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Sovremennye Tekhnologii V Meditsine 2021Proton therapy (PT) due to dosimetric characteristics (Bragg peak formation, sharp dose slowdown) is currently one of the most high-tech techniques of radiation therapy... (Review)
Review
Proton therapy (PT) due to dosimetric characteristics (Bragg peak formation, sharp dose slowdown) is currently one of the most high-tech techniques of radiation therapy exceeding the standards of photon methods. In recent decades, PT has traditionally been used, primarily, for head and neck cancers (HNC) including skull base tumors. Regardless of the fact that recently PT application area has significantly expanded, HNC still remain a leading indication for proton radiation since PT's physic-dosimetric and radiobiological advantages enable to achieve the best treatment results in these tumors. The present review is devoted to PT usage in HNC treatment in the world and Russian medicine, the prospects for further technique development, the assessment of PT's radiobiological features, a physical and dosimetric comparison of protons photons distribution. The paper shows PT's capabilities in the treatment of skull base tumors, HNC (nasal cavity, paranasal sinuses, nasopharynx, oropharynx, and laryngopharynx, etc.), eye tumors, sialomas. The authors analyze the studies on repeated radiation and provide recent experimental data on favorable profile of proton radiation compared to the conventional radiation therapy. The review enables to conclude that currently PT is a dynamic radiation technique opening up new opportunities for improving therapy of oncology patients, especially those with HNC.
Topics: Head and Neck Neoplasms; Humans; Photons; Proton Therapy; Radiometry; Skull Base Neoplasms
PubMed: 34603766
DOI: 10.17691/stm2021.13.4.08 -
Medical Physics Jun 2023The purpose of this article is to share the excitement of the science of proton therapy, told by two physicists, who started their career in this area at different... (Review)
Review
The purpose of this article is to share the excitement of the science of proton therapy, told by two physicists, who started their career in this area at different times. The authors' journey spans the evolution of proton therapy over the past 30 years, taking the reader from the time when it was an extremely exotic treatment modality until its more common use today. Over this time period, the authors' research and development aimed at an improved understanding of the physical benefits of intensity-modulated proton therapy and arc therapy, treatment planning and optimization to take proton-specific uncertainties into account, and imaging to measure the proton range in the patient. The final section focuses on emerging themes to democratize proton therapy by substantially reducing its size and price, for much greater affordability and global availability of this treatment modality.
Topics: Humans; Proton Therapy; Protons; Radiotherapy Planning, Computer-Assisted; Radiotherapy Dosage; Radiotherapy, Intensity-Modulated
PubMed: 36502491
DOI: 10.1002/mp.16118 -
Medical Physics Aug 2022Proton minibeam radiation therapy (pMBRT) is a new radiotherapy approach that has shown a significant increase in the therapeutic window in glioma-bearing rats compared...
PURPOSE
Proton minibeam radiation therapy (pMBRT) is a new radiotherapy approach that has shown a significant increase in the therapeutic window in glioma-bearing rats compared to conventional proton therapy. The dosimetry of pMBRT is challenging and error prone due to the submillimetric beamlet sizes used. The aim of this study was to perform a robustness analysis on the setup parameters utilized in current preclinical trials and provide guidelines for reproducible dosimetry. The results of this work are intended to guide upcoming implementations of pMBRT worldwide, as well as pave the way for future clinical implementations.
METHODS
Monte Carlo simulations and experimental data were used to evaluate the impact of variations in setup parameters and uncertainties in collimator specifications on lateral pMBRT dose distributions. The value of each parameter was modified individually to evaluate their effect on dose distributions. Experimental dosimetry was performed by means of high-resolution detectors, that is, radiochromic films, the IBA Razor and the Microdiamond detector. New guidelines were proposed to optimize the experimental setup in pMBRT studies and perform reproducible dosimetry.
RESULTS
The sensitivity of dose distributions to uncertainties and variations in setup parameters was quantified. Quantities that define pMBRT lateral profiles (i.e., the peak-to-valley dose ratio [PVDR], peak and valley doses, and peak width) are significantly influenced by small-scale fluctuations in several of those parameters. The setup implemented at the Orsay proton therapy center for pMBRT irradiation was optimized to increase PVDRs and peak symmetry. In addition, we proposed guidelines to perform accurate and reproducible dosimetry in preclinical studies.
