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2.
Cancer Radiother ; 24(1): 53-59, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32046915

RESUMO

PUPOSE: To compare dosimetric plans for the treatments of oligobrains metastases (2-6) using mono-isocentric arc therapy and multi-isocentric volumetric modulated arc therapy (VMAT). MATERIAL AND METHODS: A total of sixteen patients with multiple brain metastases were selected. Prescription dose was between 24 and 15Gy depending on the tumor size. For every patient,arctherapy and VMAT plans were generated respectively, with Elements Multiple Brain Mets SRS version 2.0 (BrainLab) and Eclipse SRS Treatment Planning Systeme version 15.5. The conformity index (CI), homogeinity index (HI), gradient index (GI), dose volume histogram for each organs at risk, total Monitor Units were evaluated. RESULTS: For coverage of the PTV, mono-isocentric plans showed a better CI and a better GI than multi-isocentric plans, respectively CI of 1.18±0.11 vs 1.41±0.20 (P<0.01), and GI of 3.55±0.59 vs 4.03±1.20 (P<0.01). Homogeneity index was not better with mono-isocentric plans, with respectively HI 24.32±3.87 vs 14.05±4.46 (P=1). For organs at risk, there were no statistical differences between mono and multi-isocentric plans for both eyes, both lenses, both optic nerves, chiasma, brainstem, and hippocampi.V12Gy and V10Gy of normal brain were statistically lower with mono-isocentric plans than with multi-isocentric plans, respectivellyV12Gy of 3.06Gy 95%CI [2.25;3.86]vs 5.18Gy 95%CI [3.43;6.93] (P<0,01) and V10Gy 4.66Gy 95%CI [3.33;5.98] vs7.30Gy 95%CI [4.73;9.87] (P<0.03). Total number of MU was significantly lower with mono-isocentric plans than with multi-isocentric plans, respectively 6668±1463 vs 12403±4941 (P<0.01), then treatment time was lower with mono-isocentric plans. CONCLUSION: Mono-isocentric plans had a better conformity index and gradient index than multi-isocentric plans for the treatment of multiple brain metastases. Moreover, mono-isocentric techniques gave fewer doses to normal brain and used less monitor units than multi-isocentric techniques.


Assuntos
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/efeitos da radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Planejamento da Radioterapia Assistida por Computador
3.
Int J Radiat Oncol Biol Phys ; 106(3): 604-611, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32014151

RESUMO

PURPOSE: Steep dose falloff outside of tumors is a hallmark of stereotactic radiosurgery (SRS) and radiation therapy (SRT). Dose gradient index (DGI) quantifies the dose drop off. Tables of DGIs versus target volumes have been published for body sites, but none is available for brain. This study recommends guidelines for DGIs for brain SRS/SRT treatments based on clinical CyberKnife (CK) cases. METHODS AND MATERIALS: Four hundred ninety-five plans for patients with central nervous system tumors treated with CK at our institution between March 2015 and May 2018 were analyzed. The CK treatment planning system MultiPlan was used for planning. SRS/SRT plans were stratified into 6 groups by tumor size (Group I [0-1 cm3], II [1.0-3.0 cm3], III [3.0-5.0 cm3], IV [5.0-10.0 cm3], V [10.0-15.0 cm3], and VI [15.0-40.0 cm3]). Ideal and minimally acceptable DGIs were determined for each size group. To evaluate the effect of target shape on DGI criteria, the plans were divided into 4 target shape groups: (1) homogeneous shape (circular), (2) adjacent to radiosensitive organs at risk (adjacent), (3) irregularly shaped (irregular), and (4) multiple target plans (multilesion). The mean for each target size group was defined as the ideal DGI. Minimally acceptable DGI criteria are specified to reject the lowest 10% of cases. RESULTS: The minimal acceptable DGIs were 83 (Group I), 72 (II), 65 (III), 58 (IV), 52 (V), and 35 (VI). The ideal DGI is designated to evaluate SRS/SRT plans for homogeneous circular lesions, whereas minimal DGI is chosen to assess the plans for irregular, adjacent to organs at risk, and multilesions. SRS/SRT plans with higher DGI values are correlated with lower irradiated normal tissue volumes. CONCLUSIONS: This study provides a table of DGIs for brain SRS/SRT treatments as a tool for assessing the quality of intracranial SRS/SRT plans. DGI guidelines support SRS/SRT planning that results in lower risk of radionecrosis.


