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Nature Reviews. Neurology Jun 2016Radiotherapy is an integral and highly effective aspect of the management of many paediatric CNS tumours, including embryonal tumours, astrocytic tumours and ependymal... (Review)
Review
Radiotherapy is an integral and highly effective aspect of the management of many paediatric CNS tumours, including embryonal tumours, astrocytic tumours and ependymal tumours. Nevertheless, continued improvements in long-term survivorship of such tumours means that radiotherapy-related toxicities that affect quality of life and overall functional status for survivors are increasingly problematic, and strategies that mitigate these adverse effects are needed. One such strategy is proton therapy, which has distinct advantages over conventional photon therapy and enables greater precision in the delivery of tumoricidal radiation doses with reduced irradiation of healthy tissues. These dose distribution advantages can translate into clinical benefits by reducing the risk of long-term adverse effects of radiotherapy, such as secondary malignancy, cognitive toxicity, endocrinopathy, hearing loss and vasculopathic effects. As the availability of proton therapy increases with the development of new proton centres, this treatment modality is increasingly being used in the management of paediatric CNS tumours. In this Review, we provide an introduction to the types of paediatric CNS tumours for which proton therapy can be considered, and discuss the available evidence that proton therapy limits toxicities and improves quality of life for patients. We will also consider uncertainties surrounding the use of proton therapy, evidence for its cost-effectiveness, and its future role in the management of paediatric CNS tumours.
Topics: Adolescent; Central Nervous System Neoplasms; Child; Child, Preschool; Humans; Infant; Outcome Assessment, Health Care; Proton Therapy
PubMed: 27197578
DOI: 10.1038/nrneurol.2016.70 -
Cancer Journal (Sudbury, Mass.) 2014Through unique physical dose deposition properties, proton beam therapy (PBT) potentiates radiation dose escalation to target tissue while minimizing radiation exposure... (Review)
Review
Through unique physical dose deposition properties, proton beam therapy (PBT) potentiates radiation dose escalation to target tissue while minimizing radiation exposure to nontarget organs. Proton beam therapy has been used to treat prostate cancer for several decades; however, access to proton centers has been restricted to the limited number of proton centers. Because of recent enhancements in availability and treatment delivery systems, interest in PBT has been burgeoning among oncologists, industry experts, and prostate cancer patients. As a result, the importance of understanding the collective experience to date and technical aspects of PBT delivery has become increasingly important in cancer medicine. This review article is intended to discuss the fundamentals of PBT treatment, critically review the literature on PBT for localized prostate cancer, and describe the continued development of proton beam technology for the treatment of prostate cancer.
Topics: Dose Fractionation, Radiation; Humans; Male; Neoplasms, Radiation-Induced; Prostatic Neoplasms; Proton Therapy; Radiation Dosage; Radiotherapy, Intensity-Modulated; Scattering, Radiation
PubMed: 25415688
DOI: 10.1097/PPO.0000000000000083 -
Cancer Radiotherapie : Journal de La... Oct 2021In the current spectrum of cancer treatments, despite high costs, a lack of robust evidence based on clinical outcomes or technical and radiobiological uncertainties,... (Review)
Review
In the current spectrum of cancer treatments, despite high costs, a lack of robust evidence based on clinical outcomes or technical and radiobiological uncertainties, particle therapy and in particular proton therapy (PT) is rapidly growing. Despite proton therapy being more than fifty years old (first proposed by Wilson in 1946) and more than 220,000 patients having been treated with in 2020, many technological challenges remain and numerous new technical developments that must be integrated into existing systems. This article presents an overview of on-going technical developments and innovations that we felt were most important today, as well as those that have the potential to significantly shape the future of proton therapy. Indeed, efforts have been done continuously to improve the efficiency of a PT system, in terms of cost, technology and delivery technics, and a number of different developments pursued in the accelerator field will first be presented. Significant developments are also underway in terms of transport and spatial resolution achievable with pencil beam scanning, or conformation of the dose to the target: we will therefore discuss beam focusing and collimation issues which are important parameters for the development of these techniques, as well as proton arc therapy. State of the art and alternative approaches to adaptive PT and the future of adaptive PT will finally be reviewed. Through these overviews, we will finally see how advances in these different areas will allow the potential for robust dose shaping in proton therapy to be maximised, probably foreshadowing a future era of maturity for the PT technique.
