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1.
Br J Radiol ; 93(1110): 20200047, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32187503

RESUMO

OBJECTIVE: To analyze the effect of intra- and interfractional motion during breast intensity modulated radiation therapy (IMRT) by calculating dose distribution based on four-dimensional computed tomography (4DCT). METHODS: 20 patients diagnosed with left breast cancer were enrolled. Three-dimensional CT (3DCT) along with 10 phases of 4DCT were collected for each patient, with target volumes independently delineated on both 3DCT and all phases of 4DCT. IMRT plans were generated based on 3DCT (43.2 Gy in 16 fractions). The plan parameters for each segment were split into phases based on time duration estimates for each respiratory phase, with phase-specific dose distributions calculated and summated (4D-calculated dose). The procedure is repeated for 16 fractionations by randomly allocating starting phase using random-number generation to simulate interfractional discrepancy caused by different starting phase. Comparisons of plan quality between the original and 4D-calculated doses were analyzed. RESULTS: There was a significant distortion in 4D-calculated dose induced by respiratory motion in terms of conformity and homogeneity index compared to those of the original 3D plan. Mean doses of the heart and the ipsilateral lung were significantly higher in the 4D-calculated doses compared to those of the original 3D plan (0.34 Gy, p = 0.010 and 0.59 Gy, p < 0.001), respectively). The mean internal mammary lymph node (IMN) dose was significantly greater in the 4D-calculated plan, compared to the original 3D plan (1.42 Gy, p < 0.001). CONCLUSIONS: IMN doses should be optimized during the dose-calculation for the free-breathing left breast IMRT. ADVANCES IN KNOWLEDGE: The interplay effect between respiratory motion and multileaf collimator modulation caused discrepancies in dose distribution, particularly in IMN.


Assuntos
Tomografia Computadorizada Quadridimensional , Imageamento Tridimensional/métodos , Radioterapia de Intensidade Modulada , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/radioterapia , Fracionamento da Dose de Radiação , Feminino , Coração , Humanos , Pulmão , Irradiação Linfática/métodos , Movimentos dos Órgãos , Planejamento da Radioterapia Assistida por Computador , Radioterapia Adjuvante/métodos , Respiração , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Neoplasias Unilaterais da Mama/cirurgia
2.
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
4.
Pract Radiat Oncol ; 9(6): e572-e578, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31226442

RESUMO

PURPOSE: For patients who receive treatment for left breast cancer, cardiac toxicity increases with increased radiation dose to the heart. A new method was developed using 4-dimensional computed tomography (CT) scans to improve custom cardiac blocks to minimize heart dose. METHODS AND MATERIALS: Four-dimensional CT scans were acquired, and a maximum intensity projection (MIP) heart was contoured for 20 patients. Custom heart blocks were created to fully block the MIP heart volume. A heart block based on the standard free-breathing (FB) CT image was retrospectively created. Differences in heart block sizes were compared. Differences in heart block areas and dose statistics were analyzed. RESULTS: In all 20 cases, the heart block created using the 4-dimensional scan had a larger area than the corresponding FB block. The mean increase in multileaf collimator coverage was 3.9 mm (range, 0.5-20.1 mm). The mean increase in the area of the heart block was 2.58 cm2 (range, 0.22-6.65 cm2). The dose-volume histogram showed that the MIP heart received 17.8 cGy (range, 0.02-70.3 cGy) more than the FB heart on average. Replanning with an FB heart block showed that the mean dose to the MIP heart increased by 16.2 cGy (range, 1.8-44.8 cGy) compared with the FB heart dose. CONCLUSIONS: Four-dimensional heart blocks accounting for intrinsic respiratory motion and cardiac motion were greater in size than FB heart blocks. These larger blocks resulted from the larger contour created from the MIP image and blocked more dose to the heart. This technique for improving custom heart blocks can be easily implemented with 4DCT machine capabilities that are currently available in clinical practice.


Assuntos
Tomografia Computadorizada Quadridimensional/métodos , Bloqueio Cardíaco/diagnóstico por imagem , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade
5.
Breast J ; 25(4): 682-686, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31077484

RESUMO

The purpose of this study was to analyze the effectiveness of electron beam therapy (EBT) with patient-tailored bolus (PTB) using three-dimensional printing technology to reduce heart and lung doses during post-mastectomy radiotherapy (PMRT). For 28 patients with left breast cancer, we designed customized virtual bolus for PMRT to compensate for surface irregularities on computed tomography images and developed optimized plans for EBT. As comparison between the PTB and tangential plans, the PTB plan reduced unnecessary exposure to heart and ipsilateral lung with better target coverage compared with the tangential technique.


