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1.
J Med Imaging Radiat Oncol ; 66(2): 279-290, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35243785

RESUMO

Radiation Oncology continues to rely on accurate delivery of radiation, in particular where patients can benefit from more modulated and hypofractioned treatments that can deliver higher dose to the target while optimising dose to normal structures. These deliveries are more complex, and the treatment units are more computerised, leading to a re-evaluation of quality assurance (QA) to test a larger range of options with more stringent criteria without becoming too time and resource consuming. This review explores how modern approaches of risk management and automation can be used to develop and maintain an effective and efficient QA programme. It considers various tools to control and guide radiation delivery including image guidance and motion management. Links with typical maintenance and repair activities are discussed, as well as patient-specific quality control activities. It is demonstrated that a quality management programme applied to treatment delivery can have an impact on individual patients but also on the quality of treatment techniques and future planning. Developing and customising a QA programme for treatment delivery is an important part of radiotherapy. Using modern multidisciplinary approaches can make this also a useful tool for department management.


Assuntos
Garantia da Qualidade dos Cuidados de Saúde , Radioterapia (Especialidade) , Radioterapia de Intensidade Modulada , Humanos , Controle de Qualidade , Radioterapia (Especialidade)/normas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas
2.
Technol Cancer Res Treat ; 21: 15330338211072680, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35023424

RESUMO

Background and Purpose: In this study, the absolute dose achievable between helical tomotherapy (HT) plans and RapidArc (RA) plans for total dura mater irradiation (TDMI) was compared. Materials and methods: A planning study was conducted on nine children's case datasets with dura mater metastasis of neuroblastoma. The target included the entire calvarium and skull base and formed a closed volume with a certain thickness around the brain. HT and RA plans with four coplanar full arcs (RA4) with half-field technique were generated for the comparison of absolute dose achievable. In total, 30.6 Gy was prescribed as D95% (ie, dose to 95% of PTV volume). Results: In the dosimetric comparison between the two modalities, HT provided more homogenous dose distribution than RA4 (mean HI5-95%: 1.046 vs 1.088, P < .001). The V107% and D2Gy of PTV in HT versus RA4 were 3.06% versus 30.47% and 32.59 Gy versus 33.45 Gy, respectively. HT reduced the Dmean and V5Gy of the brain, brainstem, and hippocampus by 25%-48% and 27%-56% compared with RA4, respectively. Conclusion: Both techniques could provide sufficient coverage for targets, but HT offered more homogenous dose to PTV and lower dose to the central region of the brain involving the brainstem and hippocampus. RA4 could be completed in a shorter time with lower MUs, but with relatively higher dose to the brain or hippocampus. In terms of dosimetry, HT may improve long-term cognitive decline in these young pediatric patients with TDMI.


Assuntos
Irradiação Craniana , Dura-Máter/patologia , Dura-Máter/efeitos da radiação , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas , Fatores Etários , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/radioterapia , Criança , Fracionamento da Dose de Radiação , Humanos , Tratamentos com Preservação do Órgão , Radiometria , Radioterapia Guiada por Imagem , Resultado do Tratamento
3.
Cancer Radiother ; 26(1-2): 199-205, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34953703

RESUMO

We present the update of the recommendations of the French society of oncological radiotherapy on radiotherapy for hypopharynx. Intensity-modulated radiotherapy is the gold standard treatment for hypopharynx cancers. Early T1 and T2 tumors could be treated by exclusive radiotherapy or surgery followed by postoperative radiotherapy in case of high recurrence risk. For locally advanced tumours requiring total pharyngolaryngectomy (T2 or T3) or with significant lymph nodes involvement, induction chemotherapy followed by exclusive radiotherapy or concurrent chemoradiotherapy were possible. For T4 tumour, surgery must be proposed. The treatment of lymph nodes is based on initial primary tumour treatment. In non-surgical procedure, for 35 fractions, curative dose is 70Gy (2Gy per fraction) and prophylactic dose are 50 to 56Gy (2Gy per fraction in case of sequential radiotherapy or 1.6Gy in case of integrated simultaneous boost) radiotherapy; for 33 fractions, curative dose is 69.96Gy (2.12Gy per fraction) and prophylactic dose is 52.8Gy (1.6Gy per fraction in integrated simultaneous boost radiotherapy or 54Gy in 1.64Gy per fraction); for 30 fractions, curative dose is 66Gy (2.2Gy per fraction) and prophylactic dose is 54Gy (1.8Gy per fraction in integrated simultaneous boost radiotherapy). Doses over 2Gy per fraction could be done when chemotherapy is not used regarding potential larynx toxicity. Postoperatively, radiotherapy is used in locally advanced cancer with dose levels based on pathologic criteria, 60 to 66Gy for R1 resection and 54 to 60Gy for complete resection in bed tumour; 50 to 66Gy in lymph nodes areas regarding extracapsular spread. Volume delineation were based on guidelines cited in this article.


