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1.
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
2.
Int J Radiat Oncol Biol Phys ; 106(4): 743-753, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31953061

RESUMO

PURPOSE: The purpose of our study was to provide a guide for identification and contouring of upper abdominal organs-at-risk (OARs) in the setting of online magnetic resonance imaging (MRI)-guided radiation treatment planning and delivery. METHODS AND MATERIALS: After a needs assessment survey, it was determined that an upper abdominal MRI-based atlas of normal OARs would be of benefit to radiation oncologists and radiation therapists. An anonymized diagnostic 1.5T MRI from a patient with typical upper abdominal anatomy was used for atlas development. Two MRI sequences were selected for contouring, a T1-weighted gadoxetic acid contrast-enhanced MRI acquired in the hepatobiliary phase and axial fast imaging with balanced steady-state precession. Two additional clinical MRI sequences from commercial online MRI-guided radiation therapy systems were selected for contouring and were included in the final atlas. Contours from each data set were completed and reviewed by radiation oncologists, along with a radiologist who specializes in upper abdominal imaging, to generate a consensus upper abdominal MRI-based OAR atlas. RESULTS: A normal OAR atlas was developed, including recommendations for contouring. The atlas and contouring guidance are described, and high-resolution MRI images and contours are displayed. OARs, such as the bile duct and biliary tree, which may be better seen on MRI than on computed tomography, are highlighted. The full DICOM/DICOM-RT MRI images from both the diagnostic and clinical online MRI-guided radiation therapy systems data sets have been made freely available, for educational purposes, at econtour.org. CONCLUSIONS: This MRI contouring atlas for upper abdominal OARs should provide a useful reference for contouring and education. Its routine use may help to improve uniformity in contouring in radiation oncology planning and OAR dose calculation. Full DICOM/DICOM-RT images are available online and provide a valuable educational resource for upper abdominal MRI-based radiation therapy planning and delivery.


Assuntos
Abdome/diagnóstico por imagem , Abdome/efeitos da radiação , Imagem por Ressonância Magnética , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Radioterapia (Especialidade)/normas , Humanos , Planejamento da Radioterapia Assistida por Computador , Padrões de Referência
3.
Br J Radiol ; 93(1107): 20190845, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31904261

RESUMO

OBJECTIVES: The purpose of this study is to investigate the dosimetric effect and clinical impact of delivering a focal radiotherapy boost dose to multiparametric MRI (mp-MRI)-defined dominant intraprostatic lesions (DILs) in prostate cancer using proton therapy. METHODS: We retrospectively investigated 36 patients with pre-treatment mp-MRI and CT images who were treated using pencil beam scanning (PBS) proton radiation therapy to the whole prostate. DILs were contoured on co-registered mp-MRIs. Simultaneous integrated boost (SIB) plans using intensity-modulated proton therapy (IMPT) were created based on conventional whole-prostate-irradiation for each patient and optimized with additional DIL coverage goals and urethral constraints. DIL dose coverage and organ-at-risk (OAR) sparing were compared between conventional and SIB plans. Tumor control probability (TCP) and normal tissue complication probability (NTCP) were estimated to evaluate the clinical impact of the SIB plans. RESULTS: Optimized SIB plans significantly escalated the dose to DILs while meeting OAR constraints. SIB plans were able to achieve 125, 150 and 175% of prescription dose coverage in 74, 54 and 17% of 36 patients, respectively. This was modeled to result in an increase in DIL TCP by 7.3-13.3% depending on α/ß and DIL risk level. CONCLUSION: The proposed mp-MRI-guided DIL boost using proton radiation therapy is feasible without violating OAR constraints and demonstrates a potential clinical benefit by improving DIL TCP. This retrospective study suggested the use of IMPT-based DIL SIB may represent a strategy to improve tumor control. ADVANCES IN KNOWLEDGE: This study investigated the planning of mp-MRI-guided DIL boost in prostate proton radiation therapy and estimated its clinical impact with respect to TCP and NTCP.