Assuntos
Neoplasias Encefálicas/radioterapia , Órgãos em Risco/efeitos da radiação , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Neoplasias Encefálicas/diagnóstico por imagem , Guias como Assunto , Humanos , Órgãos em Risco/diagnóstico por imagem , Tolerância a Radiação , Radiocirurgia/efeitos adversos , Dosagem Radioterapêutica , Radioterapia Conformacional/efeitos adversos , Espalhamento de Radiação
4.
Cancer Radiother ; 24(1): 21-27, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32001131

RESUMO

PURPOSE: Radiotherapy is the main treatment method for patients with locally advanced, unresectable esophageal cancer. The aim of this study is to compare overall survival (OS) using 3D radiotherapy (3DRT) alone with concurrent chemoradiotherapy (CCRT) in 296 non-surgical esophageal carcinoma patients. PATENTS AND METHODS: Over 10 years, of the 480 patients with esophageal carcinoma treated with 3DRT with or without chemotherapy, 148 patients each comprised 3DRT and CCRT groups after propensity score matching. RESULTS: The 5- and 10-year OS (P=0.337) and PFS (P=0.715) rates for 3DRT alone were 22.0%, 14.4% and 26.1%, 23.2%, respectively, compared with 28.8%, 18.6% and 34.7%, 29.1% for CCRT, respectively. CCRT did not improve 5-year and 10-year OS or PFS in 60-70Gy group (OS: 27.5% and 25.2%; 17.9% and 17.0%, P=0.938; PFS: 38.3% and 31.8%; 31.9% and 27.8%, P=0.890) nor reduce 10-year hematogenous metastasis (31.7% and 28.3%, P=0.698). CCRT improved 5-year OS and PFS of 50.0-59.9Gy group (OS: 33.3% and 12.0%, P=0.029; PFS: 33.1% and 10.6%, P=0.081). For 3DRT, the 5-year OS and PFS rates were significantly better in the 60-70Gy group (P=0.017) compared with 50.0-59.9Gy group (P=0.002). For CCRT group, 5-year OS and PFS favored the 50.0-59.9Gy group, but the difference was insignificant. Major toxicities were greater with CCRT compared with 3DRT. CONCLUSION: For non-surgical esophageal carcinoma patients, 3DRT combined with CCRT was effective in prolonging both OS and PFS.


Assuntos
Quimiorradioterapia , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/radioterapia , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Idoso , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/radioterapia , China/epidemiologia , Neoplasias Esofágicas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Intervalo Livre de Progressão , Dosagem Radioterapêutica
5.
Cancer Radiother ; 24(1): 28-37, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32007370

RESUMO

PURPOSE: To guide parotid gland (PG) sparing at the dose planning step, a specific model based on overlap between PTV and organ at risk (Moore et al.) was developed and evaluated for VMAT in head-and-neck (H&N) cancer radiotherapy. MATERIALS AND METHODS: One hundred and sixty patients treated for locally advanced H&N cancer were included. A model optimization was first performed (20 patients) before a model evaluation (110 patients). Thirty cases were planned with and without the model to quantify the PG dose sparing. The inter-operator variability was evaluated on one case, planned by 12 operators with and without the model. The endpoints were PG mean dose (Dmean), PTV homogeneity and number of monitor units (MU). RESULTS: The PG Dmean predicted by the model was reached in 89% of cases. Using the model significantly reduced the PG Dmean: -6.1±4.3Gy. Plans with the model showed lower PTV dose homogeneity and more MUs (+10.5% on average). For the inter-operator variability, PG dose volume histograms without the optimized model were significantly different compared to those with the model; the Dmean standard deviation for the ipsilateral PG decreased from 2.2Gy to 1.2Gy. For the contralateral PG, this value decreased from 2.9Gy to 0.8Gy. CONCLUSION: During the H&N inverse planning, the optimized model guides to the lowest PG achievable mean dose, allowing a significant PG mean dose reduction of -6.1Gy. Integrating this method at the treatment-planning step significantly reduced the inter-patient and inter-operator variabilities.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Órgãos em Risco , Glândula Parótida , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Carcinoma de Células Escamosas/radioterapia , Humanos , Glândula Parótida/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos
6.
Br J Radiol ; 93(1107): 20190920, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31944827

RESUMO

OBJECTIVE: For the past 20 years, Paul Scherrer Institut (PSI) has treated more than 1500 patients with deep-seated tumors using PSI-Plan, an in-house developed treatment planning system (TPS) used for proton beam scanning proton therapy, in combination with its home-built gantries. The goal of the present work is to benchmark the performance of a new TPS/Gantry system for proton therapy centers which have established already a baseline standard of care. METHODS AND MATERIALS: A total of 31 cases (=52 plans) distributed around 7 anatomical sites and 12 indications were randomly selected and re-planned using Eclipse™. The resulting plans were compared with plans formerly optimized in PSI-Plan, in terms of target coverage, plan quality, organ-at-risk (OAR) sparing and number of delivered pencil beams. RESULTS: Our results show an improvement on target coverage and homogeneity when using Eclipse™ while PSI-Plan showed superior plan conformity. As for OAR sparing, both TPS achieved the clinical constraints. The number of pencil beams required per plan was on average 3.4 times higher for PSI-Plan. CONCLUSION: Both systems showed a good capacity to produce satisfactory plans, with Eclipse™ being able to achieve better target coverage and plan homogeneity without compromising OARs. ADVANCES IN KNOWLEDGE: A benchmark between a clinically tested and validated system with a commercial solution is of interest for emerging proton therapy, equipped with commercial systems and no previous experience with proton beam scanning.


