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1.
Anticancer Res ; 39(11): 6355-6358, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31704867

RESUMO

BACKGROUND/AIM: Pneumonitis is a serious complication after radiotherapy of breast cancer. This study aimed to identify its prevalence and potential risk factors. PATIENTS AND METHODS: A total of 606 patients irradiated following breast-conserving surgery or mastectomy were retrospectively analyzed. In patients developing pneumonitis, radiation and clinical parameters were investigated to identify potential risk factors. RESULTS: Eleven patients (1.8%) developed a pneumonitis grade ≥2. Mean doses to the ipsilateral lung were >7 Gy in 5 patients (45%). Of the other patients, 5 had a chronic inflammatory disease. Six patients (55%) had another malignancy (4 previous contralateral breast cancers, 1 previous ovarian and thyroid cancer, 1 synchronous carcinoma-in-situ (pTis) at the contralateral breast). Five patients (45%) received chemotherapy including taxanes and 4 patients (36%) received trastuzumab. CONCLUSION: The prevalence of pneumonitis was 1.8%. Potential risk factors included mean radiation dose to ipsilateral lung >7 Gy, systemic treatment with taxanes or trastuzumab, chronic inflammatory disease and history of another malignancy.


Assuntos
Neoplasias da Mama/radioterapia , Pneumonite por Radiação/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anti-Inflamatórios/uso terapêutico , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/cirurgia , Carcinoma in Situ/radioterapia , Feminino , Humanos , Pulmão/efeitos da radiação , Mastectomia , Mastectomia Segmentar , Pessoa de Meia-Idade , Neoplasias Primárias Múltiplas , Prednisolona/uso terapêutico , Prevalência , Pneumonite por Radiação/tratamento farmacológico , Pneumonite por Radiação/etiologia , Estudos Retrospectivos , Fatores de Risco , Trastuzumab/administração & dosagem , Trastuzumab/efeitos adversos
2.
Medicine (Baltimore) ; 98(39): e17340, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574873

RESUMO

Radiotherapy after breast-conserving surgery or mastectomy has clinical benefits including reducing local recurrence and improving overall survival. Deep inspiration breath-hold (DIBH) technique using the Abches system is an easy and practical method to reduce radiation dose to the heart and lungs. This retrospective study was proposed to investigate the dosimetric difference between Abches system and free breathing technique in treating left-sided breast cancer.Eligible patients underwent computed tomography (CT) scans to acquire both free breathing (FB) and DIBH technique data using the Abches. For each patient, both FB and DIBH image sets were planned based on the volumetric modulated arc therapy (VMAT). Radiation dose to the heart, ipsilateral lung, and contralateral lung was compared between the Abches system and FB.No significant differences in the planning target volume (PTV) (674.58 vs 665.88 cm, P = .29), mean dose (52.28 vs 52.03 Gy, P = .13), and volume received at the prescribed dose (Vpd) (94.66% vs 93.92%, P = .32) of PTV were observed between the FB and DIBH plans. Significant differences were found in mean heart (6.71 Gy vs 4.21 Gy, P < .001), heart V5 (22.73% vs 14.39%, P = .002), heart V20 (10.96% vs. 5.62%, P < .001), mean left lung (11.51 vs 10.07 Gy, P = .01), left lung V20 (22.88% vs 19.53%, P = .02), left lung V30 (18.58 vs 15.27%, P = .005), and mean right lung dose (.89 vs 72 Gy, P = .03).This is the first report on reduced mean left lung, mean right lung dose, and V20 of left lung using VMAT and Abches. The combination of Abches and VMAT can practically and efficiently reduce extraradiation doses to the heart and lungs.


Assuntos
Radioterapia de Intensidade Modulada/métodos , Terapia Respiratória/métodos , Neoplasias Unilaterais da Mama/radioterapia , Adulto , Idoso , Suspensão da Respiração , Terapia Combinada , Feminino , Coração/efeitos da radiação , Humanos , Inalação , Pulmão/efeitos da radiação , Mastectomia , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/prevenção & controle , Órgãos em Risco/efeitos da radiação , Dosagem Radioterapêutica , Estudos Retrospectivos , Resultado do Tratamento
3.
Dokl Biochem Biophys ; 487(1): 247-250, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31559590

RESUMO

According to the results of theoretical and experimental analysis of the characteristics of the propagation of acoustic vibrations in the respiratory system, it is necessary to determine the resonant frequency of the respiratory tract to increase the vital capacity of the lungs by opening reserve alveoli by acoustic stimulation of the respiratory system and then to affect the respiratory system with scanning tonal sounds in the maximum sound absorption range (at a level of ±3 dB of the maximum absorption coefficient value).


