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1.
Medicine (Baltimore) ; 100(24): e26338, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34128879

RESUMO

ABSTRACT: The purpose of this study is to compare the longitudinal location of endoscopically-defined gross tumor volume (GTV) and positron emission tomography-based metabolic tumor volume (MTV) of esophageal cancer.A retrospective review of medical records was performed of the nine patients who underwent endoscopic placement of fiducial markers for radiotherapy of esophageal squamous cell carcinoma. Endoscopic hemoclips were used as the fiducial markers, and GTV was newly delineated solely based on the locations of the fiducial markers. The standardized uptake value (SUV) threshold corresponding to the superior and inferior borders of GTV was defined as the highest threshold that made MTV reach each border of GTV.The median fixed relative and absolute thresholds were 32% and 3.8, respectively. The coefficient of variation of the threshold values was 0.781 for the fixed relative threshold method and 0.400 for the fixed absolute threshold method, indicating more consistent results from the fixed absolute threshold method. All but two GTV borders were included in MTV with a SUV threshold of 2.5. Esophageal tumors with a maximum SUV > 20 tended to have closer threshold values corresponding to the GTV borders to 2.5 (median 2.8 vs 3.6, P = .069).The fixed absolute threshold method was suitable for determining the MTV threshold for esophageal lesions. A SUV of 2.5 was appropriate for esophageal tumors with a maximum SUV > 20. Endoscopic hemoclips were stable enough for using as the fiducial marker.


Assuntos
Endossonografia , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/patologia , Tomografia por Emissão de Pósitrons , Carga Tumoral , Idoso , Idoso de 80 Anos ou mais , Neoplasias Esofágicas/diagnóstico por imagem , Carcinoma de Células Escamosas do Esôfago/diagnóstico por imagem , Feminino , Marcadores Fiduciais , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos , Planejamento da Radioterapia Assistida por Computador/métodos , Estudos Retrospectivos
2.
Br J Radiol ; 94(1123): 20210214, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34111955

RESUMO

OBJECTIVE: To develop and evaluate a practical automatic treatment planning method for intensity-modulated radiation therapy (IMRT) in cervical cancer cases. METHODS: A novel algorithm named as Optimization Objectives Tree Search Algorithm (OOTSA) was proposed to emulate the planning optimization process and achieve a progressively improving IMRT plan, based on the Eclipse Scripting Application Programming Interface (ESAPI). 30 previously treated cervical cancer cases were selected from the clinical database and comparison was made between the OOTSA-generated plans and clinical treated plans and RapidPlan-based (RP) plans. RESULTS: In clinical evaluation, compared with plan scores of the clinical plans and the RP plans, 22 and 26 of the OOTSA plans were considered as clinically improved in terms of plan quality, respectively. The average conformity index (CI) for the PTV in the OOTSA plans was 0.86 ± 0.01 (mean ± 1 standard deviation), better than those in the RP plans (0.83 ± 0.02) and the clinical plans (0.71 ± 0.11). Compared with the clinical plans, the mean doses of femoral head, rectum, spinal cord and right kidney in the OOTSA plans were reduced by 2.34 ± 2.87 Gy, 1.67 ± 2.10 Gy, 4.12 ± 6.44 Gy and 1.15 ± 2.67 Gy. Compared with the RP plans, the mean doses of femoral head, spinal cord, right kidney and small intestine in the OOTSA plans were reduced by 3.31 ± 1.55 Gy, 4.25 ± 3.69 Gy, 1.54 ± 2.23 Gy and 3.33 ± 1.91 Gy, respectively. In the OOTSA plans, the mean dose of bladder was slightly increased, with 2.33 ± 2.55 Gy (versus clinical plans) and 1.37 ± 1.74 Gy (vs RP plans). The average elapsed time of OOTSA and clinical planning were 59.2 ± 3.47 min and 76.53 ± 5.19 min. CONCLUSION: The plans created by OOTSA have been shown marginally better than the manual plans, especially in preserving OARs. In addition, the time of automatic treatment planning has shown a reduction compared to a manual planning process, and the variation of plan quality was greatly reduced. Although improvement on the algorithm is warranted, this proof-of-concept study has demonstrated that the proposed approach can be a practical solution for automatic planning. ADVANCES IN KNOWLEDGE: The proposed method is novel in the emulation strategy of the physicists' iterative operation during the planning process. Based on the existing optimizers, this method can be a simple yet effective solution for automated IMRT treatment planning.


Assuntos
Algoritmos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada , Neoplasias do Colo do Útero/radioterapia , Adulto , Feminino , Humanos , Órgãos em Risco , Dosagem Radioterapêutica , Estudos Retrospectivos , Carga Tumoral
3.
Int J Comput Assist Radiol Surg ; 16(6): 1043-1049, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34021859

RESUMO

PURPOSE: To show the feasibility of 3D-printed fixation masks for whole brain radiation therapy in a clinical setting and perform a first comparison to an established thermoplastic mask system. METHODS: Six patients were irradiated with whole brain radiotherapy using individually 3D-printed masks. Daily image guidance and position correction were performed prior to each irradiation fraction. The vectors of the daily position correction were compared to two collectives of patients, who were irradiated using the standard thermoplastic mask system (one cohort with head masks; one cohort with head and neck masks). RESULTS: The mean systematic errors in the experimental cohort ranged between 0.59 and 2.10 mm which is in a comparable range to the control groups (0.18 mm-0.68 mm and 0.34 mm-2.96 mm, respectively). The 3D-printed masks seem to be an alternative to the established thermoplastic mask systems. Nevertheless, further investigation will need to be performed. CONCLUSION: The prevailing study showed a reliable and reproducible interfractional positioning accuracy using individually 3D-printed masks for whole brain irradiation in a clinical routine. Further investigations, especially concerning smaller target volumes or other areas of the body, need to be performed before using the system on a larger basis.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Imobilização/métodos , Máscaras , Impressão Tridimensional , Planejamento da Radioterapia Assistida por Computador/métodos , Humanos
4.
Int J Comput Assist Radiol Surg ; 16(7): 1161-1170, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34050909

