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1.
Phys Med ; 72: 88-95, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32247227

RESUMO

PURPOSE: This study aims to investigate the feasibility of using convolutional neural networks to predict an accurate and high resolution dose distribution from an approximated and low resolution input dose. METHODS: Sixty-six patients were treated for prostate cancer with VMAT. We created the treatment plans using the Acuros XB algorithm with 2 mm grid size, followed by the dose calculated using the anisotropic analytical algorithm with 5 mm grid with the same plan parameters. U-net model was used to predict 2 mm grid dose from 5 mm grid dose. We investigated the two models differing for the training data used as input, one used just the low resolution dose (D model) and the other combined the low resolution dose with CT data (DC model). Dice similarity coefficient (DSC) was calculated to ascertain how well the shape of the dose-volume is matched. We conducted gamma analysis for the following: DVH from the two models and the reference DVH for all prostate structures. RESULTS: The DSC values in the DC model were significantly higher than those in the D model (p < 0.01). For the CTV, PTV, and bladder, the gamma passing rates in the DC model were significantly higher than those in the D model (p < 0.002-0.02). The mean doses in the CTV and PTV for the DC model were significantly better matched to those in the reference dose (p < 0.0001). CONCLUSIONS: The proposed U-net model with dose and CT image used as input predicted more accurate dose.


Assuntos
Redes Neurais de Computação , Neoplasias da Próstata/radioterapia , Doses de Radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada , Humanos , Masculino , Neoplasias da Próstata/diagnóstico por imagem , Dosagem Radioterapêutica , Tomografia Computadorizada por Raios X
2.
J Radiat Res ; 60(5): 586-594, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31125068

RESUMO

This study aims to produce non-contrast computed tomography (CT) images using a deep convolutional neural network (CNN) for imaging. Twenty-nine patients were selected. CT images were acquired without and with a contrast enhancement medium. The transverse images were divided into 64 × 64 pixels. This resulted in 14 723 patches in total for both non-contrast and contrast-enhanced CT image pairs. The proposed CNN model comprises five two-dimensional (2D) convolution layers with one shortcut path. For comparison, the U-net model, which comprises five 2D convolution layers interleaved with pooling and unpooling layers, was used. Training was performed in 24 patients and, for testing of trained models, another 5 patients were used. For quantitative evaluation, 50 regions of interest (ROIs) were selected on the reference contrast-enhanced image of the test data, and the mean pixel value of the ROIs was calculated. The mean pixel values of the ROIs at the same location on the reference non-contrast image and the predicted non-contrast image were calculated and those values were compared. Regarding the quantitative analysis, the difference in mean pixel value between the reference contrast-enhanced image and the predicted non-contrast image was significant (P < 0.0001) for both models. Significant differences in pixels (P < 0.0001) were found using the U-net model; in contrast, there was no significant difference using the proposed CNN model when comparing the reference non-contrast images and the predicted non-contrast images. Using the proposed CNN model, the contrast-enhanced region was satisfactorily reduced.


Assuntos
Meios de Contraste/química , Redes Neurais de Computação , Tomografia Computadorizada por Raios X , Relação Dose-Resposta à Radiação , Humanos , Fatores de Tempo
3.
Behav Sci (Basel) ; 8(10)2018 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-30274335

RESUMO

This study hypothesized that moisturizing treatment of the skin has a positive effect on psychological and physiological aspects. In this experiment, the effect of touch with moisturizer for two minutes on the lower legs was measured in terms of brain activity, heart rate, and center of gravity unrest (X axis) in 10 healthy male and female experiment participants. The Right Laterality Ratio Score decreased after treatment, suggesting a relaxation effect of the treatment. Although it was not statistically significant, a decrease was observed. Heart rate decreased after the treatment at a level of statistical significance (p < 0.01), suggesting a relaxation effect of the treatment. Center of gravity unrest (X axis) increased after the treatment with statistical significance (p < 0.05). Therefore, skin moisturizing treatment was found to be effective both psychologically and physiologically in this experiment. The finding is expected to be applied to the field of nursing to support elderly people to enhance their mental well-being and balancing ability.

