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1.
J Appl Clin Med Phys ; 23(2): e13459, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34751499

RESUMO

PURPOSE: To assess the dosimetric advantages of apertures in intracranial single fraction proton radiosurgery. MATERIALS AND METHODS: Six neuroma and 10 meningioma patients were investigated. For each patient, six plans were computed, with two spot spacing and three aperture settings (no apertures, 5 and 8 mm margin between aperture and clinical target volume [CTV]). All plans were optimized on the CTV with the same beam arrangement and the same single-field robust optimization (2 mm setup errors, 3.5% range uncertainties). Robustness analysis was performed with 0.5 and 1.0 mm systematic setup errors and 3.5% range uncertainties. CTV coverage in the perturbed scenarios and healthy brain tissue sparing in the surrounding of the CTV were compared. RESULTS: Meningiomas were larger and at a shallow depth than neuromas. In neuromas, spot spacing did not affect OAR doses or the robustness of CTV coverage and the apertures reduced brain dose without any significant impact on CTV robustness. In meningiomas, smaller spot spacing produced a reduction in brain V5Gy and improved robustness of CTV coverage; in addition, an 8 mm margin aperture reduced low and medium brain tissue doses without affecting robustness in the 0.5 mm perturbed scenario. A 5 mm margin aperture caused a reduction of plan robustness. CONCLUSION: The optimal use of apertures is a trade-off between sparing of low and medium dose to the healthy brain and robustness of target coverage, also depending on size and depth of the lesion.


Assuntos
Neoplasias Meníngeas , Meningioma , Neurilemoma , Terapia com Prótons , Radiocirurgia , Radioterapia de Intensidade Modulada , Humanos , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/cirurgia , Meningioma/diagnóstico por imagem , Meningioma/radioterapia , Meningioma/cirurgia , Órgãos em Risco , Prótons , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
2.
Magn Reson Med ; 86(6): 3236-3245, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34268786

RESUMO

PURPOSE: To investigate MRI myelin water imaging (MWI) by multicomponent T2 relaxometry as a quantitative imaging biomarker for brain radiation-induced changes and to compare it with DTI. METHODS: Sixteen patients underwent fractionated proton therapy (PT) receiving dose to the healthy tissue because of direct or indirect (base skull tumors) irradiation. MWI was performed by a multi-echo sequence with 32 equally spaced echoes (10-320 ms). Decay data were processed to identify 3 T2 compartments: myelin water (Mw) below 40 ms, intra-extracellular water (IEw) between 40 and 250 ms, and free water (CSFw) above 250 ms. Both MWI and DTI scans were acquired pre (pre)-treatment and immediately at the end (end) of PT. After image registration, voxel-wise difference maps, obtained by subtracting MWI and DTI pre from those acquired at the end of PT, were compared with the corresponding biological equivalent dose (BED). RESULTS: Mw difference showed a positive correlation and IEw difference showed a negative correlation with BED considering end-pre changes (P < .01). The changes in CSFw were not significantly correlated with the delivered BED. The changes in DTI data, considering end-pre acquisitions, showed a positive correlation between fractional anisotropy and the delivered BED. CONCLUSION: MWI might detect early white matter radiation-induced alterations, providing additional information to DTI, which might improve the understanding of the pathogenesis of the radiation damage.


Assuntos
Terapia com Prótons , Substância Branca , Humanos , Imageamento por Ressonância Magnética , Bainha de Mielina , Prótons , Substância Branca/diagnóstico por imagem
3.
Pediatr Blood Cancer ; 68(5): e28919, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33682333

RESUMO

Meningiomas are an extremely rare histology among pediatric brain tumors, and there is a shortage of literature on their management. Proton therapy is currently used safely and effectively for many types of both pediatric and adult cancer, and its main advantage is the sparing of healthy tissues from radiation, which could translate in the reduction of late side effects. We review the literature on radiotherapy and proton therapy for pediatric meningiomas and report clinical outcomes for two aggressive pediatric meningiomas we treated with protons. Proton therapy might be a safe and effective therapeutic option for this rare subgroup of tumors.