RESUMO

PURPOSE: In low-dose-rate prostate brachytherapy (LDR-PB), treatment planning is the process of determining the arrangement of implantable radioactive sources that radiates the prostate while sparing healthy surrounding tissues. Currently, these plans are prepared manually by experts incorporating the centre's planning style and guidelines. In this article, we develop a novel framework that can learn a centre's planning strategy and automatically reproduce rapid clinically acceptable plans. METHODS: The proposed framework is based on conditional generative adversarial networks that learn our centre's planning style using a pool of 931 historical LDR-PB planning data. Two additional losses that help constrain prohibited needle patterns and produce similar-looking plans are also proposed. Once trained, this model generates an initial distribution of needles which is passed to a planner. The planner then initializes the sources based on the predicted needles and uses a simulated annealing algorithm to optimize their locations further. RESULTS: Quantitative analysis was carried out on 170 cases which showed the generated plans having similar dosimetry to that of the manual plans but with significantly lower planning durations. Indeed, on the test cases, the clinical target volumes achieving [Formula: see text] of the prescribed dose for the generated plans was on average [Formula: see text] ([Formula: see text] for manual plans) with an average planning time of [Formula: see text] min ([Formula: see text] min for manual plans). Further qualitative analysis was conducted by an expert planner who accepted [Formula: see text] of the plans with some changes ([Formula: see text] requiring minor changes & [Formula: see text] requiring major changes). CONCLUSION: The proposed framework demonstrated the ability to rapidly generate quality treatment plans that not only fulfil the dosimetric requirements but also takes into account the centre's planning style. Adoption of such a framework would save significant amount of time and resources spent on every patient; boosting the overall operational efficiency of this treatment.


Assuntos
Algoritmos , Braquiterapia/métodos , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Humanos , Masculino , Dosagem Radioterapêutica
5.
Radiat Oncol ; 16(1): 91, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001182

RESUMO

BACKGROUND: The application of delayed-enhancement magnetic resonance (DE-MR) simulation imaging in lumpectomy cavity (LC) delineation for prone radiotherapy in patients with an invisible seroma or a low seroma clarity score (SCS) after breast-conserving surgery (BCS) based on deformable image registration (DIR) was assessed. METHODS: Twenty-six patients who were suitable for radiotherapy in prone positions after BCS were enrolled, and both computed tomography (CT) and DE-MR simulation scans were acquired. The LC delineated based on titanium surgical clips on CT images was denoted as LCCT. The LC delineated based on the signal of cavity boundaries on fat-suppressed T2-weighted imaging (T2WI) and multiphase delayed-enhancement T1-weighted imaging (DE-T1WI), which was performed at 2 min, 5 min and 10 min postinjection, were denoted as LCT2, LC2T1, LC5T1 and LC10T1, respectively. Afterwards, DIR was performed to compare the volumes and locations of the LCs with MIM software. The generalized conformity index (CIgen) of inter (intra) observer (Inter-CIgen and Intra-CIgen) was also used to explore the inter(intra) observer variation for LC delineation on each image modality. RESULTS: LCCT-LC10T1 provided the best conformal index (CI) and degree of inclusion (DI), increasing by 2.08% and 4.48% compared to LCCT-LCT2, 11.36% and 2.94% for LCCT-LC2T1, and 8.89% and 7.69% for LC5T1-LCCT, respectively. The center of mass (COM) of LCCT-LC10T1 decreased by 17.86%, 6.12% and 13.21% compared with that of LCCT-LCT2, LCCT-LC2T1 and LCCT-LC5T1, respectively. The agreement of LC delineation was strongest for 10th min DE-TIWI (coefficient of variation, COV = 2.30%, Inter-CIgen = 87.06%, Intra-CIgen = 92.64%). CONCLUSION: For patients with a low SCS (SCS ≤ 2) after BCS, it is feasible to contour the LC based on prone DE-MR simulation images. Furthermore, the LC derived from prone DE-T1WI at 10 min was found to be most similar to that derived from prone CT simulation scans using titanium surgical clips regardless of the volume and location of the LC. Inter (intra) variability was minimal for the delineation of the LC based on 10th min DE-TIWI.


