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Cancer Radiotherapie : Journal de La... Oct 2021Following major advances of the best of photon-techniques such as intensity-modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT) and, to arrive soon,... (Review)
Review
Following major advances of the best of photon-techniques such as intensity-modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT) and, to arrive soon, magnetic resonance (MR)-linac radiotherapy, there are still substantial opportunities in the treatment of head and neck cancers to further reduce the toxicity burden. Proton therapy represents another attractive option in this high-quality and highly competitive precision radiotherapy landscape. Proton therapy holds promises to reduce toxicities and to escalate the dose in radioresistant cases or cases where dose distribution is not satisfactory with photons. However, the selection of patients for proton therapy needs to be done using evidence-based medicine to build arguments in favor of personalized precision radiation therapy. Referral to proton therapy versus IMRT or SBRT should be registered (ProtonShare® platform) and envisioned in a formalized clinical research perspective through randomized trials. The use of an enrichment process using a model-based approach should be done to only randomize patients doomed to benefit from proton. To tackle such great opportunities, the French proton therapy challenge is to collaborate at the national and international levels, and to demonstrate that the extra-costs of treatment are worth clinically and economically in the short, mid, and long-term. In parallel to the clinical developments, there are still preclinical issues to be tackled (e.g., proton FLASH, mini-beams, combination with immunotherapy), for which the French Radiotransnet network offers a unique platform. The current article provides a personal view of the challenges and opportunities with a focus on clinical research and randomized trial requirements as well as the needs for strong collaborations at the national and international levels for PT in squamous cell carcinomas of the head and neck to date.
Topics: Data Collection; France; Head and Neck Neoplasms; Humans; Patient Selection; Precision Medicine; Proton Therapy; Radiation Injuries; Radiation Tolerance; Radiosurgery; Radiotherapy Dosage; Radiotherapy, Intensity-Modulated; Randomized Controlled Trials as Topic; Registries
PubMed: 34272183
DOI: 10.1016/j.canrad.2021.06.018 -
Technology in Cancer Research &... Feb 2015Proton therapy through the use of the Bragg peak affords clinicians a tool with which highly conformal dose can be delivered to the target while minimizing integral dose... (Review)
Review
Proton therapy through the use of the Bragg peak affords clinicians a tool with which highly conformal dose can be delivered to the target while minimizing integral dose to surrounding healthy tissue. To gain maximum benefit from proton therapy adequate patient immobilization must be maintained to ensure accurate dose delivery. While immobilization in external beam radiation therapy is designed to minimize inter- and intra-fraction target motion, in proton therapy there are other additional aspects which must be considered, chief of which is accurately determining and maintaining the targets water-equivalent depth along the beam axis. Over the past 23 years of treating with protons, the team at the James M. Slater Proton Treatment and Research Center at Loma Linda University Medical Center have developed and implemented extensive immobilization systems to address the specific needs of protons. In this publication we review the immobilization systems that are used at Loma Linda in the treatment of head and neck, prostate, upper GI, lung and breast disease, along with a description of the intracranial radiosurgery immobilization system used in the treatment of brain metastasis and arteriovenous malformations (AVM's).
Topics: Humans; Neoplasms; Proton Therapy; Radiosurgery
PubMed: 24354755
DOI: 10.7785/tcrt.2012.500398 -
Proton beams in cancer treatments: Clinical outcomes and dosimetric comparisons with photon therapy.Cancer Treatment Reviews Feb 2016To review current evidence of the role of proton therapy (PT) in other tumors than skull base, sinusal/parasinusal, spinal and pediatric tumors; to determine... (Review)
Review
PURPOSE
To review current evidence of the role of proton therapy (PT) in other tumors than skull base, sinusal/parasinusal, spinal and pediatric tumors; to determine medico-economic aspects raised by PT.
MATERIAL AND METHODS
A systematic review on Medline was performed with the following keywords: proton therapy, proton beam, protontherapy, cancer; publications with comparison between PT and photon-therapy were also selected.
