RESUMO
PURPOSE: A daily quality assurance (QA) check in proton therapy is ensuring that the range of each proton beam energy in water is accurate to 1 mm. This is important for ensuring that the tumor is adequately irradiated while minimizing damage to surrounding healthy tissue. It is also important to verify the total charge collected against the beam model. This work proposes a time-efficient method for verifying the range and total charge of proton beams at different energies using a multilayer Faraday collector (MLFC). METHODS: We used an MLFC-128-250 MeV comprising 128 layers of thin copper foils separated by thin insulating KaptonTM layers. Protons passing through the collector induce a charge on the metallic foils, which is integrated and measured by a multichannel electrometer. The charge deposition on the foils provides information about the beam range. RESULTS: Our results show that the proton beam range obtained using MLFC correlates closely with the range obtained from commissioning water tank measurements for all proton energies. Upon applying a range calibration factor, the maximum deviation is 0.4â g/cm2. The MLFC range showed no dependence on the number of monitor units and the source-to-surface distance. Range measurements collected over multiple weeks exhibited stability. The total charge collected agrees closely with the theoretical charge from the treatment planning system beam model for low- and mid-range energies. CONCLUSIONS: We have calibrated and commissioned the use of the MLFC to easily verify range and total charge of proton beams. This tool will improve the workflow efficiency of the proton QA.
Assuntos
Terapia com Prótons , Terapia com Prótons/métodos , Terapia com Prótons/instrumentação , Humanos , Dosagem Radioterapêutica , Prótons , Planejamento da Radioterapia Assistida por Computador/métodos , Calibragem , Garantia da Qualidade dos Cuidados de Saúde , Radiometria/métodos , Neoplasias/radioterapiaRESUMO
OBJECTIVE: To compare thyroid cancer incidence rates and trends between Korean, non-Korean Asian, and non-Hispanic White populations in the United States, and between the US Korean population and the South Korean population. METHOD: Population-based analysis of cancer incidence data. Cases of thyroid cancer diagnosed during 1999-2014 from the Korean Central Cancer Registry (KCCR) and the Surveillance, Epidemiology, and End Results (SEER) 9 detailed Asian/Pacific Islander subgroup incidence and population dataset were included. Incidence rates were obtained from the datasets, and annual percent change (APC) of the incidence rates was calculated using Joinpoint regression analysis. RESULTS: Thyroid cancer incidence rate for 1999-2014 was significantly higher for South Korea (48.05 [95% CI 47.89-48.22] per 100,000 person-years) than for the US Korean population (11.12 [95% CI 10.49-11.78] per 100,000 person-years), which was slightly higher than the Non-Korean Asian population (10.23 [95% CI 10.02-10.43] per 100,000 person-years), and slightly lower than the Non-Hispanic White population (12.78 [95% CI 12.69-12.87] per 100,000 person-years). Incidence rates in South Korea increased dramatically (average APC 17.9, 95% CI 16.0-19.9), significantly higher than the US Korean population (average APC 5.0, 95% CI 3.1-6.8), which was similar to the non-Korean Asian (average APC 2.5, 95% CI 0.9-4.2) and the non-Hispanic White (average APC 5.1, 95% CI 4.7-5.6) populations. CONCLUSIONS: South Korea's high thyroid cancer incidence rates cannot be attributed to genetic factors, but are likely due to health care system factors. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:4156-4160, 2024.
Assuntos
Programa de SEER , Neoplasias da Glândula Tireoide , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Asiático/estatística & dados numéricos , Incidência , Sistema de Registros , República da Coreia/epidemiologia , Neoplasias da Glândula Tireoide/epidemiologia , Neoplasias da Glândula Tireoide/etnologia , Estados Unidos/epidemiologia , População Branca/estatística & dados numéricos , População do Leste Asiático/estatística & dados numéricosRESUMO
OBJECTIVES: To assess the correlation of the resected and ischaemic volume (RAIV), which is a preoperatively calculated volume of nephron loss, with the amount of postoperative renal function (PRF) decline after minimally invasive partial nephrectomy (PN) in a multi-institutional dataset. PATIENTS AND METHODS: We identified 348 patients from March 2005 to December 2013 at six institutions. Data on all cases of laparoscopic (n = 85) and robot-assisted PN (n = 263) performed were retrospectively gathered. Univariable and multivariable linear regression analyses were used to identify the associations between various time points of PRF and the RAIV, as a continuous variable. RESULTS: The mean (sd) RAIV was 24.2 (29.2) cm3 . The mean preoperative estimated glomerular filtration rate (eGFR) and the eGFRs at postoperative day 1, 6 and 36 months after PN were 91.0 and 76.8, 80.2 and 87.7 mL/min/1.73 m2 , respectively. In multivariable linear regression analysis, the amount of decline in PRF at follow-up was significantly correlated with the RAIV (ß 0.261, 0.165, 0.260 at postoperative day 1, 6 and 36 months after PN, respectively). This study has the limitation of its retrospective nature. CONCLUSION: Preoperatively calculated RAIV significantly correlates with the amount of decline in PRF during long-term follow-up. The RAIV could lead our research to the level of prediction of the amount of PRF decline after PN and thus would be appropriate for assessing the technical advantages of emerging techniques.