Assuntos
Neoplasias Hipofaríngeas/radioterapia , Quimiorradioterapia , Fracionamento da Dose de Radiação , França , Humanos , Neoplasias Hipofaríngeas/patologia , Neoplasias Hipofaríngeas/terapia , Quimioterapia de Indução , Laringectomia , Irradiação Linfática , Faringectomia , Radioterapia (Especialidade) , Radioterapia de Intensidade Modulada/normas
4.
Cancer Radiother ; 26(1-2): 206-212, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34953705

RESUMO

We present the update of the recommendations of the French society of oncological radiotherapy on radiotherapy of laryngeal cancers. Intensity modulated radiotherapy is the standard of care radiotherapy for the management of laryngeal cancers. Early stage T1 or T2 tumours can be treated either by radiotherapy or conservative surgery. For tumours requiring total laryngectomy (T2 or T3), an organ preservation strategy by either induction chemotherapy followed by radiotherapy or chemoradiotherapy with cisplatin is recommended. For T4 tumours, a total laryngectomy followed by radiotherapy is recommended when feasible. Dose regimens for definitive and postoperative radiotherapy are detailed in this article, as well as the selection and delineation of tumour and lymph node target volumes.


Assuntos
Neoplasias Laríngeas/radioterapia , Cisplatino/uso terapêutico , Fracionamento da Dose de Radiação , França , Humanos , Quimioterapia de Indução , Neoplasias Laríngeas/diagnóstico por imagem , Neoplasias Laríngeas/patologia , Neoplasias Laríngeas/terapia , Laringectomia , Estadiamento de Neoplasias/métodos , Tratamentos com Preservação do Órgão/métodos , Cuidados Pós-Operatórios/métodos , Radioterapia (Especialidade) , Radiossensibilizantes/uso terapêutico , Radioterapia Guiada por Imagem , Radioterapia de Intensidade Modulada/normas , Tomografia Computadorizada por Raios X
5.
Technol Cancer Res Treat ; 20: 15330338211063033, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34855577

RESUMO

Purpose: To monitor intrafraction motion during spine stereotactic body radiotherapy(SBRT) treatment delivery with readily available technology, we implemented triggered kV imaging using the on-board imager(OBI) of a modern medical linear accelerator with an advanced imaging package. Methods: Triggered kV imaging for intrafraction motion management was tested with an anthropomorphic phantom and simulated spine SBRT treatments to the thoracic and lumbar spine. The vertebral bodies and spinous processes were contoured as the image guided radiotherapy(IGRT) structures specific to this technique. Upon each triggered kV image acquisition, 2D projections of the IGRT structures were automatically calculated and updated at arbitrary angles for display on the kV images. Various shifts/rotations were introduced in x, y, z, pitch, and yaw. Gantry-angle-based triggering was set to acquire kV images every 45°. A group of physicists/physicians(n = 10) participated in a survey to evaluate clinical efficiency and accuracy of clinical decisions on images containing various phantom shifts. This method was implemented clinically for treatment of 42 patients(94 fractions) with 15 second time-based triggering. Result: Phantom images revealed that IGRT structure accuracy and therefore utility of projected contours during triggered imaging improved with smaller CT slice thickness. Contouring vertebra superior and inferior to the treatment site was necessary to detect clinically relevant phantom rotation. From the survey, detectability was proportional to the shift size in all shift directions and inversely related to the CT slice thickness. Clinical implementation helped evaluate robustness of patient immobilization. Based on visual inspection of projected IGRT contours on planar kV images, appreciable intrafraction motion was detected in eleven fractions(11.7%). Discussion: Feasibility of triggered imaging for spine SBRT intrafraction motion management has been demonstrated in phantom experiments and implementation for patient treatments. This technique allows efficient, non-invasive monitoring of patient position using the OBI and patient anatomy as a direct visual guide.


Assuntos
Fracionamento da Dose de Radiação , Movimento (Física) , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral/efeitos da radiação , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Aceleradores de Partículas , Imagens de Fantasmas , Dosagem Radioterapêutica , Radioterapia Guiada por Imagem/normas , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/normas , Tomografia Computadorizada por Raios X
6.
Technol Cancer Res Treat ; 20: 15330338211053752, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34806481