Assuntos
Neoplasias da Mama/radioterapia , Mama/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Mastectomia Segmentar , Complicações Pós-Operatórias/diagnóstico por imagem , Decúbito Ventral , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Adjuvante , Seroma/diagnóstico por imagem , Adulto , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/cirurgia , Feminino , Marcadores Fiduciais , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Seroma/etiologia , Titânio , Tomografia Computadorizada por Raios X/métodos
6.
Br J Radiol ; 94(1123): 20201177, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33882239

RESUMO

OBJECTIVES: To determine interobserver variability in axillary nodal contouring in breast cancer (BC) radiotherapy (RT) by comparing the clinical target volume of participating single centres (SC-CTV) with a gold-standard CTV (GS-CTV). METHODS: The GS-CTV of three patients (P1, P2, P3) with increasing complexity was created in DICOM format from the median contour of axillary CTVs drawn by BC experts, validated using the simultaneous truth and performance-level estimation and peer-reviewed. GS-CTVs were compared with the correspondent SC-CTVs drawn by radiation oncologists, using validated metrics and a total score (TS) integrating all of them. RESULTS: Eighteen RT centres participated in the study. Comparative analyses revealed that, on average, the SC-CTVs were smaller than GS-CTV for P1 and P2 (by -29.25% and -27.83%, respectively) and larger for P3 (by +12.53%). The mean Jaccard index was greater for P1 and P2 compared to P3, but the overlap extent value was around 0.50 or less. Regarding nodal levels, L4 showed the highest concordance with the GS. In the intra-patient comparison, L2 and L3 achieved lower TS than L4. Nodal levels showed discrepancy with GS, which was not statistically significant for P1, and negligible for P2, while P3 had the worst agreement. DICE similarity coefficient did not exceed the minimum threshold for agreement of 0.70 in all the measurements. CONCLUSIONS: Substantial differences were observed between SC- and GS-CTV, especially for P3 with altered arm setup. L2 and L3 were the most critical levels. The study highlighted these key points to address. ADVANCES IN KNOWLEDGE: The present study compares, by means of validated geometric indexes, manual segmentations of axillary lymph nodes in breast cancer from different observers and different institutions made on radiotherapy planning CT images. Assessing such variability is of paramount importance, as geometric uncertainties might lead to incorrect dosimetry and compromise oncological outcome.


Assuntos
Axila , Neoplasias da Mama/radioterapia , Metástase Linfática/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias da Mama/patologia , Feminino , Humanos , Itália , Metástase Linfática/patologia , Variações Dependentes do Observador
7.
Br J Radiol ; 94(1123): 20210146, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33914617

RESUMO

OBJECTIVES: Treatment verification for MR-only planning has focused on fiducial marker matching, however, these are difficult to identify on MR. An alternative is using the MRI for soft-tissue matching with cone beam computed tomography images (MR-CBCT). However, therapeutic radiographers have limited experience of MRI. This study aimed to assess transferability of therapeutic radiographers CT-CBCT prostate image matching skills to MR-CBCT image matching. METHODS: 23 therapeutic radiographers with 3 months-5 years' experience of online daily CT-CBCT soft-tissue matching prostate cancer patients participated. Each observer completed a baseline assessment of 10 CT-CBCT prostate soft-tissue image matches, followed by 10 MR-CBCT prostate soft-tissue image match assessment. A MRI anatomy training intervention was delivered and the 10 MR-CBCT prostate soft-tissue image match assessment was repeated. Limits of agreement were calculated as the disagreement of the observers with mean of all observers. RESULTS: Limits of agreement at CT-CBCT baseline were 2.8 mm, 2.8 mm, 0.7 mm (vertical, longitudinal, lateral). MR-CBCT matches prior to training were 3.3 mm, 3.1 mm, 0.9 mm, and after training 2.6 mm, 2.4 mm, 1.1 mm (vertical, longitudinal, lateral). Results show similar limits of agreement across the assessments, and variation reduced following the training intervention. CONCLUSION: This suggests therapeutic radiographers' prostate CBCT image matching skills are transferrable to a MRI planning scan, since MR-CBCT matching has comparable observer variation to CT-CBCT matching. ADVANCES IN KNOWLEDGE: This is the first publication assessing interobserver MR-CBCT prostate soft tissue matching in an MR-only pathway.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Imageamento por Ressonância Magnética/métodos , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Humanos , Masculino , Dosagem Radioterapêutica
8.
Am J Clin Oncol ; 44(6): 269-274, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33852456

RESUMO

PURPOSE: As patients with mediastinal lymphoma are typically young with curable disease, advanced radiation techniques such as proton therapy are often considered to minimize subacute and late toxicity. However, it is unclear which mediastinal lymphoma patients are treated with proton therapy. Within a prospective, multi-institutional proton registry, we characterized mediastinal lymphoma patients treated with proton therapy and assessed concordance with consensus recommendations published in 2018 by the International Lymphoma Radiation Oncology Group (ILROG). METHODS: Eligible patients included those with lymphoma of the mediastinum treated exclusively with proton therapy for whom digital imaging and communications in medicine (DICOM) treatment data were available for review. Given the challenge with reliably visualizing the left mainstem coronary artery, the inferior-most aspect of the left pulmonary artery (PA) was used as a surrogate. Extent of disease was characterized as upper mediastinum (above level of left PA), middle mediastinum (below left PA but at or above level of T8), or low mediastinum (below T8). RESULTS: Between November 2012 and April 2019, 56 patients were treated and met inclusion criteria. Patients treated with proton therapy were young (median, 24 y; range: 12 to 88), with over half being female (55%). Patients were most commonly treated at initial diagnosis (86%) and had Hodgkin lymphoma (79%). Most patients (96%) had mediastinal disease that extended down to the level of the heart: 48% had middle and 48% had low mediastinal involvement. Nearly all patients (96%) met the ILROG consensus recommendations: 95% had lower mediastinal disease, 46% were young females, and 9% were heavily pretreated. Heart (mean) and lung dose (mean, V5, V20) were significantly associated with lowest extent of mediastinal disease. CONCLUSIONS: Mediastinal lymphoma patients treated with proton therapy are typically young with lower mediastinal involvement. Within a prospective, multi-institutional proton registry, nearly all treated patients fit the ILROG consensus recommendations regarding which mediastinal lymphoma patients may most benefit from proton therapy.


