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INTRODUCTION: Hodgkin lymphoma (HL) is a highly curable hematological malignancy. Consolidation radiation therapy techniques have made significant progresses to improve organ-at-risk sparing in order to reduce late radiation-induced toxicity. Recent technical breakthroughs notably include intensity modulated proton therapy (IMPT), which has demonstrated a major dosimetric benefit at the cardiac level for mediastinal HL patients. However, its implementation in clinical practice is still challenging, notably due to the limited access to proton therapy facilities. In this context, the purpose of this study was to estimate the benefit of IMPT for HL proton therapy for diverse cardiac adverse events and to propose a general frame for mediastinal HL patient selection strategy for IMPT based on cardiotoxicity reduction, patient clinical factors, and IMPT treatment availability. MATERIAL AND METHODS: This retrospective dosimetric study included 30 mediastinal HL patients treated with VMAT. IMPT plans were generated on the initial simulation scans. Dose to the heart, to the left ventricle and to the valves were retrieved to calculate the relative risk (RR) of ischemic heart disease (IHD), congestive heart failure (CHF) and valvular disease (VD). Composite relative risk reduction (cRRR) of late cardiotoxicity, between VMAT and IMPT, were calculated as the weighted mean of relative risk reduction for IHD, CHF and VD, calculated across a wide range of cardiovascular risk factor combinations. The proportion of mediastinal HL patients who could benefit from IMPT was estimated in European countries, based on the country population and on the number of active gantries, to propose country-specific cRRR thresholds for patient selection. RESULTS: Compared with VMAT, IMPT significantly reduced average mean doses to the heart (2.36 Gy vs 0.99 Gy, p < 0.01), to the left ventricle (0.67 Gy vs 0.03, p < 0.01) and to the valves (1.29 Gy vs. 0.06, p < 0.01). For a HL patient without cardiovascular risk factor other than anthracycline-based chemotherapy, the relative risks of late cardiovascular complications were significantly lower after IMPT compared with VMAT for ischemic heart disease (1.07 vs 1.17, p < 0.01), for congestive heart failure (2.84 vs. 3.00, p < 0.01), and for valvular disease (1.01 vs. 1.06, p < 0.01). The median cRRR of cardiovascular adverse events with IMPT was 4.8%, ranging between 0.1% and 30.5%, depending on the extent of radiation fields and on the considered cardiovascular risk factors. The estimated proportion of HL patients currently treatable with IMPT in European countries with proton therapy facilities ranged between 8.0% and 100% depending on the country, corresponding to cRRR thresholds ranging from 24.0% to 0.0%. CONCLUSION: While a statistically significant clinical benefit is theoretically expected for ischemic heart disease, cardiac heart failure and valvular disease for mediastinal HL patients with IMPT, the overall cardiotoxicity risk reduction is notable only for a minority of patients. In the context of limited IMPT availability, this study proposed a general model-based selection approach for mediastinal HL patient based on calculated cardiotoxicity reduction, taking into consideration patient clinical characteristics and IMPT facility availability.