Assuntos
Absorção Fisico-Química , Estimulação Acústica , Pulmão/fisiologia , Modelos Biológicos , Som , Pulmão/efeitos da radiação
4.
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
5.
Br J Radiol ; 92(1101): 20190184, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31287737

RESUMO

OBJECTIVES: In non-small cell lung cancer (NSCLC) patients, to establish whether the fractional volumes of irradiated anatomic or perfused lung differed between those with and without deteriorating lung function or radiation associated lung injury (RALI). METHODS: 48 patients undergoing radical radiotherapy for NSCLC had a radiotherapy-planning CT scan and single photon emission CT lung perfusion imaging (99mTc-labelled macroaggregate albumin). CT defined the anatomic and the single photon emission CT scan (co-registered with CT) identified the perfused (threshold 20 % of maximum) lung volumes. Fractional volumes of anatomic and perfused lung receiving more than 5, 10, 13, 20, 30, 40, 50 Gy were compared between patients with deteriorating (>median decline) vs stable (30, 40, 50 Gy). Fractional volumes of anatomic and perfused lung receiving > 10 Gy best predicted decline in FEV1 (Area under receiver operating characteristic curve (Az = 0.77 and 0.76 respectively); sensitivity/specificity 75%/81 and 80%/71%) for a 32.7% anatomic and 33.5% perfused volume cut-off. Irradiating an anatomic fractional volume of 4.7% to > 50 Gy had a sensitivity/specificity of 83%/89 % for indicating RALI (Az = 0.83). CONCLUSION: A 10-20 Gy radiation dose to anatomic or perfused lung results in decline in FEV1. A fractional anatomic volume of >5% receiving >50 Gy influences development of RALI. ADVANCES IN KNOWLEDGE: Extent of low-dose radiation to normal lung influences functional respiratory decline.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico por imagem , Lesões por Radiação/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Feminino , Humanos , Pulmão/diagnóstico por imagem , Pulmão/efeitos da radiação , Neoplasias Pulmonares/radioterapia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Dosagem Radioterapêutica , Tomografia Computadorizada de Emissão de Fóton Único/métodos
6.
Int J Radiat Oncol Biol Phys ; 105(2): 346-355, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31175902

RESUMO

PURPOSE: The significance of radiation dose to the host immune system during the treatment of stage III non-small cell lung cancer (NSCLC) is unknown, but higher doses were associated with worse tumor control and overall survival (OS) in a secondary analysis of RTOG 0617. In this study, we sought to assess the impact of the estimated dose of radiation to immune cells (EDRIC) on cancer-specific outcomes in an independent cohort of patients treated at our institution. METHODS AND MATERIALS: We retrospectively identified 117 patients with stage III NSCLC treated with definitive fractionated radiation from 2004 to 2017 at a single academic center (median dose of 60 Gy; 60% underwent intensity modulated radiation therapy and 92% received concurrent platinum-based chemotherapy). EDRIC was calculated as a function of the number of radiation fractions and mean doses to the lung, heart, and remaining body based on a model developed by Jin et al. RESULTS: Median follow-up was 16 months with 77% of patients followed until death. In the entire population, 5-year OS was 11.2% with a median survival of 17.3 months. Median EDRIC for the entire cohort was 6.1 Gy (range, 2.5-10.0 Gy). A higher EDRIC was correlated with greater risk of grade ≥3 lymphopenia (P = .004). On multivariate analysis including total prescription radiation dose, planning target volume, and chemotherapy utilization, EDRIC was independently associated with OS (hazard ratio [HR] 1.17, P = .03), local progression-free survival (HR 1.17, P = .02), and disease-free survival (HR 1.15, P = .04). The median OS for patients with an EDRIC above 7.3 Gy (fourth quartile) and below 5.1 Gy (first quartile) was 14.3 and 28.2 months, respectively. CONCLUSIONS: Higher doses of radiation to the immune system were associated with tumor progression and death after the definitive treatment of stage III NSCLC. Tailoring radiation therapy to spare the immune system may be an important future direction to improve outcomes in this population.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/terapia , Quimiorradioterapia/efeitos adversos , Imunidade Celular/efeitos da radiação , Neoplasias Pulmonares/terapia , Órgãos em Risco/efeitos da radiação , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Quimiorradioterapia/métodos , Progressão da Doença , Intervalo Livre de Doença , Fracionamento da Dose de Radiação , Feminino , Coração/efeitos da radiação , Humanos , Sistema Imunitário/efeitos da radiação , Estimativa de Kaplan-Meier , Contagem de Leucócitos , Pulmão/efeitos da radiação , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Linfócitos/efeitos da radiação , Linfopenia/etiologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Neutropenia/etiologia , Neutrófilos/efeitos da radiação , Intervalo Livre de Progressão , Modelos de Riscos Proporcionais , Doses de Radiação , Radioterapia de Intensidade Modulada , Estudos Retrospectivos
7.
J Appl Clin Med Phys ; 20(7): 58-67, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31183967