Assuntos
Linfoma/radioterapia , Neoplasias do Mediastino/radioterapia , Órgãos em Risco/efeitos da radiação , Seleção de Pacientes , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Sistema de Registros/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Seguimentos , Humanos , Linfoma/patologia , Masculino , Neoplasias do Mediastino/patologia , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Dosagem Radioterapêutica , Adulto Jovem
9.
Radiol Med ; 126(7): 979-988, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33900527

RESUMO

OBJECTIVE: Accurate calculation of set-up margin is a prerequisite to arrive at the most optimal clinical to planning target volume margin. The aim of this study was to evaluate the compatibility of different on-board and in-room stereoscopic imaging modalities by calculating the set-up margins (SM) in stereotactic body radiotherapy technique accounting and unaccounting for rotational positional errors (PE). Further, we calculated separate SMs one based on residual positional errors and another based on residual + intrafraction positional errors from the imaging data obtained in a dual imaging environment. MATERIALS AND METHODS: A total of 22 lung cancer patients were included in this study. For primary image guidance, four-dimensional cone beam computed tomography (4-D CBCT) was used and stereoscopic ExacTrac was used as the auxiliary imaging. Following table position correction (TPC) based on the initial 4-D CBCT, another 4-D CBCT (post-TPC) and a pair of stereoscopic ExacTrac images were obtained. Further, during the treatment delivery, a series of ExacTrac images were acquired to identify the intrafraction PE. If a, b and c were the observed translational shifts in lateral (x-axis), longitudinal (y-axis) and vertical direction (z-axis) and α, ß and γ were the rotational shifts in radians about the same axes, respectively, then the resultant translational vectors (A, B and C) were calculated on the basis of translational and rotational values. Set-up margins were calculated using residual errors post-TPC only and also using intrafraction positional errors in addition to the residual errors. RESULTS: Residual and residual + intrafraction SM were calculated from a dataset of 82 CBCTs and 189 ExacTrac imaging sessions. CBCT-based mean ± SD shifts in translational and rotational directions were 0.3 ± 1.8 mm, 0.1 ± 1.8 mm, - 0.4 ± 1.6 mm, 0.1 ± 0.4°, 0.0 ± 1.0° and 0.3 ± 0.7°, respectively, and for ExacTrac - 0.1 ± 1.8 mm, 0.2 ± 2.4 mm, - 0.6 ± 1.8 mm, 0.1 ± 1.2°, - 0.2 ± 1.3° and - 0.1 ± 0.6°, respectively. Residual SM without considering the rotational correction in x, y and z directions were 5.0 mm, 4.5 mm and 4.4 mm; rotation-corrected SM were 4.4 mm, 4.0 mm and 5.5 mm, respectively. Residual plus intrafraction SM were 5.5 mm, 6.6 mm and 6.2 mm without considering the rotational corrections, whereas they were 5.0 mm, 6.3 mm and 6.2 mm with rotational errors accounted for. CONCLUSION: Accurate calculation of set-up margin is required to find the clinical to planning target volume margin. Primary and auxiliary imaging margins fall in the range of 4.0 to 5.5 mm and 5.0 to 7.0 mm, respectively, indicating a higher SM for X-ray-based planar imaging techniques over three-dimensional cone beam images. This study established the degree of mutual compatibility between two different kinds of widely used set-up imaging modalities, on-board CBCT and in-room stereoscopic imaging ExacTrac. It also describes the technique to calculate the residual and residual plus intrafraction SM and its variation in a dual imaging environment accounting for rotational PE in stereotactic body radiotherapy of lung.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Tomografia Computadorizada Quadridimensional/métodos , Neoplasias Pulmonares/radioterapia , Pulmão/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Adulto , Idoso , Feminino , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Pessoa de Meia-Idade
10.
Br J Radiol ; 94(1122): 20210001, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33882253

RESUMO

OBJECTIVE: The aim of this study was to evaluate the current status of the clinical use of deformable image registration (DIR) in radiotherapy and to gain an understanding of the challenges faced by centres in clinical implementation of DIR, including commissioning and quality assurance (QA), and to determine the barriers faced. The goal was to inform whether additional guidance and QA tools were needed. METHODS: A survey focussed on clinical use, metrics used, how centres would like to use DIR in the future and challenges faced, was designed and sent to 71 radiotherapy centres in the UK. Data were gathered specifically on which centres we using DIR clinically, which applications were being used, what commissioning and QA tests were performed, and what barriers were preventing the integration of DIR into the clinical workflow. Centres that did not use DIR clinically were encouraged to fill in the survey and were asked if they have any future plans and in what timescale. RESULTS: 51 out of 71 (70%) radiotherapy centres responded. 47 centres reported access to a commercial software that could perform DIR. 20 centres already used DIR clinically, and 22 centres had plans to implement an application of DIR within 3 years of the survey. The most common clinical application of DIR was to propagate contours from one scan to another (19 centres). In each of the applications, the types of commissioning and QA tests performed varied depending on the type of application and between centres. Some of the key barriers were determining when a DIR was satisfactory including which metrics to use, and lack of resources. CONCLUSION: The survey results highlighted that there is a need for additional guidelines, training, better tools for commissioning DIR software and for the QA of registration results, which should include developing or recommending which quantitative metrics to use. ADVANCES IN KNOWLEDGE: This survey has given a useful picture of the clinical use and lack of use of DIR in UK radiotherapy centres. The survey provided useful insight into how centres commission and QA DIR applications, especially the variability among centres. It was also possible to highlight key barriers to implementation and determine factors that may help overcome this which include the need for additional guidance specific to different applications, better tools and metrics.