Assuntos
Neoplasias Meníngeas/radioterapia , Meningioma/radioterapia , Terapia com Prótons/métodos , Criança , Humanos , Lactente , Masculino , Neoplasias Meníngeas/patologia , Meningioma/patologia
4.
Acta Oncol ; 58(6): 934-942, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30938217

RESUMO

Background: Different modern radiation therapy treatment solutions for breast cancer (BC) and regional nodal irradiation (RNI) have been proposed. In this study, we evaluate the potential reduction in radiation-induced skin morbidity obtained by intensity modulated proton therapy (IMPT) compared with intensity modulated photon therapy (IMXT) for left-side BC and RNI. Material and Methods: Using CT scans from 10 left-side BC patients, treatment plans were generated using IMXT and IMPT techniques. A dose of 50 Gy (or Gy [RBE] for IMPT) was prescribed to the target volume (involved breast, the internal mammary, supraclavicular, and infraclavicular nodes). Two single filed optimization IMPT (IMPT1 and IMPT2) plans were calculated without and with skin optimization. For each technique, skin dose-metrics were extracted and normal tissue complication probability (NTCP) models from the literature were employed to estimate the risk of radiation-induced skin morbidity. NTCPs for relevant organs-at-risk (OARs) were also considered for reference. The non-parametric Anova (Friedman matched-pairs signed-rank test) was used for comparative analyses. Results: IMPT improved target coverage and dose homogeneity even if the skin was included into optimization strategy (HIIMPT2 = 0.11 vs. HIIMXT = 0.22 and CIIMPT2 = 0.96 vs. CIIMXT = 0.82, p < .05). A significant relative skin risk reduction (RR = NTCPIMPT/NTCPIMXT) was obtained with IMPT2 including the skin in the optimization with a RR reduction ranging from 0.3 to 0.9 depending on the analyzed skin toxicity endpoint/model. Both IMPT plans attained significant OARs dose sparing compared with IMXT. As expected, the heart and lung doses were significantly reduced using IMPT. Accordingly, IMPT always provided lower NTCP values. Conclusions: IMPT guarantees optimal target coverage, OARs sparing, and simultaneously minimizes the risk of skin morbidity. The applied model-based approach supports the potential clinical relevance of IMPT for left-side BC and RNI and might be relevant for the setup of cost-effectiveness evaluation strategies based on NTCP predictions, as well as for establishing patient selection criteria.


Assuntos
Neoplasias da Mama/radioterapia , Linfonodos/efeitos da radiação , Terapia com Prótons/efeitos adversos , Lesões por Radiação/mortalidade , Radioterapia de Intensidade Modulada/efeitos adversos , Comportamento de Redução do Risco , Dermatopatias/prevenção & controle , Neoplasias da Mama/patologia , Feminino , Seguimentos , Humanos , Linfonodos/patologia , Órgãos em Risco/efeitos da radiação , Prognóstico , Lesões por Radiação/etiologia , Lesões por Radiação/patologia , Planejamento da Radioterapia Assistida por Computador/métodos , Estudos Retrospectivos , Dermatopatias/induzido quimicamente , Taxa de Sobrevida , Tomografia Computadorizada por Raios X/métodos
5.
Acta Oncol ; 58(12): 1720-1730, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31393203

RESUMO

Background and purpose: A collaborative network between proton therapy (PT) centres in Trento in Italy, Poland, Austria, Czech Republic and Sweden (IPACS) was founded to implement trials and harmonize PT. This is the first report of IPACS with the aim to show the level of harmonization that can be achieved for proton therapy planning of head and neck (sino-nasal) cancer.Methods: CT-data sets of five patients were included. During several face-to-face and online meetings, a common treatment planning protocol was developed. Each centre used its own treatment planning system (TPS) and planning approach with some restrictions specified in the treatment planning protocol. In addition, volumetric modulated arc therapy (VMAT) photon plans were created.Results: For CTV1, the average Dmedian was 59.3 ± 2.4 Gy(RBE) for protons and 58.8 ± 2.0 Gy(RBE) for VMAT (aim was 56 Gy(RBE)). For CTV2, the average Dmedian was 71.2 ± 1.0 Gy(RBE) for protons and 70.6 ± 0.4 Gy(RBE) for VMAT (aim was 70 Gy(RBE)). The average D2% for the spinal cord was 25.1 ± 8.5 Gy(RBE) for protons and 47.6 ± 1.4 Gy(RBE) for VMAT. The average D2% for chiasm was 46.5 ± 4.4 Gy(RBE) for protons and 50.8 ± 1.4 Gy(RBE) for VMAT, respectively. Robust evaluation was performed and showed the least robust plans for plans with a low number of beams.Discussion: In conclusion, several influences on harmonization were identified: adherence/interpretation to/of the protocol, available technology, experience in treatment planning and use of different beam arrangements. In future, all OARs that should be included in the optimization need to be specified in order to further harmonize treatment planning.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Cooperação Internacional , Órgãos em Risco , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Tronco Encefálico/efeitos da radiação , Cóclea/efeitos da radiação , Europa (Continente) , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Laringe/efeitos da radiação , Neoplasias Nasais/diagnóstico por imagem , Neoplasias Nasais/radioterapia , Nervo Óptico/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Neoplasias dos Seios Paranasais/diagnóstico por imagem , Neoplasias dos Seios Paranasais/radioterapia , Glândula Parótida/efeitos da radiação , Fótons/uso terapêutico , Radioterapia de Intensidade Modulada/métodos , Tomografia Computadorizada por Raios X , Carga Tumoral
6.
Eur Spine J ; 27(4): 874-881, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28815357