Assuntos
Coração , Radioterapia/métodos , Neoplasias Unilaterais da Mama/radioterapia , Neoplasias Unilaterais da Mama/cirurgia , Adulto , Idoso , Feminino , Humanos , Pulmão , Mastectomia , Pessoa de Meia-Idade , Tratamentos com Preservação do Órgão , Impressão Tridimensional , Radiodermatite , Radioterapia/efeitos adversos , Dosagem Radioterapêutica , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/diagnóstico por imagem
6.
Breast Cancer Res Treat ; 176(1): 87-94, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30953256

RESUMO

PURPOSE: To develop and evaluate the accuracy of a three-dimensional (3D) US method for assessing unilateral breast reconstruction and discuss the feasibility of breast ultrasound 3D reconstruction of the unilateral breast compared with 3D MRI. METHODS: Sixty-four breast lesions were collected for surgical resection. (1) MRI and US imaging were used to reconstruct the 3D models of the breast neoplasm. The diameters for maximum length, width, and depth of the negative tumor margins were used as the primary standards for comparison. (2) The measurement direction was determined by the largest gravity change between the two body positions. (3) The vertical distance from the midpoint of breast neoplasm to the ipsilateral nipple was calculated via MRI and US reconstruction. RESULTS: (1) Comparison of the measured size and histopathology of the breast neoplasm showed that US, MRI, and histopathology were highly correlated (p < 0.001). (2) When compared with the other two vertical directions, the direction with the largest gravity change had the greatest difference between MRI and US measurements. (3) The vertical distance from the breast neoplasm to the ipsilateral nipple and skin junction was significantly different (p > 0.05). CONCLUSIONS: We have presented a novel US 3D reconstruction method for evaluating tumor size, which can provide a basis for investigated advanced visualization techniques for assessing breast tissue such as holographic presentation of 3D image data. These methods can provide physicians with a novel approach for making accurate surgical plans, for better communication with patients, and for more effective navigating throughout the operation.


Assuntos
Imageamento Tridimensional , Mamoplastia , Cirurgia Assistida por Computador , Ultrassonografia Mamária , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/cirurgia , Adulto , Gerenciamento Clínico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional/instrumentação , Imageamento Tridimensional/métodos , Imagem por Ressonância Magnética/métodos , Mamoplastia/instrumentação , Mamoplastia/métodos , Pessoa de Meia-Idade , Pesquisa , Cirurgia Assistida por Computador/instrumentação , Cirurgia Assistida por Computador/métodos , Carga Tumoral , Ultrassonografia Mamária/instrumentação , Ultrassonografia Mamária/métodos , Neoplasias Unilaterais da Mama/patologia , Adulto Jovem
8.
J Appl Clin Med Phys ; 20(2): 24-29, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30653831

RESUMO

Volumetric modulated arc therapy (VMAT) has been implemented for left breast irradiation to reduce prescription dose to the heart and improve dose homogeneity across the targeted breast. Our in-house method requires application of a bolus during the optimization process with a target outside of the body, then removing the bolus during the final calculation in order to incorporate skin flash in VMAT plans. To quantify the dosimetric trade-offs between traditional 3D field-in-field tangents and VMAT with integrated skin flash for these patients, we compared nine consecutive patients who recently received radiation to their entire left breast but not their regional lymphatics. Tangent plans used non-divergent tangents of mixed energies and VMAT plans utilized four 6 MV arcs of roughly 260°. Mean dose to the heart, contralateral lung, and contralateral breast and their volume receiving 5%, 10%, and 20% of the prescription dose were higher in all nine VMAT plans than in the static tangential beam plans. For all critical structures, the mean VMAT DVH was higher in the low-dose region and crossed the 3D field-in-field DVH between 23.13% and 34.18% of the prescription dose (984.75-1454.70 cGy). However, the volume of the contralateral breast and heart receiving the prescription dose was slightly lower in the VMAT plans, but not statistically significant. VMAT provided superior homogeneity, with a mean homogeneity index of 9.41 ± 1.64 compared to 11.05 ± 1.82 for 3D tangents. Results indicate that VMAT spares the heart, contralateral lung, and contralateral breast from prescription dose at the cost of increasing their mean and low-dose volume and delivers a more homogenous dose distribution to the breast. For these reasons, VMAT is selectively applied at the request of the physician for left breast radiation without respiratory gating to spare the heart from prescription dose in cases of poor anatomical geometry.