Assuntos
Padrões de Prática Médica/estatística & dados numéricos , Garantia da Qualidade dos Cuidados de Saúde , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Humanos , Dosagem Radioterapêutica , Software , Inquéritos e Questionários , Reino Unido
11.
Anticancer Res ; 41(4): 1909-1920, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33813396

RESUMO

BACKGROUND/AIM: This comparative plan study examines a range of boost-radiation methods in adjuvant radiotherapy of breast cancer using helical intensity-modulated radiotherapy with TomoEdge-technique. Impact of hypofractionated radiation with simultaneous-integrated boost (SIB) and influence of differing assumed α/ß-values were examined. PATIENTS AND METHODS: For 10 patients with left-sided breast cancer each four helical IMRT-plans with TomoEdge-technique were created: hypofractionated+SIB (H-SIB) (42.4/54.4 Gy, 16 fractions), normofractionated+SIB (N-SIB) (50.4/64.4 Gy, 28 fractions), hypofractionated+sequential-boost (H-SB) (42.4 Gy/16 fractions+16 Gy/8 fractions), normofractionated+ sequential-boost (N-SB) (50.4 Gy/28 fractions+16 Gy/8 fractions). Equivalent doses (EQD2) to organs-at-risk (OAR) and irradiated mammary-gland were analysed for different assumed α/ß-values. RESULTS: The mean EQD2 to OAR was significantly lower using hypofractionated radiation-techniques. H-SIB and H-SB were not significantly different. H-SIB and N-SIB conformed significantly better to the breast planning-target volume (PTV) and boost-volume (BV) than H-SB and N-SB. Regarding BV, mean EQD2 was significantly higher for all α/ß-values investigated when using H-SIB and N-SIB. Regarding PTV, there were no clinically relevant differences. CONCLUSION: Relating to dosimetry, H-SIB is effective compared to standard-boost-techniques.


Assuntos
Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Hipofracionamento da Dose de Radiação , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Adulto , Neoplasias da Mama/patologia , Feminino , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Mastectomia Segmentar/métodos , Órgãos em Risco , Hipofracionamento da Dose de Radiação/normas , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia Adjuvante/efeitos adversos , Radioterapia Adjuvante/métodos , Radioterapia Adjuvante/normas , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas , Padrões de Referência , Carga Tumoral/efeitos da radiação
12.
Anticancer Res ; 41(4): 1951-1958, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33813401

RESUMO

BACKGROUND/AIM: This study focused on the hybrid-volumetric modulated arc therapy (hVMAT) for stage I esophageal cancer and compared the effects on dose distribution induced by changes in the ratio of three-dimensional conformal radiotherapy (3DCRT) to VMAT. PATIENTS AND METHODS: Fifteen patients who underwent 3DCRT for cT1bN0M0 esophageal cancer at Kanagawa Cancer Center from January 2014 to April 2019 were included in the study. The dose-volume histogram (DVH) parameters of the target volume and normal organs were evaluated in the 3DCRT, hVMAT, and VMAT treatment plans. RESULTS: The homogeneity index of the target volume was significantly lower for hVMAT. In hVMAT, as the ratio of VMAT increased, the volume of low-dose region in the heart and lung increased, whereas the volume of the middle- to high-dose region decreased. As the ratio of VMAT increased, the mean dose in the heart decreased, whereas the mean dose in the lung increased. CONCLUSION: Favorable dose concentration was obtained for the target volume in hVMAT for stage I esophageal cancer. Altering the ratio of VMAT significantly changed the DVH parameters in normal organs.


Assuntos
Adenocarcinoma/radioterapia , Neoplasias Esofágicas/radioterapia , Planejamento da Radioterapia Assistida por Computador , Radioterapia Conformacional , Adenocarcinoma/patologia , Relação Dose-Resposta à Radiação , Neoplasias Esofágicas/patologia , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Análise por Pareamento , Estadiamento de Neoplasias , Órgãos em Risco , Radiometria/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/efeitos adversos , Estudos Retrospectivos , Carga Tumoral/efeitos da radiação
13.
Anticancer Res ; 41(4): 1985-1995, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33813405

RESUMO

BACKGROUND/AIM: The aim of the study was to investigate boost volume definition, doses, and delivery techniques for rectal cancer dose intensification. PATIENTS AND METHODS: An online survey was made on 25 items (characteristics, simulation, imaging, volumes, doses, planning and treatment). RESULTS: Thirty-eight radiation oncologists joined the study. Twenty-one delivered long-course radiotherapy with dose intensification. Boost volume was delineated on diagnostic magnetic resonance imaging (MRI) in 18 centres (85.7%), and computed tomography (CT) and/or positron emission tomography-CT in 9 (42.8%); 16 centres (76.2%) performed co-registration with CT-simulation. Boost dose was delivered on gross tumor volume in 10 centres (47.6%) and on clinical target volume in 11 (52.4%). The most common total dose was 54-55 Gy (71.4%), with moderate hypofractionation (85.7%). Intensity-modulated radiotherapy (IMRT) was used in all centres, with simultaneous integrated boost in 17 (80.8%) and image-guidance in 18 (85.7%). CONCLUSION: A high quality of treatment using dose escalation can be inferred by widespread multidisciplinary discussion, MRI-based treatment volume delineation, and radiation delivery relying on IMRT with accurate image-guided radiation therapy protocols.