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Insuficiencia Cardíaca , Enfermedades de las Válvulas Cardíacas , Enfermedad de Hodgkin , Neoplasias del Mediastino , Isquemia Miocárdica , Terapia de Protones , Traumatismos por Radiación , Radioterapia de Intensidad Modulada , Cardiotoxicidad/etiología , Insuficiencia Cardíaca/etiología , Enfermedades de las Válvulas Cardíacas/etiología , Enfermedad de Hodgkin/tratamiento farmacológico , Enfermedad de Hodgkin/radioterapia , Humanos , Neoplasias del Mediastino/radioterapia , Isquemia Miocárdica/etiología , Órganos en Riesgo , Selección de Paciente , Terapia de Protones/efectos adversos , Terapia de Protones/métodos , Traumatismos por Radiación/epidemiología , Traumatismos por Radiación/etiología , Traumatismos por Radiación/prevención & control , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/efectos adversos , Radioterapia de Intensidad Modulada/métodos , Estudios RetrospectivosRESUMEN
The number of oncological patients who may benefit from proton beam radiotherapy (PBT) or carbon ion radiotherapy (CIRT), overall referred to as particle radiotherapy (RT), is expected to strongly increase in the next future, as well as the number of cardiological patients requiring cardiac implantable electronic devices (CIEDs). The management of patients with a CIED requiring particle RT deserves peculiar attention compared to those undergoing conventional photon beam RT, mostly due to the potential generation of secondary neutrons by particle beams interactions. Current consensus documents recommend managing these patients as being at intermediate/high risk of RT-induced device malfunctioning regardless of the dose on the CIED and the beam delivery method used, despite the last one significantly affects secondary neutrons generation (very limited neutrons production with active scanning as opposed to the passive scattering technique). The key issues for the current review were expressed in four questions according to the Population, Intervention, Control, Outcome criteria. Three in vitro and five in vivo studies were included. Based on the available data, PBT and CIRT with active scanning have a limited potential to interfere with CIED that has only emerged from in vitro study so far, while a significant potential for neutron-related, not severe, CIED malfunctions (resets) was consistently reported in both clinical and in vitro studies with passive scattering.
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Desfibriladores Implantables , Marcapaso Artificial , Electrónica , Humanos , Protones , Estudios RetrospectivosRESUMEN
Background and Summary: The management of endometrial cancer, in an ever-older population with considerable comorbidity, remains a challenge for gynecological and radiation oncologists. Key Message: The present paper reviews literature data on treatment options for endometrial cancer patients unfit for surgery.
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Antineoplásicos Hormonales/uso terapéutico , Braquiterapia/métodos , Neoplasias Endometriales/terapia , Anciano , Ensayos Clínicos como Asunto , Neoplasias Endometriales/patología , Femenino , Anciano Frágil , Humanos , Estadificación de NeoplasiasRESUMEN
PURPOSE: The Italian National Centre for Oncological Hadrontherapy (Centro Nazionale di Adroterapia Oncologica, CNAO), equipped with a proton and ion synchrotron, started clinical activity in September 2011. The clinical and technical characteristics of the first ten proton beam radiotherapy treatments are reported. MATERIALS AND METHODS: Ten patients, six males and four females (age range 27-73 years, median 55.5), were treated with proton beam radiotherapy. After one to two surgical procedures, seven patients received a histological diagnosis of chordoma (of the skull base in three cases, the cervical spine in one case and the sacrum in three cases) and three of low-grade chondrosarcoma (skull base). Prescribed doses were 74 GyE for chordoma and 70 GyE for chondrosarcoma at 2 GyE/fraction delivered 5 days per week. RESULTS: Treatment was well tolerated without toxicity-related interruptions. The maximal acute toxicity was grade 2, with oropharyngeal mucositis, nausea and vomiting for the skull base tumours, and grade 2 dermatitis for the sacral tumours. After 6-12 months of follow-up, no patient developed tumour progression. CONCLUSIONS: The analysis of the first ten patients treated with proton therapy at CNAO showed that this treatment was feasible and safe. Currently, patient accrual into these as well as other approved protocols is continuing, and a longer follow-up period is needed to assess tumour control and late toxicity.