Assuntos
Imageamento por Ressonância Magnética Multiparamétrica , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Terapia com Prótons/métodos , Reirradiação/métodos , Idoso , Idoso de 80 Anos ou mais , Fracionamento da Dose de Radiação , Humanos , Masculino , Pessoa de Meia-Idade , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Próstata/diagnóstico por imagem , Próstata/efeitos da radiação , Neoplasias da Próstata/patologia , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Uretra/diagnóstico por imagem
4.
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
5.
Br J Radiol ; 93(1107): 20190304, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31356107

RESUMO

Treatment planning is the process where the prescription of the radiation oncologist is translated into a deliverable treatment. With the complexity of contemporary radiotherapy, treatment planning cannot be performed without a computerized treatment planning system. Proton therapy (PT) enables highly conformal treatment plans with a minimum of dose to tissues outside the target volume, but to obtain the most optimal plan for the treatment, there are a multitude of parameters that need to be addressed. In this review areas of ongoing improvements and research in the field of PT treatment planning are identified and discussed. The main focus is on issues of immediate clinical and practical relevance to the PT community highlighting the needs for the near future but also in a longer perspective. We anticipate that the manual tasks performed by treatment planners in the future will involve a high degree of computational thinking, as many issues can be solved much better by e.g. scripting. More accurate and faster dose calculation algorithms are needed, automation for contouring and planning is required and practical tools to handle the variable biological efficiency in PT is urgently demanded just to mention a few of the expected improvements over the coming 10 years.


Assuntos
Algoritmos , Previsões , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Automação , Confiabilidade dos Dados , Humanos , Método de Monte Carlo , Determinação de Necessidades de Cuidados de Saúde , Órgãos em Risco/diagnóstico por imagem , Terapia com Prótons/tendências , Planejamento da Radioterapia Assistida por Computador/tendências , Radioterapia Conformacional/tendências , Eficiência Biológica Relativa , Fatores de Tempo
6.
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
7.
Int J Radiat Oncol Biol Phys ; 106(3): 630-638, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31759076

RESUMO

PURPOSE: Intensity modulated proton therapy (IMPT) of locally advanced prostate cancer can spare the bowel considerably compared with modern photon therapy, but simultaneous treatment of the prostate (p), seminal vesicles (sv), and lymph nodes is challenging owing to day-to-day organ motion and range uncertainties. Our purpose was, therefore, to generate a plan library for use in adaptive IMPT to mitigate these uncertainties. METHODS AND MATERIALS: We retrospectively included 27 patients with a series of computed tomography scans throughout their treatment representing day-to-day variation. In 18 of the patients, target motion was analyzed using rigid shifts of prostate gold markers relative to bony anatomy. A plan library with different p and sv planning target volume (p/sv-PTV) positions was defined from the distribution and direction of these shifts. Delivery of IMPT using plan selection from the library was simulated for image guidance on bony anatomy, in the remaining patients and compared with nonadaptive IMPT. RESULTS: The plan library consisted of 3 small margin p/sv-PTVs: (1) p/sv-PTV shifted 1.5 systematic error (Σ) of the population mean in the anterior and cranial directions, (2) p/sv-PTV shifted 1.5Σ in the posterior and caudal directions, and (3) p/sv-PTV in the planning position. The conventional p/sv-PTV was also available for backup. Plan selection compared with nonadaptive IMPT resulted in a reduction of the rectum volume receiving 60 Gy relative biological effect (RBE) (V60GyRBE) from on average 12 mL to 9 mL. For the bladder the average V45GyRBE was reduced from 36% to 30%. Large and small bowel doses were also reduced, whereas target coverage was comparable or improved compared with nonadaptive IMPT. CONCLUSIONS: Plan selection based on a population model of rigid target motion was feasible for all patients. Compared with conventional IMPT, plan selection resulted in significant dosimetric sparing of rectum and bladder without compromising target coverage.


Assuntos
Movimentos dos Órgãos , Neoplasias da Próstata/radioterapia , Terapia com Prótons/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Pontos de Referência Anatômicos/diagnóstico por imagem , Marcadores Fiduciais , Ouro , Humanos , Bibliotecas Digitais , Linfonodos/diagnóstico por imagem , Irradiação Linfática/métodos , Masculino , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/diagnóstico por imagem , Próstata/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Reto/diagnóstico por imagem , Estudos Retrospectivos , Glândulas Seminais/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Incerteza , Bexiga Urinária/diagnóstico por imagem
8.
Br J Radiol ; 93(1107): 20190572, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31651185

RESUMO

OBJECTIVE: Approximately 70 patients with large and bulky tumors refractory to prior treatments were treated with photon spatially fractionated GRID radiation (SFGRT). We identified 10 additional patients who clinically needed GRID but could not be treated with photons due to adjacent critical organs. We developed a proton SFGRT technique, and we report treatment of these 10 patients. METHODS: Subject data were reviewed for clinical results and dosimetric data. 50% of the patients were metastatic at the time of treatment and five had previous photon radiation to the local site but not via GRID. They were treated with 15-20 cobalt Gray equivalent using a single proton GRID field with an average beamlet count of 22.6 (range 7-51). 80% received an average adjuvant radiation dose to the GRID region of 40.8Gy (range 13.7-63.8Gy). Four received subsequent systemic therapy. RESULTS: The median follow-up time was 5.9 months (1.1-18.9). At last follow-up, seven patients were alive and three had died. Two patients who had died from metastatic disease had local shrinkage of tumor. Of those alive, four had complete or partial response, two had partial response but later progressed, and one had no response. For all patients, the tumor regression/local symptom improvement rate was 80%. 50% had acute side-effects of grade1/2 only and all were well-tolerated. CONCLUSION: In circumstances where patients cannot receive photon GRID, proton SFGRT is clinically feasible and effective, with a similar side-effect profile. ADVANCES IN KNOWLEDGE: Proton GRID should be considered as a treatment option earlier in the disease course for patients who cannot be treated by photon GRID.