Assuntos
Padrões de Prática Médica/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Neoplasias Retais/radioterapia , Carga Tumoral/fisiologia , Feminino , Humanos , Itália/epidemiologia , Metástase Linfática , Imageamento por Ressonância Magnética , Masculino , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/efeitos adversos , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia Guiada por Imagem/efeitos adversos , Radioterapia Guiada por Imagem/métodos , Radioterapia Guiada por Imagem/estatística & dados numéricos , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/estatística & dados numéricos , Neoplasias Retais/diagnóstico , Neoplasias Retais/mortalidade , Neoplasias Retais/patologia , Inquéritos e Questionários , Análise de Sobrevida , Carga Tumoral/efeitos da radiação
14.
BMC Cancer ; 21(1): 384, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33836670

RESUMO

BACKGROUND: The dose perturbation effect of immobilization devices is often overlooked in intensity-modulated radiation therapy (IMRT) for breast cancer (BC). This retrospective study assessed the dosimetric effects of supine immobilization devices on the skin using a commercial treatment planning system. METHODS: Forty women with BC were divided into four groups according to the type of primary surgery: groups A and B included patients with left and right BC, respectively, who received 50 Gy radiotherapy in 25 fractions after radical mastectomy, while groups C and D included patients with left and right BC, respectively, who received breast-conservation surgery (BCS) and 40.05 Gy in 15 fractions as well as a tumor bed simultaneous integrated boost to 45 Gy. A 0.2-cm thick skin contour and two sets of body contours were outlined for each patient. Dose calculations were conducted for the two sets of contours using the same plan. The dose differences were assessed by comparing the dose-volume histogram parameter results and by plan subtraction. RESULTS: The supine immobilization devices for BC resulted in significantly increased skin doses, which may ultimately lead to skin toxicity. The mean dose increased by approximately 0.5 and 0.45 Gy in groups A and B after radical mastectomy and by 2.7 and 3.25 Gy in groups C and D after BCS; in groups A-D, the percentages of total normal skin volume receiving equal to or greater than 5 Gy (V5) increased by 0.54, 1.15, 2.67, and 1.94%, respectively, while the V10 increased by 1.27, 1.83, 1.36, and 2.88%; the V20 by 0.85, 1.87, 2.76, and 4.86%; the V30 by 1.3, 1.24, 10.58, and 11.91%; and the V40 by 1.29, 0.65, 10, and 10.51%. The dose encompassing the planning target volume and other organs at risk, showed little distinction between IMRT plans without and with consideration of immobilization devices. CONCLUSIONS: The supine immobilization devices significantly increased the dose to the skin, especially for patients with BCS. Thus, immobilization devices should be included in the external contour to account for dose attenuation and skin dose increment. TRIAL REGISTRATION: This study does not report on interventions in human health care.


Assuntos
Neoplasias da Mama/radioterapia , Radiometria , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Adulto , Idoso , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/cirurgia , Terapia Combinada , Feminino , Humanos , Mastectomia Segmentar , Pessoa de Meia-Idade , Órgãos em Risco , Radiometria/instrumentação , Radiometria/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Pele/efeitos da radiação , Tomografia Computadorizada por Raios X , Dispositivos Eletrônicos Vestíveis
15.
Anticancer Res ; 41(4): 2101-2110, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33813420

RESUMO

BACKGROUND/AIM: To evaluate if topical support therapy during static-intensity modulated radiotherapy (sIMRT) course is able to equal the characteristic minimum risk for radiation proctitis of Image-guided volumetric modulated arc therapy (IG-VMAT) treatment among localized prostate cancer patients. PATIENTS AND METHODS: Rectal toxicity data of the above patients were retrospectively collected throughout three different clinical periods at our Radiotherapy Deparment: from October 2011 to December 2012, prostate cancer patients were treated with sIMRT and in advance supported by means of daily topical corticosteroids; from January 2013 to November 2016, topical corticosteroids were replaced by daily hyaluronic acid enemas; from December 2016 to May 2018 eligible patients were treated with newly introduced IG-VMAT supported by only on-demand topical corticosteroids. RESULTS: Among 359 eligible patients, IG-VMAT was proven generally more effective than sIMRT supported by topical medications in terms of proctitis reduction, although without clinical and practical relevance. CONCLUSION: Topical medications might have a role in radiation proctitis prevention.


Assuntos
Anti-Inflamatórios/administração & dosagem , Proctite/prevenção & controle , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/radioterapia , Radioterapia de Intensidade Modulada , Administração Tópica , Idoso , Idoso de 80 Anos ou mais , Beclometasona/administração & dosagem , Enema/métodos , Humanos , Ácido Hialurônico/administração & dosagem , Itália , Masculino , Pessoa de Meia-Idade , Tratamentos com Preservação do Órgão/métodos , Proctite/etiologia , Neoplasias da Próstata/patologia , Hipofracionamento da Dose de Radiação , Lesões por Radiação/prevenção & controle , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/efeitos adversos , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos
16.
BMC Cancer ; 21(1): 243, 2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33685404