4.
Behav Sci (Basel) ; 8(10)2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30336552

RESUMO

Two experiments were conducted to measure both the psychological and physiological effects of touching on the HPA axis related parts of the body. HPA stands for the hypothalamus, pituitary, and adrenal. One experiment was conducted with a group of healthy experiment participants, and another was with a group of traumatized participants who had Adverse Childhood Experiences (ACE). In the experiments, the back of an experiment participant was touched, where a kidney-adrenal was supposed to reside, and both the psychological and physiological effects were measured. As a result, respiratory sinus arrhythmia (RSA), an indicator of the parasympathetic nerve system function and, especially, an indicator of the social engagement system increased, by a statistically significant degree, as a consequence of HPA touching in both the healthy and the trauma group, in comparison with the control. The traumatized participants had a lower RSA, and this was increased by HPA touching, accompanied by a decrease of the heart rate. It is worth noting that the social engagement function was possibly enhanced by HPA touching, especially in the trauma group, whose members tend to have difficulty being pro-social. This touching method is very simple, so it can be administered not only by oneself, but also by psycho-therapists and body workers in order to enhance both psychological and physiological well-being.

5.
Cardiovasc Drugs Ther ; 31(4): 401-411, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28779371

RESUMO

PURPOSE: We evaluated the effects of an alpha-glucosidase inhibitor, voglibose, on cardiovascular events in patients with a previous myocardial infarction (MI) and impaired glucose tolerance (IGT). METHODS: This prospective, randomized, open, blinded-endpoint study was conducted in 112 hospitals and clinics in Japan in 3000 subjects with both previous MI and IGT receiving voglibose (0.6 mg/day, n = 424) or no drugs (n = 435) for 2 years. The Data and Safety Monitoring Board (DSMB) recommended discontinuation of the study in June 2012 after an interim analysis when the outcomes of 859 subjects were obtained. The primary endpoint was cardiovascular events including cardiovascular death, nonfatal MI, nonfatal unstable angina, nonfatal stroke, and percutaneous coronary intervention/coronary artery bypass graft. Secondary endpoints included individual components of the primary endpoint in addition to all-cause mortality and hospitalization due to heart failure. RESULTS: The age, ratio of males, and HbA1C were 65 vs. 65 years, 86 vs. 87%, and 5.6 vs. 5.5% in the groups with and without voglibose, respectively. Voglibose improved IGT; however, Kaplan-Meier analysis showed no significant between-group difference with respect to cardiovascular events [12.5% with voglibose vs. 10.1% without voglibose for the primary endpoint (95% confidence interval, 0.82-1.86)]; there were no significant differences in secondary endpoints. CONCLUSION: Although voglibose effectively treated IGT, no additional benefits for cardiovascular events in patients with previous MI and IGT were observed. Voglibose may not be a contributing therapy to the secondary prevention in patients with MI and IGT. TRIAL REGISTRATION: Clinicaltrials.gov number: NCT00212017.


Assuntos
Doenças Cardiovasculares/prevenção & controle , Intolerância à Glucose/tratamento farmacológico , Inositol/análogos & derivados , Infarto do Miocárdio/prevenção & controle , Idoso , Doenças Cardiovasculares/epidemiologia , Feminino , Inibidores de Glicosídeo Hidrolases/uso terapêutico , Humanos , Hipoglicemiantes/uso terapêutico , Inositol/uso terapêutico , Japão , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Prevenção Secundária , Resultado do Tratamento
6.
PLoS One ; 12(3): e0173643, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28282417