Assuntos
Benchmarking , Institutos de Câncer , Neoplasias/radioterapia , Terapia com Prótons/instrumentação , Melhoria de Qualidade , Planejamento da Radioterapia Assistida por Computador/normas , Algoritmos , Humanos , Terapia com Prótons/normas , Suíça
7.
Br J Radiol ; 93(1108): 20190792, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31939310

RESUMO

OBJECTIVES: To evaluate the feasibility and optimal restricted angle of the complete-directional-complete block (CDCB) technique in helical tomotherapy (HT) by including regional nodal irradiation (RNI) with the internal mammary node (IMN) in left-sided breast cancer. METHODS: Ten left-sided breast cancer patients treated with 50 Gy in 25 fractions were compared with five-field intensity-modulated radiation therapy (5F-IMRT) and six types of HT plans. In the HT plans, complete block (CB), organ-based directional block (OBDB) and CDCB with different restricted angles were used. RESULTS: The conformity index (CI) between the CDCB0,10,15,20 and 5F-IMRT groups was similar. Compared to CB, OBDB and 5F-IMRT, CDCB20 resulted in a decreased ipsilateral mean lung dose. The low-dose region (V5) of the ipsilateral lung in OBDB (84.0%) was the highest among all techniques (p < 0.001). The mean dose of the heart in CB was significantly reduced (by 11.5-22.4%) compared with other techniques. The V30 of the heart in CDCB20 (1.9%) was significantly lower than that of CB, OBDB and 5F-IMRT. Compared to the mean dose of the left anterior descending (LAD) artery of 5F-IMRT (27.0 Gy), CDCB0, CDCB10, CDCB15, CDCB20 and OBDB reduced the mean dose effectively by 31.7%, 38.3%, 39.6%, 42.0 and 56.2%, respectively. Considering the parameters of the organs-at-risk (OARs), CDCB10,15,20 had higher expectative values than the other techniques (p = 0.01). CONCLUSIONS: HT with the CDCB technique is feasible for treating left-sided breast cancer patients. The CDCB10-20 techniques not only achieved similar planning target volume coverage, homogeneity and dose conformity but also allowed better sparing of the heart and bilateral lungs. ADVANCES IN KNOWLEDGE: For left-sided breast cancer patients whose RNI field includes the IMN, heart avoidance is an important issue. The CDCB technique achieved good PTV coverage, homogeneity and dose conformity and allowed better sparing of the mean dose of the lung, the LAD artery, and the heart and reduced the V30 of the heart.


Assuntos
Coração/efeitos da radiação , Pulmão/efeitos da radiação , Irradiação Linfática/métodos , Órgãos em Risco/efeitos da radiação , Lesões por Radiação/prevenção & controle , Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia , Fracionamento da Dose de Radiação , Estudos de Viabilidade , Feminino , Humanos , Órgãos em Risco/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias Unilaterais da Mama/diagnóstico por imagem
8.
Br J Radiol ; 93(1108): 20190789, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31971829

RESUMO

OBJECTIVE: Prostate stereotactic ablative radiotherapy (SABR) delivers large doses using a fast dose rate. This amplifies the effect geometric uncertainties have on normal tissue dose. The aim of this study was to determine whether the treatment dose-volume histogram (DVH) agrees with the planned dose to organs at risk (OAR). METHODS: 41 low-intermediate risk prostate cancer patients were treated with SABR using a linac based technique. Dose prescribed was 35 Gy in five fractions delivered on alternate days, planned using volumetric modulated arc therapy (VMAT) with 10X flattening filter free (FFF). On treatment, prostate was matched to fiducial markers on cone beam CT (CBCT). OAR were retrospectively delineated on 205 pre-treatment CBCT images. Daily CBCT contours were overlaid on the planning CT for dosimetric analysis. Verification plan used to evaluate the daily DVH for each structure. The daily doses received by OAR were recorded using the D%. RESULTS: The median rectum and bladder volumes at planning were 67.1 cm3 (interquartile range 56.4-78.2) and 164.4 cm3 (interquartile range 120.3-213.4) respectively. There was no statistically significant difference in median rectal volume at each of the five treatment scans compared to the planning scan (p = 0.99). This was also the case for median bladder volume (p = 0.79). The median dose received by rectum and bladder at each fraction was higher than planned, at the majority of dose levels. For rectum the increase ranged from 0.78-1.64Gy and for bladder 0.14-1.07Gy. The percentage of patients failing for rectum D35% < 18 Gy (p = 0.016), D10% < 28 Gy (p = 0.004), D5% < 32 Gy (p = 0.0001), D1% < 35 Gy (p = 0.0001) and bladder D1% < 35 Gy (p = 0.001) at treatment were all statistically significant. CONCLUSION: In this cohort of prostate SABR patients, we estimate the OAR treatment DVH was higher than planned. This was due to rectal and bladder organ variation. ADVANCES IN KNOWLEDGE: OAR variation in prostate SABR using a FFF technique, may cause the treatment DVH to be higher than planned.