Assuntos
Imageamento Tridimensional/métodos , Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Pele/efeitos da radiação , Neoplasias Unilaterais da Mama/radioterapia , Feminino , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Prognóstico , Dosagem Radioterapêutica , Tomografia Computadorizada por Raios X/métodos , Neoplasias Unilaterais da Mama/diagnóstico por imagem
9.
Radiol Oncol ; 53(1): 123-130, 2019 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-30661060

RESUMO

Background The aim of the study was to evaluate and compare four different external beam radiotherapy techniques of accelerated partial breast irradiation (APBI) considering target coverage, dose to organs at risk and overall plan quality. The investigated techniques were three dimensional conformal radiotherapy (3D-CRT), "step and shoot" (SS) and "sliding window" (SW) intensity-modulated radiotherapy (IMRT), intensity-modulated arc therapy (RA). Patients and methods CT scans of 40 APBI patients were selected for the study. The planning objectives were set up according to the international recommendations. Homogeneity, conformity and plan quality indices were calculated from volumetric and dosimetric parameters of target volumes and organs at risk. The total monitor units and feasibility were also investigated. Results There were no significant differences in the coverage of the target volume between the techniques. The homogeneity indices of 3D-CRT, SS, SW and RA plans were 0.068, 0.074, 0.058 and 0.081, respectively. The conformation numbers were 0.60, 0.80, 0.82 and 0.89, respectively. The V50% values of the ipsilateral breast for 3D-CRT, SS, SW and RA were 47.5%, 40.2%, 39.9% and 31.6%, respectively. The average V10% and V40% values of ipsilateral lung were 13.1%, 28.1%, 28%, 36% and 2.6%, 1.9%, 1.9%, 3%, respectively. The 3D-CRT technique provided the best heart protection, especially in the low dose region. All contralateral organs received low doses. The SW technique achieved the best plan quality index (PQI). Conclusions Good target volume coverage and tolerable dose to the organs at risk are achievable with all four techniques. Taking into account all aspects, we recommend the SW IMRT technique for APBI.


Assuntos
Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Neoplasias Unilaterais da Mama/radioterapia , Mama/diagnóstico por imagem , Mama/efeitos da radiação , Feminino , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Doses de Radiação , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Coluna Vertebral/efeitos da radiação , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/patologia
10.
Radiat Oncol ; 13(1): 254, 2018 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-30587208

RESUMO

BACKGROUND: This study aimed to evaluate the inter-fraction set-up error and intra-fraction motion during reverse semi-decubitus (RSD) breast radiotherapy, and to determine a planning target volume (PTV) margin. MATERIAL AND METHODS: Pre- and post-treatment cone-beam computed tomography (CBCT) scans were prospectively acquired at fractions 1, 4, 7, 8, 11, and 14 for 30 patients who underwent RSD breast radiotherapy. Online correction for initial set-up error greater than 5 mm or 2° was performed and post-correction CBCT was acquired. An off-line analysis was performed to quantify initial and residual inter-fraction set-up errors and intra-fraction motion in three-dimensions. Patient inter-fraction errors were analysed for time trends during the course of radiotherapy. PTV margins were calculated from the systematic and random errors. RESULTS: The initial inter-fraction population systematic errors were 1.8-3.3 mm (translation) and 0.5° (rotation); random errors were 1.8-2.1 mm (translation) and 0.3-0.5° (rotation). After online correction, the residual inter-fraction population systematic errors were 1.2-1.8 mm (translation) and 0.3-0.4° (rotation); random errors were 1.4-1.6 mm (translation) and 0.3-0.4° (rotation). Intra-fraction population systematic and random errors were ≤ 1.3 mm (translation) and ≤ 0.2° (rotation). The magnitude of inter-fraction set-up errors in the anterior-posterior direction, roll, and yaw were significantly correlated with higher body weight and body mass index (BMI). The inter-fraction set-up error did not change significantly as a function of time during the course of radiotherapy. The magnitude of intra-fraction motion was not correlated with patient characteristics and treatment time. The total PTV margins accounting for pre-correction and intra-fraction errors were 6.5-10.2 mm; those accounting for post-correction and intra-fraction errors were 4.7-6.3 mm. CONCLUSIONS: CBCT is an effective modality to evaluate and improve the inter-fraction set-up reproducibility in RSD breast radiotherapy, particularly for patients with higher BMI. Intra-fraction motion was minimal during RSD breast radiotherapy.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Erros de Configuração em Radioterapia/prevenção & controle , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia , Adulto , Idoso , Feminino , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Dosagem Radioterapêutica , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/patologia
11.
Radiat Oncol ; 13(1): 187, 2018 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-30249274