RESUMO

This study evaluated a method for prostate intensity-modulated radiation therapy (IMRT) based on edge-enhanced (EE) intensity in the presence of intrafraction organ deformation using the data of 37 patients treated with step-and-shoot IMRT. On the assumption that the patient setup error was already accounted for by image guidance, only organ deformation over the treatment course was considered. Once the clinical target volume (CTV), rectum, and bladder were delineated and assigned dose constraints for dose optimization, each voxel in the CTV derived from the DICOM RT-dose grid could have a stochastic dose from the different voxel location according to the probability density function as an organ deformation. The stochastic dose for the CTV was calculated as the mean dose at the location through changing the voxel location randomly 1000 times. In the EE approach, the underdose region in the CTV was delineated and optimized with higher dose constraints that resulted in an edge-enhanced intensity beam to the CTV. This was compared to a planning target volume (PTV) margin (PM) approach in which a CTV to PTV margin equivalent to the magnitude of organ deformation was added to obtain an optimized dose distribution. The total monitor units, number of segments, and conformity index were compared between the two approaches, and the dose based on the organ deformation of the CTV, rectum, and bladder was evaluated. The total monitor units, number of segments, and conformity index were significantly lower with the EE approach than with the PM approach, while maintaining the dose coverage to the CTV with organ deformation. The dose to the rectum and bladder were significantly reduced in the EE approach compared with the PM approach. We conclude that the EE approach is superior to the PM with regard to intrafraction organ deformation.


Assuntos
Próstata/patologia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/radioterapia , Radioterapia de Intensidade Modulada/métodos , Humanos , Masculino , Reto/patologia , Bexiga Urinária/patologia
7.
J Radiat Res ; 58(5): 675-684, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28199706

RESUMO

The purpose of this study was to correlate the modulation complexity score (MCS) with organ location and to predict potential dose errors for organs before beam delivery for intensity-modulated radiation therapy (IMRT) dosimetry. Sixteen head and neck cancer patients treated with IMRT were selected. Distribution of the relative dose error on each beam was performed using forward projection to the planned dose to compute the predicted dose after doing per-beam quality assurance. Original organ-specific modulation complexity score (oMCS) was created based on a modified MLC, which depended on organ location. First, MCS was calculated based on the change in leaf position between adjacent MLC leaves. Second, the segment edge map (SEM) calculated from the intensity map for each beam was applied to the calculation volume. The oMCS with segment edge (oMCSedge) was derived from the product of oMCS and SEM. The correlation between the dose errors (planned and predicted) and oMCSedge values was evaluated for the target and organs at risk. We have also expanded the original MCS concept to oMCSedge including the organ location. We observed a moderate correlation between the dose errors and oMCSedge for all organs and volumes of interest except the gross tumor volume, brain stem, and spinal cord. In other organs, a moderate improvement in sensitivity was observed on the SEM, which was correlated with dose errors. Although the implementation of oMCSedge would be impractical for normal clinical settings, it is expected that oMCSedge would help a treatment planner to judge whether or not the treatment plan would be acceptably delivered.


Assuntos
Relação Dose-Resposta à Radiação , Especificidade de Órgãos/efeitos da radiação , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos
8.
J Radiat Res ; 57(6): 691-701, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27534793

RESUMO

The purpose of this study was to evaluate the impact of the motion interplay effect in early-stage left-sided breast cancer intensity-modulated radiation therapy (IMRT), incorporating the radiobiological gamma index (RGI). The IMRT dosimetry for various breathing amplitudes and cycles was investigated in 10 patients. The predicted dose was calculated using the convolution of segmented measured doses. The physical gamma index (PGI) of the planning target volume (PTV) and the organs at risk (OAR) was calculated by comparing the original with the predicted dose distributions. The RGI was calculated from the PGI using the tumor control probability (TCP) and the normal tissue complication probability (NTCP). The predicted mean dose and the generalized equivalent uniform dose (gEUD) to the target with various breathing amplitudes were lower than the original dose (P < 0.01). The predicted mean dose and gEUD to the OARs with motion were higher than for the original dose to the OARs (P < 0.01). However, the predicted data did not differ significantly between the various breathing cycles for either the PTV or the OARs. The mean RGI gamma passing rate for the PTV was higher than that for the PGI (P < 0.01), and for OARs, the RGI values were higher than those for the PGI (P < 0.01). The gamma passing rates of the RGI for the target and the OARs other than the contralateral lung differed significantly from those of the PGI under organ motion. Provided an NTCP value <0.05 is considered acceptable, it may be possible, by taking breathing motion into consideration, to escalate the dose to achieve the PTV coverage without compromising the TCP.