CONCLUSIONS
This study revealed the importance of adopting guidelines and protocols tailored to the distinct dose delivery method and dose distributions in pMBRT. This new methodology leads to reproducible dosimetry, which is imperative in preclinical trials. The results and guidelines presented in this manuscript can ease the initiation of pMBRT investigations in other centers.
Topics: Animals; Glioma; Monte Carlo Method; Proton Therapy; Protons; Radiometry; Radiotherapy Dosage; Rats
PubMed: 35621386
DOI: 10.1002/mp.15780 -
Cancer Treatment Reviews Jul 2021Children and adolescents and young adults (AYAs) with cancer are often treated with a multidisciplinary approach. This includes use of radiotherapy, which is important... (Review)
Review
Children and adolescents and young adults (AYAs) with cancer are often treated with a multidisciplinary approach. This includes use of radiotherapy, which is important for local control, but may also cause adverse events in the long term, including second cancer. The risks for limited growth and development, endocrine dysfunction, reduced fertility and second cancer in children and AYAs are reduced by proton beam therapy (PBT), which has a dose distribution that decreases irradiation of normal organs while still targeting the tumor. To define the outcomes and characteristics of PBT in cancer treatment in pediatric and AYA patients, this document was developed by the Japanese Society for Radiation Oncology (JASTRO) and the Japanese Society of Pediatric Hematology/Oncology (JSPHO).
Topics: Adolescent; Adult; Child; Humans; Neoplasms; Practice Guidelines as Topic; Proton Therapy; Societies, Medical; Young Adult
PubMed: 33984606
DOI: 10.1016/j.ctrv.2021.102209 -
Physics in Medicine and Biology Apr 2015The physics of proton therapy has advanced considerably since it was proposed in 1946. Today analytical equations and numerical simulation methods are available to... (Review)
Review
The physics of proton therapy has advanced considerably since it was proposed in 1946. Today analytical equations and numerical simulation methods are available to predict and characterize many aspects of proton therapy. This article reviews the basic aspects of the physics of proton therapy, including proton interaction mechanisms, proton transport calculations, the determination of dose from therapeutic and stray radiations, and shielding design. The article discusses underlying processes as well as selected practical experimental and theoretical methods. We conclude by briefly speculating on possible future areas of research of relevance to the physics of proton therapy.
Topics: Humans; Proton Therapy; Protons; Radiation Dosage
PubMed: 25803097
DOI: 10.1088/0031-9155/60/8/R155 -
Chinese Clinical Oncology Aug 2016Proton beam radiotherapy of uveal melanoma and other malignant and benign ocular tumors has shown tremendous development and success over the past four decades. Proton... (Review)
Review
Proton beam radiotherapy of uveal melanoma and other malignant and benign ocular tumors has shown tremendous development and success over the past four decades. Proton beam is associated with the lowest overall risk of local tumor recurrence in uveal melanoma, compared with other eye-conserving forms of primary treatment. Proton beam is also utilized for other malignant and benign tumors as primary, salvage, or adjuvant treatment with combined modality therapy. The physical characteristics of proton therapy allows for uniform dose distribution, minimal scatter, and sharp dose fall off making it an ideal therapy for ocular tumors in which critical structures lay in close proximity to the tumor. High radiation doses can be delivered to tumors with relative sparing of adjacent tissues from collateral damage. Proton beam therapy for ocular tumors has resulted in overall excellent chances for tumor control, ocular conservation, and visual preservation.
Topics: Eye; Eye Neoplasms; Humans; Melanoma; Proton Therapy; Uveal Neoplasms
PubMed: 27558251
DOI: 10.21037/cco.2016.07.06 -
International Journal of Radiation... Jul 2019Prior authorization (PA) has been widely implemented for proton beam therapy (PBT). We sought to determine the association between PA determination and patient...
PURPOSE
Prior authorization (PA) has been widely implemented for proton beam therapy (PBT). We sought to determine the association between PA determination and patient characteristics, practice guidelines, and potential treatment delays.
METHODS AND MATERIALS
A single-institution retrospective analysis was performed of all patients considered for PBT between 2015 and 2018 at a National Cancer Institute-designated Comprehensive Cancer Center. Differences in treatment start times and denial rates over time were compared, and multivariable logistic regression was used to identify predictors of initial denial.