Topics: Cancer Care Facilities; Cyclotrons; Forecasting; Humans; Neoplasms; Neutron Activation Analysis; Organ Sparing Treatments; Organs at Risk; Proton Therapy; Quality Assurance, Health Care; Radiotherapy, Image-Guided; Synchrotrons
PubMed: 34272182
DOI: 10.1016/j.canrad.2021.06.017 -
International Journal of Urology :... Oct 2019Although prostate cancer control using radiotherapy is dose-dependent, dose-volume effects on late toxicities in organs at risk, such as the rectum and bladder, have... (Review)
Review
Although prostate cancer control using radiotherapy is dose-dependent, dose-volume effects on late toxicities in organs at risk, such as the rectum and bladder, have been observed. Both protons and carbon ions offer advantageous physical properties for radiotherapy, and create favorable dose distributions using fewer portals compared with photon-based radiotherapy. Thus, particle beam therapy using protons and carbon ions theoretically seems suitable for dose escalation and reduced risk of toxicity. However, it is difficult to evaluate the superiority of particle beam radiotherapy over photon beam radiotherapy for prostate cancer, as no clinical trials have directly compared the outcomes between the two types of therapy due to the limited number of facilities using particle beam therapy. The Japanese Society for Radiation Oncology organized a joint effort among research groups to establish standardized treatment policies and indications for particle beam therapy according to disease, and multicenter prospective studies have been planned for several common cancers. Clinical trials of proton beam therapy for intermediate-risk prostate cancer and carbon-ion therapy for high-risk prostate cancer have already begun. As particle beam therapy for prostate cancer is covered by the Japanese national health insurance system as of April 2018, and the number of facilities practicing particle beam therapy has increased recently, the number of prostate cancer patients treated with particle beam therapy in Japan is expected to increase drastically. Here, we review the results from studies of particle beam therapy for prostate cancer and discuss future developments in this field.
Topics: Disease-Free Survival; Humans; Male; Practice Guidelines as Topic; Prostate; Prostatic Neoplasms; Proton Therapy; Randomized Controlled Trials as Topic
PubMed: 31284326
DOI: 10.1111/iju.14041 -
Clinical Oncology (Royal College of... May 2018With the current UK expansion of proton therapy there is a great opportunity for clinical oncologists to develop a translational interest in the associated scientific...
With the current UK expansion of proton therapy there is a great opportunity for clinical oncologists to develop a translational interest in the associated scientific base and clinical results. In particular, the underpinning controversy regarding the conversion of photon dose to proton dose by the relative biological effectiveness (RBE) must be understood, including its important implications. At the present time, the proton prescribed dose includes an RBE of 1.1 regardless of tissue, tumour and dose fractionation. A body of data has emerged against this pragmatic approach, including a critique of the existing evidence base, due to choice of dose, use of only acute-reacting in vivo assays, analysis methods and the reference radiations used to determine the RBE. Modelling systems, based on the best available scientific evidence, and which include the clinically useful biological effective dose (BED) concept, have also been developed to estimate proton RBEs for different dose and linear energy transfer (LET) values. The latter reflect ionisation density, which progressively increases along each proton track. Late-reacting tissues, such as the brain, where α/β = 2 Gy, show a higher RBE than 1.1 at a low dose per fraction (1.2-1.8 Gy) at LET values used to cover conventional target volumes and can be much higher. RBE changes with tissue depth seem to vary depending on the method of beam delivery used. To reduce unexpected toxicity, which does occasionally follow proton therapy, a more rational approach to RBE allocation, using a variable RBE that depends on dose per fraction and the tissue and tumour radiobiological characteristics such as α/β, is proposed.