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Condrosarcoma/radioterapia , Cordoma/radioterapia , Neoplasias de la Base del Cráneo/radioterapia , Neoplasias de la Columna Vertebral/radioterapia , Adulto , Anciano , Fraccionamiento de la Dosis de Radiación , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Italia , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Protones , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador , Radioterapia Asistida por Computador , Sincrotrones , Tomografía Computarizada por Rayos XRESUMEN
Proton therapy (PT) is an advancing radiotherapy modality increasingly integrated into clinical settings, transitioning from research facilities to hospital environments. A critical aspect of the commissioning of a proton pencil beam scanning delivery system is the acquisition of experimental beam data for accurate beam modelling within the treatment planning system (TPS). These guidelines describe in detail the acquisition of proton pencil beam modelling data. First, it outlines the intrinsic characteristics of a proton pencil beam-energy distribution, angular-spatial distribution and particle number. Then, it lists the input data typically requested by TPSs. Finally, it describes in detail the set of experimental measurements recommended for the acquisition of proton pencil beam modelling data-integrated depth-dose curves, spot maps in air, and reference dosimetry. The rigorous characterization of these beam parameters is essential for ensuring the safe and precise delivery of proton therapy treatments.
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This paper provides insights into the use of Proton Beam Therapy (PBT) in pediatric patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS). NRSTS are a heterogeneous group of rare and aggressive mesenchymal extraskeletal tumors, presenting complex and challenging clinical management scenarios. The overall survival rate for patients with NRSTS is around 70%, but the outcome is strictly related to the presence of various variables, such as the histological subtype, grade of malignancy and tumor stage at diagnosis. Multimodal therapy is typically considered the preferred treatment for high-grade NRSTS. Radiotherapy plays a key role in the treatment of children and adolescents with NRSTS. However, the potential for radiation-induced side effects partially limits its use. Therefore, PBT represents a very suitable therapeutic option for these patients. The unique depth-dose characteristics of protons can be leveraged to minimize doses to healthy tissue significantly, potentially allowing for increased tumor doses and enhanced preservation of surrounding tissues. These benefits suggest that PBT may improve local control while reducing toxicity and improving quality of life. While clear evidence of therapeutic superiority of PBT over other modern photon techniques in NRSTS is still lacking-partly due to the limited data available-PBT can be an excellent treatment option for young patients with these tumors. A dedicated international comprehensive collaborative approach is essential to better define its role within the multidisciplinary management of NRSTS. Shared guidelines for PBT indications-based on the patient's age, estimated outcome, and tumor location-and centralization in high-level referral centers are needed to optimize the use of resources, since access to PBT remains a challenge due to the limited number of available proton therapy facilities.
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The growing interest in proton therapy (PT) in recent decades is justified by the evidence that protons dose distribution allows maximal dose release at the tumor depth followed by sharp distal dose fall-off. But, in the holistic management of head and neck cancer (HNC), limiting the potential of PT to a mere dosimetric advantage appears reductive. Indeed, the precise targeting of PT may help evaluate the effectiveness of de-escalation strategies, especially for patients with human papillomavirus associated-oropharyngeal cancer (OPC) and nasopharyngeal cancer (NPC). Furthermore, PT could have potentially greater immunogenic effects than conventional photon therapy, possibly enhancing both the radiotherapy (RT) capability to activate anti-tumor immune response and the effectiveness of immunotherapy drugs. Based on these premises, the aim of the present paper is to conduct a narrative review reporting the safety and efficacy of PT compared to photon RT focusing on NPC and OPC. We also provide a snapshot of ongoing clinical trials comparing PT with photon RT for these two clinical scenarios. Finally, we discuss new insights that may further develop clinical research on PT for HNC.