RESUMO

PURPOSE: To investigate the plan quality and doses to the heart, contralateral breast (CB), ipsilateral lung (IL), and contralateral lung (CL) in tangential breast treatments using the Halcyon linac with megavoltage setup fields. METHODS: Radiotherapy treatment plans with tangential beams from 25 breast cancer patients previously treated on a C-arm linac were replanned for Halcyon. Thirteen corresponded to right-sided breasts and 12 to left-sided breasts, all with a dose prescription of 50 Gy in 25 fractions. Plans were created with the following setup imaging techniques: low-dose (LD) MVCBCT, high-quality (HQ) MVCBCT, LD-MV and HQ-MV pairs and the imaging dose was included in the plans. Plan quality metric values for the lumpectomy cavity, whole-breast and doses to the organs at risk (OARs) were measured and compared with those from the original plans. RESULTS: No significant differences in plan quality were observed between the original and Halcyon plans. An increase in the mean dose (Mean) for all the organs was observed for the Halcyon plans. For right-sided plans, the accumulated Mean over the 25 fractions in the C-arm plans was 0.4 ± 0.3, 0.2 ± 0.2, 5.4 ± 1.3, and 0.1 ± 0.1 Gy for the heart, CB, IL, and CL, respectively, while values in the MVCBCT-LD Halcyon plans were 1.2 ± 0.2, 0.6 ± 0.1, 6.5 ± 1.4, and 0.4 ± 0.1 Gy, respectively. For left-sided treatments, Mean in the original plans was 0.9 ± 0.2, 0.1 ± 0.0, 4.2 ± 1.2, and 0.0 ± 0.0 Gy, while for the MVCBCT-LD Halcyon plans values were 1.9 ± 0.2, 0.6 ± 0.2, 5.1 ± 1.2, and 0.5 ± 0.2 Gy, respectively. CONCLUSIONS: Plan quality for breast treatments using Halcyon is similar to the quality for a 6 MV, C-arm plan. For treatments using megavoltage setup fields, the dose contribution to OARs from the imaging fields can be equal or higher than the dose from treatment fields.


Assuntos
Neoplasias da Mama/radioterapia , Coração/efeitos da radiação , Pulmão/efeitos da radiação , Mastectomia Segmentar/métodos , Órgãos em Risco/efeitos da radiação , Aceleradores de Partículas/instrumentação , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Prognóstico , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos
8.
Radiat Oncol ; 14(1): 109, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215458

RESUMO

BACKGROUND: The aim of this study was to compare dose-volume histogram (DVH) with dose-mass histogram (DMH) parameters for treatment of left-sided breast cancer in deep inspiration breath-hold (DIBH) and free breathing (FB). Additionally, lung expansion and anatomical factors were analyzed and correlated to dose differences. METHODS: For 31 patients 3D conformal radiation therapy plans were retrospectively calculated on FB and DIBH CTs in the treatment planning system. The calculated doses, structures and CT data were transferred into MATLAB and DVHs and DMHs were calculated. Mean doses (Dmean), volumes and masses receiving certain doses (Vx, Mx) were determined for the left lung and the heart. Additionally, expansion of the left lung was evaluated using deformable image registration. Differences in DVH and DMH dose parameters between FB and DIBH were statistically analyzed and correlated to lung expansion and anatomical factors. RESULTS: DIBH reduced Dmean (DVH) and relative V20 (V20 [%]) of the left lung in all patients, on average by - 19 ± 9% (mean ± standard deviation) and - 24 ± 10%. Dmean (DMH) and M20 [%] were also significantly reduced (- 12 ± 11%, - 16 ± 13%), however 4 patients had higher DMH values in DIBH than in FB. Linear regression showed good correlations between DVH and DMH parameters, e.g. a dosimetric benefit smaller than 8.4% for Dmean (DVH) in DIBH indicated more irradiated lung mass in DIBH than in FB. The mean expansion of the left lung between FB and DIBH was 1.5 ± 2.4 mm (left), 16.0 ± 4.0 mm (anterior) and 12.2 ± 4.6 mm (caudal). No significant correlations were found between expansions and differences in Dmean for the left lung. The heart dose in DIBH was reduced in all patients by 53% (Dmean) and this dosimetric benefit correlated to lung expansion in anterior. CONCLUSIONS: Treatment of left-sided breast cancer in DIBH reduced dose to the heart and in most cases the lung dose, relative irradiated lung volume and lung mass. A mass related dosimetric benefit in DIBH can be achieved as long as the volume related benefit is about ≥8-9%. The lung expansion (breathing pattern) showed no impact on lung dose, but on heart dose. A stronger chest breathing (anterior expansion) for DIBH seems to be more beneficial than abdominal breathing.


Assuntos
Suspensão da Respiração , Pulmão/efeitos da radiação , Tratamentos com Preservação do Órgão/estatística & dados numéricos , Órgãos em Risco/efeitos da radiação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias Unilaterais da Mama/radioterapia , Feminino , Coração/efeitos da radiação , Humanos , Processamento de Imagem Assistida por Computador/métodos , Prognóstico , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Radioterapia Conformacional/métodos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Neoplasias Unilaterais da Mama/patologia
9.
Radiat Oncol ; 14(1): 108, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31208439