Assuntos
Neoplasias/radioterapia , Terapia com Prótons/métodos , Fracionamento da Dose de Radiação , Estudos de Viabilidade , Seguimentos , Humanos , Neoplasias/mortalidade , Neoplasias/patologia , Órgãos em Risco/diagnóstico por imagem , Fótons/uso terapêutico , Resultado do Tratamento
10.
Cancer Radiother ; 23(6-7): 765-772, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31451358

RESUMO

Image-guided brachytherapy is crucial in the management of locally advanced cervical cancers and has benefited from advances in imaging over recent decades. The recommendations of the European Brachytherapy - European Society for Radiation Oncology (GEC-ESTRO) have resulted in harmonized practices and improved clinical outcomes in terms of efficacy and toxicity. Post-implant magnetic resonance imaging (MRI) has become the reference imaging modality to guide brachytherapy. There is an increasing interest for other multimodal imaging in these patients. The metabolic information provided by Positrons Emission Tomography/computed tomodensitometry (PET/CT) is also very promising approach to guide personalized dose escalation strategies. The prognostic values of MRI and PET scanner before brachytherapy make it possible to consider personalizing the dose delivered in brachytherapy and to propose a dose escalation to patients who really need it and to possibly consider a deescalation strategy in patients with a very good prognosis. However, further studies are needed to confirm this approach.


Assuntos
Braquiterapia/métodos , Imagem por Ressonância Magnética Intervencionista/métodos , Imagem Multimodal/métodos , Órgãos em Risco/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Radioterapia Guiada por Imagem/métodos , Neoplasias do Colo do Útero/diagnóstico por imagem , Neoplasias do Colo do Útero/radioterapia , Feminino , Humanos , Neoplasias do Colo do Útero/patologia
11.
Radiol Med ; 124(12): 1324-1332, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31317381

RESUMO

BACKGROUND: The prognosis of locally advanced non-small cell lung cancer (NSCLC) treated with conventional radiotherapy remains poor. Hypofractionation reduces overall treatment time increasing biological effect in patients not suitable for concurrent chemo-radiotherapy. METHOD: From January 2009 to October 2016, 76 inoperable locally advanced primary or recurrent NSCLC patients were treated with 60 Gy in 20 fractions of 3 Gy/each for 4 weeks as exclusive or post-chemotherapy treatment. Fifty-eight patients (76.3%) had stage III and 18 (23.7%) stage IV (≤ 2 metastases) disease: 63 primary (82.9%) and 13 recurrent (17.1%). RESULTS: Median and 2-year overall survival were 17 months and 38.9%, respectively. Median and 2-year loco-regional progression free survival were 27 months and 55.3%, respectively. Univariate and multivariate analyses demonstrated that patients with complete response presented better outcomes, whereas no statistically relevant difference was evidenced in terms of previous chemotherapy, recurrent vs primary disease, volume and stage. Thirty patients (39.5%) presented acute esophagitis (1-grade 3) and 19 (25.0%) acute pneumonitis (2-grade 3). Six patients (7.9%) developed grade 2-3 late pneumonitis and 3 patients (3.9%) grade 1 late esophagitis. CONCLUSION: In patients not suitable of concurrent radio-chemotherapy, exclusive or sequential hypofractionated schedule using 60 Gy in 20 fractions was well tolerated and presented promising results. Complete local response was a predictor of better outcomes, and any efforts will be made to perform prospective clinical trials to further evaluate hypofractionated regimens with increased lesional BED.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Recidiva Local de Neoplasia/radioterapia , Doença Aguda , Idoso , Análise de Variância , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Esofagite/patologia , Feminino , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Órgãos em Risco/diagnóstico por imagem , Intervalo Livre de Progressão , Hipofracionamento da Dose de Radiação , Lesões por Radiação/patologia , Pneumonite por Radiação/patologia , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
12.
Int J Radiat Oncol Biol Phys ; 105(2): 329-337, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31299242

