduced exposure to surrounding healthy structures, making it particularly suited for RMS in critical anatomical regions. Long-term clinical outcome data for this new radiation technique are scarce. Purpose: This study reports long-term outcomes and quality of life after PBS PT in children and adolescents with rhabdomyosarcoma (RMS). Methods and Materials: We retrospectively reviewed 114 children and adolescents with RMS (mostly embryonal, n = 100; 87.7%) treated between 2000 and 2020. Their median age was 4.6 years (range, 0.3–18). All received systemic chemotherapy according to prospective protocols. The median total PT dose delivered was 52 Gy (RBE; range, 41.4–64.8). Results: After a median follow-up period of 7.1 years (range, 0.3 to 17 years), we observed 26 failures overall; 21 (80.8%) occurred in-field. The 5-year local control and overall survival were 81.2% and 81%, respectively. The composite endpoint (non-ocular grade ≥3 toxicity- and failure-free survival) counting the first occurrence of any failure (local or distant), death, or non-ocular CTCAE v5.0 grade ≥3 toxicity was 77.3% at 5 years. At the start of PT, parents and children reported a quality of life significantly worse than that of a German normative group, but during the follow-up period, their scores improved to normal values in nearly all domains within two years. Conclusions: Our two decades of experience with PBS PT provide data that reflect good local control rates and minimal late non-ocular grade 3 toxicity. We also show that quality of life returned to normal scores in nearly all domains within 2 years. Children and adolescents with RMS seem to benefit from PBS PT in terms of toxicity and quality of life, but further prospective, multi-institutional comparative trials are needed. Full article

In view of the great need for quality assurance in radiotherapy, this paper proposes a stitching-based detector (SBD) technique and a set of intelligent algorithms that can reconstruct the information of projected particle beams. The reconstructed information includes the intensity, sigma value, and location of the maximum intensity of the beam under test. To verify the effectiveness of the proposed technique and algorithms, this research study adopts the pencil beam scanning (PBS) form of proton beam therapy (PBT) as an example. Through the SBD technique, it is possible to utilize 128 × 128 ionization chambers, which constitute an ionization plate of 25.6 cm², with an acceptable number of 4096 analog-to-digital converters (ADCs) and a resolution of 0.25 mm. Through simulation, the proposed SBD technique and intelligent algorithms are proven to exhibit satisfactory and practical performance. By using two kinds of maximum intensity definitions, sigma values ranging from 10 to 120, and two definitions in an erroneous case, the maximum error rate is found to be 3.95%, which is satisfactorily low. Through analysis, this research study discovers that most errors occur near the symmetrical and peripheral boundaries. Furthermore, lower sigma values tend to aggravate the error rate because the beam becomes more like an ideal particle, which leads to greater imprecision caused by symmetrical sensor structures as its sigma is reduced. However, because proton beams are normally not projected onto the border region of the sensed area, the error rate in practice can be expected to be even lower. Although this research study adopts PBS PBT as an example, the proposed SBD technique and intelligent algorithms are applicable to any type of particle beam reconstruction in the field of radiotherapy, as long as the particles under analysis follow a Gaussian distribution. Full article