Assuntos
Neoplasias da Mama/radioterapia , Radioterapia de Intensidade Modulada/métodos , Feminino , Humanos , Pulmão/efeitos da radiação , Movimento (Física) , Garantia da Qualidade dos Cuidados de Saúde , Doses de Radiação , Radiometria , Planejamento da Radioterapia Assistida por Computador , Reprodutibilidade dos Testes , Respiração
9.
J Appl Clin Med Phys ; 17(1): 259-271, 2016 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-26894363

RESUMO

Patient-specific quality assurance for intensity-modulated radiation therapy (IMRT) dose verification is essential. The aim of this study is to provide a new method based on the relative error distribution by comparing the fluence map from the treatment planning system (TPS) and the incident fluence deconvolved from the electronic portal imaging device (EPID) images. This method is validated for 10 head and neck IMRT cases. The fluence map of each beam was exported from the TPS and EPID images of the treatment beams were acquired. Measured EPID images were deconvolved to the incident fluence with proper corrections. The relative error distribution between the TPS fluence map and the incident fluence from the EPID was created. This was also created for a 2D diode array detector. The absolute point dose was measured with an ionization chamber, and the dose distribution was measured by a radiochromic film. In three cases, MLC leaf positions were intentionally changed to create the dose error as much as 5% against the planned dose and our fluence-based method was tested using gamma index. Absolute errors between the predicted dose of 2D diode detector and of our method and measurements were 1.26% ± 0.65% and 0.78% ± 0.81% respectively. The gamma passing rate (3% global / 3 mm) of the TPS was higher than that of the 2D diode detector (p< 0.02), and lower than that of the EPID (p < 0.04). The gamma passing rate (2% global / 2 mm) of the TPS was higher than that of the 2D diode detector, while the gamma passing rate of the TPS was lower than that of EPID (p < 0.02). For three modified plans, the predicted dose errors against the measured dose were 1.10%, 2.14%, and -0.87%. The predicted dose distributions from the EPID were well matched to the measurements. Our fluence-based method provides very accurate dosimetry for IMRT patients. The method is simple and can be adapted to any clinic for complex cases.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador/instrumentação , Neoplasias/radioterapia , Aceleradores de Partículas/instrumentação , Imagens de Fantasmas , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Humanos , Neoplasias/patologia , Dosagem Radioterapêutica
10.
Sci Rep ; 5: 16868, 2015 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-26585690

RESUMO

During ice-free periods, the Northern Sea Route (NSR) could be an attractive shipping route. The decline in Arctic sea-ice extent, however, could be associated with an increase in the frequency of the causes of severe weather phenomena, and high wind-driven waves and the advection of sea ice could make ship navigation along the NSR difficult. Accurate forecasts of weather and sea ice are desirable for safe navigation, but large uncertainties exist in current forecasts, partly owing to the sparse observational network over the Arctic Ocean. Here, we show that the incorporation of additional Arctic observations improves the initial analysis and enhances the skill of weather and sea-ice forecasts, the application of which has socioeconomic benefits. Comparison of 63-member ensemble atmospheric forecasts, using different initial data sets, revealed that additional Arctic radiosonde observations were useful for predicting a persistent strong wind event. The sea-ice forecast, initialised by the wind fields that included the effects of the observations, skilfully predicted rapid wind-driven sea-ice advection along the NSR.

11.
Clin J Gastroenterol ; 8(5): 264-7, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26275390

RESUMO

A 62-year-old male was admitted to our hospital due to left lower abdominal pain. Three days before admission, he ate seafood in a Japanese restaurant. Two days before admission, he suffered from intermittent left lower abdominal pain. One day before admission, he developed a high fever and subsequently visited our hospital the following day. Localized tenderness and rebound pain were observed in the left lower abdomen, and C-reactive protein was elevated. Computed tomography revealed a linear high-density object in the distal portion of the small intestine accompanied by edema of the wall, suggesting penetration by something like a fishbone. On the ninth hospital day, double-balloon endoscopy was performed via the transanal route. Yellow foreign material was found in the ileum and was then successfully removed with biopsy forceps. The removed material measured 3 mm in width, 3 cm in length and was slightly curved. It proved to be a bone of the forefoot of a soft-shelled turtle, which had been included on the menu of the restaurant. The patient was completely cured and discharged on the 14th hospital day.