RESULTS
A total of 444 patients were considered for PBT, including 396 adult and 48 pediatric patients. The American Society for Radiation Oncology model policy supported PBT coverage for 77% of the cohort. Of adult patients requiring PA, 64% were initially denied and 32% remained denied after appeal. In patients considered for reirradiation or randomized phase 3 trial enrollment, initial denial rates were 57% and 64%, respectively. Insurance coverage was not related to diagnosis, reirradiation, trial enrollment, or the American Society for Radiation Oncology model policy guidelines, but it was related to insurance category on multivariable analysis (P < .001). Over a 3-year timespan, initial denial rates increased from 55% to 74% (P = .034). PA delayed treatment start by an average of 3 weeks (and up to 4 months) for those requiring appeal (P < .001) and resulted in 19% of denied patients abandoning radiation treatment altogether. Of pediatric patients, 9% were initially denied, all of whom were approved after appeal, and PA requirement did not delay treatment start (P = .47).
CONCLUSIONS
PA requirements in adults represent a significant burden in initiating PBT and cause significant delays in patient care. Insurance approval is arbitrary and has become more restrictive over time, discordant with national clinical practice guidelines. Payors and providers should seek to streamline coverage policies in alignment with established guidelines to ensure appropriate and timely patient care.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Female; Humans; Insurance Claim Review; Insurance Coverage; Insurance, Health, Reimbursement; Male; Medicare; Middle Aged; Neoplasms; Prior Authorization; Proton Therapy; Regression Analysis; Retrospective Studies; Time-to-Treatment; United States; Young Adult
PubMed: 30557673
DOI: 10.1016/j.ijrobp.2018.12.021 -
The British Journal of Radiology Mar 2020Range uncertainty is a much discussed topic in proton therapy. Although a very real aspect of proton therapy, its magnitude and consequences are sometimes misunderstood... (Review)
Review
Range uncertainty is a much discussed topic in proton therapy. Although a very real aspect of proton therapy, its magnitude and consequences are sometimes misunderstood or overestimated. In this article, the sources and consequences of range uncertainty are reviewed, a number of myths associated with the effect discussed with the aim of putting range uncertainty into clinical context and attempting to de-bunk some of the more exaggerated claims made as to its consequences.
Topics: Absorption, Radiation; Humans; Neoplasms, Radiation-Induced; Patient Positioning; Photons; Proton Therapy; Radiotherapy Dosage; Treatment Outcome; Uncertainty; Water
PubMed: 31778317
DOI: 10.1259/bjr.20190582 -
Radiotherapy and Oncology : Journal of... Mar 2022With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of...
BACKGROUND AND PURPOSE
With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of radiation to organs at risk (OARs) contribute to elevated risks of secondary malignancy and cardiopulmonary disease. We sought to characterize the radiation dose to OARs, toxicities, and outcomes for pediatric HL patients treated with proton therapy (PT).
MATERIALS AND METHODS
Fifty patients aged 11-21 with HL consecutively treated with PT were evaluated 1-2 months following completion of PT and every 6 months thereafter. Acute and late toxicities were captured retrospectively using CTCAE v5. Patterns of relapse were characterized, and survival was assessed using Kaplan-Meier method.
RESULTS
Most (47, 94%) patients received PT to the mediastinum. Median mean heart dose was 4.3 Gy (RBE) and median bilateral lung V20Gy was 5.8%. Median integral dose was 1.7 Gy. For the 27 female patients, a median mean dose of 0.4 and 0.3 Gy (RBE) was delivered to ipsilateral and contralateral breast tissue, respectively. No on-treatment grade 3-5 toxicities were seen. At a median follow-up of 5.3 years, no PT-related grade 3-5 toxicities or secondary malignancies developed. Five patients relapsed at a median time of 9.2 months after PT (range 2.5-24.9 months; 5-year recurrence free survival 90%). Recurrences were both in- and out-of-field in all 5 cases with no marginal failures. All relapsed patients were successfully salvaged (5-year overall survival 100%).
CONCLUSION
For pediatric HL patients, proton treatment resulted in marked dose sparing of OARs with low rates of toxicity, no marginal failures, and excellent 5-year survival.
Topics: Adolescent; Adult; Child; Female; Hodgkin Disease; Humans; Neoplasm Recurrence, Local; Organs at Risk; Proton Therapy; Radiotherapy Dosage; Retrospective Studies; Young Adult
PubMed: 35101461
DOI: 10.1016/j.radonc.2022.01.016 -
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