Assuntos
Órgãos em Risco/efeitos da radiação , Neoplasias da Próstata/radioterapia , Radiocirurgia/métodos , Radioterapia de Intensidade Modulada/métodos , Reto/efeitos da radiação , Bexiga Urinária/efeitos da radiação , Idoso , Fracionamento da Dose de Radiação , Humanos , Masculino , Próstata , Radiometria , Planejamento da Radioterapia Assistida por Computador/métodos , Reto/diagnóstico por imagem , Estudos Retrospectivos , Bexiga Urinária/diagnóstico por imagem
9.
Cancer Radiother ; 24(1): 38-43, 2020 Feb.
Artigo em Francês | MEDLINE | ID: mdl-31992518

RESUMO

PURPOSE: The aim of this work is to evaluate the anatomical changes of the glandular structures during the NPC IMRT and to study their dosimetric impacts. PATIENTS AND METHODS: Twenty patients receiving IMRT for NPC were included. For each patient, a second dosimetric CT was performed at a dose of 38Gy, which was fused with the initial planning dosimetric CT. We calculated the volume percent change, the positional and dosimetric variation between the 2 scanners for the glandular structures (parotid, submaxillary, thyroid and pituitary). RESULTS: We observed a decrease in the volume of right and left parotids (-27.9% and -27.54%). It was correlated with the initial dose planned at its level. For the sub maxillary glands, the decrease was -36.1% on the right and -27.28% on the left. The value of reduction of the thyroid gland was -18.01%. A medial supra-millimeter migration of 2 and 1.15mm was found for right and left parotid glands respectively, correlated with GTV N reduction volume. We found a significant increase in mean doses for the parotid glands. It was 1.8±2.3Gy for the right and 1.5±2.7Gy for the left. For the right sub maxillary gland, the increase was about 0.35±2Gy and 3.79±5.2Gy for the thyroid. CONCLUSION: The modifications observed for glandular structures during NPC IMRT can explain the different toxicities caused by radiation. It seems also that a careful adaptation of the treatment plan should be considered during therapy.


Assuntos
Neoplasias Nasofaríngeas/radioterapia , Órgãos em Risco , Radioterapia de Intensidade Modulada , Carcinoma/diagnóstico por imagem , Carcinoma/radioterapia , Humanos , Neoplasias Nasofaríngeas/diagnóstico por imagem , Glândula Parótida/efeitos da radiação , Hipófise/efeitos da radiação , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Glândula Submandibular/efeitos da radiação , Glândula Tireoide/efeitos da radiação , Tomografia Computadorizada por Raios X
10.
Int J Radiat Oncol Biol Phys ; 106(2): 310-319, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31682968

RESUMO

PURPOSE: This phase II study evaluated the utility of magnetic resonance imaging (MRI) and positron emission tomography for planning radiation and brachytherapy in patients with postsurgical recurrence of cervical cancer. METHODS AND MATERIALS: The study (NCT01391065) recruited patients with residual or recurrent disease after hysterectomy. Patients underwent baseline T2 weighted (T2W) MRI, 18F-flouro-deoxyglucose (18F-FDG), 18F-flouro thymidine (18F-FLT) and 18F-flouromisonidazole (18F-F Miso) positron emission tomography (PET) and received external radiation (50 Gy/25 fractions for 5 weeks) and weekly cisplatin (40 mg/m2). MRI was performed at brachytherapy and used for delineation of clinical target volume (CTV). Patients with parametrial disease at baseline received interstitial brachytherapy (16-20 Gy/4-5 fractions) and those with vaginal disease received intracavitary brachytherapy (12-14 Gy/2-4 fractions). Kaplan-Meier analysis was performed to evaluate locoregional relapse, disease free survival, and overall survival. Common Toxicity Criteria for adverse event reporting (CTCAE) v4.1 was used for toxicity scoring and European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questtionaire Core 30 (QLQC-30) and Cx 24 for quality-of-life reporting. RESULTS: Between January 2011 and February 2016, 60 patients were included, of which 50 received study treatment. The mean gross tumor volume on T2 W MR was 20 (IQR 3.6-90) cc. The metabolic tumor volume was 15 (interquartile range [IQR] 2.1-56.1) cc. The median FLT volume was 10 (IQR 0-48) cc. A total of 8 patients had 18-F F Miso uptake. The median CTV at brachytherapy was 38 (12-85) cc. The median CTVD90 and D 98 was 71 (53-74) and 74 (53-74) Gy. At a median follow-up of 60 (5-93) months, the 5-year local control, disease free survival, and overall survival were 84%, 73%, and 74.5%, respectively. Grade III and IV proctitis and cystitis were observed in 4% and 2% of patients. On multivariate analysis baseline tumor volume, on T2 W MR impacted disease free (91% vs 65%, P = .03) and overall survival (96% vs 77%, P = .06). CONCLUSIONS: Image-guided assisted radiation and brachytherapy are associated with good to excellent local control and survival in patients with vaginal recurrences of cervical cancer.