RESUMO

BACKGROUND: Protocols including combination of surgery and radiotherapy are more and more frequent in the treatment of bone tumors of the spine. In metastatic disease, combination of surgery and radiotherapy is since long time accepted, as based on clinical evidence. In primary tumors, combination of surgery and radiotherapy can be considered in all the cases in which a satisfactory oncological margin cannot be achieved: high-grade malignancies, recurrent tumors, huge tumors expanding in an extracompartimental area, and when tumor-free margin requires unacceptable functional sacrifices. However, metal implants are an obstacle in the collaboration between surgeons and radiation oncologists. Carbon-fiber-reinforced polyethil-ether-ether-ketone (CFR-PEEK) composite implants could make easier and more effective the treatment as radiolucent and not interfering with ionizing radiation and accelerated particles. The purpose of this article is to report the preliminary results from a cohort of patients treated with CFR-PEEK and to evaluate the safety and the non-inferiority of the device respect the commonly used titanium implants. MATERIALS AND METHODS: This study concerns an ambispective cohort series of 34 tumor patients (14 metastases and 20 primaries, most of them recurrent) submitted to thoracic and lumbar spine fixation with a CFR-PEEK composite implants. Oncologic surgery was palliative decompression and fixation in 9 cases, tumor excision in 21, and enbloc resection in 4. Data collected for this preliminary report were all intraoperative remarks, incidence of complications, changes in neurological status, local control, and survival. All the cases were followed 6-36 months (mean 13 months). RESULTS: Only one intraoperative screw breakage occurred out of 232 implanted screws. Pain control and neurological improvement were the early clinical results. Two sacral screws loosening were found at 9 and 12 months in multilevel constructs performed on multirecurrent tumors. Six local recurrences were early found thanks to the implant radiolucency. Radiation oncologists' opinion was favourable as concerning better treatment planning on CT and lacking of scattering effect during the treatment. CONCLUSIONS: No artifacts on imaging studies mean early local recurrence detection. For radiation oncologists, no artifacts on imaging studies mean easier planning and no scattering effect means more effective and safe radiotherapy, particularly when particles are used. Moreover, it seems that the clinical use of CFR-PEEK composite implants may be safe and at least comparable with the commonly used titanium implants in terms of intraoperative complications, stability at weight bearing and at functional recovery. Larger patient series and longer follow-up are required to confirm these data.


Assuntos
Materiais Biocompatíveis/efeitos adversos , Parafusos Ósseos/efeitos adversos , Procedimentos Ortopédicos/instrumentação , Neoplasias da Coluna Vertebral/cirurgia , Adolescente , Adulto , Idoso , Benzofenonas , Materiais Biocompatíveis/uso terapêutico , Fibra de Carbono/efeitos adversos , Feminino , Humanos , Cetonas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Procedimentos Ortopédicos/efeitos adversos , Procedimentos Ortopédicos/métodos , Polietilenoglicóis/efeitos adversos , Polímeros , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Desenho de Prótese/efeitos adversos , Desenho de Prótese/métodos , Neoplasias da Coluna Vertebral/radioterapia , Coluna Vertebral/patologia , Coluna Vertebral/cirurgia , Resultado do Tratamento , Adulto Jovem
7.
Radiol Med ; 121(9): 735-43, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27255503