RESUMO

Purpose: A novel in-house technology "Non-Uniform VMAT (NU-VMAT)" was developed for automated cardiac dose reduction and treatment planning optimization in the left breast radiotherapy. Methods: The NU-VMAT model based on IGM (gantry MLC Movement coefficient index) was established to optimize the volumetric modulated arc therapy (VMAT) MLC movement and modulation intensity in certain gantry angles. The ESAPI embedded in Eclipse® was employed to connect TPS and the optimization program via I/O relevant DICOM RT files. The adjuvant whole-breast radiotherapy of 14 patients with left breast cancer was replanned using our NU-VMAT technology in comparison with VMAT and IMRT technology. Dosimetric parameters including D1%, D99%, and Dmean of PTV, V5, V10, and V20 of ipisilateral lung, V5, D20, D30, and Dmean of heart, monitor units (MUs), and delivery time derived from IMRT, VMAT, and NU-VMAT plans were evaluated for plan quality and delivery efficiency. The quality assurance (QA) was conducted using both point-dose and planar-dose measurements for all treatment plans. Results: The IGM-NU-VMAT curves with plan optimization (range from 50% to 147%) were converged more significantly than IGM-VMAT curves (range from 0% to 297%). The dose distribution requirements of the target and normal tissues could be met using IMRT, VMAT, or NU-VMAT; the lowest Dmean was achieved in NU-VMAT plans (5.38 ± 0.46 Gy vs 5.63 ± 0.61 Gy in IMRT and 7.95 ± 0.52 Gy in VMAT plans). Statistically significant differences were found in terms of delivery time and MU when comparing IMRT with VMAT and NU-VMAT plans (P < .05). In comparison with IMRT plans, the MU and delivery time in NU-VMAT plans dramatically decreased by 69.8% and 28.4%, respectively. Moreover, NU-VMAT plans showed a high gamma passing rate (96.5% ± 1.11) in plane dose verification and minimal dose difference (2.4% ± 0.19) in point absolute dose verification. Conclusion: Our non-uniform VMAT facilitated the treatment strategy optimization for left breast cancer radiotherapy with dosimetric advantage in cardiac dose reduction and delivery efficiency in comparison with the conventional VMAT and IMRT.


Assuntos
Neoplasias da Mama/radioterapia , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Algoritmos , Neoplasias da Mama/diagnóstico , Tomada de Decisão Clínica , Árvores de Decisões , Gerenciamento Clínico , Feminino , Coração/efeitos da radiação , Humanos , Imageamento Tridimensional , Modelos Teóricos , Tratamentos com Preservação do Órgão/normas , Garantia da Qualidade dos Cuidados de Saúde , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem , Radioterapia de Intensidade Modulada/normas , Tomografia Computadorizada por Raios X , Resultado do Tratamento
7.
Technol Cancer Res Treat ; 20: 15330338211060170, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34806489

RESUMO

Objective: Cognitive decline and alopecia after radiotherapy are challenging problems. We aimed to compare whole brain radiotherapy (WBRT) plans reducing radiation dose to the hippocampus and scalp between helical tomotherapy (HT) and intensity-modulated proton therapy (IMPT). Methods: We conducted a planning study of WBRT for 10 patients. The clinical target volume was defined as the whole brain excluding the hippocampus avoidance (HA) region. The prescribed dose was 30 Gy in 10 fractions to cover 95% of the target. Constraint goals were defined for the target and organs at risk (OAR). Results: Both techniques met the dose constraints for the target and OAR. However, the coverage of the target (dose covering 95% [D95%] and 98% [D98%] of the volume) were better in IMPT than HT (HT vs IMPT: D95%, 29.9 Gy vs 30.0 Gy, P < .001; D98%, 26.7 Gy vs 28.1 Gy, P = .002). The homogeneity and conformity of the target were also better in IMPT than HT (HT vs IMPT: homogeneity index, 1.50 vs 1.28, P < .001; conformity index, 1.30 vs 1.14, P < .001). IMPT reduced the D100% of the hippocampus by 59% (HT vs IMPT: 9.3 Gy vs 3.8 Gy, P < .001) and reduced the Dmean of the hippocampus by 37% (HT vs IMPT: 11.1 Gy vs 7.0 Gy, P < .001) compared with HT. The scalp IMPT reduced the percentage of the volume receiving at least 20 Gy (V20Gy) and V10Gy compared with HT (HT vs IMPT: V20Gy, 56.7% vs 6.6%, P < .001; V10Gy, 90.5% vs 37.1%, P < .001). Conclusion: Both techniques provided acceptable target dose coverage. Especially, IMPT achieved excellent hippocampus- and scalp-sparing. HA-WBRT using IMPT is a promising treatment to prevent cognitive decline and alopecia.