RESUMO

PURPOSE: The purpose of this study is to evaluate the impact of two methods of reporting planned dose distributions on the Gamma analysis pass rates for comparison with measured 2D film dose and simulated delivered 3D dose for proton pencil beam scanning treatment of the Imaging and Radiation Oncology Core (IROC) proton lung and liver mobile phantoms. METHODS AND MATERIALS: Four-dimensional (4D) computed-tomography (CT) image sets were acquired for IROC proton lung and liver mobile phantoms, which include dosimetry inserts that contains targets, thermoluminescent dosimeters and EBT2 films for plan dose verification. 4DCT measured fixed motion magnitudes were 1.3 and 1.0 cm for the lung and liver phantoms, respectively. To study the effects of motion magnitude on the Gamma analysis pass rate, three motion magnitudes for each phantom were simulated by creating virtual 4DCT image sets with motion magnitudes scaled from the scanned phantom motion by 50, 100, and 200%. The internal target volumes were contoured on the maximum intensity projection CTs of the 4DCTs for the lung phantom and on the minimum intensity projection CTs of the 4DCTs for the liver phantom. Treatment plans were optimized on the average intensity projection (AVE) CTs of the 4DCTs using the RayStation treatment planning system. Plan doses were calculated on the AVE CTs, which was defined as the planned AVE dose (method one). Plan doses were also calculated on all 10 phase CTs of the 4DCTs and were registered using target alignment to and equal-weight-summed on the 50% phase (T50) CT, which was defined as the planned 4D dose (method two). The planned AVE doses and 4D doses for phantom treatment were reported to IROC, and the 2D-2D Gamma analysis pass rates for measured film dose relative to the planned AVE and 4D doses were compared. To evaluate motion interplay effects, simulated delivered doses were calculated for each plan by sorting spots into corresponding respiratory phases using spot delivery time recorded in the log files by the beam delivery system to calculate each phase dose and accumulate dose to the T50 CTs. Ten random beam starting phases were used for each beam to obtain the range of the simulated delivered dose distributions. 3D-3D Gamma analyses were performed to compare the planned 4D/AVE doses with simulated delivered doses. RESULTS: The planned 4D dose matched better with the measured 2D film dose and simulated delivered 3D dose than the planned AVE dose. Using planned 4D dose as institution reported planned dose to IROC improved IROC film dose 2D-2D Gamma analysis pass rate from 92 to 96% on average for three films for the lung phantom (7% 5 mm), and from 92 to 94% in the sagittal plane for the liver phantom (7% 4 mm), respectively, compared with using the planned AVE dose. The 3D-3D Gamma analysis (3% 3 mm) pass rate showed that the simulated delivered doses for lung and liver phantoms using 10 random beam starting phases for each delivered beam matched the planned 4D dose significantly better than the planned AVE dose for phantom motions larger than 1 cm (p ≤ 0.04). CONCLUSIONS: It is recommended to use the planned 4D dose as the institution reported planned dose to IROC to compare with the measured film dose for proton mobile phantoms to improve film Gamma analysis pass rate in the IROC credentialing process.


Assuntos
Tomografia Computadorizada Quadridimensional/métodos , Fígado/efeitos da radiação , Pulmão/efeitos da radiação , Movimento , Imagens de Fantasmas , Prótons , Planejamento da Radioterapia Assistida por Computador/métodos , Algoritmos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Órgãos em Risco/efeitos da radiação , Radiometria/métodos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Respiração
10.
Acta Med Okayama ; 73(3): 247-257, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31235973

RESUMO

We investigated the feasibility of simultaneous integrated boost (SIB) volumetric modulated arc therapy (VMAT) using elective nodal irradiation (ENI) for middle or lower esophageal cancer and compared it with three-dimensional conformal radiotherapy (3D-CRT). The study included 15 patients. The prescribed doses included a standard dose (50.4 Gy) and a high dose (60 Gy) for the planning target volume (PTV) of the involved lesions. The objective of the whole lung volume receiving ≥ 20 Gy (V20Gy) was < 30%, and the mean lung dose (MLD) was < 20 Gy. The volumes of the lung receiving 5 Gy (V5Gy) and the heart receiving 30-50 Gy (V30-50Gy) were kept as low as reasonably achievable. As a result, SIB-VMAT showed superior dose conformity for the PTV (p<0.001). Although the lung V5Gy was significantly increased (p<0.001), the V20Gy and MLD showed no significant increase. The heart V30-50Gy showed a > 20% reduction in the mean against 3D-CRTs. Our results demonstrate the feasibility of SIB-VMAT for the treatment of middle or lower esophageal cancer with ENI. Although attention should be paid to the low-dose area of the lungs, SIB-VMAT would be a promising treatment option with improved outcomes for esophageal cancer.


Assuntos
Neoplasias Esofágicas/radioterapia , Linfonodos/efeitos dos fármacos , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pulmão/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Doses de Radiação
11.
Radiat Oncol ; 14(1): 72, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036015