Assuntos
Neoplasias Renais/cirurgia , Rim , Nefrectomia , Tratamentos com Preservação do Órgão , Cuidados Pré-Operatórios/métodos , Adulto , Idoso , Feminino , Taxa de Filtração Glomerular , Humanos , Rim/fisiopatologia , Rim/cirurgia , Neoplasias Renais/fisiopatologia , Masculino , Pessoa de Meia-Idade , Nefrectomia/métodos , Nefrectomia/estatística & dados numéricos , Tratamentos com Preservação do Órgão/métodos , Tratamentos com Preservação do Órgão/estatística & dados numéricos , Estudos RetrospectivosRESUMO
OBJECTIVE: To investigate the feasibility of exponential apparent diffusion coefficient (eADC) derived from diffusion-weighted imaging (DWI) in evaluating prostate cancers at 3 T. METHODS: 74 consecutive patients with surgically confirmed single peripheral zone (PZ) prostate cancer ≥0.5 cm(3) who underwent pre-operative DWI at 3 T were retrospectively selected. Based on radiological-pathological correlation, eADC and apparent diffusion coefficient (ADC) (×10(-3) mm(2) s(-1)) for the cancers and benign PZ were measured by two independent readers. Tumour eADC or ADC was correlated with Gleason score. Receiver operating characteristic curve analysis was performed to differentiate between Gleason score 6 and 7 or higher, by eADC and ADC. Lesion-to-background contrast ratio was compared between eADC and ADC. RESULTS: Mean tumour eADC (0.48-0.50) and ADC (0.72-0.75) were significantly different from those of benign PZ (eADC, 0.20-0.27; ADC, 1.34-1.66), respectively (p < 0.001). A moderate correlation between tumour eADC or ADC and Gleason score was seen. For differentiating between Gleason score 6 and 7 or higher, eADC (0.818-0.883) showed a similar area under the curve with ADC (0.840-0.889) (p > 0.05). Lesion-to-background contrast ratio of eADC (Reader 1, 2.43; Reader 2, 2.23) was significantly greater than that of ADC (Reader 1, 2.21; Reader 2, 2.12) (p < 0.001). CONCLUSION: The eADC may offer similar diagnostic utility with ADC in the differentiation of the cancer from benign prostate tissue. Moreover, the eADC appears to allow improved tissue contrast. ADVANCES IN KNOWLEDGE: The eADC may be a comparable alternative to ADC for evaluating prostate cancer, with removing T2 shine-through effects from DWI.
Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias da Próstata/patologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Viabilidade , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Neoplasias da Próstata/cirurgia , Estudos RetrospectivosRESUMO
This paper demonstrates the development of pH and thermo-responsive fluorescent nanoparticles, which are composed of graphene oxide (GO) with BODIPY conjugated PEG, to trigger the detection of cancer cells through imaging based on intracellular accommodation. Responsiveness to pH is studied using atomic force microscopy and apparent thickness differences are seen with changes in pH. Confocal images of the nanoparticles (NPs) exhibit remarkably bright fluorescence at lysosomal pH, while no fluorescence is observed under a physiological environment, making the NPs a novel fluorescent probe. The NPs are able to accumulate the hydrophobic anticancer drug DOX due to the hydrophobic surface of GO and show excellent drug release behavior. Therefore, the NPs developed are novel candidates for a fluorescent probe to identify cancer cells and a drug carrier for cancer therapy.
Assuntos
Compostos de Boro/química , Corantes Fluorescentes/química , Grafite/química , Nanopartículas/química , Polietilenoglicóis/química , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Polietilenoglicóis/síntese químicaRESUMO
The purpose of this work is to investigate the consistency of determining N(pp)(gas) and N(pp)(D) by using three independent calibration methods from the AAPM TG 39 and IAEA TRS 381 protocols: 1) calibration with a high-energy electron beam in a phantom; 2) in-phantom calibration in a (60)Co beam; and 3) in-air calibration in a (60)Co beam. The plane-parallel chamber considered was the PTW-Markus and the comparisons were made against a calibrated PTW cylindrical Farmer-type chamber 30001. The phantom material used for the electron beam and (60)Co in-phantom methods was a solid water phantom (RW3). For the electron beam method, the nominal energies were 18 and 21 MeV. An acrylic buildup of 0.5 g/cm(2) thickness was used for the (60)Co in-air method. For each method, N(pp)(gas) and N(pp)(D) were obtained for the plane-parallel chamber as proposed by the AAPM TG 39 and IAEA TRS 381 protocols. The absorbed doses were measured along the central axis at a distance of 100 cm (SSD=100 cm) with 10 x 10 cm(2) field size at the depth of the maximum for each electron beam. The values of N(pp)(gas) by the three independent calibration methods agreed to within +/-0.6%. This meant that any of the methods would give a fairly good value. Similar results were obtained for N(pp)(D). In comparing the results for the electron beam method at energies of 18 and 21 MeV, the latter gave better agreement. The ratios of N(pp)(gas) and N(pp)(D) for the three methods were in agreement within 0.7%. The results for the absorbed dose intercomparison in the AAPM TG 39 and IAEA TRS 381 protocols showed that they agreed to within +/-0.7% which meant that any of the calibration methods and two different protocols would give an accurate result.