Assuntos
Irradiação Craniana/métodos , Hipocampo/efeitos da radiação , Terapia com Prótons/métodos , Dosagem Radioterapêutica , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Tomografia Computadorizada Espiral , Irradiação Craniana/efeitos adversos , Irradiação Craniana/normas , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Órgãos em Risco , Terapia com Prótons/efeitos adversos , Terapia com Prótons/normas , Radiometria , Planejamento da Radioterapia Assistida por Computador , Radioterapia Guiada por Imagem/efeitos adversos , Radioterapia Guiada por Imagem/normas , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/normas
8.
Technol Cancer Res Treat ; 20: 15330338211059937, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34821195

RESUMO

OBJECTIVE: This study analyzed the correlation between the average segment width (ASW) and gamma passing rate according to the multi-leaf collimator (MLC) position error. METHOD: To evaluate the changes in the gamma passing rate according to the MLC position error, 21 volumetric modulated arc therapy (VMAT) plans were generated using pelvic lymph node metastatic prostate cancer patient's data which is sensitive to MLC position errors as they involve several long, narrow, irregular fields. The ASW for each VMAT plan was calculated using our own code developed using Visual Basic for Applications (VBA). The gamma passing rate of the VMAT plan according to the MLC position error was evaluated using ArcCHECK (Sun Nuclear, Melbourne, FL, USA) while inducing symmetric MLC position errors in 0.25 mm intervals from -1 mm to +1 mm in the infinity medical linear accelerator (Elekta AB, Stockholm, Sweden). Finally, we examined the correlation between the change in the passing rate (γgradient) due to the MLC position error and the ASW in VMAT through linear regression analysis using the least squares method. RESULTS: The ASW and γgradient were found to have a linear correlation according to the MLC position error, and the coefficient of determination was 0.88. For a 1 mm position error of MLC in VMAT, the gamma passing rate improved by approximately 11.9% as the ASW increased by 10 mm. CONCLUSION: These results are expected to be employed as guidelines to minimize the dose uncertainty due to MLC position error in VMAT.


Assuntos
Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas , Algoritmos , Tomada de Decisão Clínica , Gerenciamento Clínico , Raios gama , Humanos , Masculino , Pelve/patologia , Pelve/efeitos da radiação , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/radioterapia
9.
Technol Cancer Res Treat ; 20: 15330338211036325, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34490802

RESUMO

PURPOSE: In radiotherapy, geometric indices are often used to evaluate the accuracy of contouring. However, the ability of geometric indices to identify the error of contouring results is limited primarily because they do not consider the clinical background. The purpose of this study is to investigate the relationship between geometric and clinical dosimetric indices. METHODS: Four different types of targets were selected (C-shaped target, oropharyngeal cancer, metastatic spine cancer, and prostate cancer), and the translation, scaling, rotation, and sine function transformation were performed with the software Python to introduce systematic and random errors. The transformed contours were regarded as reference contours. Dosimetric indices were obtained from the original dose distribution of the radiotherapy plan. The correlations between geometric and dosimetric indices were quantified by linear regression. RESULTS: The correlations between the geometric and dosimetric indices were inconsistent. For systematic errors, and with the exception of the sine function transformation (R2: 0.023-0.04, P > 0.05), the geometric transformations of the C-shaped target were correlated with the D98% and Dmean (R2: 0.689-0.988), 80% of which were P < 0.001. For the random errors, the correlations obtained by the all targets were R2 > 0.384, P < 0.05. The Wilcoxon signed-rank test was used to compare the spatial direction resolution capability of geometric indices in different directions of the C-shaped target (with systematic errors), and the results showed only the volumetric geometric indices with P < 0.05. CONCLUSIONS: Clinically, an assessment of the contour accuracy of the region-of-interest is not feasible based on geometric indices alone. Dosimetric indices should be added to the evaluations of the accuracy of the delineation results, which can be helpful for explaining the clinical dose response relationship of delineation more comprehensively and accurately.


Assuntos
Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Análise de Dados , Diagnóstico por Imagem/métodos , Humanos , Neoplasias/diagnóstico por imagem , Neoplasias/radioterapia , Órgãos em Risco , Radioterapia (Especialidade)/métodos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas
10.
Medicine (Baltimore) ; 100(33): e27023, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34414997

RESUMO

ABSTRACT: Induction chemotherapy (IC) and adjuvant chemotherapy (AC) are used to enhance tumor locoregional control and support early treatment for distant metastases. However, optimum combinatorial treatment of these chemoradiotherapy regimens with radiotherapy in curing locoregionally advanced nasopharyngeal carcinoma (NPC) remains unclear. Here, we evaluate the efficacy and therapeutic outcome of a combinatorial treatment strategy involving IC, intensity-modulated radiotherapy (IMRT), and AC, by retrospectively analyzing 243 NPC patients who were treated by IC followed by IMRT and AC. The rates of 3-/5-year local-regional control rate, distant failure-free rate (DFFR), progression-free survival (PFS), and overall survival (OS) were 93.3%/90.3%, 84.2%/79.4%, 79.6%/74.4%, and 84.0%/72.6%, respectively. The 3-/5-year OS rates of patients in stage III or IVA were 91.5%/75.1% and 86.5%/56.5%, respectively. Combination cisplatin with paclitaxel showed no significance in OS as compared to cisplatin plus 5-fluorouracil (P-value = .17). Total four-cycle IC and AC was significantly beneficious versus three-cycle in DFFR (P-value = .04), as well as total 6 chemotherapy cycles compared to 4 in DFFR and PFS (P-value = .03 and P-value = .01, respectively). All survival indicators were adversely affected by T-category, while N-category could only predict DFFR and PFS. Radiation dosage represented as a second prognostic factor for local control. We propose that IC combined with IMRT and AC for locoregionally advanced NPC shows effective treatment outcomes.