RESUMO

PURPOSE: The ongoing phase 2/3 PRODIGE 26/CONCORDE trial compares chemoradiation therapy with and without dose escalation in patients with locally advanced or unresectable esophageal cancer. The results of a benchmark case procedure are reported here to evaluate the protocol compliance of participating centers as part of quality assurance for radiation therapy. METHODS AND MATERIALS: Volume delineation, target coverage, and dose constraints to the organs at risk (OARs) were assessed on treatment plans of a common benchmark case performed by each participating center. The centers were classified in 3 categories: per protocol, minor acceptable deviation (MiD), or major unacceptable deviation (MaD). A plan was rejected if ≥4 MiDs or 1 MaD were found. RESULTS: Thirty-5 centers submitted 43 plans. Among them, 14 (32.6%) were per protocol, 19 (44.2%) presented at least 1 MiD, 2 (4.6%) presented at least 1 MaD, and 8 (18.6%) presented both MiD and MaD. Overall, 11 (25.6%) plans were rejected. Only 1 plan was rejected because gross tumor volume was not correctly delineated. The OAR delineation was respected in all cases. Dose constraints to the OARs were respected in the majority of cases except for the heart, where one-third of the plans presented a deviation. As for the target volume, 3 plans (5.8%) had a major underdosage and 1 plan (1.9%) had a major overdosage. Overall, 58% of all treatments were planned with intensity modulated radiation therapy, whereas 42% were planned with 3-dimensional chemoradiation therapy. Significantly more plans in the intensity modulated radiation therapy group were accepted compared with the 3-dimensional chemoradiation therapy group (P = .03). CONCLUSION: The high frequency of protocol deviations underlines the importance of a quality assurance program in clinical trials. Further work should assess the impact of quality assurance for radiation therapy on patient outcomes.


Assuntos
Carcinoma de Células Escamosas/diagnóstico por imagem , Quimiorradioterapia/normas , Neoplasias Esofágicas/diagnóstico por imagem , Órgãos em Risco/diagnóstico por imagem , Garantia da Qualidade dos Cuidados de Saúde , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/normas , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Benchmarking , Institutos de Câncer/classificação , Institutos de Câncer/normas , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Quimiorradioterapia/métodos , Cisplatino/administração & dosagem , Esquema de Medicação , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/terapia , Fluoruracila/administração & dosagem , França , Fidelidade a Diretrizes/classificação , Fidelidade a Diretrizes/normas , Fidelidade a Diretrizes/estatística & dados numéricos , Coração/efeitos da radiação , Humanos , Rim/diagnóstico por imagem , Leucovorina/administração & dosagem , Fígado/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Linfonodos/diagnóstico por imagem , Linfonodos/patologia , Irradiação Linfática/métodos , Irradiação Linfática/normas , Masculino , Compostos Organoplatínicos/administração & dosagem , Órgãos em Risco/efeitos da radiação , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/classificação , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia Conformacional/normas , Medula Espinal/diagnóstico por imagem , Carga Tumoral
13.
Cancer Radiother ; 23(8): 922-925, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31257097

RESUMO

The purpose of this work was reducing treatment-related toxicity for Hodgkin lymphomas using practical procedure inspired by the ILROG guidelines. Reporting the first case of localized Hodgkin lymphoma treated with protontherapy in France. A 24-year-old female with mediastinal, bulky, localized, mixed-cellularity, classic Hodgkin lymphoma required an involved-site radiation therapy after complete response following polychemotherapy. Three-dimensional conformal radiation therapy was not acceptable due to high doses to breasts, heart and lungs. We realized a four-dimensional computed tomography (CT) to evaluate target movements and another CT with gating and breath-hold technique. Delineation was performed on both CT using the initial fluorodeoxyglucose positron-emission tomography/CT. One dosimetric plan with rotational intensity-modulated radiation therapy with a helical Tomotherapy© was realized and compared to another one with conformational protontherapy. Ninety-five percent of the planning target volume was covered by 98 and 99% of the prescribed dose with protontherapy and helical Tomotherapy©. Protontherapy provided the best organ at risk protection. Lung and heart protections were better with protontherapy: lung mean dose (3.7Gy vs. 8.4Gy) and median dose (0.002Gy vs. 6.9Gy), heart mean dose (2.6Gy vs. 3.7Gy). Breast sparing was better for both breasts using protontherapy: right breast mean dose (2.4Gy vs. 4.4Gy) and left (1.9Gy vs. 4.6Gy). The biggest difference was seen with low doses, which were better with protontherapy: volume of lung receiving 5Gy was 17.5% vs. 54.2% with Helical Tomotherapy©. In view of these results, we decided to treat our patient with protontherapy using respiratory assessment. We delivered 30Gy (15 fractions) using protontherapy with one direct anterior field using pencil beam scanning and deep inspiration breath-hold technique. We observed only grade 1 skin erythema during treatment and no toxicity during early follow-up.