Assuntos
Braquiterapia/métodos , Recidiva Local de Neoplasia/radioterapia , Radioterapia Guiada por Imagem/métodos , Neoplasias do Colo do Útero/radioterapia , Adulto , Idoso , Antineoplásicos/uso terapêutico , Braquiterapia/efeitos adversos , Cisplatino/uso terapêutico , Cistite/etiologia , Cistite/patologia , Intervalo Livre de Doença , Feminino , Humanos , Histerectomia , Estimativa de Kaplan-Meier , Imagem por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/mortalidade , Neoplasia Residual , Tomografia por Emissão de Pósitrons/métodos , Proctite/etiologia , Proctite/patologia , Estudos Prospectivos , Qualidade de Vida , Compostos Radiofarmacêuticos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/efeitos adversos , Carga Tumoral , Neoplasias do Colo do Útero/diagnóstico por imagem , Neoplasias do Colo do Útero/mortalidade , Neoplasias do Colo do Útero/terapia
11.
Br J Radiol ; 93(1107): 20190583, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31696729

RESUMO

OBJECTIVE: To identify a subgroup of lung cancer plans where the analytical dose calculation (ADC) algorithm may be clinically acceptable compared to Monte Carlo (MC) dose calculation in intensity modulated proton therapy (IMPT). METHODS: Robust-optimised IMPT plans were generated for 20 patients to a dose of 70 Gy (relative biological effectiveness) in 35 fractions in Raystation. For each case, four plans were generated: three with ADC optimisation using the pencil beam (PB) algorithm followed by a final dose calculation with the following algorithms: PB (PB-PB), MC (PB-MC) and MC normalised to prescription dose (PB-MC scaled). A fourth plan was generated where MC optimisation and final dose calculation was performed (MC-MC). Dose comparison and γ analysis (PB-PB vs PB-MC) at two dose thresholds were performed: 20% (D20) and 99% (D99) with PB-PB plans as reference. RESULTS: Overestimation of the dose to 99% and mean dose of the clinical target volume was observed in all PB-MC compared to PB-PB plans (median: 3.7 Gy(RBE) (5%) (range: 2.3 to 6.9 Gy(RBE)) and 1.8 Gy(RBE) (3%) (0.5 to 4.6 Gy(RBE))). PB-MC scaled plans resulted in significantly higher CTVD2 compared to PB-PB (median difference: -4 Gy(RBE) (-6%) (-5.3 to -2.4 Gy(RBE)), p ≤ .001). The overall median γ pass rates (3%-3 mm) at D20 and D99 were 93.2% (range:62.2-97.5%) and 71.3 (15.4-92.0%). On multivariate analysis, presence of mediastinal disease and absence of range shifters were significantly associated with high γ pass rates. Median D20 and D99 pass rates with these predictors were 96.0% (95.3-97.5%) and 85.4% (75.1-92.0%). MC-MC achieved similar target coverage and doses to OAR compared to PB-PB plans. CONCLUSION: In the presence of mediastinal involvement and absence of range shifters Raystation ADC may be clinically acceptable in lung IMPT. Otherwise, MC algorithm would be recommended to ensure accuracy of treatment plans. ADVANCES IN KNOWLEDGE: Although MC algorithm is more accurate compared to ADC in lung IMPT, ADC may be clinically acceptable where there is mediastinal involvement and absence of range shifters.


Assuntos
Algoritmos , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Método de Monte Carlo , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Análise de Variância , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/patologia , Fracionamento da Dose de Radiação , Tomografia Computadorizada Quadridimensional , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Neoplasias do Mediastino/radioterapia , Análise Multivariada , Órgãos em Risco/efeitos da radiação , Eficiência Biológica Relativa , Incerteza
12.
Int J Radiat Oncol Biol Phys ; 106(2): 430-439, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31678227

RESUMO

PURPOSE: To evaluate whether automated knowledge-based planning (KBP) (a) is noninferior to human-driven planning across multiple disease sites and (b) systematically affects dosimetric plan quality and variability. METHODS AND MATERIALS: Clinical KBP automated planning routines were developed for prostate, prostatic fossa, hypofractionated lung, and head and neck. Clinical implementation consisted of independent generation of human-generated and KBP plans (145 cases across all sites), followed by blinded plan selection. Reviewing physicians were prompted to select a single plan; when plan equivalence was volunteered, this scored as KBP selection. Plan selection analysis used a noninferiority framework testing the hypothesis that KBP is not worse than human-driven planning (threshold: lower 95% confidence interval [CI] > 0.45 = noninferiority; > 0.5 = superiority). Target and organ-at-risk metrics were compared by dose differencing: ΔDx = Dx, human-Dx, KBP (2-tailed paired t test, Bonferroni-corrected P < .05 significance threshold). To evaluate the aggregated effect of KBP on planning performance, we examined post-KBP dosimetric parameters against 183 plans generated just before KBP implementation (2-tailed unpaired t test, Bonferroni-corrected P < .05). RESULTS: Across all disease sites, the KBP success rate (physician preferred + equivalent) was noninferior compared with human-driven planning (83 of 145 = 57.2%; range, 49.2%-65.3%) but did not cross the threshold for superiority. The KBP success rate in respective disease sites was superior with head and neck ([22 + 2]/36 = 66.7%; 95% CI, 51%-82%) and noninferior for lung stereotactic body radiation therapy ([21 + 2]/36 = 63.9%; 95% CI, 48%-80%) but did not meet noninferiority criteria with prostate ([16 + 3]/41 = 46.3%; 95% CI, 31%-62%) or prostatic fossa ([17 + 0]/32 = 53.1%; 95% CI, 36%-70%). Prostate, prostatic fossa, and head and neck showed significant differences in KBP-selected plans versus human-selected plans, with KBP generally exhibiting greater organ-at-risk sparing and human plans exhibiting better target homogeneity. Analysis of plan quality pre- and post-KBP showed some reductions in organ doses and quality metric variability in prostate and head and neck. CONCLUSIONS: Fully automated KBP was noninferior to human-driven plan optimization across multiple disease sites. Dosimetric analysis of treatment plans before and after KBP implementation showed a systematic shift to higher plan quality and lower variability with the introduction of KBP.