RESUMO

BACKGROUND: An objective way to qualify the effect of radiotherapy (RT) on lung tissue is the analysis of CT scans after RT. In this analysis we focused on the changes in Hounsfield units (ΔHU) and the correlation with the corresponding radiation dose after RT. METHODS: Pre- and post-RT CT scans were matched and ΔHU was calculated using customized research software. ΔHU was calculated in 5-Gy-intervals and the correlation between ΔHU and the corresponding dose was calculated as well as the regression coefficients. Additionally the mean ΔHU and ΔHU in 5-Gy-intervals were calculated for each tumor entity. RESULTS: The mean density changes at 12 weeks and 6 months post RT were 28,16 HU and 32,83 HU. The correlation coefficient between radiation dose and ΔHU at 12 weeks and 6 months were 0,166 (p = 0,000) and 0,158 (p = 0,000). The resulting regression coefficient were 1439 HU/Gy (p = 0,000) and 1612 HU/Gy (p = 0,000). The individual regression coefficients for each patient range from - 2,23 HU/Gy to 7,46 HU/Gy at 12 weeks and - 0,45 HU/Gy to 10,51 HU/Gy at 6 months. When looking at the three tumor entities individually the highest ΔHU at 12 weeks was seen in patients with SCLC (38,13 HU) and at 6 month in those with esophageal carcinomas (40,98 HU). CONCLUSION: For most dose intervals there was an increase of ΔHU with an increased radiation dose. This is reflected by a statistically significant, although low correlation coefficient. The regression coefficients of all patients show large interindividual differences.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Pulmão/patologia , Tecido Parenquimatoso/patologia , Radioterapia/efeitos adversos , Carcinoma de Pequenas Células do Pulmão/radioterapia , Neoplasias Torácicas/radioterapia , Tomografia Computadorizada por Raios X/métodos , Idoso , Carcinoma Pulmonar de Células não Pequenas/patologia , Feminino , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Pulmão/diagnóstico por imagem , Pulmão/efeitos da radiação , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/radioterapia , Masculino , Tecido Parenquimatoso/diagnóstico por imagem , Tecido Parenquimatoso/efeitos da radiação , Prognóstico , Carcinoma de Pequenas Células do Pulmão/patologia , Neoplasias Torácicas/patologia
12.
Med Phys ; 46(9): 3929-3940, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31063600

RESUMO

PURPOSE: Current treatment planning for 90 Y radioembolization estimates lung mean dose (LMD) by measuring the lung shunt fraction (LSF) from 99m Tc-macroaggregated albumin (MAA) planar imaging and assuming a 1-kg lung mass. This methodology, however, overestimates LSF and LMD and could therefore unnecessarily limit the dose to target volume(s). We propose an improved LMD calculation that derives LSF from 99m Tc-MAA SPECT/CT and the patient-specific lung mass from diagnostic chest CT. Furthermore, we investigated the errors in lung mass, LSF, and LMD arising from contour variability in patient data in order to estimate the precision of our proposed methodology. METHODS: Our proposed LMD (LMDnew ) calculation consisted of the following steps: (a) estimate liver counts from the MAA SPECT/CT liver contour; (b) estimate total lung counts by multiplying density (counts/g) from the MAA SPECT/CT left-lung contour by the total lung mass (g) from the diagnostic CT lung contours; (c) compute LSFnew from liver and lung counts; (d) calculate LMDnew using LSFnew and the total lung mass from the diagnostic CT (Mnew ). LMDnew , LSFnew , and Mnew estimates were compared to standard model values (LMDclin , LSFclin , and 1 kg, respectively) in 52 consecutive patients with hepatocellular carcinoma who underwent radioembolization using 90 Y glass microspheres. The precision of our methodology was quantified by varying lung and liver contours in the same patient population and calculating the resulting relative errors in the liver count, lung count, and lung mass measurements. RESULTS: The median Mnew was 839 g (range, 550-1178 g) for men and 731 g (range, 548-869 g) for women. The median LSFnew was 0.02 (range, 0.01-0.11), while the median LMDnew was 4.9 Gy (range, 0.3-25.5 Gy). Mnew , LSFnew , and LMDnew were significantly lower than Mclin , LSFclin , and LMDclin , with respective relative mean (±SD) differences of -20% (±16%) for Mnew , -63% (±15%) for LSFnew , and -53% (±23%) for LMDnew . The estimated 1-sigma uncertainties in Mnew , LSFnew , and LMDnew were 9%, 10%, and 13%, respectively. CONCLUSIONS: We derived a method to calculate lung mass and LSF using routinely available diagnostic chest CT and 99m Tc-MAA SPECT/CT. More importantly, we systematically quantified the errors in our measurements to establish the precision of the estimated lung dose (13%). The proposed methodology provides a more accurate LMD and an estimate of its precision, which will improve treatment and retreatment planning for 90 Y radioembolizations.


Assuntos
Embolização Terapêutica , Pulmão/efeitos da radiação , Doses de Radiação , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Agregado de Albumina Marcado com Tecnécio Tc 99m , Tórax/diagnóstico por imagem , Radioisótopos de Ítrio/uso terapêutico , Humanos , Pulmão/diagnóstico por imagem , Erros Médicos , Microesferas , Planejamento da Radioterapia Assistida por Computador , Radioisótopos de Ítrio/química
13.
Tech Vasc Interv Radiol ; 22(2): 70-73, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31079713

RESUMO

Y90 radioembolization is an alternative to transarterial chemoembolization for the intra-arterial treatment of hepatocellular carcinoma (HCC). However, the optimal treatment of HCC varies by tumor stage, underlying liver function and functional status, and local expertise. Therefore, the appropriate selection of patients for Y90 radioembolization is of paramount importance for optimal outcomes. Data on the role of Y90 radioembolization for HCC are most robust in the palliative treatment of inoperable, liver-confined disease. However, data are also present on the role of Y90 radioembolization as a bridge to or to downstage patients for transplant. Outcomes for radiation segmentectomy (ablative radiation doses) with curative intent or prior to resection are also discussed.