RESULTS
In silico studies have shown superiority (better dose delivery to the target and/or to organs at risk) of PT toward photon-therapy in most of thoracic and abdominal malignant tumors. Potential benefits of PT could be: reduction of toxicities (including radiation-induced cancer), increase of tumor control through a dose-escalation approach, hypofractionation. Cost of treatment is always cited as an issue which actually can be managed by a precise patient selection making PT a cost-effective procedure. Comparison plan with photon therapy may be useful to determine the dosimetric and clinical advantages of PT (Normal Tissue Complications Probability).
CONCLUSION
PT may be associated with a great advantage compared to the best photon-therapies in various types of cancers. Accumulation of clinical data is on-going and will challenge the in silico data analysis. Some indications are associated with strong superiority of PT and may be discussed as a new standard within prospective observational studies.
Topics: Abdominal Neoplasms; Cost-Benefit Analysis; Humans; Patient Selection; Proton Therapy; Radiation Dose Hypofractionation; Radiation Monitoring; Radiometry; Thoracic Neoplasms; Treatment Outcome
PubMed: 26827698
DOI: 10.1016/j.ctrv.2015.12.007 -
Scientific Reports May 2022The objective of this study was to improve the precision of linear energy transfer (LET) measurements using [Formula: see text] optically stimulated luminescence...
The objective of this study was to improve the precision of linear energy transfer (LET) measurements using [Formula: see text] optically stimulated luminescence detectors (OSLDs) in proton beams, and, with that, improve OSL dosimetry by correcting the readout for the LET-dependent ionization quenching. The OSLDs were irradiated in spot-scanning proton beams at different doses for fluence-averaged LET values in the (0.4-6.5) [Formula: see text] range (in water). A commercial automated OSL reader with a built-in beta source was used for the readouts, which enabled a reference irradiation and readout of each OSLD to establish individual corrections. Pulsed OSL was used to separately measure the blue (F-center) and UV ([Formula: see text]-center) emission bands of [Formula: see text] and the ratio between them (UV/blue signal) was used for the LET measurements. The average deviation between the simulated and measured LET values along the central beam axis amounts to 5.5% if both the dose and LET are varied, but the average deviation is reduced to 3.5% if the OSLDs are irradiated with the same doses. With the measurement procedure and automated equipment used here, the variation in the signals used for LET estimates and quenching-corrections is reduced from 0.9 to 0.6%. The quenching-corrected OSLD doses are in agreement with ionization chamber measurements within the uncertainties. The automated OSLD corrections are demonstrated to improve the LET estimates and the ionization quenching-corrections in proton dosimetry for a clinically relevant energy range up to 230 MeV. It is also for the first time demonstrated how the LET can be estimated for different doses.
Topics: Linear Energy Transfer; Luminescence; Proton Therapy; Protons; Radiometry
PubMed: 35585205
DOI: 10.1038/s41598-022-10575-4 -
International Journal of Radiation... Mar 2022This study aimed to highlight the value and key findings of on-site proton audits.
PURPOSE
This study aimed to highlight the value and key findings of on-site proton audits.
METHODS AND MATERIALS
The authors performed 38 on-site measurement-based peer reviews of proton centers participating in National Cancer Institute-funded clinical trials. The reviews covered beam calibration, lateral and depth measurements, mechanical checks, treatment planning and clinical practice, and quality assurance (QA) practices. Program deficiencies were noted, and recommendations were made about ways institutions could improve their practices.
RESULTS
Institutions received an average of 3 (range, 1-8) recommendations for practice improvements. The number of deficiencies did not decrease over time, highlighting the continued need for this type of peer review. The most common deficiencies were for Task Group-recommended QA compliance (97% of centers), computed tomography number (CTN) to relative linear stopping power conversion (59%), and QA procedures (53%). In addition, 32% of institutions assessed failed at least 1 lateral beam profile measurement (<90% of pixels passing 3% [global]/3 mm; 10% threshold), despite passing internal QA measurements. These failures occurred for several different plan configurations (large, small, shallow, and deep targets) and at different depths in the beam path (proximal to target, central, and distal). CTN to relative linear stopping power conversion curves showed deviations at low, mid, and high CTNs and highlighted areas of inconsistency between proton centers, with many centers falling outside of 2 sigma of the mean curve of their peers. All deficiencies from the peer review were discussed with the institutions, and many implemented dosimetric treatment planning and practice changes to improve the accuracy of their system and consistency with other institutions.