RESUMO

BACKGROUND: Despite dosimetric benefits of volumetric modulated arc therapy (VMAT) in breast cancer patients with implant reconstruction receiving regional nodal irradiation (RNI), low dose to the thoracic structures remains a concern. Our goal was to report dosimetric effects of adding deep inspiration breath hold (DIBH) to VMAT in left-sided breast cancer patients with tissue expander (TE)/permanent implant (PI) reconstruction receiving RNI. METHODS: Ten consecutive breast cancer patients with unilateral or bilateral TE/PI reconstruction who were treated with a combination of VMAT and DIBH to the left reconstructed chest wall and regional nodes were prospectively identified. Free breathing (FB) and DIBH CT scans were acquired for each patient. VMAT plans for the same arc geometry were compared for FB versus DIBH. Prescription dose was 50 Gy in 25 fractions. Dosimetric differences were tested for statistical significance. RESULTS: For comparable coverage and target dose homogeneity, the mean dose to the heart reduced on average by 2.9 Gy (8.2 to 5.3 Gy), with the addition of DIBH (p < 0.05). The maximum dose to the left anterior descending (LAD) artery was reduced by 9.9 Gy (p < 0.05), which related closely to the reduction in the maximum heart dose (9.4 Gy). V05 Gy to the heart, ipsilateral lung, contralateral lung and total lung (p < 0.05) decreased on average by 29.6%, 5.8%, 15.4% and 10.8% respectively. No significant differences were seen in the ipsilateral lung V20 Gy or mean dose as well as in the mean contralateral breast/implant dose. However, V04 Gy and V03 Gy of the contralateral breast/implant were respectively reduced by 13.2% and 18.3% using DIBH (p < 0.05). CONCLUSION: Combination of VMAT and DIBH showed significant dosimetric gains for low dose to the heart, lungs and contralateral breast/implant. Not surprisingly, the mean and maximum dose to the heart and to the LAD were also reduced. DIBH should be considered with the use of VMAT in breast cancer patients with implant reconstructions receiving RNI.


Assuntos
Implantes de Mama , Suspensão da Respiração , Irradiação Linfática/métodos , Órgãos em Risco/efeitos da radiação , Exposição à Radiação/prevenção & controle , Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia , Mama/diagnóstico por imagem , Mama/efeitos da radiação , Vasos Coronários/efeitos da radiação , Feminino , Coração/efeitos da radiação , Humanos , Inalação , Pulmão/efeitos da radiação , Mamoplastia/instrumentação , Estudos Prospectivos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Dispositivos para Expansão de Tecidos , Neoplasias Unilaterais da Mama/diagnóstico por imagem
12.
Ann Surg Oncol ; 25(13): 3843-3848, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30203404