Assuntos
Carcinoma Hepatocelular/radioterapia , Neoplasias Hepáticas/radioterapia , Seleção de Pacientes , Radiografia Intervencionista/métodos , Radioisótopos de Ítrio/uso terapêutico , Carcinoma Hepatocelular/diagnóstico por imagem , Humanos , Testes de Função Hepática , Neoplasias Hepáticas/diagnóstico por imagem , Transplante de Fígado , Pulmão/efeitos da radiação , Dosagem Radioterapêutica
14.
Int J Radiat Biol ; 95(8): 1072-1084, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31140892

RESUMO

Purpose: Diagnostic radiation is an important part of patient care in the Intensive Care Unit; however, there is little data on the acute effects of exposure to these doses. We investigated pulmonary and splenic response 30 minutes, 4 hours or 24 hours after exposure to 2 mGy, 20 mGy, 200 mGy or 4 Gy whole-body X-radiation in a Sprague Dawley rat model. Materials and methods: Lung injury was assessed via respiratory mechanics, pulmonary edema, cellular, and proteinaceous fluid infiltrate and protein expression of oxidative stress markers. The radiation effect on the spleen was determined via proliferation, apoptosis and protein expression of oxidative stress markers. Results: All measurements of the lung did not differ from sham animals except for an increase in catalase after high dose exposure. Stimulated splenocyte proliferation increased after sham and low dose exposure, did not change after 200 mGy exposure and was significantly lower after 4 Gy exposure. The number of apoptotic cells increased 4 hours after 4 Gy exposure. There were fewer apoptotic cells after low dose exposure compared to sham. Both catalase and MnSOD were increased after 4 Gy exposure. Conclusion: There was no measured effect on pulmonary function while there was an impact to the spleen after low and high dose exposure.


Assuntos
Pulmão/efeitos da radiação , Baço/efeitos da radiação , Irradiação Corporal Total , Animais , Apoptose/efeitos da radiação , Proliferação de Células/efeitos da radiação , Relação Dose-Resposta à Radiação , Pulmão/patologia , Masculino , Estresse Oxidativo/efeitos da radiação , Doses de Radiação , Ratos , Mecânica Respiratória/efeitos da radiação , Baço/patologia
15.
Radiat Oncol ; 14(1): 87, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31133030

RESUMO

BACKGROUND: This study set out to evaluate the effect of dose rate on normal tissues (the lung, in particular) and the variation in the treatment efficiency as determined by the monitor unit (MU) and energy applied in Linac-based volumetric arc therapy (VMAT) total marrow irradiation (TMI). METHODS: Linac-based VMAT plans were generated for the TMI for six patients. The planning target volume (PTV) was divided into six sub-volumes, each of which had their own isocenter. To examine the effect of the dose rate and energy, a range of MU rates (40, 60, 80, 100, 300, and 600 MU/min) were selected for 6, 10, and 15 MV. All the plans were verified by portal dosimetry. RESULTS: The dosimetric parameters for the target and normal tissue were consistent in terms of the energy and MU rate. The beam-on time was changed from 59.6 to 6 min for 40 and 600 MU/min. When 40 MU/min was set for the lung, the dose rate delivered to the lung was less than 6 cGy/min (that is, 90%), while the beam-on time was approximately 10 min. The percentage volume of the lung receiving 20 cGy/min was 1.47, 3.94, and 6.22% at 6, 10, and 15 MV, respectively. However, for 600 MU/min, the total lung volume received over 6 cGy/min regardless of the energy, and over 20 cGy/min for 10 and 15 MV (i.e., 54.4% for 6 MV). CONCLUSIONS: In TMI treatment, reducing the dose rate administered to the lung can decrease the incidence of pulmonary toxicity. To reduce the probability of normal tissue complications, the selection of the lowest MU rate is recommended for fields including the lung. To minimize the total treatment time, the maximum MU rate can be applied to other fields.


Assuntos
Medula Óssea/efeitos da radiação , Radiocirurgia/métodos , Radioterapia de Intensidade Modulada/métodos , Irradiação Corporal Total/métodos , Relação Dose-Resposta à Radiação , Feminino , Humanos , Pulmão/efeitos da radiação , Lesão Pulmonar/prevenção & controle , Masculino , Órgãos em Risco/efeitos da radiação , Radiometria , Radiocirurgia/efeitos adversos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/efeitos adversos , Irradiação Corporal Total/efeitos adversos
16.
Radiat Oncol ; 14(1): 85, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31126307

RESUMO

BACKGROUND: The prognostic significance of radiation dose to the lung or heart is unknown in esophageal cancer patients receiving neoadjuvant chemoradiotherapy followed by surgery (trimodal therapy). This study aimed to determine the association between lung and heart radiation dose volumes and prognosis of esophageal cancer after trimodal therapy. METHODS: This study reviewed 123 esophageal cancer patients treated with trimodal therapy in two tertiary institutions between 2010 and 2015. The dose-volume histogram parameter of Vx was defined as the percentage of total organ volume receiving a radiation dose of x (Gy) or more. Predictors of overall survival (OS) were identified using Cox regression models. Receiver-operating characteristic curves were used to select cut-off values for dose-volume. RESULTS: Median follow-up was 28.3 months (range: 4.7-92.8 months). Median OS and progression-free survival were 34.0 months (95% confidence interval [CI]: 27.4-40.6 months) and 24.8 months (95% CI, 18.9-30.7 months), respectively. Multivariate analyses showed that lung V20 (hazard ratio, 1.09; 95% CI: 1.04-1.14; p < 0.001) and lung V5 (hazard ratio, 1.02; 95% CI: 1.00-1.05; p = 0.03) were associated with OS when adjusting for surgical margin and pathological treatment response. The 5-year OS for patients with lung V20 ≤ 23% vs. patients with lung V20 > 23% was 54.4% vs. 5% (p < 0.001) whereas that for patients with lung V5 ≤ 56% vs. patients with lung V5 > 56% was 81.5% vs. 23.4% (p < 0.001). Mean heart dose showed no association with survival outcomes. CONCLUSIONS: Lung radiation dose was independently associated with survival outcomes in esophageal cancer patients treated with neoadjuvant chemoradiotherapy and surgery.