Assuntos
Doença de Hodgkin/radioterapia , Neoplasias do Mediastino/radioterapia , Fótons/uso terapêutico , Terapia com Prótons/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Bleomicina/administração & dosagem , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Etoposídeo/administração & dosagem , Feminino , Coração/diagnóstico por imagem , Doença de Hodgkin/diagnóstico por imagem , Doença de Hodgkin/tratamento farmacológico , Humanos , Pulmão/diagnóstico por imagem , Neoplasias do Mediastino/diagnóstico por imagem , Neoplasias do Mediastino/tratamento farmacológico , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/diagnóstico por imagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Guias de Prática Clínica como Assunto , Prednisona/administração & dosagem , Procarbazina/administração & dosagem , Lesões por Radiação/prevenção & controle , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada , Vincristina/administração & dosagem , Adulto Jovem
14.
Int J Radiat Oncol Biol Phys ; 105(3): 514-524, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31306734

RESUMO

PURPOSE: To benchmark and improve, through means of a targeted intervention, the quality of intensity modulated radiation therapy treatment planning for locally advanced head and neck cancer (HNC) in the Netherlands. The short and long-term impact of this intervention was assessed. METHODS AND MATERIALS: A delineated computed tomography-scan of an oropharynx HNC case was sent to all 15 Dutch radiation therapy centers treating HNC. Aims for planning target volume and organ-at-risk (OAR) dosimetry were established by consensus. Each center generated a treatment plan. In a targeted intervention, OAR sparing of all plans was discussed, and centers with the best OAR sparing shared their planning strategies. Impact of the intervention was assessed by (1) short-term (half a year after intervention) replanning of the original case and (2) long-term (1 and 3 years after intervention) planning of new cases. RESULTS: Benchmarking revealed substantial difference in OAR doses. Initial mean doses were 22 Gy (range, 15-31 Gy), 35 Gy (18-49 Gy), and 37 Gy (20-46 Gy) for the contralateral parotid gland, contralateral submandibular gland, and combined swallowing structures, respectively. Replanning after targeted intervention significantly reduced mean doses and variation, but clinically relevant differences still remained: 18 Gy (14-22 Gy), 28 Gy (17-45 Gy), and 29 Gy (18-39 Gy), respectively. One and 3 years later the variation remained stable. CONCLUSIONS: Despite many years of HNC intensity modulated radiation therapy experience, initial treatment plans showed surprisingly large variations. The simple targeted intervention used in this analysis improved OAR sparing, and its impact was durable; however, fairly large dose differences still continue to exist. Additional work is needed to understand these variations and to minimize them. A national radiation oncology platform can be instrumental for developing and maintaining high-quality planning protocols.


Assuntos
Benchmarking/métodos , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/radioterapia , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/normas , Benchmarking/normas , Pesquisas sobre Serviços de Saúde , Humanos , Países Baixos , Tratamentos com Preservação do Órgão/normas , Órgãos em Risco/diagnóstico por imagem , Glândula Parótida/diagnóstico por imagem , Glândula Parótida/efeitos da radiação , Músculos Faríngeos/diagnóstico por imagem , Músculos Faríngeos/efeitos da radiação , Melhoria de Qualidade , Doses de Radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Glândula Submandibular/diagnóstico por imagem , Glândula Submandibular/efeitos da radiação , Fatores de Tempo , Língua/diagnóstico por imagem , Língua/efeitos da radiação , Neoplasias Tonsilares/diagnóstico por imagem , Neoplasias Tonsilares/radioterapia
15.
Br J Radiol ; 92(1102): 20190317, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31295011