RESUMO

BACKGROUND: It is very important to accurately delineate the CTV on the patient's three-dimensional CT image in the radiotherapy process. Limited to the scarcity of clinical samples and the difficulty of automatic delineation, the research of automatic delineation of cervical cancer CTV based on CT images for new patients is slow. This study aimed to assess the value of Dense-Fully Connected Convolution Network (Dense V-Net) in predicting Clinical Target Volume (CTV) pre-delineation in cervical cancer patients for radiotherapy. METHODS: In this study, we used Dense V-Net, a dense and fully connected convolutional network with suitable feature learning in small samples to automatically pre-delineate the CTV of cervical cancer patients based on computed tomography (CT) images and then we assessed the outcome. The CT data of 133 patients with stage IB and IIA postoperative cervical cancer with a comparable delineation scope was enrolled in this study. One hundred and thirteen patients were randomly designated as the training set to adjust the model parameters. Twenty cases were used as the test set to assess the network performance. The 8 most representative parameters were also used to assess the pre-sketching accuracy from 3 aspects: sketching similarity, sketching offset, and sketching volume difference. RESULTS: The results presented that the DSC, DC/mm, HD/cm, MAD/mm, ∆V, SI, IncI and JD of CTV were 0.82 ± 0.03, 4.28 ± 2.35, 1.86 ± 0.48, 2.52 ± 0.40, 0.09 ± 0.05, 0.84 ± 0.04, 0.80 ± 0.05, and 0.30 ± 0.04, respectively, and the results were greater than those with a single network. CONCLUSIONS: Dense V-Net can correctly predict CTV pre-delineation of cervical cancer patients and can be applied in clinical practice after completing simple modifications.


Assuntos
Colo do Útero/diagnóstico por imagem , Imageamento Tridimensional , Redes Neurais de Computação , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias do Colo do Útero/terapia , Colo do Útero/patologia , Colo do Útero/cirurgia , Feminino , Humanos , Estadiamento de Neoplasias , Radioterapia Adjuvante/métodos , Tomografia Computadorizada por Raios X , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/patologia
17.
BMC Cancer ; 21(1): 261, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33691654

RESUMO

BACKGROUND: To investigate the beam complexity and monitor unit (MU) efficiency issues for two different volumetric modulated arc therapy (VMAT) delivery technologies for patients with left-sided breast cancer (BC) and nasopharyngeal carcinoma (NPC). METHODS: Twelve left-sided BC and seven NPC cases were enrolled in this study. Each delivered treatment plan was optimized in the Pinnacle3 treatment planning system with the Auto-Planning module for the Trilogy and Synergy systems. Similar planning dose objectives and beam configurations were used for each site in the two different delivery systems to produce clinically acceptable plans. The beam complexity was evaluated in terms of the segment area (SA), segment width (SW), leaf sequence variability (LSV), aperture area variability (AAV), and modulation complexity score (MCS) based on the multileaf collimator sequence and MU. Plan delivery and a gamma evaluation were performed using a helical diode array. RESULTS: With similar plan quality, the average SAs for the Trilogy plans were smaller than those for the Synergy plans: 55.5 ± 21.3 cm2 vs. 66.3 ± 17.9 cm2 (p < 0.05) for the NPC cases and 100.7 ± 49.2 cm2 vs. 108.5 ± 42.7 cm2 (p < 0.05) for the BC cases, respectively. The SW was statistically significant for the two delivery systems (NPC: 6.87 ± 1.95 cm vs. 6.72 ± 2.71 cm, p < 0.05; BC: 8.84 ± 2.56 cm vs. 8.09 ± 2.63 cm, p < 0.05). The LSV was significantly smaller for Trilogy (NPC: 0.84 ± 0.033 vs. 0.86 ± 0.033, p < 0.05; BC: 0.89 ± 0.026 vs. 0.90 ± 0.26, p < 0.05). The mean AAV was significantly larger for Trilogy than for Synergy (NPC: 0.18 ± 0.064 vs. 0.14 ± 0.037, p < 0.05; BC: 0.46 ± 0.15 vs. 0.33 ± 0.13, p < 0.05). The MCS values for Trilogy were higher than those for Synergy: 0.14 ± 0.016 vs. 0.12 ± 0.017 (p < 0.05) for the NPC cases and 0.42 ± 0.106 vs. 0.30 ± 0.087 (p < 0.05) for the BC cases. Compared with the Synergy plans, the average MUs for the Trilogy plans were larger: 828.6 ± 74.1 MU and 782.9 ± 85.2 MU (p > 0.05) for the NPC cases and 444.8 ± 61.3 MU and 393.8 ± 75.3 MU (p > 0.05) for the BC cases. The gamma index agreement scores were never below 91% using 3 mm/3% (global) distance to agreement and dose difference criteria and a 10% lower dose exclusion threshold. CONCLUSIONS: The Pinnacle3 Auto-Planning system can optimize BC and NPC plans to achieve the same plan quality using both the Trilogy and Synergy systems. We found that these two systems resulted in different SAs, SWs, LSVs, AAVs and MCSs. As a result, we suggested that the beam complexity should be considered in the development of further methodologies while optimizing VMAT autoplanning.