Assuntos
Quimioterapia Adjuvante/normas , Quimioterapia de Indução/normas , Neoplasias Nasofaríngeas/terapia , Radioterapia de Intensidade Modulada/normas , Idoso , Quimioterapia Adjuvante/métodos , Quimioterapia Adjuvante/estatística & dados numéricos , China/epidemiologia , Feminino , Humanos , Quimioterapia de Indução/métodos , Quimioterapia de Indução/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Neoplasias Nasofaríngeas/epidemiologia , Neoplasias Nasofaríngeas/fisiopatologia , Prognóstico , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/estatística & dados numéricos , Estudos Retrospectivos , Resultado do Tratamento
11.
Technol Cancer Res Treat ; 20: 15330338211036542, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34328800

RESUMO

BACKGROUND: Plastic scintillator detector (PSD) Exradin W1 has shown promising performance in small field dosimetry due to its water equivalence and small sensitive volume. However, few studies reported its capability in measuring fields of conventional sizes. Therefore, the purpose of this study is to assess the performance of W1 in measuring point dose of both conventional IMRT plans and VMAT SRS plans. METHODS: Forty-seven clinical plans (including 29 IMRT plans and 18 VMAT SRS plans with PTV volume less than 8 cm3) from our hospital were included in this study. W1 and Farmer-Type ionization chamber Exradin A19 were used in measuring IMRT plans, and W1 and microchamber Exradin A16 were used in measuring SRS plans. The agreement between the results of different types of detectors and TPS was evaluated. RESULTS: For IMRT plans, the average differences between measurements and TPS in high-dose regions were 0.27% ± 1.66% and 0.90% ± 1.78% (P = 0.056), and were -0.76% ± 1.47% and 0.37% ± 1.34% in low-dose regions (P = 0.000), for W1 and A19, respectively. For VMAT SRS plans, the average differences between measurements and TPS were -0.19% ± 0.96% and -0.59% ± 1.49% for W1 and A16 with no statistical difference (P = 0.231). CONCLUSION: W1 showed comparable performance with application-dedicated detectors in point dose measurements for both conventional IMRT and VMAT SRS techniques. It is a potential one-stop solution for general radiotherapy platforms that deliver both IMRT and SRS plans.


Assuntos
Garantia da Qualidade dos Cuidados de Saúde , Dosímetros de Radiação , Radiocirurgia/normas , Radioterapia de Intensidade Modulada/normas , Calibragem , Humanos , Dosagem Radioterapêutica/normas , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Contagem de Cintilação/instrumentação
12.
J Cancer Res Ther ; 17(2): 455-462, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34121692

RESUMO

PURPOSE: To classify the available plan evaluation indices and compare the dosimetric suitability of these indices. MATERIALS AND METHODS: Available published plan evaluation indices were categorized. Conformity index (CI) into two groups, one group contains those CI formulas which do not consider critical structure and other group contains those CI formulas which consider planning target volume (PTV) coverage, normal tissue and critical structure sparing simultaneously. Various homogeneity index (HI) formulas extracted from literature. Structure data sets of 25 patients were taken under consideration comprising of various sites. For each patient, two plans were created using Volumetric Arc Therapy technique. First type of plan (Plan-A) were generated considering all tissue objectives for targets and Organ at Risks (OARs) whereas second type of plan (Plan-B) were generated considering only targets tissue objectives and excluding OARs tissue objectives during plan optimization and dose calculation. Planning evaluation parameters were compared between Plan-A and Plan-B. RESULTS: CI calculated by various formulas in two different scenarios presented <2% variation. Any commonly used CI formula failed to differentiate the two different planning situations. On comparison between HI of two different scenario, it is observed that there are four formulas of HI which showed negligible variation but two formulae: S-index and HI (D) showed marginal variation. It is also observed that when OARs are removed from optimization dose homogeneity improved which is specifically pointed by sigma index formula. CONCLUSION: CI, which has assimilated the presence of OAR in their formulation, shows more reliability in plan evaluation. Sigma index was found to be more efficient formula while evaluating homogeneity of a treatment plan.