RESUMO

OBJECTIVE: In this study, we used the concept of organ-equivalent dose (OED) to evaluate the excess absolute risk (EAR) for secondary cancer in various organs after radiation treatment for breast cancer. METHODS: Using CT data set of 12 patients, we generated three different whole-breast radiation treatment plans using 50 Gy in 2 Gy fractions: three-dimensional conformal radiotherapy with a field-in-field (FinF) technique, intensity modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT). The OEDs were calculated from differential dose-volume histograms on the basis of the "linear-exponential," "plateau," and "full mechanistic" dose-response models. Secondary cancer risks of the contralateral breast (CB), contralateral lung (CL), and ipsilateral lung (IL) were estimated and compared. RESULTS: The lowest EARs for the CB, CL, and IL were achieved with FinF, which reduced the EARs by 77%, 88%, and 56% relative to those with IMRT, and by 77%, 84%, and 58% relative to those with VMAT, respectively. The secondary cancer risk for FinF was significantly lower than those of IMRT and VMAT. OED-based secondary cancer risks for CB and IL were similar when IMRT and VMAT were used, but the risk for CL was statistically lower when VMAT was used. CONCLUSION: The overall estimation of EAR indicated that the radiation-induced cancer risk of breast radiation therapy was lower with FinF than with IMRT and VMAT. Therefore, when secondary cancer risk is a major concern, FinF is considered to be the preferred treatment option in irradiation of whole-breast. ADVANCES IN KNOWLEDGE: Secondary malignancy estimation after breast radiotherapy is becoming an important subject for comparative treatment planning.When secondary cancer risk a major concern, FinF technique is considered the preferred treatment option in whole breast patients.


Assuntos
Neoplasias da Mama/radioterapia , Neoplasias Induzidas por Radiação/etiologia , Segunda Neoplasia Primária/etiologia , Radioterapia Conformacional/efeitos adversos , Radioterapia de Intensidade Modulada/efeitos adversos , Mama/diagnóstico por imagem , Mama/efeitos da radiação , Fracionamento da Dose de Radiação , Relação Dose-Resposta à Radiação , Feminino , Coração/diagnóstico por imagem , Coração/efeitos da radiação , Humanos , Pulmão/diagnóstico por imagem , Pulmão/efeitos da radiação , Neoplasias Pulmonares/etiologia , Números Necessários para Tratar , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Medição de Risco/métodos , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/etiologia
16.
Int J Radiat Oncol Biol Phys ; 105(4): 875-883, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31330175

RESUMO

PURPOSE: To investigate differences between prescribed and postimplant calculated dose in 192Ir high-dose-rate endorectal brachytherapy (HDR-EBT) by evaluating dose to clinical target volume (CTV) and organs at risk (OARs) calculated with a Monte Carlo-based dose calculation software, RapidBrachyMC. In addition, dose coverage, conformity, and homogeneity were compared among the radionuclides 192Ir, 75Se, and 169Yb for use in HDR-EBT. METHODS AND MATERIALS: Postimplant dosimetry was evaluated using 23 computed tomography (CT) images from patients treated with HDR-EBT using the 192Ir microSelectron v2 (Elekta AB, Stockholm, Sweden) source and the Intracavitary Mold Applicator Set (Elekta AB, Stockholm, Sweden), which is a flexible applicator capable of fitting a tungsten rod for OAR shielding. Four tissue segmentation schemes were evaluated: (1) TG-43 formalism, (2) materials and nominal densities assigned to contours of foreign objects, (3) materials and nominal densities assigned to contoured organs in addition to foreign objects, and (4) materials specified as in (3) but with voxel mass densities derived from CT Hounsfield units. Clinical plans optimized for 192Ir were used, with the results for 75Se and 169Yb normalized to the D90 of the 192Ir clinical plan. RESULTS: In comparison to segmentation scheme 4, TG-43-based dosimetry overestimates CTV D90 by 6% (P = .00003), rectum D50 by 24% (P = .00003), and pelvic bone D50 by 5% (P = .00003) for 192Ir. For 169Yb, CTV D90 is overestimated by 17% (P = .00003) and rectum D50 by 39% (P = .00003), and pelvic bone D50 is significantly underestimated by 27% (P = .007). Postimplant dosimetry calculations also showed that a 169Yb source would give 20% (P = .00003) lower rectum V60 and 17% (P = .00008) lower rectum D50. CONCLUSIONS: Ignoring high-Z materials in dose calculation contributes to inaccuracies that may lead to suboptimal dose optimization and disagreement between prescribed and calculated dose. This is especially important for low-energy radionuclides. Our results also show that with future magnetic resonance imaging-based treatment planning, loss of CT density data will only affect calculated dose in nonbone OARs by 2% or less and bone OARs by 13% or less across all sources if material composition and nominal mass densities are correctly assigned.