Assuntos
Quimiorradioterapia Adjuvante , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/terapia , Pulmão/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Neoplasias Esofágicas/radioterapia , Neoplasias Esofágicas/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Prognóstico , Dosagem Radioterapêutica , Estudos Retrospectivos , Taxa de Sobrevida
17.
J BUON ; 24(2): 838-843, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31128044

RESUMO

PURPOSE: The purpose of this study was to investigate the dosimetric equivalency of dynamic conformal arc therapy (DCAT) against volumetric modulated arc therapy (VMAT) plans in stereotactic body radiation therapy (SBRT) of lung and liver lesions and to examine if efficiency can be increased. METHODS: Nineteen patients previously treated for lung and liver cancer lesions with SBRT were included. Organs at risk (OAR) and targets were contoured by a single radiation oncologist. All plans were optimized by the same dosimetrist using ELEKTA Monaco treatment planning system version 5.0 for 6MV flattening filter free (FFF) photon beam in a VersaHD (ELEKTA, Crawley, UK). A VMAT and DCAT plan was optimized using the same objectives using coplanar arcs of 225o arc span. RESULTS: All plans have achieved the target and OAR planning objectives. The target dose conformity was comparable (mean VMAT PTVr=1.3 and DCAT PTVr=1.4), and the low dose spillage were similar (mean VMAT R50=4.5 and DCAT R50=4.6). However, monitor units (MU) for DCAT plans were lower by 2.5 times on average than VMAT plans. It was observed that in 75% of cases where OARs overlapped with the PTV, maximum doses to OAR were higher in VMAT than DCAT plans, but the difference was not significant. Patient specific quality assurance (QA) plans were measured using the Scandidos Delta4 phantom and gamma analysis performed using 2mm distance to agreement (DTA) and 2% dose difference yielded more than 95% passing rates on both VMAT and DCAT plans. CONCLUSIONS: DCAT delivery for lung and liver SBRT is a dosimetrically equivalent and an efficient alternative to VMAT plans.


Assuntos
Neoplasias Hepáticas/radioterapia , Neoplasias Pulmonares/radioterapia , Radiocirurgia , Radioterapia de Intensidade Modulada , Feminino , Humanos , Fígado/patologia , Fígado/efeitos da radiação , Neoplasias Hepáticas/patologia , Pulmão/patologia , Pulmão/efeitos da radiação , Neoplasias Pulmonares/patologia , Masculino , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia Conformacional/métodos
18.
J Appl Clin Med Phys ; 20(5): 55-63, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30955251

RESUMO

PURPOSE/OBJECTIVES: Due to higher radiosensitivity, non-target normal tissue dose is a major concern in stereotactic body radiation therapy (SBRT) treatment. The aim of this report was to estimate the dosimetric impact, specifically the reduction of normal lung dose in the treatment of single-isocenter/two-lesion lung SBRT via volumetric modulated arc therapy with jaw tracking (JT-VMAT). MATERIALS/METHODS: Twelve patients with two peripherally located early-stage non-small-cell-lung cancer (NSCLC) lung lesions underwent single-isocenter highly conformal non-coplanar JT-VMAT SBRT treatment in our institution. The mean isocenter to tumors distance was 5.6 ± 1.9 (range 4.3-9.5) cm. The mean combined planning target volume (PTV) was 38.7 ± 22.7 (range 5.0-80.9) cc. A single isocenter was placed between the two lesions. Doses were 54 and 50 Gy in three and five fractions, respectively. Plans were optimized in Eclipse with AcurosXB algorithm utilizing jaw tracking options for the Truebeam with a 6 MV-FFF beam and standard 120 leaf millennium multi-leaf collimators. For comparison, the JT-VMAT plans were retrospectively re-computed utilizing identical beam geometry, objectives, and planning parameters, but without jaw tracking (no JT-VMAT). Both plans were normalized to receive the same target coverage. The conformity and heterogeneity indices, intermediate-dose spillage [D2cm , R50, Gradient Index (GI), Gradient Distance (GD)], organs at risks (OAR) doses including normal lung as well as modulation factor (MF) were compared for both plans. RESULTS: For similar target coverage, GI, R50, GD, as well as the normal lung V5, V10, V20, mean lung dose (MLD), and maximum dose received by 1000 cc of lungs were statistically significant. Normal lung doses were reduced by 8%-11% with JT-VMAT. Normal lung dose increased as a function of tumor distance from isocenter. For the other OAR, up to 1%-16% reduction of non-target doses were observed with JT-VMAT. The MF and beam-on time were similar for both plans, however, MF increased as a function of tumors distance, consequently, delivering higher dose to normal lungs. CONCLUSION: Utilizing jaw tracking options during optimization for single-isocenter/two-lesion lung SBRT VMAT plans reduced doses to the normal lung and other OAR, reduced intermediate-dose spillage and provided superior/similar target coverage. Application of jaw tracking did not affect delivery efficiency and provided excellent plan quality with similar MF and beam-on time. Jaw tracking is recommended for future clinical SBRT plan optimization.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/cirurgia , Arcada Osseodentária/fisiologia , Pulmão/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Imagens de Fantasmas , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Algoritmos , Fenômenos Biomecânicos , Tomografia Computadorizada Quadridimensional , Humanos , Arcada Osseodentária/efeitos da radiação , Registro da Relação Maxilomandibular , Neoplasias Pulmonares/cirurgia , Prognóstico , Radiometria/métodos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos , Carga Tumoral
19.
Phys Med ; 60: 50-57, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31000086