Assuntos
Neoplasias da Mama/radioterapia , Carcinoma Nasofaríngeo/radioterapia , Neoplasias Nasofaríngeas/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/instrumentação , Fracionamento da Dose de Radiação , Feminino , Humanos , Órgãos em Risco , Radiometria , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos
18.
Br J Radiol ; 94(1120): 20201397, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33684308

RESUMO

The efficiency of radiotherapy treatment regimes varies from tumour to tumour and from patient to patient but it is generally highly influenced by the tumour microenvironment (TME). The TME can be described as a heterogeneous composition of biological, biophysical, biomechanical and biochemical milieus that influence the tumour survival and its' response to treatment. Preclinical research faces challenges in the replication of these in vivo milieus for predictable treatment response studies. 2D cell culture is a traditional, simplistic and cost-effective approach to culture cells in vitro, however, the nature of the system fails to recapitulate important features of the TME such as structure, cell-cell and cell-matrix interactions. At the same time, the traditional use of animals (Xenografts) in cancer research allows realistic in vivo architecture, however foreign physiology, limited heterogeneity and reduced tumour mutation rates impairs relevance to humans. Furthermore, animal research is very time consuming and costly. Tissue engineering is advancing as a promising biomimetic approach, producing 3D models that capture structural, biophysical, biochemical and biomechanical features, therefore, facilitating more realistic treatment response studies for further clinical application. However, currently, the application of 3D models for radiation response studies is an understudied area of research, especially for pancreatic ductal adenocarcinoma (PDAC), a cancer with a notoriously complex microenvironment. At the same time, specific novel and/or more enhanced radiotherapy tumour-targeting techniques such as MRI-guided radiotherapy and proton therapy are emerging to more effectively target pancreatic cancer cells. However, these emerging technologies may have different biological effectiveness as compared to established photon-based radiotherapy. For example, for MRI-guided radiotherapy, the novel use of static magnetic fields (SMF) during radiation delivery is understudied and not fully understood. Thus, reliable biomimetic platforms to test new radiation delivery strategies are required to more accurately predict in vivo responses. Here, we aim to collate current 3D models for radiation response studies of PDAC, identifying the state of the art and outlines knowledge gaps. Overall, this review paper highlights the need for further research on the use of 3D models for pre-clinical radiotherapy screening including (i) 3D (re)-modeling of the PDAC hypoxic TME to allow for late effects of ionising radiation (ii) the screening of novel radiotherapy approaches and their combinations as well as (iii) a universally accepted 3D-model image quantification method for evaluating TME components in situ that would facilitate accurate post-treatment(s) quantitative comparisons.


Assuntos
Modelos Biológicos , Neoplasias Pancreáticas/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Humanos
19.
Anticancer Res ; 41(3): 1529-1538, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33788746

RESUMO

BACKGROUND/AIM: This study aimed to analyze the dosimetric gain of the deep-inspiration-breath-hold (DIBH) technique over the free-breathing (FB) one in left breast cancer (LBC) 3D-conformal-radiotherapy (3D-CRT), and simultaneously investigate the anatomical parameters related to heart RT-exposure. PATIENTS AND METHODS: Treatment plans were generated in both DIBH and FB scenarios for 116 LBC patients monitored by the Varian RPM™ respiratory gating system for delivery of conventional or moderately hypofractionated schedules (±sequential boost). For comparison, we considered cardiac and ipsilateral lung doses and volumes. RESULTS: A significant reduction of cardiac and pulmonary doses using DIBH technique was achieved compared to FB plans. Larger clinical target volumes generally need longer distance between medial and lateral entrances of tangent fields at body surface, thus conditioning a worse heart RT-exposure. CONCLUSION: The DIBH technique reduces cardiac and pulmonary doses for LBC patients. Through easily detectable anatomical parameters, it is possible to predict which patients benefit most from DIBH-RT.


Assuntos
Neoplasias da Mama/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Adulto , Idoso , Suspensão da Respiração , Feminino , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Pessoa de Meia-Idade , Órgãos em Risco , Hipofracionamento da Dose de Radiação , Dosagem Radioterapêutica , Radioterapia Conformacional/efeitos adversos
20.
Phys Med Biol ; 66(3): 035023, 2021 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-33522498

RESUMO

The aim of this study was to evaluate the clinical impact of relative biological effectiveness (RBE) variations in proton beam scanning treatment (PBS) for left-sided breast cancer versus the assumption of a fixed RBE of 1.1, particularly in the context of comparisons with photon-based three-dimensional conformal radiotherapy (3DCRT) and volumetric modulated arc therapy (VMAT). Ten patients receiving radiation treatment to the whole breast/chest wall and regional lymph nodes were selected for each modality. For PBS, the dose distributions were re-calculated with both a fixed RBE and a variable RBE using an empirical RBE model. Dosimetric indices based on dose-volume histogram analysis were calculated for the entire heart wall, left anterior descending artery (LAD) and left lung. Furthermore, normal tissue toxicity probabilities for different endpoints were evaluated. The results show that applying a variable RBE significantly increases the RBE-weighted dose and consequently the calculated dosimetric indices increases for all organs compared to a fixed RBE. The mean dose to the heart and the maximum dose to the LAD and the left lung are significantly lower for PBS assuming a fixed RBE compared to 3DCRT. However, no statistically significant difference is seen when a variable RBE is applied. For a fixed RBE, lung toxicities are significantly lower compared to 3DCRT but when applying a variable RBE, no statistically significant differences are noted. A disadvantage is seen for VMAT over both PBS and 3DCRT. One-to-one plan comparison on 8 patients between PBS and 3DCRT shows similar results. We conclude that dosimetric analysis for all organs and toxicity estimation for the left lung might be underestimated when applying a fixed RBE for protons. Potential RBE variations should therefore be considered as uncertainty bands in outcome analysis.


Assuntos
Coração/efeitos da radiação , Pulmão/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Neoplasias Unilaterais da Mama/radioterapia , Feminino , Humanos , Eficiência Biológica Relativa
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