Assuntos
Braquiterapia/métodos , Radioisótopos de Irídio/administração & dosagem , Órgãos em Risco/efeitos da radiação , Radioisótopos/administração & dosagem , Neoplasias Retais/radioterapia , Radioisótopos de Selênio/administração & dosagem , Itérbio/administração & dosagem , Braquiterapia/instrumentação , Fêmur/efeitos da radiação , Humanos , Método de Monte Carlo , Órgãos em Risco/diagnóstico por imagem , Ossos Pélvicos/efeitos da radiação , Dosagem Radioterapêutica , Reto/efeitos da radiação , Tomografia Computadorizada por Raios X , Bexiga Urinária/efeitos da radiação
17.
Cancer Radiother ; 23(5): 408-415, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31331841

RESUMO

PURPOSE: Radiotherapy is a treatment method performed using ionizing radiation on cancer patients either alone or with surgery and/or chemotherapy. Although modern radiotherapy techniques provide a significant advantage in protecting healthy tissues, it is inevitable that normal tissues are also located in the areas targeted by radiations. In this study, we aimed to examine the bone mineral density changes in bone structures commonly included in the irradiated area such as, L5 vertebra, sacrum, and femur heads, in patients who have received pelvic radiotherapy; and the relationship between these changes with radiation dose. MATERIAL AND METHODS: Patients included in the study had been previously diagnosed with rectal cancer, which were operated or not. Preoperative or postoperative pelvic radiotherapy was planned for all patients. In terms of convenience when comparing with future scans, all densitometry and CT scans were performed with the same devices. Fifteen patients were included in the study. In order to determine the dose of radiation each identified area had taken after radiotherapy, the sacrum, L5 vertebra, bilateral femoral heads, and L1 regions were contoured in the CT scans in which treatment planning was done. Sagittal cross-sectional images were taken advantage of while these regions were being contoured. RESULTS: Bone mineral density was evaluated with CT and dual-energy X-ray absorptiometry before and after the treatment. The regions that have theoretically been exposed to irradiation, such as L5, sacrum, left to right femur were found to have significant difference in terms of bone density. According to CT evaluation, there was a significant decrease in bone intensity of L5, sacrum, left and right femurs. Dual-energy X-ray absorptiometry assessment revealed that the whole of the left femoral head, left femur neck and Ward's region were significantly affected by radiotherapy. However, there was no significant difference in the sacrum and L5 vertebra before and after radiotherapy. CONCLUSION: More accurate results could be achieved if the same study was conducted on a larger patient population, with a longer follow-up period. When the reduction in bone density is at maximum or a cure is likely in a long-term period, bone mineral density could be determined by measurements performed at regular intervals.


Assuntos
Densidade Óssea , Cabeça do Fêmur/efeitos da radiação , Vértebras Lombares/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Radioterapia Conformacional/efeitos adversos , Neoplasias Retais/radioterapia , Sacro/efeitos da radiação , Absorciometria de Fóton , Adulto , Idoso , Doenças Ósseas Metabólicas/diagnóstico por imagem , Doenças Ósseas Metabólicas/etiologia , Terapia Combinada , Estudos Transversais , Feminino , Cabeça do Fêmur/diagnóstico por imagem , Cabeça do Fêmur/patologia , Seguimentos , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/patologia , Masculino , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/patologia , Neoplasias Retais/cirurgia , Sacro/diagnóstico por imagem , Sacro/patologia , Tomografia Computadorizada por Raios X
18.
Radiat Oncol ; 14(1): 92, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31167658

RESUMO

Magnetic Resonance-guided radiotherapy (MRgRT) marks the beginning of a new era. MR is a versatile and suitable imaging modality for radiotherapy, as it enables direct visualization of the tumor and the surrounding organs at risk. Moreover, MRgRT provides real-time imaging to characterize and eventually track anatomical motion. Nevertheless, the successful translation of new technologies into clinical practice remains challenging. To date, the initial availability of next-generation hybrid MR-linac (MRL) systems is still limited and therefore, the focus of the present preview was on the initial applicability in current clinical practice and on future perspectives of this new technology for different treatment sites.MRgRT can be considered a groundbreaking new technology that is capable of creating new perspectives towards an individualized, patient-oriented planning and treatment approach, especially due to the ability to use daily online adaptation strategies. Furthermore, MRL systems overcome the limitations of conventional image-guided radiotherapy, especially in soft tissue, where target and organs at risk need accurate definition. Nevertheless, some concerns remain regarding the additional time needed to re-optimize dose distributions online, the reliability of the gating and tracking procedures and the interpretation of functional MR imaging markers and their potential changes during the course of treatment. Due to its continuous technological improvement and rapid clinical large-scale application in several anatomical settings, further studies may confirm the potential disruptive role of MRgRT in the evolving oncological environment.