Assuntos
Protocolos Clínicos , Neoplasias de Cabeça e Pescoço/radioterapia , Gestão do Conhecimento , Neoplasias Pulmonares/radioterapia , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Bases de Conhecimento , Neoplasias Pulmonares/patologia , Masculino , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco , Neoplasias da Próstata/patologia , Garantia da Qualidade dos Cuidados de Saúde , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/normas , Equipolência Terapêutica
13.
Br J Radiol ; 93(1107): 20190595, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31687833

RESUMO

OBJECTIVE: Accurate patient positioning is crucial in particle therapy due to the geometrical selectivity of particles. We report and discuss the National Center for Oncological Hadrontherapy (CNAO) experience in positioning accuracy and stability achieved with solid thermoplastic masks fixed on index base plates and assessed by daily orthogonal X-ray imaging. METHODS: Positioning data were retrospectively collected (between 2012 and 2018) and grouped according to the treated anatomical site. 19696 fractions of 1325 patients were evaluated.The study was designed to assess:(i) the number of fractions in which a single correction vector was applied(SCV);(ii) the number of fractions in which further setup verification was performed (SV);(iii) the number of fractions in which SV lead to an additional correction within (MCV<5min) or after (MCV>5min) 5 minutes from the first setup correction;(iv) the systematic (Σ) and random (σ) error components of the correction vectors applied. RESULTS: A SCV was applied in 71.5% of fractions, otherwise SV was required. In 30.6% of fractions with SV, patient position was not further revised. In the remaining fractions, MCV<5min and MCV>5min were applied mainly in extracranial and cranial sites respectively.Interfraction Σ was ≤ 1.7 mm/0.7° and σ was ≤ 1.2 mm/0.6° in cranial sites while in extracranial sites Σ was ≤ 5.5 mm/0.9° and σ was ≤4.4 mm/0.9°. Setup residuals were submillimetric in all sites. In cranial patients, maximum intrafractional Σ was 0.8 mm/0.4°. CONCLUSION: This report extensively quantifies inter- and intrafraction setup accuracy on an institutional basis and confirms the need of image guidance to fully benefit from the geometrical selectivity of particles. ADVANCES IN KNOWLEDGE: The reported analysis provides a board institutional data set on the evaluation of patient immobilization and bony anatomy alignment for several particle therapy clinical indications.


Assuntos
Imobilização/instrumentação , Máscaras , Neoplasias/radioterapia , Posicionamento do Paciente/métodos , Erros de Configuração em Radioterapia/prevenção & controle , Institutos de Câncer , Fracionamento da Dose de Radiação , Feminino , Humanos , Imobilização/métodos , Masculino , Pessoa de Meia-Idade , Neoplasias/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador , Radioterapia Guiada por Imagem , Reprodutibilidade dos Testes , Estudos Retrospectivos , Fatores de Tempo , Tomografia Computadorizada por Raios X , Incerteza
14.
Br J Radiol ; 93(1107): 20190334, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31738081

RESUMO

Dose in proton radiotherapy is generally prescribed by scaling the physical proton dose by a constant value of 1.1. Relative biological effectiveness (RBE) is defined as the ratio of doses required by two radiation modalities to cause the same level of biological effect. The adoption of an RBE of 1.1. assumes that the biological efficacy of protons is similar to photons, allowing decades of clinical dose prescriptions from photon treatments and protocols to be utilized in proton therapy. There is, however, emerging experimental evidence that indicates that proton RBE varies based on technical, tissue and patient factors. The notion that a single scaling factor may be used to equate the effects of photons and protons across all biological endpoints and doses is too simplistic and raises concern for treatment planning decisions. Here, we review the models that have been developed to better predict RBE variations in tissue based on experimental data as well as using a mechanistic approach.