RESUMO

BACKGROUND: The proportion of patients eligible for breast-conservation therapy (BCT) yet opting for mastectomy is increasing. This decision is often driven by the desire to eliminate future screening and/or biopsy of the remaining breast or breasts. This study investigated the incidence of post-mastectomy imaging and biopsy. METHODS: A retrospective review of all unilateral mastectomy (UM) and bilateral mastectomy (BM) cases managed at a single institution was undertaken. Post-mastectomy imaging and biopsy rates were determined. RESULTS: Between 2009 and 2015, 185 UM and 200 BM cases managed for breast cancer were identified. The mean follow-up period was 30 months (range 3-75 months). For the patients with UM, imaging studies and biopsies done on the contralateral side were excluded given the standard of care for continued surveillance of the contralateral breast. Of the 185 UM patients, 19 (10%) underwent ipsilateral imaging (all ultrasounds) for physical examination findings, 11 (6%) underwent biopsy, and 2 (1%) had malignant findings. Of the 200 BM patients, 31 (15.5%) required imaging (29 ultrasounds and 2 MRIs), with 76% of the ultrasounds performed on the side with previous cancer. Subsequently, 16 (8%) of the BM patients had biopsy, with 11 (69%) of the 16 biopsies performed on the ipsilateral side. Three (1.5%) of the biopsies done on ipsilateral side demonstrated malignancy, whereas all the contralateral biopsies were benign. CONCLUSIONS: For 10-15.5% of patients who undergo mastectomy, either UM or BM, subsequent imaging is required, whereas 6-8% undergo biopsy. The yield of malignancy is low, approximately 1%. Thus, after mastectomy, the need for imaging and biopsy is not eliminated. This information is critical for patient understanding and expectation related to surgical decision making.


Assuntos
Carcinoma Ductal de Mama/diagnóstico por imagem , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/diagnóstico por imagem , Carcinoma Intraductal não Infiltrante/patologia , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Mama/diagnóstico por imagem , Mama/patologia , Carcinoma Ductal de Mama/cirurgia , Carcinoma Intraductal não Infiltrante/cirurgia , Feminino , Seguimentos , Humanos , Imagem por Ressonância Magnética , Mastectomia , Pessoa de Meia-Idade , Determinação de Necessidades de Cuidados de Saúde , Período Pós-Operatório , Estudos Retrospectivos , Ultrassonografia Mamária , Neoplasias Unilaterais da Mama/cirurgia
13.
Phys Med ; 52: 81-85, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30139613

RESUMO

Proton therapy has shown potential for reducing doses to normal tissues in breast cancer radiotherapy. However data on the impact of protons when including internal mammary nodes (IMN) in the target for breast radiotherapy is comparatively scarce. This study aimed to evaluate normal tissue doses when including the IMN in regional RT with scanned proton beams, with and without respiratory gating. The study cohort was composed of ten left-sided breast patients CT-scanned during enhanced inspiration gating (EIG) and free-breathing (FB). Proton plans were designed for the target including or excluding the IMN. Targets and organs-at-risk were delineated according to RTOG guidelines. Comparison was performed between dosimetric parameters characterizing target coverage and OAR radiation burden. Statistical significance of differences was tested using a paired, two-tailed Student's t-test. Inclusion of the IMN in the target volume led to a small increase of the cardiopulmonary burden. The largest differences were seen for the ipsilateral lung where the mean dose increased from 6.1 to 6.6 Gy (RBE) (P < 0.0001) in FB plans and from 6.9 to 7.4 Gy (RBE) (P = 0.003) in EIG plans. Target coverage parameters were very little affected by the inclusion of IMN into the treatment target. Radiotherapy with scanned proton beams has the potential of maintaining low cardiovascular burden when including the IMN into the target, irrespective of whether respiratory gating is used or not.


Assuntos
Linfonodos , Terapia com Prótons/métodos , Neoplasias Unilaterais da Mama/radioterapia , Coração/diagnóstico por imagem , Coração/efeitos da radiação , Humanos , Pulmão/diagnóstico por imagem , Pulmão/efeitos da radiação , Linfonodos/diagnóstico por imagem , Linfonodos/efeitos da radiação , Órgãos em Risco , Dosagem Radioterapêutica , Respiração , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/diagnóstico por imagem
14.
Phys Med ; 52: 86-92, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30139614