Assuntos
Imagem por Ressonância Magnética , Neoplasias/radioterapia , Radioterapia Guiada por Imagem , Humanos , Neoplasias/diagnóstico por imagem , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Medicina de Precisão , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia Guiada por Imagem/tendências , Radioterapia de Intensidade Modulada , Reprodutibilidade dos Testes
19.
Cardiovasc Intervent Radiol ; 42(8): 1135-1141, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31073823

RESUMO

PURPOSE: Estimate the incidence of nontarget embolization (NTE) as identified on immediate post-hepatic artery embolization CT. MATERIALS AND METHODS: Two hundred hepatic embolizations performed with particles alone (bland embolization) in 147 patients between August 16, 2013 and August 26, 2014 with immediate post-procedure CT were retrospectively reviewed. Arterial anatomy, vessels treated, imaging findings of NTE, patient demographics, length of hospital stay following embolization, and procedure-related complications were recorded. The data were analyzed using two-sided t-tests and chi-squared tests. RESULTS: Evidence of NTE was seen on post-procedure CT in 64 of 200 cases (64/200, 32%). Six organs were affected, with 69 discrete sites in 64 patients. The majority (49/69, 71.0%) involved the gallbladder. The mean length of hospital stay (LOS) for patients with and without NTE was 2.9 ± 1.5 nights (range 1-7) and 2.9 ± 2.3 nights (range 0-21), respectively (P = 0.81). NTE was more common following embolization of replaced or accessory hepatic vessels. There were three complications in the NTE group (3/64, 4.7%) following the embolization procedure, one of which was cholecystitis directly related to NTE. The other two were one incidence each of contrast-induced nephropathy and pneumonia. In the group without NTE, seven complications occurred (7/136, 5.1%, P = 0.889), including one death resulting from hepatic failure, two gastrointestinal bleeds, two hepatic abscesses, flash pulmonary edema, and pancreatitis. CONCLUSION: Unanticipated NTE is not uncommon after bland hepatic artery embolization, particularly after treating accessory or replaced vessels, but does not increase complications or LOS. LEVEL OF EVIDENCE: Level 2b, Retrospective Cohort.


Assuntos
Embolização Terapêutica/métodos , Artéria Hepática/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/terapia , Órgãos em Risco/diagnóstico por imagem , Feminino , Artéria Hepática/patologia , Humanos , Incidência , Tempo de Internação/estatística & dados numéricos , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Radiografia Intervencionista/métodos , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
20.
Acta Oncol ; 58(8): 1178-1186, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31066326

RESUMO

Purpose: To evaluate the rate and dose response of brachial plexus toxicity post stereotactic body radiation therapy (SBRT) of apically situated lung lesions. Material/methods: We retrospectively identified all patients with apically located tumors, defined by the epicenter of the tumor being located superiorly to the aortic arch, and treated with SBRT between 2008 and 2013. Patients with a shorter follow-up than 6 months were excluded. Primary aim was to evaluate radiation-induced brachial plexopathy (RIBP). Dose to the plexus was assessed by a retrospective delineation of the brachial plexus on the CT used for treatment planning. Then, Dmax, D0.1cc, D1cc and D3.0cc of the brachial plexus were collected from the dose-volume histograms (DVH) and recalculated to the biologically effective dose (BED) using α/ß = 3 Gy. A normal tissue complication probability (NTCP) model, based on four different dose-volume parameters (BED3,max, BED3,0.1cc, BED3,1.0cc, BED3,3.0cc) was fitted to the data. Results: Fifty-two patients with 56 apically located tumors were identified. Median prescription dose per fraction was 15 Gy (range 6-17) and median number of fractions was 3 (3-10). With a median follow-up of 30 months (6.1-72) seven patients experienced maximum grade 2 (scored 3 times) or 3 (scored 4 times) RIBP after a median of 8.7 months (range 4.0-31). Three patients had combined symptoms with pain, sensory and motor affection and four patients had isolated pain. Median BED3,max for the patients experiencing RIBP was 381 Gy (range 30-524) versus BED3,max of 34 Gy (range 0.10-483) for the patients without RIBP. The NTCP models showed a very high predictive ability (area under the receiver operating characteristic curve (AUC) 0.80-0.88). Conclusion: SBRT of apically located lung lesions may cause severe neurological symptoms; for a three-fraction treatment, we suggest that the maximum dose to the plexus should be kept ≤30 Gy (130 Gy BED3).


Assuntos
Neuropatias do Plexo Braquial/epidemiologia , Neoplasias Pulmonares/radioterapia , Lesões por Radiação/epidemiologia , Radiocirurgia/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Plexo Braquial/diagnóstico por imagem , Plexo Braquial/efeitos da radiação , Neuropatias do Plexo Braquial/diagnóstico , Neuropatias do Plexo Braquial/etiologia , Fracionamento da Dose de Radiação , Relação Dose-Resposta à Radiação , Feminino , Seguimentos , Humanos , Pulmão/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Lesões por Radiação/diagnóstico , Lesões por Radiação/etiologia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Estudos Retrospectivos , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X
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