RESUMO

PURPOSE: Measurements and Monte-Carlo simulations were carried out to model the dose distribution of a prototype electron beam linear accelerator (Kinetron LINAC) to determine the dose to organs in small animal irradiations experiments. Dose distributions were simulated using the GATE8.0/Geant4.10.3 Monte-Carlo platform, and measured in air and solid water phantoms using a commercial scintillating screen detector and new EBT-XD Gafchromic films. METHODS: The LINAC is able to produce 4.5 MeV electron beams at dose-rates ranging from Gy/min to thousands of Gy/s, and is used to study the radiobiological effects of very-high dose-rates that have been shown to protect normal tissues from radiation toxicity. Numerical simulations and experimental dosimetric characterisation of this electron accelerator were performed with the Monte-Carlo toolkit and various detectors. Absolute dose distributions in solid water were measured and compared with simulations. Realistic electron irradiation conditions were simulated in voxelised mice CT images. 3D dose distributions and dose-volume histograms in lungs of mice were simulated and analyzed. RESULTS: Measured and calculated depth-dose profiles for several beam configurations (energy and dose-rate) were compared. Beam emittance was validated by comparing measured and calculated beam sizes along the central axis in air: the deviation for all conditions was less than 1 mm. A good agreement was obtained between experimental dose distributions and the results obtained with simulations (<2% dose differences for lateral and depth-dose profiles). CONCLUSIONS: The method presented here, relying on few free parameters, can be adapted to very-high dose-rate electron irradiation to support the analysis of preclinical research experiments.


Assuntos
Aceleradores de Partículas , Animais , Simulação por Computador , Elétrons , Desenho de Equipamento , Pulmão/diagnóstico por imagem , Pulmão/efeitos da radiação , Camundongos , Método de Monte Carlo , Imagens de Fantasmas , Radiometria/instrumentação , Tomografia Computadorizada por Raios X , Água
20.
Int J Radiat Oncol Biol Phys ; 104(5): 1074-1083, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30991100

RESUMO

PURPOSE: To evaluate the prognostic potential of lipopolysaccharide-binding protein (LBP) levels after breast cancer radiation therapy (RT) for incipient cardiac dysfunction. METHODS AND MATERIALS: In this single-centered study, we prospectively enrolled female patients treated for left breast cancer. Healthy age- and sex-matched participants were recruited as controls. LBP levels, cardiac troponin T, N-terminal propeptide of the brain natriuretic peptide, fatty acid binding protein, and C-reactive protein were assessed at three timepoints-before RT, after the last RT fraction, and 1 month after the last fraction. Echocardiographic evaluation was done 3 to 3.75 years after RT. RESULTS: We recruited 51 patients and 78 controls. Baseline LBP concentrations in the study group were significantly higher than in controls at baseline (P < .001), at 24 hours, and at 1 month after RT (P = .003 and P < .001, respectively). Other biomarkers (cardiac troponin T, N-terminal propeptide of the brain natriuretic peptide, fatty acid binding protein, and C-reactive protein) did not differ in any of the timepoints. Posttreatment LBP concentrations were significantly and positively correlated with heart- and lung-associated dose-volume histogram variables. Posttreatment and follow-up LBP levels correlated positively with the E/E' echocardiographic index reflective of the diastolic function. After adjustment for left anterior descending artery mean dose, left ventricle mean dose, mean heart dose, and type of surgery, LBP remained significantly correlated with E/E' when measured 24 hours after RT (beta = 0.41, P = .032) and 1 month after RT (beta = 0.43, P = .028). CONCLUSIONS: Serum LBP concentrations correlate with diastolic function evaluated 3 years after the completion of RT, making LBP a potentially useful prognostic parameter.


Assuntos
Neoplasias da Mama/radioterapia , Proteínas de Transporte/sangue , Coração/efeitos da radiação , Glicoproteínas de Membrana/sangue , Lesões por Radiação/sangue , Proteínas da Fase Aguda , Biomarcadores/sangue , Neoplasias da Mama/sangue , Neoplasias da Mama/cirurgia , Proteína C-Reativa/análise , Estudos de Casos e Controles , Ecocardiografia , Proteínas de Ligação a Ácido Graxo/sangue , Feminino , Humanos , Pulmão/efeitos da radiação , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , Estudos Prospectivos , Fatores de Tempo , Troponina T/sangue
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