RESUMO

PURPOSE: To report the results of the first Italian survey investigating the role of liver-directed radiotherapy in the multidisciplinary approach of primary and metastatic liver cancer. MATERIALS AND METHODS: A 21-item, two-section questionnaire was sent to all Italian radiotherapy centers on June 2014. The two sections aimed at: (1) evaluating the presence of a multidisciplinary liver tumor board and describing the role of radiation oncologists within the latter, (2) analyzing Radiotherapy treatment details and differences between centers. RESULTS: A total of 37 centers completed the survey. A multidisciplinary liver tumor board was available in most centers (73 %), with a radiation oncologist routinely attending the latter in the majority of cases (85 %). Most of the respondents considered liver-directed Radiotherapy as the third line choice when other therapies were not indicated or technically suitable. 18 centers reported the use of liver-directed radiotherapy. The majority of centers started liver irradiation after 2010. The most adopted motion management strategy was abdominal compression. The most adopted GTV-CTV expansion was 0 and 5 mm for metastases and hepatocellular carcinoma, respectively. Stereotactic body radiotherapy was the technique of choice; several treatment schedules were registered, being 45 Gy in three fractions the most reported fractionation scheme. Dose was prescribed at the PTV margin in most cases. CONCLUSION: Liver-directed radiotherapy represents a new field of interest which is currently adopted by 10 % of all Italian Centers. The technical equipment seems adequate. The variations observed in the treatment regimens reflect the lack of a well-established standard schedule.


Assuntos
Neoplasias Hepáticas/radioterapia , Radioterapia (Especialidade)/organização & administração , Terapia Combinada , Humanos , Itália , Padrões de Prática Médica/estatística & dados numéricos , Inquéritos e Questionários
8.
Acta Oncol ; 53(10): 1312-20, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24797885

RESUMO

BACKGROUND: Adjuvant chemoradiotherapy improves both overall- and relapse-free survival in patients with resected gastric cancer. However, this comes at the cost of increased treatment-related toxicity. Proton therapy (PT) has distinct dosimetric characteristics that may reduce dose to normal tissues, improving the therapeutic ratio. The purpose of this treatment planning study is to compare PT and intensity-modulated x-ray therapy (IMXT) in gastric cancer with regards to normal tissue sparing. MATERIAL AND METHODS: The patient population consisted of resected gastric cancer patients treated at a single institution between 2008 and 2013. Patients who had undergone 4D CT simulation were replanned to the originally delivered doses (45-54 Gy in 25-30 daily fractions) using six-field photon IMXT and 2-3-field PT (double scattering-uniform scanning techniques). RESULTS: Thirteen patients were eligible for the planning comparison. IMXT provided slightly higher homogeneity indices (median values 0.04 ± 0.01 vs. 0.07 ± 0.01, p = 0.03). PT resulted in significantly (p < 0.05) lower intermediate-low doses for all the normal tissues examined (small bowel V15 82 ml vs. 133 ml, liver mean doses Gy 11.9 vs. 14.4 Gy, left/right kidney mean doses 5/0.9 Gy vs. 7.8/3.1 Gy, heart mean doses 7.4 Gy vs. 9.5 Gy). The total energy deposited outside the target volume was significantly lower with PT (median integral dose 90.1 J vs. 129 J). Four patients were treated with PT: treatment was feasible and verifications scans showed that target coverage was robust. CONCLUSION: PT can contribute to normal tissue sparing in the adjuvant treatment of gastric cancer, with a potential benefit in terms of compliance to treatment, acute and late toxicities.


Assuntos
Órgãos em Risco/efeitos da radiação , Terapia com Prótons/métodos , Radioterapia de Intensidade Modulada/métodos , Neoplasias Gástricas/radioterapia , Estudos de Viabilidade , Humanos , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/diagnóstico por imagem , Lesões por Radiação/prevenção & controle , Radiografia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia
9.
J Appl Clin Med Phys ; 15(1): 4399, 2014 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-24423836