Assuntos
Endoscopia Gastrointestinal , Corpos Estranhos/complicações , Corpos Estranhos/cirurgia , Íleo/lesões , Alimentos Marinhos/efeitos adversos , Dor Abdominal/etiologia , Animais , Osso e Ossos , Corpos Estranhos/diagnóstico por imagem , Humanos , Íleo/diagnóstico por imagem , Íleo/cirurgia , Masculino , Pessoa de Meia-Idade , Radiografia , Tartarugas
12.
Int J Radiat Oncol Biol Phys ; 92(4): 779-86, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25936816

RESUMO

PURPOSE: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). METHODS AND MATERIALS: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV, spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. RESULTS: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03-.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. CONCLUSIONS: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.


Assuntos
Algoritmos , Neoplasias de Cabeça e Pescoço/radioterapia , Órgãos em Risco/efeitos da radiação , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Cabeça do Fêmur/efeitos da radiação , Humanos , Masculino , Órgãos em Risco/diagnóstico por imagem , Glândula Parótida/efeitos da radiação , Próstata/efeitos da radiação , Garantia da Qualidade dos Cuidados de Saúde , Radiografia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada/normas , Reto/efeitos da radiação , Medula Espinal , Bexiga Urinária/efeitos da radiação
13.
J Radiat Res ; 56(3): 594-605, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25742866

RESUMO

Pretreatment dose verification with beam-by-beam analysis for intensity-modulated radiation therapy (IMRT) is commonly performed with a gantry angle of 0° using a 2D diode detector array. Any changes in multileaf collimator (MLC) position between the actual treatment gantry angle and 0° may result in deviations from the planned dose. We evaluated the effects of MLC positioning errors between the actual treatment gantry angles and nominal gantry angles. A gantry angle correction (GAC) factor was generated by performing a non-gap test at various gantry angles using an electronic portal imaging device (EPID). To convert pixel intensity to dose at the MLC abutment positions, a non-gap test was performed using an EPID and a film at 0° gantry angle. We then assessed the correlations between pixel intensities and doses. Beam-by-beam analyses for 15 prostate IMRT cases as patient-specific quality assurance were performed with a 2D diode detector array at 0° gantry angle to determine the relative dose error for each beam. The resulting relative dose error with or without GAC was added back to the original dose grid for each beam. We compared the predicted dose distributions with or without GAC for film measurements to validate GAC effects. A gamma pass rate with a tolerance of 2%/2 mm was used to evaluate these dose distributions. The gamma pass rate with GAC was higher than that without GAC (P = 0.01). The predicted dose distribution improved with GAC, although the dosimetric effect to a patient was minimal.


Assuntos
Algoritmos , Artefatos , Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Dosagem Radioterapêutica , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
14.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 70(10): 1160-5, 2014 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-25327426

RESUMO

A semi-solid polymer dosimetry system using agar was developed to measure the dose distribution close to metallic implants. Dosimetry of heterogeneous fields where electron density markedly varies is often problematic. This prompted us to develop a polymer gel dosimetry technique using agar to measure the dose distribution near substance boundaries. Varying the concentration of an oxygen scavenger (tetra-hydroxymethyl phosphonium chloride) showed the absorbed dose and transverse relaxation rate of the magnetic resonance signal to be linear between 3 and 12 Gy. Although a change in the dosimeter due to oxidization was observed in room air after 24 hours, no such effects were observed in the first 4 hours. The dose distribution around the metal implants was measured using agar dosimetry. The metals tested were a lead rod, a titanium hip joint, and a metallic stent. A maximum 30% dose increase was observed near the lead rod, but only a 3% increase in the absorbed dose was noted near the surface of the titanium hip joint and metallic stent. Semi-solid polymer dosimetry using agar thus appears to be a useful method for dosimetry around metallic substances.