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Purpose: The aim of this study is to determine the most beneficial radiation treatment technique for pediatric patients with thoracic and abdominal neuroblastoma (NBL), through a dosimetric comparison between photon Volumetric Modulated Arc Therapy and proton Intensity-Modulated Proton Therapy treatment plans. Materials and Methods: A retrospective analysis was conducted on a multicentre case series of 19 patients with thoracic and/or abdominal NBL who underwent radiation therapy, following the recommendations of the European protocol for high-risk NBL (HR-NBL2/SIOPEN). The prescribed dose was 21.6 Gy in 12 fractions (1.8 Gy/fraction) delivered over the preoperative disease volume. The dose volume histograms were analyzed for each patient, and a Wilcoxon signed-rank test with a significance level of 0.01 was employed to assess statistical differences between the dosimetric parameters investigated. Two homogeneity indices (HI and newHI) were compared to evaluate the uniformity in dose, delivered to the adjacent vertebrae (VBs_Adj). Results: Both radiation techniques conform to the protocol regarding CTV/PTV coverage for every location. Proton therapy resulted in statistically significant dose sparing for the heart and lungs in supradiaphragmatic locations and for the contralateral kidney, liver, spleen, and bowel in subdiaphragmatic locations. For both techniques, sparing the non-adjacent vertebrae (VBs_NAdj) results more challenging, although promising results were obtained. Furthermore, the dose delivered to the VBs_Adj was not statistically different, in terms of homogeneity, for the 2 radiation techniques that both met the protocol's requirements. Conclusion: This dosimetric analysis highlights the potential of protons to reduce radiation dose to healthy tissue. These findings apply to all the investigated patients, regardless of primary tumor location, making proton therapy a valuable option for the treatment of neuroblastoma. However, a multidisciplinary assessment of each case is essential to ensure the selection of the most effective and suitable treatment modality.
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PURPOSE: As carbon ion radiotherapy increases in use, there are limited phantom materials for heterogeneous or anthropomorphic phantom measurements. This work characterized the radiological clinical equivalence of several phantom materials in a therapeutic carbon ion beam. METHODS: Eight materials were tested for radiological material-equivalence in a carbon ion beam. The materials were computed tomography (CT)-scanned to obtain Hounsfield unit (HU) values, then irradiated in a monoenergetic carbon ion beam to determine relative linear stopping power (RLSP). The corresponding HU and RLSP for each phantom material were compared to clinical carbon ion calibration curves. For absorbed dose comparison, ion chamber measurements were made in the center of a carbon ion spread-out Bragg peak (SOBP) in water and in the phantom material, evaluating whether the material perturbed the absorbed dose measurement beyond what was predicted by the HU-RLSP relationship. RESULTS: Polyethylene, solid water (Gammex and Sun Nuclear), Blue Water (Standard Imaging), and Techtron HPV had measured RLSP values that agreed within ±4.2% of RLSP values predicted by the clinical calibration curve. Measured RLSP for acrylic was 7.2% different from predicted. The agreement for balsa wood and cork varied between samples. Ion chamber measurements in the phantom materials were within 0.1% of ion chamber measurements in water for most materials (solid water, Blue Water, polyethylene, and acrylic), and within 1.9% for the rest of the materials (balsa wood, cork, and Techtron HPV). CONCLUSIONS: Several phantom materials (Blue Water, polyethylene, solid water [Gammex and Sun Nuclear], and Techtron HPV) are suitable for heterogeneous phantom measurements for carbon ion therapy. Low density materials should be carefully characterized due to inconsistencies between samples.
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Radioterapia de Iones Pesados , Fantasmas de Imagen , Radioterapia de Iones Pesados/instrumentación , Calibración , Tomografía Computarizada por Rayos X , HumanosRESUMEN
Objective. This study characterized optically-stimulated luminescent dosimeter (OSLD) nanoDots for use in a therapeutic carbon beam using the Imaging and Radiation Oncology Core (IROC) framework for remote output verification.Approach. The absorbed dose correction factors for OSLD (fading, linearity, beam quality, angularity, and depletion), as defined by AAPM TG 191, were characterized for carbon beams. For the various correction factors, the effect of linear energy transfer (LET) was examined by characterizing in both a low and high LET setting.Main results. Fading was not statistically different between reference photons and carbon, nor between low and high LET beams; thus, the standard IROC-defined exponential function could be used to characterize fading. Dose linearity was characterized with a linear fit; while low and high LET carbon linearity was different, these differences were small and could be rolled into the uncertainty budget if using a single linearity correction. A linear fit between beam quality and dose-averaged LET was determined. The OSLD response at various angles of incidence was not statistically different, thus a correction factor need not be applied. There was a difference in depletion between low and high LET irradiations in a primary carbon beam, but this difference was small over the standard five readings. The largest uncertainty associated with the use of OSLDs in carbon was because of thekQcorrection factor, with an uncertainty of 6.0%. The overall uncertainty budget was 6.3% for standard irradiation conditions.Significance. OSLD nanoDot response was characterized in a therapeutic carbon beam. The uncertainty was larger than for traditional photon applications. These findings enable the use of OSLDs for carbon absorbed dose measurements, but with less accuracy than conventional OSLD audit programs.