Topics: Humans; Neoplasms; Proton Therapy; Radiobiology; Radiotherapy Planning, Computer-Assisted; Relative Biological Effectiveness
PubMed: 29454504
DOI: 10.1016/j.clon.2018.01.010 -
Archives of Disease in Childhood Apr 2016
Topics: Adolescent; Cerebellar Neoplasms; Child; Child, Preschool; Humans; Medulloblastoma; Proton Therapy; Young Adult
PubMed: 26988077
DOI: 10.1136/archdischild-2016-310667 -
International Journal of Radiation... Mar 2024Our purpose was to report the clinical and dosimetric attributes of patients with large unresectable hepatocellular carcinoma (HCC) undergoing proton or photon radiation...
PURPOSE
Our purpose was to report the clinical and dosimetric attributes of patients with large unresectable hepatocellular carcinoma (HCC) undergoing proton or photon radiation therapy.
METHODS AND MATERIALS
We retrospectively analyzed the outcomes and dosimetric indices of 159 patients with >5 cm nonmetastatic HCC who underwent definitive radiation therapy using either protons (N = 105) or photons (N = 54) between 2014 and 2018. Additional photon plans were performed in the 105 proton-treated patients using the same dose prescription criteria for intragroup dosimetric comparison.
RESULTS
After a median follow-up of 47 months, patients with biologically effective dose (BED10) ≥ 75 Gy exhibited significantly better local control (LC; 2-year: 85.6% vs 20.5%; P < .001), progression-free survival (PFS; median, 7.4 vs 3.2 months; P < .001), and overall survival (OS; median, 18.1 vs 7.3 months; P < .001) compared with those with BED10 < 75 Gy. Notably, proton-treated patients had a significantly higher BED10 (96 vs 67 Gy; P < .001) and improved LC (2-year: 88.5% vs 33.8%; P < .001), PFS (median, 7.4 vs 3.3 months; P = .001), and OS (median, 18.9 vs 8.3 months; P < .001) than those undergoing photon radiation therapy. Furthermore, patients treated with protons had significantly lower V1 of the liver (P < .001), mean upper gastrointestinal tract dose (P < .001), and mean splenic dose (P < .001), with significantly decreased incidences of radiation-induced liver disease (P = .007), grade ≥3 upper gastrointestinal bleeding (P = .001), and grade ≥3 lymphopenia (P = .003). On multivariate analysis, proton radiation therapy consistently correlated with superior LC (P < .001), PFS (P < .001), and OS (P < .001). In intragroup dosimetric comparison, photon plans demonstrated significantly higher mean liver dose (P < .001) compared with actually delivered proton treatments, and 72 (69%) of them had mean liver dose exceeding 28 Gy, which necessitated target dose de-escalation.
CONCLUSIONS
In the context of large HCC radiation therapy, a higher target BED10 was associated with improved outcomes. Notably, proton therapy has demonstrated the capability to deliver ablative doses while also being accompanied by fewer instances of severe toxicity.
Topics: Humans; Carcinoma, Hepatocellular; Protons; Retrospective Studies; Liver Neoplasms; Radiation Injuries; Proton Therapy; Radiotherapy Dosage
PubMed: 37778426
DOI: 10.1016/j.ijrobp.2023.09.049 -
Physics in Medicine and Biology Oct 2022Dose delivery uncertainty is a major concern in proton therapy, adversely affecting the treatment precision and outcome. Recently, a promising technique, proton-acoustic...