CONCLUSIONS
This peer review program has been integral in confirming and promoting consistency and best practice across proton centers for clinical trials, minimizing deviations for outcomes data.
Topics: Calibration; Clinical Audit; Humans; National Cancer Institute (U.S.); Proton Therapy; Quality Assurance, Health Care; Radiometry; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; United States
PubMed: 34780973
DOI: 10.1016/j.ijrobp.2021.10.145 -
Physics in Medicine and Biology Apr 2024To biologically optimise proton therapy, models which can accurately predict variations in proton relative biological effectiveness (RBE) are essential. Current...
To biologically optimise proton therapy, models which can accurately predict variations in proton relative biological effectiveness (RBE) are essential. Current phenomenological models show large disagreements in RBE predictions, due to different model assumptions and differences in the data to which they were fit. In this work, thirteen RBE models were benchmarked against a comprehensive proton RBE dataset to evaluate predictions when all models are fit using the same data and fitting techniques, and to assess the statistical robustness of the models.Model performance was initially evaluated by fitting to the full dataset, and then a cross-validation approach was applied to assess model generalisability and robustness. The impact of weighting the fit and the choice of biological endpoint (either single or multiple survival levels) was also evaluated.Fitting the models to a common dataset reduced differences between their predictions, however significant disagreements remained due to different underlying assumptions. All models performed poorly under cross-validation in the weighted fits, suggesting that some uncertainties on the experimental data were significantly underestimated, resulting in over-fitting and poor performance on unseen data. The simplest model, which depends linearly on the LET but has no tissue or dose dependence, performed best for a single survival level. However, when fitting to multiple survival levels simultaneously, more complex models with tissue dependence performed better. All models had significant residual uncertainty in their predictions compared to experimental data.This analysis highlights that poor quality of error estimation on the dose response parameters introduces substantial uncertainty in model fitting. The significant residual error present in all approaches illustrates the challenges inherent in fitting to large, heterogeneous datasets and the importance of robust statistical validation of RBE models.
Topics: Protons; Relative Biological Effectiveness; Benchmarking; Linear Energy Transfer; Proton Therapy
PubMed: 38471187
DOI: 10.1088/1361-6560/ad3329 -
Journal of Clinical Oncology : Official... Sep 2014Proton beam therapy, the most common form of heavy-particle radiation therapy, is not a new invention, but it has gained considerable public attention because of the... (Review)
Review
Proton beam therapy, the most common form of heavy-particle radiation therapy, is not a new invention, but it has gained considerable public attention because of the high cost of installing and operating the rapidly increasing number of treatment centers. This article reviews the physical properties of proton beam therapy and focuses on the up-to-date clinical evidence comparing proton beam therapy with the more standard and widely available radiation therapy treatment alternatives. In a cost-conscious era of health care, the hypothetical benefits of proton beam therapy will have to be supported by demonstrable clinical gains. Proton beam therapy represents, through its scale and its cost, a battleground for the policy debate around managing expensive technology in modern medicine.
Topics: Dose-Response Relationship, Radiation; Humans; Neoplasms; Proton Therapy; Protons; Radiotherapy Dosage; Randomized Controlled Trials as Topic
PubMed: 25113772
DOI: 10.1200/JCO.2014.55.1945 -
Bulletin Du Cancer Sep 2018Sarcomas are a common type of tumor within the pediatric population. The utilization of proton therapy as a primary attribute the ability to spare adjacent healthy... (Review)
Review
Sarcomas are a common type of tumor within the pediatric population. The utilization of proton therapy as a primary attribute the ability to spare adjacent healthy tissue, therefore, proton therapy has become a preferential indication in pediatrics compared to other photon irradiation modalities. Proton therapy is also a proven and historically validated irradiation technique in the treatment of chondrosarcomas and chordomas of the skull base and spine. Additionally, proton therapy can potentially limit irradiated healthy tissue volumes in adults and limit the risk of acute and late toxicities. The evaluation of the effectiveness of proton therapy in sarcomas is underway in many clinical situations in prospective trials, some of which are randomized.