RESUMO

Since reirradiation in recurrent head and neck patients is limited by previous treatment, a marked reduction of maximum doses to spinal cord and brain stem was investigated in the initial irradiation of stage III/IV head and neck cancers. Eighteen patients were planned by simultaneous integrated boost, prescribing 69.3 Gy to PTV1 and 56.1 Gy to PTV2. Nine 6 MV coplanar photon beams at equispaced gantry angles were chosen for each patient. Step-and-shoot IMRT was calculated by direct machine parameter optimization, with the maximum number of segments limited to 80. In the standard plan, optimization considered organs at risk (OAR), dose conformity, maximum dose < 45 Gy to spinal cord and < 50 Gy to brain stem. In the sparing plans, a marked reduction to spinal cord and brain stem were investigated, with/without changes in dose conformity. In the sparing plans, the maximum doses to spinal cord and brain stem were reduced from the initial values (43.5 ± 2.2 Gy and 36.7 ± 14.0 Gy), without significant changes on the other OARs. A marked difference (-15.9 ± 1.9 Gy and -10.1 ± 5.7 Gy) was obtained at the expense of a small difference (-1.3% ± 0.9%) from initial PTV195% coverage (96.6% ± 0.9%). Similar difference (-15.7 ± 2.2 Gy and -10.2 ± 6.1 Gy) was obtained compromising dose conformity, but unaffecting PTV195% and with negligible decrease in PTV295% (-0.3% ± 0.3% from the initial 98.3% ± 0.8%). A marked spinal cord and brain stem preventive sparing was feasible at the expense of a decrease in dose conformity or slightly compromising target coverage. A sparing should be recommended in highly recurrent tumors, to make potential reirradiation safer.


Assuntos
Tronco Encefálico/efeitos da radiação , Neoplasias de Cabeça e Pescoço/radioterapia , Tratamentos com Preservação do Órgão , Lesões por Radiação/prevenção & controle , Proteção Radiológica/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Medula Espinal/efeitos da radiação , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Estadiamento de Neoplasias , Dosagem Radioterapêutica , Radioterapia Conformacional
10.
J Neurooncol ; 111(2): 177-85, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23264191

RESUMO

To investigate the increase in MRI contrast enhancement (CE) occurring in glioblastoma during the period between surgery and initiation of chemo-radiotherapy, thirty-seven patients with newly diagnosed glioblastoma were analyzed by early post-operative magnetic resonance (EPMR) imaging within three days of surgery and by pre-adjuvant magnetic resonance (PAMR) examination before adjuvant therapy. Areas of new CE were investigated by use of EPMR diffusion-weighted imaging and PAMR perfusion imaging (by arterial spin-labeling). PAMR was acquired, on average, 29.9 days later than EPMR (range 20-37 days). During this period an increased area of CE was observed for 17/37 patients. For 3/17 patients these regions were confined to areas of reduced EPMR diffusion, suggesting postsurgical infarct. For the other 14/17 patients, these areas suggested progression. For 11/17 patients the co-occurrence of hyperperfusion in PAMR perfusion suggested progression. PAMR perfusion and EPMR diffusion did not give consistent results for 3/17 patients for whom small new areas of CE were observed, presumably because of the poor spatial resolution of perfusion imaging. Before initiation of adjuvant therapy, areas of new CE of resected glioblastomas are frequently observed. Most of these suggest tumor progression, according to EPMR diffusion and PAMR perfusion criteria.


Assuntos
Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Glioblastoma/patologia , Glioblastoma/terapia , Adulto , Idoso , Neoplasias Encefálicas/mortalidade , Terapia Combinada , Meios de Contraste , Imagem de Difusão por Ressonância Magnética , Progressão da Doença , Feminino , Glioblastoma/mortalidade , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo
12.
Front Oncol ; 11: 651137, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33828992

RESUMO

PURPOSE: To demonstrate that quantitative multicomponent T2 relaxation can be more sensitive than conventional FLAIR imaging for detecting cerebral tissue abnormalities. METHODS: Six patients affected by lower-grade non-enhancing gliomas underwent T2 relaxation and FLAIR imaging before a radiation treatment by proton therapy (PT) and were examined at follow-up. The T2 decay signal obtained by a thirty-two-echo sequence was decomposed into three main components, attributing to each component a different T2 range: water trapped in the lipid bilayer membrane of myelin, intra/extracellular water and cerebrospinal fluid. The T2 quantitative map of the intra/extracellular water was compared with FLAIR images. RESULTS: Before PT, in five patients a mismatch was observed between the intra/extracellular water T2 map and FLAIR images, with peri-tumoral areas of high T2 that typically extended outside the area of abnormal FLAIR hyper-intensity. Such mismatch regions evolved into two different types of patterns. The first type, observed in three patients, was a reduced extension of the abnormal regions on T2 map with respect to FLAIR images (T2 decrease pattern). The second type, observed in two patients, was the appearance of new areas of abnormal hyper-intensity on FLAIR images matching the anomalous T2 map extension (FLAIR increase pattern), that was considered as asymptomatic radiation induced damage. CONCLUSION: Our preliminarily results suggest that quantitative T2 mapping of the intra/extracellular water component was more sensitive than conventional FLAIR imaging to subtle cerebral tissue abnormalities, deserving to be further investigated in future clinical studies.