Dose delivery uncertainty is a major concern in proton therapy, adversely affecting the treatment precision and outcome. Recently, a promising technique, proton-acoustic (PA) imaging, has been developed to provide real-time3D dose verification. However, its dosimetry accuracy is limited due to the limited-angle view of the ultrasound transducer. In this study, we developed a deep learning-based method to address the limited-view issue in the PA reconstruction. A deep cascaded convolutional neural network (DC-CNN) was proposed to reconstruct 3D high-quality radiation-induced pressures using PA signals detected by a matrix array, and then derive precise 3D dosimetry from pressures for dose verification in proton therapy. To validate its performance, we collected 81 prostate cancer patients' proton therapy treatment plans. Dose was calculated using the commercial software RayStation and was normalized to the maximum dose. The PA simulation was performed using the open-source k-wave package. A matrix ultrasound array with 64 × 64 sensors and 500 kHz central frequency was simulated near the perineum to acquire radiofrequency (RF) signals during dose delivery. For realistic acoustic simulations, tissue heterogeneity and attenuation were considered, and Gaussian white noise was added to the acquired RF signals. The proposed DC-CNN was trained on 204 samples from 69 patients and tested on 26 samples from 12 other patients. Predicted 3D pressures and dose maps were compared against the ground truth qualitatively and quantitatively using root-mean-squared-error (RMSE), gamma-index (GI), and dice coefficient of isodose lines. Results demonstrated that the proposed method considerably improved the limited-view PA image quality, reconstructing pressures with clear and accurate structures and deriving doses with a high agreement with the ground truth. Quantitatively, the pressure accuracy achieved an RMSE of 0.061, and the dose accuracy achieved an RMSE of 0.044, GI (3%/3 mm) of 93.71%, and 90%-isodose line dice of 0.922. The proposed method demonstrates the feasibility of achieving high-quality quantitative 3D dosimetry in PA imaging using a matrix array, which potentially enables the online 3D dose verification for prostate proton therapy.
Topics: Male; Humans; Proton Therapy; Protons; Prostate; Deep Learning; Acoustics; Phantoms, Imaging
PubMed: 36206745
DOI: 10.1088/1361-6560/ac9881 -
Cancer Journal (Sudbury, Mass.) 2014Many radiotherapy centers desire proton therapy (PrT) because the unique physical dosimetry allows for improved dose distribution in some clinical situations. These... (Review)
Review
Many radiotherapy centers desire proton therapy (PrT) because the unique physical dosimetry allows for improved dose distribution in some clinical situations. These benefits are best described in skull base and many pediatric lesions. However, there are significant challenges to PrT that are overlooked or simply ignored when centers embark on the PrT journey particularly as it applies to pediatric patients.In this review, we review the Indiana University Health Proton Therapy Center experience regarding benefits and drawbacks of PrT for pediatric patients. In conclusion, centers aspiring to PrT capacity should be aware not only of the well-described benefits in some clinical scenarios, but also the significant challenges to the modality in its practical clinical application.
Topics: Adolescent; Anesthesia, General; Child; Child Welfare; Child, Preschool; Craniospinal Irradiation; Humans; Neoplasm Seeding; Neoplasms; Parental Consent; Proton Therapy; Radiation Dosage; Scoliosis; Spinal Neoplasms
PubMed: 25415684
DOI: 10.1097/PPO.0000000000000075 -
Medical Physics Jul 2018Acoustic waves are induced via the thermoacoustic effect in objects exposed to a pulsed beam of ionizing radiation. This phenomenon has interesting potential... (Review)
Review
Acoustic waves are induced via the thermoacoustic effect in objects exposed to a pulsed beam of ionizing radiation. This phenomenon has interesting potential applications in both radiotherapy dosimetry and treatment guidance as well as low-dose radiological imaging. After initial work in the field in the 1980s and early 1990s, little research was done until 2013 when interest was rejuvenated, spurred on by technological advances in ultrasound transducers and the increasing complexity of radiotherapy delivery systems. Since then, many studies have been conducted and published applying ionizing radiation-induced acoustic principles into three primary research areas: Linear accelerator photon beam dosimetry, proton therapy range verification, and radiological imaging. This review article introduces the theoretical background behind ionizing radiation-induced acoustic waves, summarizes recent advances in the field, and provides an outlook on how the detection of ionizing radiation-induced acoustic waves can be used for relative and in vivo dosimetry in photon therapy, localization of the Bragg peak in proton therapy, and as a low-dose medical imaging modality. Future prospects and challenges for the clinical implementation of these techniques are discussed.
Topics: Acoustics; Diagnostic Imaging; Humans; Image Processing, Computer-Assisted; Particle Accelerators; Proton Therapy; Radiometry
PubMed: 29679491
DOI: 10.1002/mp.12929