Medicare and Amyloid PET Imaging: The Battle Over Evidence

We examine a recent dispute regarding the Centers for Medicare and Medicaid Services’ (CMS) refusal to unconditionally pay for amyloid positron emission tomography (PET) imaging for Medicare beneficiaries being assessed for Alzheimer’s disease. CMS will only pay for amyloid PET imaging when patients are enrolled in clinical trials that meet certain criteria. The dispute reflects CMS’s willingness in certain circumstances to require effectiveness evidence that differs from the Food and Drug Administration’s standard for pre-market approval of a medical intervention and reveals how stakeholders with differing perspectives about evidentiary standards have played a role in attempting to shape the Medicare program’s coverage policies.     

Covariate adjustment in partial least squares (PLS) regression for the extraction of the spatial–temporal pattern from positron emission tomography data

Positron emission tomography (PET) imaging can be used to study the effects of pharmacologic intervention on brain function. Partial least squares (PLS) regression is a standard tool that can be applied to characterize such effects throughout the brain volume and across time. We have extended the PLS regression methodology to adjust for covariate effects that may influence spatial and temporal aspects of the functional image data over the brain volume. The extension involves multi-dimensional latent variables, experimental design variables based upon sequential PET scanning, and covariates. An illustration is provided using a sequential PET data set acquired to study the effect of d-amphetamine on cerebral blood flow in baboons. An iterative algorithm is developed and implemented and validation results are provided through computer simulation studies.     

食品包装用PET再生料安全评价方法研究

文中对食品包装用PET再生料安全性能评价的程序及要求进行了研究。提出通过5个程序对企业生产的PET 再生料进行评价：生产企业质量安全管理制度、生产工艺流程及质量检验控制、再生PET树脂卫生性能检验、挑战性试 验即生产净化能力评价、迁移研究。提出了食品包装用PET再生料安全评价方案,对原生与再生PET进行了对比分析, 介绍了国外对再生PET质量的要求,对我国PET再生企业的生产和监管提出了建议。