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Carbono , Carbono/química , Carbono/uso terapéutico , Radiometría/métodos , Transferencia Lineal de Energía , Incertidumbre , Dosimetría con Luminiscencia Ópticamente Estimulada/métodos , Dosificación Radioterapéutica , HumanosRESUMEN
BACKGROUND AND PURPOSE: As no guidelines for pencil beam scanning (PBS) proton therapy (PT) of paediatric posterior fossa (PF) tumours exist to date, this study investigated planning techniques across European PT centres, with special considerations for brainstem and spinal cord sparing. MATERIALS AND METHODS: A survey and a treatment planning comparison were initiated across nineteen European PBS-PT centres treating paediatric patients. The survey assessed all aspects of the treatment chain, including but not limited to delineations, dose constraints and treatment planning. Each centre planned two PF tumour cases for focal irradiation, according to their own clinical practice but based on common delineations. The prescription dose was 54 Gy(RBE) for Case 1 and 59.4 Gy(RBE) for Case 2. For both cases, planning strategies and relevant dose metrics were compared. RESULTS: Seventeen (89 %) centres answered the survey, and sixteen (80 %) participated in the treatment planning comparison. In the survey, thirteen (68 %) centres reported using the European Particle Therapy Network definition for brainstem delineation. In the treatment planning study, while most centres used three beam directions, their configurations varied widely across centres. Large variations were also seen in brainstem doses, with a brainstem near maximum dose (D2%) ranging from 52.7 Gy(RBE) to 55.7 Gy(RBE) (Case 1), and from 56.8 Gy(RBE) to 60.9 Gy(RBE) (Case 2). CONCLUSION: This study assessed the European PBS-PT planning of paediatric PF tumours. Agreement was achieved in e.g. delineation-practice, while wider variations were observed in planning approach and consequently dose to organs at risk. Collaboration between centres is still ongoing, striving towards common guidelines.
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Neoplasias Infratentoriales , Terapia de Protones , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador , Humanos , Terapia de Protones/métodos , Neoplasias Infratentoriales/radioterapia , Europa (Continente) , Niño , Planificación de la Radioterapia Asistida por Computador/métodos , Preescolar , Masculino , Femenino , Órganos en Riesgo/efectos de la radiación , Tronco Encefálico/efectos de la radiaciónRESUMEN
This paper offers an insight into the use of Proton Beam Therapy (PBT) in paediatric patients with rhabdomyosarcoma (RMS). This paper provides a comprehensive analysis of the literature, investigating comparative photon-proton dosimetry, outcome, and toxicity. In the complex and multimodal scenario of the treatment of RMS, clear evidence of the therapeutic superiority of PBT compared to other modern photon techniques has not yet been demonstrated; however, PBT can be considered an excellent treatment option, in particular for young children and patients with specific primary sites, such as the head and neck area (and especially the parameningeal regions), genito-urinary, pelvic, and paravertebral regions. The unique depth-dose characteristics of protons can be exploited to achieve significant reductions in normal tissue doses and may allow an escalation of tumour doses and greater sparing of normal tissues, thus potentially improving local control while at the same time reducing toxicity and improving quality of life. However, access of children with RMS (and more in general with solid tumors) to PBT remains a challenge, due to the limited number of available proton therapy installations.