13.
Diagnostics (Basel) ; 11(6)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207471

RESUMO

Chordoma in pediatric patients is very rare. Proton therapy has become a gold standard in the treatment of these neoplasms, as high dose escalation can be achieved regarding the target while maximizing the sparing of the healthy tissues near the tumor. The aim of the work was to assess the evolution of morphological sequences during treatment using T1/T2-weighted magnetic resonance imaging (MRI) for the early response assessment of a classic chordoma of the skull base in a pediatric patient who had undergone surgical excision. Our results demonstrated a significant quantitative reduction in the residual nodule component adhered to the medullary bulb junction, with an almost complete recovery of normal anatomy at the end of the irradiation treatment. This was mainly shown in the T2-weighted MRI. On the other hand, the classic component of the lesion was predominantly present and located around the tooth of the axis. The occipital condyles were morphologically and dimensionally stable for the entire irradiation period. In conclusion, the application of this type of monitoring methodology, which is unusual during the administration of a proton treatment for chordoma, highlighted the unexpected early response of the disease. At the same time, it allowed the continuous assessment of the reliability of the treatment plan.

14.
Int J Part Ther ; 8(1): 328-338, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34285959

RESUMO

This review aims to present and assess available and new methodologies to increase the clinical evidence of proton therapy data for patients with head and neck cancer. Despite the increasing number of scientific reports showing the feasibility and effectiveness of proton therapy in head and neck cancer, clinical evidence on the potential benefits of its use remains low for several reasons. In this article, the pros and cons of consolidated and new methodologies in this setting such as randomized clinical trials, the model-based approach, and the use of prospective multicentric registries will be detailed.

15.
Radiother Oncol ; 154: 137-144, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32976870

RESUMO

PURPOSE: To present our technique for liver cancer treatments with proton therapy in pencil beam scanning mode and to evaluate the impact of uncertainties on plan quality. MATERIALS AND METHODS: Seventeen patients affected by liver cancer were included in this study. Patients were imaged and treated in forced breath-hold using the Active Breathing Coordinator system and monitored with an optical tracking system. Three simulation CTs were acquired to estimate the anatomical variability between breath-holds and generate an internal target volume (ITV). The treatment plans were optimized with a Single Field Optimization technique aimed at minimizing the use of range shifter. Plan robustness was tested simulating systematic range and setup uncertainties, as well as the interplay effect between breath-holds. The appropriateness of margin was further verified based on the actual positioning data acquired during treatment. RESULTS: The dose distributions of the nominal plans achieved a satisfactory target coverage in 11 out of 17 patients, while in the remaining 6 D95 to the PTV was affected by the constraint on mean liver dose. The constraints for all other organs at risk were always within tolerances. The interplay effect had a limited impact on the dose distributions: the worst case scenario showed a D95 reduction in the ITV < 3.9 GyRBE and no OAR with D1 > 105% of the prescription dose. The robustness analysis showed that for 13 out of 17 patients the ITV coverage in terms of D95 was better than D95 of the PTV in the nominal plan. For the remaining 4 patients, the maximum difference between ITV D95 and PTV D95 was ≤0.7% even for the largest simulated setup error and it was deemed clinically acceptable. Hot spots in the OARs were always lower than 105% of the prescription dose. Positioning images confirmed that the breath hold technique and the PTV margin were adequate to compensate for inter- and intra-breath-hold variations in liver position. CONCLUSION: We designed and clinically applied a technique for the treatment of liver cancer with proton pencil beam scanning in forced deep expiration breath-hold. The initial data on plan robustness and patient positioning suggest that the choices in terms of planning technique and treatment margins are able to reach the desired balance between target coverage and organ at risk sparing.