Assuntos
Neoplasias/radioterapia , Radioterapia (Especialidade)/métodos , Radiometria/normas , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Conjuntos de Dados como Assunto , Humanos , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Radioterapia (Especialidade)/normas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/normas , Reprodutibilidade dos Testes
13.
Radiat Oncol ; 16(1): 102, 2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34107984

RESUMO

PURPOSE: To investigate the interobserver variability (IOV) in target volume delineation of definitive radiotherapy for thoracic esophageal cancer (TEC) among cancer centers in China, and ultimately improve contouring consistency as much as possible to lay the foundation for multi-center prospective studies. METHODS: Sixteen cancer centers throughout China participated in this study. In Phase 1, three suitable cases with upper, middle, and lower TEC were chosen, and participants were asked to contour a group of gross tumor volume (GTV-T), nodal gross tumor volume (GTV-N) and clinical target volume (CTV) for each case based on their routine experience. In Phase 2, the same clinicians were instructed to follow a contouring protocol to re-contour another group of target volume. The variation of the target volume was analyzed and quantified using dice similarity coefficient (DSC). RESULTS: Sixteen clinicians provided routine volumes, whereas ten provided both routine and protocol volumes for each case. The IOV of routine GTV-N was the most striking in all cases, with the smallest DSC of 0.37 (95% CI 0.32-0.42), followed by CTV, whereas GTV-T showed high consistency. After following the protocol, the smallest DSC of GTV-N was improved to 0.64 (95% CI 0.45-0.83, P = 0.005) but the DSC of GTV-T and CTV remained constant in most cases. CONCLUSION: Variability in target volume delineation was observed, but it could be significantly reduced and controlled using mandatory interventions.


Assuntos
Neoplasias Esofágicas/radioterapia , Variações Dependentes do Observador , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/normas , Neoplasias Torácicas/radioterapia , Carga Tumoral , China , Neoplasias Esofágicas/patologia , Humanos , Órgãos em Risco/efeitos da radiação , Prognóstico , Dosagem Radioterapêutica , Neoplasias Torácicas/patologia
14.
Radiat Oncol ; 16(1): 79, 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33882972

RESUMO

BACKGROUND: The optimal dose and fractionation scheme of stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) remains unclear due to different tolerated liver volumes and degrees of cirrhosis. In this study, we aimed to verify the dose-survival relationship to optimize dose selection for treatment of HCC. METHODS: This multicenter retrospective study included 602 patients with HCC, treated with SBRT between January 2011 and March 2017. The SBRT dosage was classified into high dose, moderate dose, and low dose levels: SaRT (BED10 ≥ 100 Gy), SbRT (EQD2 > 74 Gy to BED10 < 100 Gy), and ScRT (EQD2 < 74 Gy). Overall survival (OS), progression-free survival (PFS), local control (LC), and intrahepatic control (IC) were evaluated in univariable and multivariable analyses. RESULTS: The median tumor size was 5.6 cm (interquartile range [IQR] 1.1-21.0 cm). The median follow-up time was 50.0 months (IQR 6-100 months). High radiotherapy dose correlated with better outcomes. After classifying into the SaRT, SbRT, and ScRT groups, three notably different curves were obtained for long-term post-SBRT survival and intrahepatic control. On multivariate analysis, higher radiation dose was associated with improved OS, PFS, and intrahepatic control. CONCLUSIONS: If tolerated by normal tissue, we recommend SaRT (BED10 ≥ 100 Gy) as a first-line ablative dose or SbRT (EQD2 ≥ 74 Gy) as a second-line radical dose. Otherwise, ScRT (EQD2 < 74 Gy) is recommended as palliative irradiation.


Assuntos
Carcinoma Hepatocelular/radioterapia , Neoplasias Hepáticas/radioterapia , Radiocirurgia/normas , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/normas , Adulto , Carcinoma Hepatocelular/patologia , Feminino , Humanos , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos , Taxa de Sobrevida
15.
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
16.
Radiat Oncol ; 16(1): 26, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33541394

RESUMO

BACKGROUND: Segmentation is a crucial step in treatment planning that directly impacts dose distribution and optimization. The aim of this study was to evaluate the inter-individual variability of common cranial organs at risk (OAR) delineation in neurooncology practice. METHODS: Anonymized simulation contrast-enhanced CT and MR scans of one patient with a solitary brain metastasis was used for delineation and analysis. Expert professionals from 16 radiotherapy centers involved in brain structures delineation were asked to segment 9 OAR on their own treatment planning system. As reference, two experts in neurooncology, produced a unique consensual contour set according to guidelines. Overlap ratio, Kappa index (KI), volumetric ratio, Commonly Contoured Volume, Supplementary Contoured Volume were evaluated using Artiview™ v 2.8.2-according to occupation, seniority and level of expertise of all participants. RESULTS: For the most frequently delineated and largest OAR, the mean KI are often good (0.8 for the parotid and the brainstem); however, for the smaller OAR, KI degrade (0.3 for the optic chiasm, 0.5% for the cochlea), with a significant discrimination (p < 0.01). The radiation oncologists, members of Association des Neuro-Oncologue d'Expression Française society performed better in all indicators compared to non-members (p < 0.01). Our exercise was effective in separating the different participating centers with 3 of the reported indicators (p < 0.01). CONCLUSION: Our study illustrates the heterogeneity in normal structures contouring between professionals. We emphasize the need for cerebral OAR delineation harmonization-that is a major determinant of therapeutic ratio and clinical trials evaluation.