Assuntos
Modelos Teóricos , Neoplasias/radioterapia , Terapia com Prótons/métodos , Lesões por Radiação , Eficiência Biológica Relativa , Algoritmos , Animais , Linhagem Celular Tumoral , DNA/efeitos da radiação , Reparo do DNA , Humanos , Modelos Biológicos , Método de Monte Carlo , Órgãos em Risco/efeitos da radiação , Fótons/uso terapêutico , Planejamento da Radioterapia Assistida por Computador
16.
Br J Radiol ; 93(1107): 20190669, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31799859

RESUMO

OBJECTIVE: This study is part of ongoing efforts aiming to transit from measurement-based to combined patient-specific quality assurance (PSQA) in intensity-modulated proton therapy (IMPT). A Monte Carlo (MC) dose-calculation algorithm is used to improve the independent dose calculation and to reveal the beam modeling deficiency of the analytical pencil beam (PB) algorithm. METHODS: A set of representative clinical IMPT plans with suboptimal PSQA results were reviewed. Verification plans were recalculated using an MC algorithm developed in-house. Agreements of PB and MC calculations with measurements that quantified by the γ passing rate were compared. RESULTS: The percentage of dose planes that met the clinical criteria for PSQA (>90% γ passing rate using 3%/3 mm criteria) increased from 71.40% in the original PB calculation to 95.14% in the MC recalculation. For fields without beam modifiers, nearly 100% of the dose planes exceeded the 95% γ passing rate threshold using the MC algorithm. The model deficiencies of the PB algorithm were found in the proximal and distal regions of the SOBP, where MC recalculation improved the γ passing rate by 11.27% (p < 0.001) and 16.80% (p < 0.001), respectively. CONCLUSIONS: The MC algorithm substantially improved the γ passing rate for IMPT PSQA. Improved modeling of beam modifiers would enable the use of the MC algorithm for independent dose calculation, completely replacing additional depth measurements in IMPT PSQA program. For current users of the PB algorithm, further improving the long-tail modeling or using MC simulation to generate the dose correction factor is necessary. ADVANCES IN KNOWLEDGE: We justified a change in clinical practice to achieve efficient combined PSQA in IMPT by using the MC algorithm that was experimentally validated in almost all the clinical scenarios in our center. Deficiencies in beam modeling of the current PB algorithm were identified and solutions to improve its dose-calculation accuracy were provided.


Assuntos
Algoritmos , Método de Monte Carlo , Terapia com Prótons/normas , Garantia da Qualidade dos Cuidados de Saúde , Radioterapia de Intensidade Modulada/normas , Análise de Dados , Humanos , Terapia com Prótons/instrumentação , Terapia com Prótons/métodos , Controle de Qualidade , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/normas , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia de Intensidade Modulada/instrumentação , Radioterapia de Intensidade Modulada/métodos , Reprodutibilidade dos Testes , Síncrotrons
17.
Br J Radiol ; 93(1107): 20190879, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31804145

RESUMO

OBJECTIVE: Locally recurrent disease is of increasing concern in (non-)small cell lung cancer [(N)SCLC] patients. Local reirradiation with photons or particles may be of benefit to these patients. In this multicentre in silico trial performed within the Radiation Oncology Collaborative Comparison (ROCOCO) consortium, the doses to the target volumes and organs at risk (OARs) were compared when using several photon and proton techniques in patients with recurrent localised lung cancer scheduled to undergo reirradiation. METHODS: 24 consecutive patients with a second primary (N)SCLC or recurrent disease after curative-intent, standard fractionated radio(chemo)therapy were included in this study. The target volumes and OARs were centrally contoured and distributed to the participating ROCOCO sites. Remaining doses to the OARs were calculated on an individual patient's basis. Treatment planning was performed by the participating site using the clinical treatment planning system and associated beam characteristics. RESULTS: Treatment plans for all modalities (five photon and two proton plans per patient) were available for 22 patients (N = 154 plans). 3D-conformal photon therapy and double-scattered proton therapy delivered significantly lower doses to the target volumes. The highly conformal techniques, i.e., intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), CyberKnife, TomoTherapy and intensity-modulated proton therapy (IMPT), reached the highest doses in the target volumes. Of these, IMPT was able to statistically significantly decrease the radiation doses to the OARs. CONCLUSION: Highly conformal photon and proton beam techniques enable high-dose reirradiation of the target volume. They, however, significantly differ in the dose deposited in the OARs. The therapeutic options, i.e., reirradiation or systemic therapy, need to be carefully weighed and discussed with the patients. ADVANCES IN KNOWLEDGE: Highly conformal photon and proton beam techniques enable high-dose reirradiation of the target volume. In light of the abilities of the various highly conformal techniques to spare specific OARs, the therapeutic options need to be carefully weighed and patients included in the decision-making process.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Recidiva Local de Neoplasia/radioterapia , Órgãos em Risco/efeitos da radiação , Fótons/uso terapêutico , Terapia com Prótons/métodos , Reirradiação/métodos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Conjuntos de Dados como Assunto , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Órgãos em Risco/diagnóstico por imagem , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Resultado do Tratamento
18.
Br J Radiol ; 93(1107): 20190573, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31778315

