Silica-based scintillators: basic properties of radioluminescence kinetics.

Radioluminescent silica-based fiber dosimeters offer great advantages for designing miniaturized realtime sensors for high dose-rate dosimetry. Rise and fall kinetics of their response must be properly understood to better assess their performances in terms of measurement speed and repeatability. A standard model of radioluminescence (RL) has already been quantitatively validated for doped silica glasses, but beyond conclusive comparisons with specific experiments, a comprehensive understanding of the processes and parameters determining transient and equilibrium kinetics of RL is still lacking.

Beam monitor chamber calibration of a synchro-cyclotron high dose rate per pulse pulsed scanned proton beam.

. Ionization chambers, mostly used for beam calibration and for reference dosimetry, can show high recombination effects in pulsed high dose rate proton beams. The aims of this paper are: first, to characterize the linearity response of newly designed asymmetrical beam monitor chambers (ABMC) in a 100-226 MeV pulsed high dose rate per pulse scanned proton beam; and secondly, to calibrate the ABMC with a PPC05 (IBA Dosimetry) plane parallel ionization chamber and compare to calibration with a home-made Faraday cup (FC).

Single-Masked Randomized Phase 2 Study Assessing 2 Forms of Hypofractionated Proton Therapy in Patients With Large Choroidal Melanomas.

Purpose: Patients with large uveal melanomas are at major risk of liver metastases. Some patients are reluctant to undergo the standard treatment (ie, immediate enucleation). Proton therapy yields 5-year local control rates and eyeball retention of >85% and ≈20% in large uveal melanomas.

Range verification of a clinical proton beam in an abdominal phantom by co-registration of ionoacoustics and ultrasound.

The range uncertainty in proton radiotherapy is a limiting factor to achieve optimum dose conformity to the tumour volume. Ionoacoustics is a promising approach forrange verification, which would allow to reduce the size of the irradiated volume relative to the tumour volume. The energy deposition of a pulsed proton beam leads to an acoustic pressure wave (ionoacoustics), the detection of which allows conclusion about the distance between the Bragg peak and the acoustic detector.

Visual outcomes of macular melanocytic lesions after early or delayed proton beam therapy.

Purpose: During their initial management, some macular melanocytic lesions can be closely monitored to wait for a documented growth before advocating a treatment by irradiation. However, the visual outcomes of this strategy have not yet been assessed. This study compares the visual outcomes of macular melanocytic lesions that underwent delayed proton beam therapy (PBT) after an initial observation to those treated early.

Proton beam range verification by means of ionoacoustic measurements at clinically relevant doses using a correlation-based evaluation.

Purpose: The Bragg peak located at the end of the ion beam range is one of the main advantages of ion beam therapy compared to X-Ray radiotherapy. However, verifying the exact position of the Bragg peak within the patient online is a major challenge. The goal of this work was to achieve submillimeter proton beam range verification for pulsed proton beams of an energy of up to 220 MeV using ionoacoustics for a clinically relevant dose deposition of typically 2 Gy per fraction by i) using optimal proton beam characteristics for ionoacoustic signal generation and ii) improved signal detection by correlating the signal with simulated filter templates.

Fabrication and characterization of a multimodal 3D printed mouse phantom for ionoacoustic quality assurance in image-guided pre-clinical proton radiation research.

Image guidance and precise irradiation are fundamental to ensure the reliability of small animal oncology studies. Accurate positioning of the animal and the in-beam monitoring of the delivered radio-therapeutic treatment necessitate several imaging modalities. In the particular context of proton therapy with a pulsed beam, information on the delivered dose can be retrieved by monitoring the thermoacoustic waves resulting from the brief and local energy deposition induced by a proton beam (ionoacoustics).

QUANTITATIVE ANALYSIS OF CHORIOCAPILLARIS ALTERATIONS IN SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY-ANGIOGRAPHY DURING RADIATION RETINOPATHY.

Purpose: To evaluate choriocapillaris alterations following proton beam therapy irradiation using swept-source optical coherence tomography-angiography, and to assess their correlation with the grade of radiation retinopathy (RR).

Methods: Eyes with uveal melanoma evaluated before and after irradiation with proton beam therapy were included, as well as the healthy fellow eye. The gradation of RR was based on a previously published classification.

Dental management in head and neck cancers: from intensity-modulated radiotherapy with photons to proton therapy.

Introduction: Despite reduction of xerostomia with intensity-modulated compared to conformal X-ray radiotherapy, radiation-induced dental complications continue to occur. Proton therapy is promising in head and neck cancers to further reduce radiation-induced side-effects, but the optimal dental management has not been defined.

Material And Methods: Dental management before proton therapy was assessed compared to intensity-modulated radiotherapy based on a bicentric experience, a literature review and illustrative cases.

Non-Cancer Effects following Ionizing Irradiation Involving the Eye and Orbit.

The eye is an exemplarily challenging organ to treat when considering ocular tumors. It is at the crossroads of several major aims in oncology: tumor control, organ preservation, and functional outcomes including vision and quality of life. The proximity between the tumor and organs that are susceptible to radiation damage explain these challenges.

Characterization of the HollandPTC proton therapy beamline dedicated to uveal melanoma treatment and an interinstitutional comparison.

Purpose: Eye-dedicated proton therapy (PT) facilities are used to treat malignant intraocular lesions, especially uveal melanoma (UM). The first commercial ocular PT beamline from Varian was installed in the Netherlands. In this work, the conceptual design of the new eyeline is presented.

A time-of-flight-based reconstruction for real-time prompt-gamma imaging in proton therapy.