Topics: Bone Neoplasms; Child; Chondrosarcoma; Chordoma; Humans; Proton Therapy; Radiation Tolerance; Sarcoma; Skull Base Neoplasms; Soft Tissue Neoplasms; Spinal Neoplasms
PubMed: 30126610
DOI: 10.1016/j.bulcan.2018.05.008 -
Medical Physics Dec 2022Challenges in proton therapy include identifying patients most likely to benefit; ensuring consistent, high-quality plans as its adoption becomes more widespread; and...
PURPOSE
Challenges in proton therapy include identifying patients most likely to benefit; ensuring consistent, high-quality plans as its adoption becomes more widespread; and recognizing biological uncertainties that may be related to increased relative biologic effectiveness driven by linear energy transfer (LET). Knowledge-based planning (KBP) is a domain that may help to address all three.
METHODS
Artificial neural networks were trained using 117 unique treatment plans and associated dose and dose-weighted LET (LET ) distributions. The data set was split into training (n = 82), validation (n = 17), and test (n = 18) sets. Model performance was evaluated on the test set using dose- and LET -volume metrics in the clinical target volume (CTV) and nearby organs at risk and Dice similarity coefficients (DSC) comparing predicted and planned isodose lines at 50%, 75%, and 95% of the prescription dose.
RESULTS
Dose-volume metrics significantly differed (α = 0.05) between predicted and planned dose distributions in only one dose-volume metric, D to the CTV. The maximum observed root mean square (RMS) difference between corresponding metrics was 4.3 Gy (8% of prescription) for D to optic chiasm. DSC were 0.90, 0.93, and 0.88 for the 50%, 75%, and 95% isodose lines, respectively. LET -volume metrics significantly differed in all but one metric, L of the brainstem. The maximum observed difference in RMS differences for LET metrics was 1.0 keV/μm for L to brainstem.
CONCLUSIONS
We have devised the first three-dimensional dose and LET -prediction model for cranial proton radiation therapy has been developed. Dose accuracy compared favorably with that of previously published models in other treatment sites. The agreement in LET supports future investigations with biological doses in mind to enable the full potential of KBP in proton therapy.
Topics: Humans; Proton Therapy; Radiotherapy Dosage; Linear Energy Transfer; Radiotherapy Planning, Computer-Assisted; Relative Biological Effectiveness; Neural Networks, Computer
PubMed: 36227617
DOI: 10.1002/mp.16043 -
The British Journal of Radiology Sep 2015Proton radiography and tomography have long promised benefit for proton therapy. Their first suggestion was in the early 1960s and the first published proton radiographs... (Review)
Review
Proton radiography and tomography have long promised benefit for proton therapy. Their first suggestion was in the early 1960s and the first published proton radiographs and CT images appeared in the late 1960s and 1970s, respectively. More than just providing anatomical images, proton transmission imaging provides the potential for the more accurate estimation of stopping-power ratio inside a patient and hence improved treatment planning and verification. With the recent explosion in growth of clinical proton therapy facilities, the time is perhaps ripe for the imaging modality to come to the fore. Yet many technical challenges remain to be solved before proton CT scanners become commonplace in the clinic. Research and development in this field is currently more active than at any time with several prototype designs emerging. This review introduces the principles of proton radiography and tomography, their historical developments, the raft of modern prototype systems and the primary design issues.
Topics: Algorithms; History, 20th Century; History, 21st Century; Humans; Proton Therapy; Radiotherapy Planning, Computer-Assisted; Tomography, X-Ray Computed
PubMed: 26043157
DOI: 10.1259/bjr.20150134