RESUMO

OBJECTIVE: Classical robust optimization (cRO) in intensity-modulated proton therapy (IMPT) considers isocenter position and particle range uncertainties; anatomical robust optimization (aRO) aims to consider additional non-rigid positioning variations. This work compares the influence of different uncertainty sources on the robustness of cRO and aRO IMPT plans for head and neck squamous cell carcinoma (HNSCC). METHODS: Two IMPT plans were optimized for 20 HNSCC patients who received weekly control CTs (cCT): cRO, using solely the planning CT, and aRO, including 2 additional cCTs. The robustness of the plans in terms of clinical target volume (CTV) coverage and organ at risk (OAR) sparing was analyzed considering stepwise the influence of (1) non-rigid anatomical variations given by the weekly cCT, (2) with fraction-wise added rigid random setup errors and (3) additional systematic proton range uncertainties. RESULTS: cRO plans presented significantly higher nominal CTV coverage but are outperformed by aRO plans when considering non-rigid anatomical variations only, as cRO and aRO plans presented a median target coverage (D98%) decrease for the low-risk/high-risk CTV of 1.8/1.1 percentage points (pp) and -0.2 pp/-0.3 pp, respectively. Setup and range uncertainties had larger influence on cRO CTV coverage, but led to similar OAR dose changes in both plans. Considering all error sources, 10/2 cRO/aRO patients missed the CTV coverage and a limited number exceeded some OAR constraints in both plans. CONCLUSION: Non-rigid anatomical variations are mainly responsible for critical target coverage loss of cRO plans, whereas the aRO approach was robust against such variations. Both plans provide similar robustness of OAR parameters. ADVANCES IN KNOWLEDGE: The influence of different uncertainty sources was quantified for robust IMPT HNSCC plans.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Carcinoma de Células Escamosas de Cabeça e Pescoço/radioterapia , Incerteza , Humanos , Órgãos em Risco/efeitos da radiação , Posicionamento do Paciente , Lesões por Radiação/prevenção & controle , Erros de Configuração em Radioterapia , Radioterapia de Intensidade Modulada/normas , Estudos Retrospectivos
19.
Radiol Med ; 125(2): 157-164, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31591701

RESUMO

PURPOSE: MR-guided radiotherapy (MRgRT) relies on the daily assignment of a relative electron density (RED) map to allow the fraction specific dose calculation. One approach to assign the RED map consists of segmenting the daily magnetic resonance image into five different density levels and assigning a RED bulk value to each level to generate a synthetic CT (sCT). The aim of this study is to evaluate the dose calculation accuracy of this approach for applications in MRgRT. METHODS: A planning CT (pCT) was acquired for 26 patients with abdominal and pelvic lesions and segmented in five levels similar to an online approach: air, lung, fat, soft tissue and bone. For each patient, the median RED value was calculated for fat, soft tissue and bone. Two sCTs were generated assigning different bulk values to the segmented levels on pCT: The sCTICRU uses the RED values recommended by ICRU46, and the sCTtailor uses the median patient-specific RED values. The same treatment plan was calculated on two the sCTs and the pCT. The dose calculation accuracy was investigated in terms of gamma analysis and dose volume histogram parameters. RESULTS: Good agreement was found between dose calculated on sCTs and pCT (gamma passing rate 1%/1 mm equal to 91.2% ± 6.9% for sCTICRU and 93.7% ± 5.3% b or sCTtailor). The mean difference in estimating V95 (PTV) was equal to 0.2% using sCTtailor and 1.2% using sCTICRU, respect to pCT values CONCLUSIONS: The bulk sCT guarantees a high level of dose calculation accuracy also in presence of magnetic field, making this approach suitable to MRgRT. This accuracy can be improved by using patient-specific RED values.


Assuntos
Abdome/diagnóstico por imagem , Imagem por Ressonância Magnética , Pelve/diagnóstico por imagem , Radioterapia Guiada por Imagem , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
20.
Br J Radiol ; 93(1107): 20190594, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31647313

RESUMO

It is recognized that the use of a single plan calculated on an image acquired some time before the treatment is generally insufficient to accurately represent the daily dose to the target and to the organs at risk. This is particularly true for protons, due to the physical finite range. Although this characteristic enables the generation of steep dose gradients, which is essential for highly conformal radiotherapy, it also tightens the dependency of the delivered dose to the range accuracy. In particular, the use of an outdated patient anatomy is one of the most significant sources of range inaccuracy, thus affecting the quality of the planned dose distribution. A plan should be ideally adapted as soon as anatomical variations occur, ideally online. In this review, we describe in detail the different steps of the adaptive workflow and discuss the challenges and corresponding state-of-the art developments in particular for an online adaptive strategy.


Assuntos
Neoplasias/diagnóstico por imagem , Neoplasias/radioterapia , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Fluxo de Trabalho , Humanos , Órgãos em Risco , Fótons/uso terapêutico , Dosagem Radioterapêutica
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