Assuntos
Próteses e Implantes , Radiometria , Reagentes de Ligações Cruzadas/química , Géis/química , Metais , Polímeros/química , Radiometria/métodos
15.
J Appl Clin Med Phys ; 15(5): 4874, 2014 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-25207574

RESUMO

Dose verifications for intensity-modulated radiation therapy (IMRT) are generally performed once before treatment. A 39-fraction treatment course for prostate cancer delivers a dose prescription of 78 Gy in eight weeks. Any changes in multileaf collimator leaf position over the treatment course may affect the dosimetry. To evaluate the magnitude of deviations from the predicted dose over an entire treatment course with MLC leaf calibrations performed every two weeks, we tracked weekly changes in relative dose error distributions measured with two-dimensional (2D) beam-by-beam analysis. We compared the dosimetric results from 20 consecutive patient-specific IMRT quality assurance (QA) tests using beam-by-beam analysis and a 2D diode detector array to the dose plans calculated by the treatment planning system (TPS). We added back the resulting relative dose error measured weekly into the original dose grid for each beam. To validate the prediction method, the predicted doses and dose distributions were compared to the measurements using an ionization chamber and film. The predicted doses were in good agreement, within 2% of the measured doses, and the predicted dose distributions also presented good agreement with the measured distributions. Dose verification results measured once as a pretreatment QA test were not completely stable, as results of weekly beam-by-beam analysis showed some variation. Because dosimetric errors throughout the treatment course were averaged, the overall dosimetric impact to patients was small.


Assuntos
Neoplasias da Próstata/radioterapia , Radiometria/instrumentação , Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/instrumentação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Masculino , Dosagem Radioterapêutica , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
J Radiat Res ; 55(1): 191-9, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-23979076

RESUMO

A linear accelerator vendor and the AAPM TG-142 report propose that quality assurance testing for image-guided devices such megavoltage cone-beam CT (MV-CBCT) be conducted on a monthly basis. In clinical settings, however, unpredictable errors such as image artifacts can occur even when quality assurance results performed at this frequency are within tolerance limits. Here, we evaluated the imaging performance of MV-CBCT on a weekly basis for ∼ 1 year using a Siemens ONCOR machine with a 6-MV X-ray and an image-quality phantom. Image acquisition was undertaken using 15 monitor units. Geometric distortion was evaluated with beads evenly distributed in the phantom, and the results were compared with the expected position in three dimensions. Image-quality characteristics of the system were measured and assessed qualitatively and quantitatively, including image noise and uniformity, low-contrast resolution, high-contrast resolution and spatial resolution. All evaluations were performed 100 times each. For geometric distortion, deviation between the measured and expected values was within the tolerance limit of 2 mm. However, a subtle systematic error was found which meant that the phantom was rotated slightly in a clockwise manner, possibly due to geometry calibration of the MV-CBCT system. Regarding image noise and uniformity, two incidents over tolerance occurred in 100 measurements. This phenomenon disappeared after dose calibration of beam output for MV-CBCT. In contrast, all results for low-contrast resolution, high-contrast resolution and spatial resolution were within their respective tolerances.


Assuntos
Artefatos , Tomografia Computadorizada de Feixe Cônico/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Radioterapia Guiada por Imagem/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de Tempo
17.
J Radiat Res ; 53(5): 798-806, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22843372

RESUMO

We investigated an electronic portal image device (EPID)-based method to see whether it provides effective and accurate relative dose measurement at abutment leaves in terms of positional errors of the multi-leaf collimator (MLC) leaf position. A Siemens ONCOR machine was used. For the garden fence test, a rectangular field (0.2 20 cm) was sequentially irradiated 11 times at 2-cm intervals. Deviations from planned leaf positions were calculated. For the nongap test, relative doses at the MLC abutment region were evaluated by sequential irradiation of a rectangular field (2 20 cm) 10 times with a MLC separation of 2 cm without a leaf gap. The integral signal in a region of interest was set to position A (between leaves) and B (neighbor of A). A pixel value at position B was used as background and the pixel ratio (A/B 100) was calculated. Both tests were performed at four gantry angles (0, 90, 180 and 270°) four times over 1 month. For the nongap test the difference in pixel ratio between the first and last period was calculated. Regarding results, average deviations from planned positions with the garden fence test were within 0.5 mm at all gantry angles, and at gantry angles of 90 and 270° tended to decrease gradually over the month. For the nongap test, pixel ratio tended to increase gradually in all leaves, leading to a decrease in relative doses at abutment regions. This phenomenon was affected by both gravity arising from the gantry angle, and the hardware-associated contraction of field size with this type of machine.