We propose a novel prompt-gamma (PG) imaging modality for real-time monitoring in proton therapy: PG time imaging (PGTI). By measuring the time-of-flight (TOF) between a beam monitor and a PG detector, our goal is to reconstruct the PG vertex distribution in 3D. In this paper, a dedicated, non-iterative reconstruction strategy is proposed (PGTI reconstruction).

Dose-Response and Normal Tissue Complication Probabilities after Proton Therapy for Choroidal Melanoma.

Purpose: Normal tissue complication probability (NTCP) models could aid the understanding of dose dependence of radiation-induced toxicities after eye-preserving radiotherapy of choroidal melanomas. We performed NTCP-modeling and established dose-response relationships for visual acuity (VA) deterioration and common late complications after treatments with proton therapy (PT).

Design: Retrospective study from single, large referral center.

COMPARATIVE EFFECTIVENESS OF PROTON BEAM VERSUS PHOTODYNAMIC THERAPY TO SPARE THE VISION IN CIRCUMSCRIBED CHOROIDAL HEMANGIOMA.

Purpose: The aim of this study was to compare the functional and anatomical effectiveness of photodynamic therapy (PDT) versus proton beam therapy (PBT) in a real-life setting for the treatment of circumscribed choroidal hemangioma.

Methods: A total of 191 patients with a diagnosis of circumscribed choroidal hemangioma and treated by PBT or PDT were included for analyses.

Results: The 119 patients (62.

Proton therapy for head and neck squamous cell carcinomas: A review of the physical and clinical challenges.

The quality of radiation therapy has been shown to significantly influence the outcomes for head and neck squamous cell carcinoma (HNSCC) patients. The results of dosimetric studies suggest that intensity-modulated proton therapy (IMPT) could be of added value for HNSCC by being more effective than intensity-modulated (photon) radiation therapy (IMRT) for reducing side effects of radiation therapy. However, the physical properties of protons make IMPT more sensitive than photons to planning uncertainties.

Oncologic and visual outcomes after postoperative proton therapy of localized conjunctival melanomas.

Introduction: conjunctival melanomas have high local relapse rates. Oncologic and visual outcomes can be improved with proton therapy and no-touch surgery.

Material And Methods: a monocentric retrospective study of consecutive patients treated with surgery and proton therapy for conjunctival melanoma was conducted.

Ultra-widefield fundus photography for radiation therapy planning of ocular tumours.

Purpose: The use of planar ultra-widefield fundus photography (UWF) may result in distortions and inaccurate measurement. The aim of the study was to evaluate the accuracy of UWF instead of the standard narrow field (SF) for the treatment planning phase of ocular tumours.

Methods: Distortions between conformal SF and UWF were assessed in 43 patients with choroidal melanoma treated with either proton therapy or brachytherapy.

RGD-functionalized magnetosomes are efficient tumor radioenhancers for X-rays and protons.

Although chemically synthesized ferro/ferrimagnetic nanoparticles have attracted great attention in cancer theranostics, they lack radio-enhancement efficacy due to low targeting and internalization ability. Herein, we investigated the potential of RGD-tagged magnetosomes, bacterial biogenic magnetic nanoparticles naturally coated with a biological membrane and genetically engineered to express an RGD peptide, as tumor radioenhancers for conventional radiotherapy and proton therapy. Although native and RGD-magnetosomes similarly enhanced radiation-induced damage to plasmid DNA, RGD-magnetoprobes were able to boost the efficacy of radiotherapy to a much larger extent than native magnetosomes both on cancer cells and in tumors.

Activation of Collimators Irradiated With Clinical Proton Beams and Development of a Semiempirical Model for Activity Calculation.

Patient-specific collimators used in proton therapy are activated after use. The aim of this work is to assess the residual activity in brass collimators considering clinical beams, so far studied only for monoenergetic beams, and to develop a model to calculate the activity. Eight brass collimators irradiated with different clinical and monoenergetic beams were included in the study.

Proton radiotherapy in advanced malignant melanoma of the conjunctiva.

Background: The management of conjunctival melanoma is challenging and frequently ends in exenteration. The aim of this retrospective study was to evaluate the long-term results of proton beam radiation with regard to various clinical parameters.

Methods: Eighty-nine patients with extended conjunctival melanoma (≥T2) and multifocal bulbar located tumors (T1c/d) were treated consecutively with proton radiotherapy (dose 45 Gy).

The Lens Opacities Classification System III Grading in Irradiated Uveal Melanomas to Characterize Proton Therapy-Induced Cataracts.

Purpose: To evaluate the use of the Lens Opacities Classification System III grading (LOCS III) for the characterization of radiation-induced cataract, and to correlate the proton beam projection onto the lens with cataract location and grade as defined by the LOCS III.

Design: Prospective, interventional case series.

Methods: Fifty-two consecutive patients with cataract following proton therapy were included.

Study of the responses and calibration procedures of neutron and gamma area and environmental detectors for use in proton therapy.

Ambient dose equivalent measurements with radiation protection instruments are associated to large uncertainties, mostly due to the energy dependence of the instrument response and to the dissimilarity between the spectra of the standard calibration source and the workplace field. The purpose of this work is to evaluate its impact on the performance of area and environmental detectors in the proton therapy environment, and to provide practical solutions whenever needed and possible. The study was carried out at the Centre Antoine Lacassagne (CAL) proton therapy site, and included a number of commercially available area detectors and a home-made environmental thermoluminescent dosimeter based on a polyethylene moderator loaded with TLD600H/TLD700H pairs.

Management of Invasive Squamous Cell Carcinomas of the Conjunctiva.

Purpose: Ocular surface squamous neoplasia includes a spectrum of diseases from dysplasia to invasive squamous cell carcinoma (SCC) of the conjunctiva. Whether the degree of invasion influences outcomes is debated. We evaluated the outcomes and management of conjunctival carcinomas defined as ≤0.