Assuntos
Neoplasias Hepáticas , Terapia com Prótons , Radioterapia de Intensidade Modulada , Suspensão da Respiração , Humanos , Neoplasias Hepáticas/radioterapia , Órgãos em Risco , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
16.
Diagnostics (Basel) ; 11(5)2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34069450

RESUMO

Rosette-forming glioneuronal tumors (RGNTs) are rare, grade I, central nervous system (CNS) tumors typically localized to the fourth ventricle. We describe a 9-year-old girl with dizziness and occipital headache. A magnetic resonance imaging (MRI) revealed a large hypodense posterior fossa mass lesion in relation to the vermis, with cystic component. Surgical resection of the tumor was performed. A RGNT diagnosis was made at the histopathological examination. During follow-up, the patient experienced a first relapse, which was again surgically removed. Eight months after, MRI documented a second recurrence at the local level. She was a candidate for the proton beam therapy (PBT) program. Three years after the end of PBT, the patient had no evidence of disease recurrence. This report underlines that, although RGNTs are commonly associated with an indolent course, they may have the potential for aggressive behavior, suggesting the need for treatment in addition to surgery. Controversy exists in the literature regarding effective management of RGNTs. Chemotherapy and radiation are used as adjuvant therapy, but their efficacy management has not been adequately described in the literature. This is the first case report published in which PBT was proposed for adjuvant therapy in place of chemotherapy in RGNT relapse.

17.
Phys Med ; 88: 226-234, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34311160

RESUMO

PURPOSE: To perform the validation of the GPU-based (Graphical Processing Unit based) proton Monte Carlo (MC) dose engine implemented in a commercial TPS (RayStation 10B) and to report final dose calculation times for clinical cases. MATERIALS AND METHODS: 440 patients treated at the Proton Therapy Center of Trento, Italy, between 2018 and 2019 were selected for this study. 636 approved plans with 3361 beams computed with the clinically implemented CPU-MC dose engine (version 4.2 and 4.5), were used for the validation of the new algorithm. For each beam, the dose was recalculated using the new GPU-MC dose engine with the initial CPU computation settings and compared to the original CPU-MC dose. Beam dose difference distributions were studied to ensure that the two dose distributions were equal within the expected fluctuations of the MC statistical uncertainty (s) of each computation. Plan dose distributions were compared with respect to the dosimetric indices D98, D50 and D1 of all ROIs defined as targets. A complete assessment of the computation time as a function of s and dose grid voxel size was done. RESULTS: The median over all mean beam dose differences between CPU- and GPU-MC was -0.01% and the median of the corresponding standard deviations was close to (√2s) both for simulations with an s of 0.5% and 1.0% per beam. This shows that the two dose distributions can be considered equal. All the DVH indices showed an average difference below 0.04%. About half of the plans were computed with 1.0% statistical uncertainty on a 2 mm dose calculation grid, for which the median computation time was 5.2 s. The median computational speed for all plans in the study was 8.4 million protons/second. CONCLUSION: A validation of a clinical MC algorithm running on GPU was performed on a large pool of patients treated with pencil beam scanning proton therapy. We demonstrated that the differences with the previous CPU-based MC were only due to the intrinsic statistical fluctuations of the MC method, which translated to insignificant differences on plan dose level. The significant increase in dose calculation speed is expected to facilitate new clinical workflows.


Assuntos
Terapia com Prótons , Algoritmos , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
18.
Tumori ; 107(1): 71-79, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32648818

RESUMO

BACKGROUND: Evidence for the efficacy of radiation therapy for primary liver cancer is growing. In this context, proton therapy (PT) can potentially improve the therapeutic ratio, as demonstrated by recent clinical studies. Here we report the first European clinical experience on the use of PT for primary liver cancer. METHODS: All patients treated for primary liver cancer in our center entered the analysis. Patients were simulated during deep expiration breath-hold. A 15-fraction treatment schedule was adopted using active scanning PT. Clinical outcome and toxicity were retrospectively analyzed. RESULTS: Between January 2018 and December 2019, 18 patients were treated. Fourteen patients had hepatocellular carcinoma (HCC), three patients had intrahepatic cholangiocarcinoma (ICC), and one patient had synchronous ICC-HCC. The Child-Pugh score was A5 in the majority of patients with HCC (71.4%). Median prescription dose was 58.05 Gy (range, 50.31-67.5). Median follow-up was 10 months (range, 1-19). The majority of deaths occurred from liver tumor progression. One-year overall survival (OS) was 63%. A significant correlation between worse OS and patient performance status, vascular invasion, and tumor stage was recorded. One-year local control was 90%. Toxicity was low, with a decrease in Child-Pugh score ⩾2 points detected in one patient. No cases of classic radiation-induced liver disease occurred. CONCLUSIONS: Our initial results of active scanning PT for primary liver cancer demonstrated the feasibility, safety, and effectiveness of this advanced technique in this setting. The potential of the combination of PT with other locoregional therapies is under evaluation.