Assuntos
Radioterapia de Intensidade Modulada/normas , Humanos , Neoplasias/radioterapia , Garantia da Qualidade dos Cuidados de Saúde/métodos , Planejamento da Radioterapia Assistida por Computador/instrumentação , Planejamento da Radioterapia Assistida por Computador/normas , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia de Intensidade Modulada/instrumentação , Radioterapia de Intensidade Modulada/estatística & dados numéricos
18.
Clin J Gastroenterol ; 2(6): 384-387, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26192791

RESUMO

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of gastrointestinal tract, and bleeding is among the primary symptoms. If the tumor is located in the small intestine, diagnosis might be difficult because of its inaccessibility by endoscope. This report presents a case of duodenal GIST diagnosed with the aid of diffusion-weighted (DW) magnetic resonance imaging (MRI). A 66-year-old male was admitted to the hospital because of shortness of breath and melena. The patient demonstrated marked anemia. Esophagogastroduodenoscopy and colonoscopy revealed no involvement of the mucosa of the gastrointestinal tract in regard to the observed bleeding. Thereafter, computed tomography was done and showed a tumorous lesion 4.2 cm in diameter located around the ligament of Treitz. The area showed significant high intensity by DW-MRI, strongly suggesting malignant character. Examination with a long endoscope demonstrated a large submucosal tumor with wide ulceration located at the third portion of the duodenum. The biopsy sample contained spindle-shaped cells that were positive for CD34 and c-kit on histochemistry, and the tumor was diagnosed as GIST. The patient underwent surgery and survived for 16 months without any recurrence.

19.
Pathol Int ; 58(7): 432-5, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18577112

RESUMO

Herein is described two patients with early-stage primary malignant melanoma of the esophagus with long-term survival who were treated with esophagectomy. Both tumors had similar pathological findings, and were mainly at the stage of radial growth phase. Widespread melanoses were present in the mucosa surrounding the tumors in both cases. The two patients recovered uneventfully after surgery and were in remission at follow up of 33 months and 53 months.


Assuntos
Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Melanoma/mortalidade , Melanoma/patologia , Idoso , Neoplasias Esofágicas/cirurgia , Esofagectomia , Humanos , Imuno-Histoquímica , Masculino , Melanoma/cirurgia , Pessoa de Meia-Idade
20.
Psychiatry Clin Neurosci ; 60(5): 590-7, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16958943

RESUMO

This study examined the direct effects of short-term psychoeducation on relatives of inpatients with schizophrenia, with the goal of introducing this type of support program into standard care. The subjects were 46 relatives of inpatients with schizophrenia who attended three or four sessions of psychoeducation. Levels of anxiety and subjective burden and distress were measured before and after sessions using self-administered rating scales. In addition, levels of expressed emotion were also measured. Results showed that both state and trait anxiety on the State-Trait Anxiety Inventory were significantly lower after psychoeducational intervention than before intervention. In addition, subjective burden and distress reported by the family significantly decreased on the subscales for family confusion resulting from a lack of knowledge of the illness and anxiety about the future, subjective burden and depression resulting from the patient's illness, and difficulties in the relatives' relationships with the patient. Comparison of high and low expressed emotion families showed that the intervention was almost equally effective for the two groups. However, its effectiveness with regard to the subjective burden and depression experienced by the families was significantly greater among high expressed emotion families. The present study confirmed that family psychoeducation during hospitalization, even for a short period, is effective for all families, whether high or low expressed emotion. Moreover, the results suggested that the intervention may have a greater effect on emotional factors in high expressed emotion families than in low expressed emotion families.


Assuntos
Cuidadores/psicologia , Educação de Pacientes como Assunto , Esquizofrenia , Adulto , Ansiedade/diagnóstico , Ansiedade/psicologia , Efeitos Psicossociais da Doença , Emoções Manifestas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Recidiva , Psicologia do Esquizofrênico , Resultado do Tratamento
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