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Sinonasal cancers (SNCs) are rare and heterogeneous in histology and biological behavior. The prognosis is generally unfavorable, especially in inoperable cases. In recent years, for some histologies, such as undifferentiated sinonasal carcinoma (SNUC), multimodal treatment with a combination of induction chemotherapy, surgery, and chemo/radiotherapy (RT) has improved the prognosis. Nevertheless, still about half of the patients treated incur a recurrence, in most of the cases at the local site. Surgery with and without RT is usually the treatment choice in cases of recurrence after previous RT in combination with systemic therapy or RT in a histology-driven fashion. In the case of inoperable disease or contraindications to surgery, RT is still a valid treatment option. In this context, hadron therapy with protons (PT) or carbon ions (CIRT) is often preferred due to the physical and biological characteristics of charged particles, allowing the administration of high doses to the tumor target while sparing the surrounding healthy tissues and potentially limiting the side effects due to the high cumulative dose. In the absence of a standard of care for the recurrent setting, we aimed to investigate the role of re-RT with PT or CIRT. We retrospectively analysed 15 patients with recurrent, previously irradiated, SNCs treated at our institution between 2013 and 2020. Local control (LC) and overall survival (OS) were estimated by the Kaplan-Meier method. Acute and late toxicities were scored according to the National Cancer Institute's Common Terminology Criteria for Adverse Events CTCAE version 5.0. A total of 13 patients received CIRT and 2 patients received PT. The median re-RT dose was 54 GyRBE (range 45-64 GyRBE) delivered in 3 or 4 GyRBE/fr (fraction) for the CIRT, and 2 Gy RBE/fr for the PT schedule. LC was 44% at the 1-year follow-up and 35.2% at the 3-year follow-up. OS at 1 and 3 years were 92.9% and 38.2%, respectively. Fourteen patients developed G1-G2 acute toxicity (dermatitis and mucositis), and no patients developed G3-G5. Regarding late toxicity, 10 patients encountered at maximum G1-2 events, and 4 did not experience any toxicity. Only for one patient G3 late toxicity was reported (dysphagia requiring a percutaneous endoscopic gastrostomy).
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PURPOSE: To fully characterize the flat panel detector of the new Sphinx Compact device with scanned proton and carbon ion beams. MATERIALS AND METHODS: The Sphinx Compact is designed for daily QA in particle therapy. We tested its repeatability and dose rate dependence as well as its proportionality with an increasing number of particles and potential quenching effect. Potential radiation damage was evaluated. Finally, we compared the spot characterization (position and profile FWHM) with our radiochromic EBT3 film baseline. RESULTS: The detector showed a repeatability of 1.7% and 0.9% for single spots of protons and carbon ions, respectively, while for small scanned fields it was inferior to 0.2% for both particles. The response was independent from the dose rate (difference from nominal value < 1.5%). We observed an under-response due to quenching effect for both particles, mostly for carbon ions. No radiation damage effects were observed after two months of weekly use and approximately 1350 Gy delivered to the detector. Good agreement was found between the Sphinx and EBT3 films for the spot position (central-axis deviation within 1 mm). The spot size measured with the Sphinx was larger compared to films. For protons, the average and maximum differences over different energies were 0.4 mm (3%) and 1 mm (7%); for carbon ions they were 0.2 mm (4%) and 0.4 mm (6%). CONCLUSIONS: Despite the quenching effect the Sphinx Compact fulfills the requirements needed for constancy checks and could represent a time-saving tool for daily QA in scanned particle beams.