RESUMO

PURPOSE: To find the optimal dose weighting for hybrid volumetric modulated arc therapy (H-VMAT), a combination of conventional 3DCRT and VMAT plans for left sided chest wall and supraclavicular radiation therapy. METHODS & MATERIALS: 20 left-sided breast cancer patients who received adjuvant radiotherapy were considered for this study. To find the optimal weighting, 5 H-VMAT plans were generated for each study case by combining different dose proportions of 3DCRT and VMAT plans including: 90% 3DCRT/10% VMAT, 80% 3DCRT/20% VMAT, 70% 3DCRT/30% VMAT, 60% 3DCRT/40% VMAT, 50% 3DCRT/50% VMAT. Further field-in-field, optimal H-VMAT and VMAT alone plans were compared. RESULTS: All H-VMAT plans achieved the expected target coverage. A higher conformity index was achieved for 50% 3DCRT/50% VMAT plan, while better homogeneity index was achieved for 80% 3DCRT/20% VMAT plan. Mean and low doses were less in 90% 3DCRT/10% VMAT plan. Compared with other proportions, 80% 3DCRT/20% VMAT and 70% 3DCRT/30% VMAT weighted H-VMAT plans achieved balanced results for PTVs and OARs. CONCLUSION: The optimal dose mixture for H-VMAT technique is 70% to 80% for 3DCRT and 20% to 30% for VMAT. The optimal H-VMAT achieved balanced results for the PTVs and OARs compared with field-in-field and VMAT alone plans.


Assuntos
Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia , Humanos , Órgãos em Risco , Terapia com Prótons/métodos , Radiometria , Dosagem Radioterapêutica , Respiração , Técnicas de Imagem de Sincronização Respiratória , Estudos Retrospectivos , Parede Torácica/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/diagnóstico por imagem
15.
Radiat Oncol ; 13(1): 124, 2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-29973243

RESUMO

BACKGROUND: Heart-sparing techniques are time and resource intensive, although not all patients require the use of these strategies. This study evaluates the performance of different distance metrics in predicting the need for breath-hold radiotherapy in left-sided breast cancer patients receiving adjuvant radiotherapy. METHODS: Fifty left-sided breast cancer patients treated with breast conserving surgery and adjuvant radiotherapy to the breast from a single institution were retrospectively studied. The left breast and organs at risk were contoured in accordance to guidelines and a plan with tangents was obtained using the free-breathing CT in supine position. Heart (mean heart dose (MHD), heart V25 Gy) and left anterior descending artery dosimetry were computed and compared against distance metrics under investigation (Contact Heart, 4th Arch and 5th Arch). Recursive partitioning analysis (RPA) was used to determine optimal cut-points for distance metrics for dosimetric end points. Receiver operating characteristic curves and Pearson correlation coefficients were used to evaluate the association between distance metrics and dosimetric endpoints. Univariable and multivariable logistic regression analysis was performed to identify significant predictors of dosimetric end points. RESULTS: The mean MHD and heart V25 Gy were 2.3 Gy and 10.4 cm3, respectively. With tangents, constraints for MHD (< 1.7 Gy and V25 Gy < 10 cm3) were unattainable in 80% and 46% of patients, respectively. Optimal RPA thresholds included: Contact Heart (73 mm), 4th Arch (7 mm) and 5th Arch (41 mm). Of these, the 4th Arch had the highest overall accuracy, sensitivity, concordance index and correlation coefficient. All metrics were statistically significant predictors for MHD ≥ 1.7 Gy based on univariable logistic regression. Fifth Arch did not reach significance for heart V25 Gy ≥ 10 cm3. Fourth Arch was the only predictor to remain statistically significant after multivariable analysis. CONCLUSIONS: We propose a novel "4th Arch" metric as an accurate and practical tool to determine the need for breath-hold radiotherapy for left-sided breast cancer patients undergoing adjuvant radiotherapy with standard tangents. Further validation in an external cohort is necessary.


Assuntos
Suspensão da Respiração , Vasos Coronários/efeitos da radiação , Coração/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Neoplasias Unilaterais da Mama/radioterapia , Vasos Coronários/diagnóstico por imagem , Feminino , Coração/diagnóstico por imagem , Humanos , Pessoa de Meia-Idade , Análise Multivariada , Órgãos em Risco/diagnóstico por imagem , Curva ROC , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia Adjuvante , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/cirurgia
17.
PLoS One ; 13(5): e0195506, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29746482