Assuntos
Neoplasias Encefálicas/radioterapia , Variações Dependentes do Observador , Órgãos em Risco/patologia , Guias de Prática Clínica como Assunto/normas , Radioterapia (Especialidade)/normas , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/normas , Humanos , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Dosagem Radioterapêutica , Tomografia Computadorizada por Raios X/métodos
17.
Anticancer Res ; 41(1): 417-427, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33419839

RESUMO

BACKGROUND/AIM: The use of intensity-modulated radiation therapy (IMRT) in the treatment of breast cancer is increasing worldwide. Despite clear benefits concerning normal tissue sparing and dose homogeneity, the effects of breathing motion and setup error during breast IMRT should be considered. This study aimed to assess the dosimetric impact of respiratory motion on breast IMRT using four-dimensional (4D) dose calculations. PATIENTS AND METHODS: Multiple computed tomography datasets acquired in three representative respiratory amplitudes, were retrospectively re-planned. Based on the reference dose distribution (RDD), motion-adjusted dose distributions (MDD) were recalculated. All 4D dose distributions were calculated by the voxel-based accumulation of RDD and MDD using five temporal probabilities. The dosimetric parameters of the 4D plans were compared to those of RDD. RESULTS: The dosimetric parameters of the planning target volume (PTV) were not significantly different between the RDD and 4D plans. Of the parameters of tumor bed (TB) simultaneous-integrated boost (SIB), the mean dose and V95% for the 4D plans were significantly reduced compared to those of RDD, and the percentage difference in the TB V95% ranged from -1.1% to -5.7% (p<0.05). CONCLUSION: The breast IMRT plan was robust against respiratory motion during tidal breathing. However, special considerations should be made when designing the TB SIB.


Assuntos
Neoplasias da Mama/radioterapia , Movimento (Física) , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Respiração , Neoplasias da Mama/diagnóstico por imagem , Feminino , Humanos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas , Tomografia Computadorizada por Raios X
18.
Cancer Radiother ; 25(2): 191-199, 2021 Apr.
Artigo em Francês | MEDLINE | ID: mdl-33402287

RESUMO

PURPOSE: In breast cancer, radiotherapy is an essential component of the treatment. However, indications of irradiation of the internal mammary chain and axillary area are debatables. Axillary recurrence in patients with invasive breast carcinoma remains an issue. Currently, the substitution of axillary lymph node dissection by sentinel node biopsy leads to revisit the role of axillary irradiation. Breast irradiation including level I, II and III might decrease the risk of axillary recurrence. MATERIAL AND METHODS: A literature search was performed in PubMed and the Cochrane library to identify articles publishing data regarding dose-volume analysis of axillary levels in breast irradiation aiming to determine the potential therapeutic implications. RESULTS: Eleven articles were retained. A total of 375 treatment plans were analyzed. The results concerning the irradiation technique, initial dose prescribed to breast, delineated volumes and dose received at axillary levels were heterogeneous. The average dose delivered to axilla levels I-III with 3D-conformal radiotherapy using standard fields were between 24Gy and 43.5Gy, 3Gy and 32.5Gy and between 1.0Gy and 20.5Gy respectively. The average doses delivered to axilla levels I-III with 3D-conformal radiotherapy using high tangential fields were between 38Gy and 49.7Gy, 11Gy and 47.1Gy and 5Gy 38.7Gy, 32.1Gy and 5Gy (result available for only one study) respectively. Finally, the average doses delivered to axilla levels I-III with intensity modulated radiation therapy were between 14.5Gy and 42.6Gy, 3.4Gy and 35Gy and between 1.2Gy and 25.5Gy respectively. CONCLUSIONS: Incidental axillary dose seems insufficient to be therapeutic regardless of the irradiation technique. There are meaningful differences between intensity modulated radiation therapy and 3D-conformal radiotherapy.