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Terapia de Protones , Protones , Radiometría , Carbono , Dosimetría por PelículaRESUMEN
BACKGROUND: Currently, 13 Asian and European facilities deliver carbon ion radiotherapy (CIRT) for preclinical and clinical activity, and, to date, 55 clinical studies including CIRT for adult and paediatric solid neoplasms have been registered. The National Center for Oncological Hadrontherapy (CNAO) is the only Italian facility able to accelerate both protons and carbon ions for oncological treatment and research. METHODS: To summarise and critically evaluate state-of-the-art knowledge on the application of carbon ion radiotherapy in oncological settings, the authors conducted a literature search till December 2022 in the following electronic databases: PubMed, Web of Science, MEDLINE, Google Scholar, and Cochrane. The results of 68 studies are reported using a narrative approach, highlighting CNAO's clinical activity over the last 10 years of CIRT. RESULTS: The ballistic and radiobiological hallmarks of CIRT make it an effective option in several rare, radioresistant, and difficult-to-treat tumours. CNAO has made a significant contribution to the advancement of knowledge on CIRT delivery in selected tumour types. CONCLUSIONS: After an initial ramp-up period, CNAO has progressively honed its clinical, technical, and dosimetric skills. Growing engagement with national and international networks and research groups for complex cancers has led to increasingly targeted patient selection for CIRT and lowered barriers to facility access.
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BACKGROUND: With rapid evolutions of fast and sophisticated calculation techniques and delivery technologies, clinics are almost facing a daily patient-specific (PS) plan adaptation, which would make a conventional experimental quality assurance (QA) workflow unlikely to be routinely feasible. Therefore, in silico approaches are foreseen by means of second-check independent dose calculation systems possibly handling machine log-files. PURPOSE: To validate the in-house developed GPU-dose engine, FRoG, for light ion beam therapy (protons and carbon ions) as a second-check independent calculation system and to integrate machine log-file analysis into the patient-specific quality assurance (PSQA) program. METHODS: Spot sizes, depth-dose distributions, and absolute dose calibrations were configured into FRoG and a set of nine regular-shaped targets in combination with more than 170 clinical treatment fields were tested against pinpoint ionization chamber measurements. Both the treatment planning system DICOM RTplans and machine treatment log-files were used as input for the dose kernel in water, and a 3D local γ (1 mm/2%) index was used as the main evaluation metric. RESULTS: Calculated configuration data matched experimental measurements with submillimetric agreement. For regular-shaped targets, the unsigned average relative difference between calculated and measured dose values was less than 2% for both protons and carbon ions. The mean γ passing rate (PR) was around 98% for both particle species. For clinical treatment beams, DICOM-based recalculations showed a γ-PR more than 99% for both particle species. The same level of agreement was preserved for protons when moving to log-file-based recalculations. A score of around 95% was registered for carbon ion beams, once excluding low-quality machine log-files. Unsigned average relative difference against acquired data was less than 2% also for real clinical beams. CONCLUSIONS: FRoG was proven as an accurate and reliable tool for PSQA in scanning light ion beam therapy. The proposed method allows for an extremely efficient workflow, without compromising the quality of the plan verification procedure.
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Protones , Radiometría , Humanos , Dosificación Radioterapéutica , Fantasmas de Imagen , Planificación de la Radioterapia Asistida por Computador/métodos , Garantía de la Calidad de Atención de Salud/métodos , Método de MontecarloRESUMEN
(1) Background: In this work, we aim to provide selection criteria based on normal tissue complication probability (NTCP) models and additional explanatory dose-volume histogram parameters suitable for identifying locally advanced sinonasal cancer patients with orbital invasion benefitting from proton therapy. (2) Methods: Twenty-two patients were enrolled, and two advanced radiation techniques were compared: intensity modulated proton therapy (IMPT) and photon volumetric modulated arc therapy (VMAT). Plans were optimized with a simultaneous integrated boost modality: 70 and 56 Gy(RBE) in 35 fractions were prescribed to the high risk/low risk CTV. Several endpoints were investigated, classified for their severity and used as discriminating paradigms. In particular, when NTCP models were already available, a first selection criterion based on the delta-NTCP was adopted. Additionally, an overall analysis in terms of DVH parameters was performed. Furthermore, a second selection criterion based on a weighted sum of the ΔNTCP and ΔDVH was adopted. (3) Results: Four patients out of 22 (18.2%) were suitable for IMPT due to ΔNTCP > 3% for at least one severe toxicity, 4 (18.2%) due to ΔNTCP > 20% for at least three concurrent intermediate toxicities and 16 (72.7%) due to the mixed sum of ΔNTCP and ΔDVH criterion. Since, for some cases, both criteria were contemporary fulfilled, globally 17/22 patients (77.3%) would benefit from IMPT. (4) Conclusions: For this rare clinical scenario, the use of a strategy including DVH parameters and NTCPs when comparing VMAT and IMPT is feasible. We showed that patients affected by sinonasal cancer could profit from IMPT compared to VMAT in terms of optical and central nervous system organs at risk sparing.