RESUMO

BACKGROUND: Voluntary deep inspiration breath hold technique (vDIBH) is considered as the key to achieving the widest cardiac sparing in whole breast irradiation. Several techniques have been implemented to achieve a reproducible, fast and friendly treatment. The aim of the present study is to implement vDIBH using the ExacTrac (BrainLAB AG, Germany) monitoring system. METHODS: Women with left-sided breast cancer, younger than 50 years or with cardiac disease, underwent whole breast RT with vDIBH using the ExacTrac (BrainLAB AG, Germany) monitoring system. Simulations were performed with patients positioned supine on a breast board with both arms raised above the head. Five optical markers were placed on the skin around the border of the left breast gland and their position was referenced with ink marking. Each patient received a training session to find the individual deep inspiration level. Finally, a vDIBH CT was taken. All patients were also studied in free breathing (FB) in order to compare the dose distribution for PTV, heart and left anterior descending coronary artery (LAD). Pre-treatment verification was carried out through the ExacTrac (BrainLAB AG, Germany) system and verified with electronic portal imaging (EPI). Moreover, daily real time EPIs in during modality (captured during the beam delivery) were taken in order to check the reproducibility. RESULTS: 34 patients have been evaluated and 30 were eligible for vDIBH. Most patients showed small setup errors during the treatment course of below 5 mm in 94.9% of the recorded fields. Mean Displacement was less in cranio-caudal direction. Mean intra-fraction displacement was below 3 mm in all directions. vDIBH plans provided better cardiac dosimetry. CONCLUSIONS: vDIBH technique using ExacTrac (BrainLAB AG, Germany) monitoring system was applied with good reproducibility.


Assuntos
Suspensão da Respiração , Raios Infravermelhos , Dispositivos Ópticos , Planejamento da Radioterapia Assistida por Computador/métodos , Erros de Configuração em Radioterapia/prevenção & controle , Radioterapia Guiada por Imagem/instrumentação , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Adulto , Idoso , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Coração/efeitos da radiação , Humanos , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia
18.
Int J Radiat Oncol Biol Phys ; 100(1): 263-269, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29066123

RESUMO

PURPOSE: To assess the differences in unintended regional nodal irradiation between free breathing (FB) and deep-inspiration breath-hold (DIBH) during tangential field irradiation. METHODS AND MATERIALS: We randomly chose 32 patients from our database who underwent both DIBH and FB treatment planning. Contouring of the axillary lymph node levels (LI, LII, and LIII) was performed retrospectively according to the Radiation Therapy Oncology Group contouring atlas. We assessed the center of mass of each level and the planning target volume, as well as the dose distribution (Dmean, Dmedian, Dmax, Dmin, V30, and V40) in the lymph node levels I-III. Subsequently center of mass movement and dose changes due to deep inspiration treatment planning were calculated. RESULTS: All lymph node levels showed significant (P<.001) movement in anterior and cranial directions due to DIBH. The overall median movement (range) in the x (lateral), y (anterior-posterior), and z (cranio-caudal) directions was 0.1 cm (0.0-1.1 cm), 0.9 cm (0.1-2.0 cm), and 1.2 cm (0.0-2.6 cm), respectively. Movement of the planning target volume showed significant correlation (r=0.72, r=0.63, r=0.63; P<.05) with levels I-III. The average Dmean during FB/DIBH was as follows: LI 33.9 Gy/30.8 Gy (P<.001), LII 23.7 Gy/24.1 Gy (P=.74), and LIII 14.0 Gy/15.6 Gy (P=.14). V30 was as follows: LI 63.8%/56.5% (P<.001), LII 44.6%/45.5% (P=.76), and LIII 24.2%/27.8% (P<.05). V40 was as follows: LI 58.9%/51.0% (P<.001), LII 39.3%/40.1% (P=.79), and LIII 20.4%/23.9% (P<.05). CONCLUSIONS: Deep-inspiration breath-hold results in a significant dose reduction in level I. Only minor changes in dose distribution were recorded for levels II and III. Thus, DIBH seems to have an impact on unintended regional nodal irradiation as compared with FB.


Assuntos
Suspensão da Respiração , Inalação , Linfonodos/diagnóstico por imagem , Linfonodos/efeitos da radiação , Movimentos dos Órgãos , Neoplasias Unilaterais da Mama/radioterapia , Axila/diagnóstico por imagem , Feminino , Humanos , Irradiação Linfática , Tratamentos com Preservação do Órgão , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Adjuvante , Respiração , Neoplasias Unilaterais da Mama/diagnóstico por imagem
19.
Int J Radiat Oncol Biol Phys ; 99(1): 182-190, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28816145