Assuntos
Neoplasias Hepáticas/radioterapia , Fígado/efeitos da radiação , Terapia com Prótons/efeitos adversos , Lesões por Radiação/patologia , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Humanos , Fígado/lesões , Fígado/patologia , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Lesões por Radiação/epidemiologia , Lesões por Radiação/etiologia , Estudos Retrospectivos , Resultado do Tratamento
19.
Neurosurg Rev ; 33(2): 155-65, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19921291

RESUMO

Chondrosarcoma (CSA) of the skull base (SB) is an uncommon, slowly growing, neoplasm comprising approximately 0.1% of all intracranial tumors and 6% of SB lesions. Even though its growth is slow, CSA is a potentially lethal tumor. The therapeutic approach to CSA of the SB is still controversial and clinical experience is limited because of the relative rarity of this tumor. The use of proton therapy (PT) after maximal surgery is widely accepted, but there are no controlled studies demonstrating the need of PT and its superiority in comparison to radiotherapy with photons. We conducted a systematic review of the scientific literature published during the period between January 1980 and June 2008 on data regarding irradiation of CSA of the SB with PT and a series of inclusion criteria. During August 2008, two independent reviewers (M.A. and D.A.), by applying the key words "skull base", "chondrosarcoma", and "proton therapy" selected those studies from the PubMed database in which a minimum of ten patients received palliative, radical, or postoperative irradiation with protons and which furnished a minimum of 24 months of follow-up. Forty nine reports were retrieved. There were no prospective trials (randomized or nonrandomized) but just nine uncontrolled single-arm studies for PT mainly related to advanced and frequently incompletely resected tumors. According to the inclusion criteria, only four articles, reporting the most recent updated results of the publishing institution, were included in the analysis providing clinical outcomes for 254 patients in total. Therapeutic approach to CSA of the SB has traditionally relied on surgical control. Radiation therapy has demonstrated to be a valuable modality for local control in the postoperative setting or in advanced/inoperable cases treated with definitive intent. The use of PT following maximal surgical resection shows a very high probability of medium- and long-term cure with a relatively low risk of significant complications.


Assuntos
Condrossarcoma/radioterapia , Terapia com Prótons , Neoplasias da Base do Crânio/radioterapia , Fracionamento da Dose de Radiação , Humanos , Íons/uso terapêutico , Fótons/uso terapêutico , Radiocirurgia
20.
J Cancer Res Clin Oncol ; 146(6): 1615-1622, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32200460

RESUMO

PURPOSE: Proton therapy could minimize the risk of side effects and, therefore, reduce the possible detrimental effect on health-related quality of life (HRQOL) of re-irradiation. The aim of this study was to determine the effect of re-irradiation with active scanning proton therapy on recurrent glioblastoma (GBM) in terms of HRQOL scored by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-C30 and EORTC Quality of Life Questionnaire Brain Cancer Module (QLQ-BN20). METHODS: Thirty-three patients with recurrent GBM were re-irradiated with active scanning proton therapy. Subscales within the EORTC QLQ-C30 include five functional scales, six single-item scales, and global QoL. The BN20 assessed visual disorders, motor function, communication deficit, various disease symptoms, treatment, toxicity, and future uncertainty. The patients completed the questionnaires before starting proton therapy, the last day of proton therapy, and at every follow-up visit until progression of disease. RESULTS: The treatment was associated with improvement or stability in most of the preselected HRQOL domains. Global health improved over time with a maximum difference of six points between baseline and 3-months follow-up. Social functioning and motor dysfunction improved over time with a maximum difference of eight and two points, respectively. We showed a non-significant decrease in cognitive and emotional functioning. Fatigue remained stable during the analysis such as the other preselected domains. CONCLUSIONS: Re-irradiation with proton therapy is a safe and effective treatment in patients with recurrent glioblastoma. Proton therapy does not negatively effect on HRQOL, but rather it seems to preserve HRQOL until the time of disease progression.


Assuntos
Neoplasias Encefálicas/fisiopatologia , Glioblastoma/fisiopatologia , Terapia com Prótons , Qualidade de Vida , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
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