Assuntos
Neoplasias da Mama/radioterapia , Irradiação Linfática/métodos , Axila , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mastectomia , Terapia Neoadjuvante/métodos , Recidiva Local de Neoplasia/prevenção & controle , Recidiva Local de Neoplasia/radioterapia , Dosagem Radioterapêutica , Radioterapia Conformacional/métodos , Radioterapia Conformacional/normas , Radioterapia de Intensidade Modulada/métodos , Radioterapia de Intensidade Modulada/normas , Biópsia de Linfonodo Sentinela
19.
Phys Med Biol ; 66(4): 045006, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32413883

RESUMO

PURPOSE: To develop a novel treatment planning process (TPP) with simultaneous optimization of modulated photon, electron and proton beams for improved treatment plan quality in radiotherapy. METHODS: A framework for fluence map optimization of Monte Carlo (MC) calculated beamlet dose distributions is developed to generate treatment plans consisting of photon, electron and spot scanning proton fields. Initially, in-house intensity modulated proton therapy (IMPT) plans are compared to proton plans created by a commercial treatment planning system (TPS). A triple beam radiotherapy (TriB-RT) plan is generated for an exemplary academic case and the dose contributions of the three particle types are investigated. To investigate the dosimetric potential, a TriB-RT plan is compared to an in-house IMPT plan for two clinically motivated cases. Benefits of TriB-RT for a fixed proton beam line with a single proton field are investigated. RESULTS: In-house optimized IMPT are of at least equal or better quality than TPS-generated proton plans, and MC-based optimization shows dosimetric advantages for inhomogeneous situations. Concerning TriB-RT, for the academic case, the resulting plan shows substantial contribution of all particle types. For the clinically motivated case, improved sparing of organs at risk close to the target volume is achieved compared to IMPT (e.g. myelon and brainstem [Formula: see text] -37%) at cost of an increased low dose bath (healthy tissue V 10% +22%). In the scenario of a fixed proton beam line, TriB-RT plans are able to compensate the loss in degrees of freedom to substantially improve plan quality compared to a single field proton plan. CONCLUSION: A novel TPP which simultaneously optimizes photon, electron and proton beams was successfully developed. TriB-RT shows the potential for improved treatment plan quality and is especially promising for cost-effective single-room proton solutions with a fixed beamline in combination with a conventional linac delivering photon and electron fields.


Assuntos
Elétrons , Neoplasias de Cabeça e Pescoço/radioterapia , Neoplasias Pélvicas/radioterapia , Imagens de Fantasmas , Fótons/uso terapêutico , Terapia com Prótons/normas , Planejamento da Radioterapia Assistida por Computador/normas , Humanos , Método de Monte Carlo , Terapia com Prótons/métodos , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/normas
20.
Phys Med Biol ; 66(3): 035020, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33207321

RESUMO

Ultra-high dose rate in radiotherapy (FLASH) has been shown to increase the therapeutic index with markedly reduced normal tissue toxicity and the same or better tumor cell killing. The challenge to achieve FLASH using x-rays, besides developing a high output linac, is to intensity-modulate the high-dose-rate x-rays so that the biological gain is not offset by the lack of physical dose conformity. In this study, we develop the ROtational direct Aperture optimization with a Decoupled ring-collimator (ROAD) to achieve simultaneous ultrafast delivery and complex dose modulation. The ROAD design includes a fast-rotating slip-ring linac and a decoupled collimator-ring with 75 pre-shaped multi-leaf-collimator (MLC) modules. The ring-source rotates at 1 rotation per second (rps) clockwise while the ring-collimator is either static or rotating at 1 rps counterclockwise, achieving 75 (ROAD-75) or 150 (ROAD-150) equal-angular beams for one full arc. The Direct Aperture Optimization (DAO) for ROAD was formulated to include a least-square dose fidelity, an anisotropic total variation term, and a single segment term. The FLASH dose (FD) and FLASH biological equivalent dose (FBED) were computed voxelwise, with the latter using a spatiotemporal model accounting for radiolytic oxygen depletion. ROAD was compared with clinical volumetric modulated arc therapy (VMAT) on a brain, a lung, a prostate, and a head and neck cancer patient. The mean dose rate of ROAD-75 and ROAD-150 are 76.2 Gy s-1 and 112 Gy s-1 respectively to deliver 25 Gy single-fraction dose in 1 s. With improved PTV homogeneity, ROAD-150 reduced (max, mean) OAR physical dose by (4.8 Gy, 6.3 Gy). The average R50 and integral dose of (VMAT, ROAD-75, ROAD-150) are (4.8, 3.2, 3.2) and (89, 57, 56) Gy×Liter, respectively. The FD and FBED showed model dependent FLASH effects. The novel ROAD design achieves ultrafast dose delivery and improves physical dosimetry compared with clinical VMAT, providing a potentially viable engineering solution for x-ray FLASH radiotherapy.


Assuntos
Aceleradores de Partículas/normas , Equipamentos e Provisões para Radiação/normas , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Glioblastoma/radioterapia , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Neoplasias Pulmonares/radioterapia , Masculino , Aceleradores de Partículas/instrumentação , Neoplasias da Próstata/radioterapia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/instrumentação , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/instrumentação , Radioterapia de Intensidade Modulada/normas
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