RESUMO

PURPOSE: We examined the utility of echocardiographic 2-dimensional speckle tracking strain imaging (SI) for the evaluation of segmental myocardial dysfunction before and after radiation therapy (RT) and the relationship to dose exposure. METHODS AND MATERIALS: We prospectively recruited 40 women with left-sided breast cancer, undergoing only adjuvant RT to the left chest. Comparisons of traditional echocardiographic parameters and SI parameters at baseline and 6 weeks after RT were analyzed. Regional strain and strain rate (SR) parameters were obtained from all 18 left ventricular segments. The correlation of change in strain parameters with segmental radiation dose was examined. RESULTS: We observed a significant reduction in global and segmental systolic strain parameters at 6 weeks after RT compared with baseline, with the largest decrement in the apical segments; this corresponded with the segments receiving the highest radiation dose exposure (apical peak systolic strain of -21.21% ± 3.49% before RT vs -18.69% ± 3.34% after RT, percentage change of 11.88%, P=.002; apical peak systolic SR of -1.17 ± 0.24 s-1 before RT vs -1.04 ± 0.19 s-1 after RT, percentage change of 11.11%, P=.008). There was a modest correlation between the apical segment systolic strain reduction and radiation dose exposure (apical segment Δ change and apical radiation dose, r=0.345, P=.031; apical segment percentage change and apical radiation dose, r=0.346, P=.031). A significant reduction in early diastolic SR was observed in the apical segments after treatment compared with baseline (apical early diastolic SR, 1.54 ± 0.45 s-1 before RT vs 1.35 ± 0.33 after RT s-1; percentage change, 12.34%; P=.034). CONCLUSIONS: Two-dimensional SI detected dose-related regional myocardial dysfunction in the acute phase after RT in chemotherapy-naive left-sided breast cancer patients. Although the long-term effects remain unknown, this imaging modality may have a potential role in the evaluation of irradiation-related cardiotoxicity.


Assuntos
Coração/efeitos da radiação , Neoplasias Unilaterais da Mama/radioterapia , Disfunção Ventricular Esquerda/diagnóstico por imagem , Relação Dose-Resposta à Radiação , Ecocardiografia Doppler/métodos , Feminino , Coração/diagnóstico por imagem , Humanos , Mastectomia Segmentar/métodos , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Prospectivos , Doses de Radiação , Sístole/fisiologia , Sístole/efeitos da radiação , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/cirurgia
20.
Pract Radiat Oncol ; 7(6): e361-e367, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28666899

RESUMO

PURPOSE: The purpose of this study was to evaluate the utility of moderate deep inspiration breathhold (mDIBH) in reducing heart exposure in left breast cancer patients who have unfavorable cardiac anatomy and need internal mammary lymph node (IMLN) radiation therapy (RT). METHODS AND MATERIALS: We used maximum heart distance (MHD), defined as the maximum distance of the heart within the treatment field, >1 cm as a surrogate for unfavorable cardiac anatomy. Twenty-two left breast cancer patients with unfavorable cardiac anatomy requiring IMLN-RT underwent free-breathing (FB) and mDIBH computed tomography simulation and planning. Three-dimensional partially wide tangents (3D-PWTs) and intensity modulated RT plans were generated. Dose-volume histograms were used to compare heart and lung dosimetric parameters. Duration of treatment delivery was recorded for all fractions. RESULTS: MHD decreased significantly in mDIBH scans. mDIBH significantly reduced mean heart dose (222.7 vs 578.4 cGy; P < .0001) and percentage of left lung receiving doses ≥20 Gy (V20; 31.93 vs 38.41%; P = .0006) in both 3D-PWT and intensity modulated RT plans. The change in MHD after breathhold reliably predicted mean heart dose reduction after mDIBH. Radiation was effectively delivered in 11.31 ± 3.40 minutes with an average of 10.06 ± 2.74 breathholds per fraction. CONCLUSIONS: mDIBH is efficient and can effectively decrease mean heart dose in patients with unfavorable cardiac anatomy who need IMLN-RT, thus simplifying planning and delivery for them. The reduction in mean heart dose is proportional to the reduction in maximum heart distance.


Assuntos
Suspensão da Respiração , Dosagem Radioterapêutica , Neoplasias Unilaterais da Mama/radioterapia , Feminino , Coração/anatomia & histologia , Coração/efeitos da radiação , Humanos , Linfonodos/patologia , Linfonodos/efeitos da radiação , Tratamentos com Preservação do Órgão , Fatores de Tempo , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/cirurgia
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