RESUMO
This review updates earlier work addressing the epidemiology and toxicity of wollastonite. Earlier chronic animal bioassay and human mortality data were inadequate (IARC term) or negative and no new studies of these types have been published. Wollastonite has been determined to have low biopersistence in both in vivo and in vitro studies, which probably accounts for its relative lack of toxicity. Earlier morbidity studies of mining/mineral processing facilities in Finland and New York State indicated that exposure to wollastonite might result in pleural plaques (Finland) or decrements in certain measures of lung function (New York). More recent analysis of data from an ongoing health surveillance program at one facility (New York) indicates that there are no pleural plaques or interstitial lung disease or decrements in lung function among never smokers or former smokers occupationally exposed to wollastonite. This result probably reflects continued reduction in exposures as part of an ongoing product stewardship program at this facility and suggests that wollastonite has relatively low toxicity as currently managed.
Assuntos
Poluentes Atmosféricos/toxicidade , Compostos de Cálcio/toxicidade , Pneumopatias/induzido quimicamente , Silicatos/toxicidade , Animais , HumanosRESUMO
The future of radiation oncology is exceptionally strong as we are increasingly involved in nearly all oncology disease sites due to extraordinary advances in radiation oncology treatment management platforms and improvements in treatment execution. Due to our technology and consistent accuracy, compressed radiation oncology treatment strategies are becoming more commonplace secondary to our ability to successfully treat tumor targets with increased normal tissue avoidance. In many disease sites including the central nervous system, pulmonary parenchyma, liver, and other areas, our service is redefining the standards of care. Targeting of disease has improved due to advances in tumor imaging and application of integrated imaging datasets into sophisticated planning systems which can optimize volume driven plans created by talented personnel. Treatment times have significantly decreased due to volume driven arc therapy and positioning is secured by real time imaging and optical tracking. Normal tissue exclusion has permitted compressed treatment schedules making treatment more convenient for the patient. These changes require additional study to further optimize care. Because data exchange worldwide have evolved through digital platforms and prisms, images and radiation datasets worldwide can be shared/reviewed on a same day basis using established de-identification and anonymization methods. Data storage post-trial completion can co-exist with digital pathomic and radiomic information in a single database coupled with patient specific outcome information and serve to move our translational science forward with nimble query elements and artificial intelligence to ask better questions of the data we collect and collate. This will be important moving forward to validate our process improvements at an enterprise level and support our science. We have to be thorough and complete in our data acquisition processes, however if we remain disciplined in our data management plan, our field can grow further and become more successful generating new standards of care from validated datasets.
RESUMO
In July 2002, NYCO Minerals, Inc., discovered a heretofore unknown contaminant in its wollastonite ore. The contaminant was first believed to be tremolite asbestos. Immediate efforts were made to eliminate this material. Additional studies were initiated to fully characterize the contaminant and its distribution in the ore body. Subsequent study by NYCO and their consultants led to the identification of the contaminant as a transition material (TM) intermediate between tremolite and talc. In vitro dissolution rate measurements indicated that the TM dissolved much more rapidly than tremolite asbestos. This article provides background information on wollastonite mineralogy and NYCO's product stewardship program (PSP). At present, NYCO Minerals uses selective mining to control the trace levels of TM in the ore and finished product verified by periodic monitoring of workplace air and finished product.
Assuntos
Compostos de Cálcio/química , Silicatos/química , Poluição do Ar em Ambientes Fechados , Monitoramento Ambiental/métodos , Mineração , Exposição OcupacionalRESUMO
BACKGROUND: Whole brain radiation therapy (WBRT) is widely used for the treatment of brain metastases. Cognitive decline and alopecia are recognized adverse effects of WBRT. Recently hippocampus sparing whole brain radiation therapy (HS-WBRT) has been shown to reduce the incidence of memory loss. In this study, we found that multi-field intensity modulated radiation therapy (IMRT), with strict constraints to the brain parenchyma and to the hippocampus, reduces follicular scalp dose and prevents alopecia. METHODS: Suitable patients befitting the inclusion criteria of the RTOG 0933 trial received Hippocampus sparing whole brain radiation. On follow up, they were noticed to have full scalp hair preservation. 5 mm thickness of follicle bearing scalp in the radiation field was outlined in the planning CT scans. Conventional opposed lateral WBRT radiation fields were applied to these patient-specific image sets and planned with the same nominal dose of 30 Gy in 10 fractions. The mean and maximum dose to follicle bearing skin and Dose Volume Histogram (DVH) data were analyzed for conventional and HS-WBRT. Paired t-test was used to compare the means. RESULTS: All six patients had fully preserved scalp hair and remained clinically cognitively intact 1-3 months after HS-WBRT. Compared to conventional WBRT, in addition to the intended sparing of the Hippocampus, HS-WBRT delivered significantly lower mean dose (22.42 cGy vs. 16.33 cGy, p < 0.0001), V24 (9 cc vs. 44 cc, p < 0.0000) and V30 (9 cc vs. 0.096 cc, p = 0.0106) to follicle hair bearing scalp and prevented alopecia. There were no recurrences in the Hippocampus area. CONCLUSIONS: HS-WBRT, with an 11-field set up as described, while attempting to conserve hippocampus radiation and maintain radiation dose to brain inadvertently spares follicle-bearing scalp and prevents alopecia.
Assuntos
Alopecia/prevenção & controle , Neoplasias Encefálicas/radioterapia , Irradiação Craniana/métodos , Hipocampo/efeitos da radiação , Lesões por Radiação/prevenção & controle , Neoplasias Encefálicas/secundário , Irradiação Craniana/efeitos adversos , Humanos , Radiometria , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada , Estudos Retrospectivos , Couro Cabeludo/efeitos da radiaçãoRESUMO
OBJECTIVE: Image-guided radiation therapy allows precise tumor targeting using real-time tracking of radiopaque fiducial markers. To enable appropriate tracking, it is recommended to place fiducials with "ideal fiducial geometry" (IFG). Our objectives were to determine the proportion of patients in whom IFG can be achieved when fiducials are placed by endoscopic ultrasound (EUS) and surgery and to determine if attaining IFG is necessary for delivering radiation. METHODS: This single-center retrospective cohort study included 77 patients with biopsy-proven advanced pancreatic cancer who underwent either EUS-guided or laparotomy/laparoscopy-assisted fiducial placement between September 2005 and July 2009. RESULTS: Gold fiducials were implanted by EUS in 39 patients (51%) and by surgery in 38 patients (49%). The proportion of patients with IFG was significantly higher for surgical placement [18/38, 47%; 95% confidence interval (CI), 32%-63%] compared with EUS-guided placement (7/39, 18%; 95% CI, 8%-32%), P = 0.0011. However, fiducial tracking was successfully used for Cyberknife therapy in 35 (90%) of 39 (95% CI, 77%-97%) patients in the EUS group compared with 31 (82%) of 38 (95% CI, 67%-92%) patients in the surgery group. There were 5 procedure-related complications in the EUS group. CONCLUSIONS: Achieving IFG appears unnecessary for successful tracking and delivery of radiation.