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Background: Cardiac arrhythmias, such as ventricular tachycardia, are disruptions in the normal cardiac function that originate from problems in the electrical conduction of signals inside the heart. Recently, a non-invasive treatment option based on external photon or proton beam irradiation has been used to ablate the arrhythmogenic structures. Especially in proton therapy, based on its steep dose gradient, it is crucial to monitor the motion of the heart in order to ensure that the radiation dose is delivered to the correct location. Transthoracic ultrasound imaging has the potential to provide guidance during this treatment delivery. However, it has to be noted that the presence of an ultrasound probe on the chest of the patient introduces constraints on usable beam angles for both protons and photon treatments. This case report investigates the possibility to generate a clinically acceptable proton treatment plan while the ultrasound probe is present on the chest of the patient. Case: A treatment plan study was performed based on a 4D cardiac-gated computed tomography scan of a 55 year-old male patient suffering from refractory ventricular tachycardia who underwent cardiac radioablation. A proton therapy treatment plan was generated for the actual treatment target in presence of an ultrasound probe on the chest of this patient. The clinical acceptability of the generated plan was confirmed by evaluating standard target dose-volume metrics, dose to organs-at-risk and target dose conformity and homogeneity. Conclusion: The generation of a clinically acceptable proton therapy treatment plan for cardiac radioablation of ventricular tachycardia could be performed in the presence of an ultrasound probe on the chest of the patient. These results establish a basis and justification for continued research and product development for ultrasound-guided cardiac radioablation.
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(1) Background: we proposed an integrated strategy to support clinical allocation of nasopharyngeal patients between proton and photon radiotherapy. (2) Methods: intensity-modulated proton therapy (IMPT) plans were optimized for 50 consecutive nasopharyngeal carcinoma (NPC) patients treated with volumetric modulated arc therapy (VMAT), and differences in dose and normal tissue complication probability (ΔNTCPx-p) for 16 models were calculated. Patient eligibility for IMPT was assessed using a model-based selection (MBS) strategy following the results for 7/16 models describing the most clinically relevant endpoints, applying a model-specific ΔNTCPx-p threshold (15% to 5% depending on the severity of the complication) and a composite threshold (35%). In addition, a comprehensive toxicity score (CTS) was defined as the weighted sum of all 16 ΔNTCPx-p, where weights follow a clinical rationale. (3) Results: Dose deviations were in favor of IMPT (ΔDmean ≥ 14% for cord, esophagus, brainstem, and glottic larynx). The risk of toxicity significantly decreased for xerostomia (-12.5%), brain necrosis (-2.3%), mucositis (-3.2%), tinnitus (-8.6%), hypothyroidism (-9.3%), and trismus (-5.4%). There were 40% of the patients that resulted as eligible for IMPT, with a greater advantage for T3-T4 staging. Significantly different CTS were observed in patients qualifying for IMPT. (4) Conclusions: The MBS strategy successfully drives the clinical identification of NPC patients, who are most likely to benefit from IMPT. CTS summarizes well the expected global gain.