Nuclear Physics Enterprises

Marlton, NJ, United States

Nuclear Physics Enterprises

Marlton, NJ, United States
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PubMed | U.S. Food and Drug Administration, Nuclear Physics Enterprises and North Carolina A&T State University
Type: | Journal: Biological theory | Year: 2016

Radiation science is dominated by a paradigm based on an assumption without empirical foundation. Known as the linear no-threshold (LNT) hypothesis, it holds that all ionizing radiation is harmful no matter how low the dose or dose rate. Epidemiological studies that claim to confirm LNT either neglect experimental and/or observational discoveries at the cellular, tissue, and organismal levels, or mention them only to distort or dismiss them. The appearance of validity in these studies rests on circular reasoning, cherry picking, faulty experimental design, and/or misleading inferences from weak statistical evidence. In contrast, studies based on biological discoveries demonstrate the reality of hormesis: the stimulation of biological responses that defend the organism against damage from environmental agents. Normal metabolic processes are far more damaging than all but the most extreme exposures to radiation. However, evolution has provided all extant plants and animals with defenses that repair such damage or remove the damaged cells, conferring on the organism even greater ability to defend against subsequent damage. Editors of medical journals now admit that perhaps half of the scientific literature may be untrue. Radiation science falls into that category. Belief in LNT informs the practice of radiology, radiation regulatory policies, and popular culture through the media. The result is mass radiophobia and harmful outcomes, including forced relocations of populations near nuclear power plant accidents, reluctance to avail oneself of needed medical imaging studies, and aversion to nuclear energy-all unwarranted and all harmful to millions of people.


Stabin M.G.,Vanderbilt University | Siegel J.A.,Nuclear Physics Enterprises
Health Physics | Year: 2015

An analysis is presented of the possible dosimetric consequences of various potential contamination events involving 223Ra dichloride (Xofigo), the FDA-approved therapeutic agent used in the treatment of bone metastases in patients with castration-resistant prostate cancer. Three exposure scenarios are considered: inhalation dose to an individual due to the hypothetical inhalation of 219Rn and its progeny assumed to be released into the air from a liquid spill on the floor, external dose from direct photon exposure of an individual assigned to clean up a spill, and skin dose to an individual should the liquid material come into contact with their skin. Doses from the first two scenarios were very small; 2.8 × 10-3 mSv and 8.1 × 10-4 mSv, respectively. Using extremely conservative assumptions, the skin dose was estimated to be 72 mSv; in a realistic scenario, this dose would likely be an order of magnitude or more lower. These doses are very small compared to regulatory limits, and good health physics practices likely to be employed in such incidents would lower them still further. The authors conclude that the medical use of Xofigo does not pose any significant radiation safety issue with respect to potential contamination events, even if multiple incidents might occur during the course of a year, since all worst-case potential contamination events considered in this study will not result in significant radiation exposures to workers. © 2015 Lippincott Williams & Wilkins.


Siegel J.A.,Nuclear Physics Enterprises | Silberstein E.B.,University of Cincinnati
Thyroid | Year: 2014

Background: Clinical and historical uncertainty exists surrounding the regulations of the Atomic Energy Commission/Nuclear Regulatory Commission (AEC/NRC) requiring patient hospitalization when 131I activities exceed mCi. This review investigates the sometimes disturbing regulatory and clinical origins and consequences of the use of this low, mCi dose as a prescription for thyroid remnant ablation. Summary: As early as in the 1940s, activities of 131I between 30 and 200mCi, often fractionated, were employed. The AEC deliberated from 1947 to the early 1960s before imposing as a license condition the requirement of hospitalizing patients until they contained


Siegel J.A.,Nuclear Physics Enterprises | Stabin M.G.,Vanderbilt University | Sharkey R.M.,Center for Molecular Medicine and Immunology
Cancer Biotherapy and Radiopharmaceuticals | Year: 2010

This study evaluates the predictive value of absorbed dose, biological effective dose, and time-dose-fractionation factors for use in patients receiving peptide radionuclide receptor therapy treatments by reanalyzing data in two different patient populations that have been reported in the literature. The analysis suggested that the alternative time-dose-fractionation model is as good and, in some cases, may be better in predicting kidney toxicity in these two patient populations than biological effective dose. This study suggests that future investigations proceed with more critical evaluation of different dosimetric quantities that may be more clinically useful in providing optimal patient treatment prescriptions for peptide radionuclide receptor therapy, rather than rely solely on a single methodology derived from experience with external-beam therapy. Copyright 2010, Mary Ann Liebert, Inc.


Gulec S.A.,Florida International University | Sztejnberg M.L.,Purdue University | Siegel J.A.,Nuclear Physics Enterprises | Jevremovic T.,Purdue University | Stabin M.,Vanderbilt University
Journal of Nuclear Medicine | Year: 2010

Selective internal radiation treatment (SIRT) via intrahepatic arterial administration of 90Y microspheres is an effective therapeutic modality. The conventional and generally applied MIRD schema is based on the premise that the distribution of microspheres in the liver parenchyma is uniform. In reality, however, the distribution of the microspheres follows a distinct pattern, requiring that a model be developed to more appropriately estimate radiation absorbed doses to the different structural/functional elements of the hepatic microanatomy. Methods: A systematic investigation was performed encompassing a conventional average absorbed dose assessment, a compartmental macrodosimetric approach that accounts for the anticipated higher tumor-to-normal liver activity concentration ratio, dose point-kernel convolution-derived estimates, and Monte Carlo dose estimates employing a spherical and 3-dimensional hexagonal liver model, including various subunits of the hepatic anatomy, down to the micrometer level. Results: Detailed specifics of the radiation dose deposition of 90Y microspheres demonstrated a rapid decrease in absorbed dose in and around the portal tracts where the microspheres are deposited. The model also demonstrated that the hepatocellular parenchymal and central vein doses could be at significant levels because of a cross-fire effect. Conclusion: The reported microstructural dosimetry models can help in the detailed assessment of the dose distributions in the hepatic functional subunits and in relating these doses to their effects. Thesemodels have also revealed that the there is a consistent relationship between the average liver dose as calculated byMIRDmacrodosimetry and the structural dosimetry estimates in support of the clinical utility of theMIRD methodology. This relationship could be used tomore realistically assess patterns of hepatic toxicity associated with the 90Y SIRT treatment. Copyright © 2010 by the Society of Nuclear Medicine, Inc.


Siegel J.A.,Nuclear Physics Enterprises | Welsh J.S.,Loyola University Chicago
Technology in Cancer Research and Treatment | Year: 2016

In the past several years, there has been a great deal of attention from the popular media focusing on the alleged carcinogenicity of low-dose radiation exposures received by patients undergoing medical imaging studies such as X-rays, computed tomography scans, and nuclear medicine scintigraphy. The media has based its reporting on the plethora of articles published in the scientific literature that claim that there is “no safe dose” of ionizing radiation, while essentially ignoring all the literature demonstrating the opposite point of view. But this reported “scientific” literature in turn bases its estimates of cancer induction on the linear no-threshold hypothesis of radiation carcinogenesis. The use of the linear no-threshold model has yielded hundreds of articles, all of which predict a definite carcinogenic effect of any dose of radiation, regardless of how small. Therefore, hospitals and professional societies have begun campaigns and policies aiming to reduce the use of certain medical imaging studies based on perceived risk:benefit ratio assumptions. However, as they are essentially all based on the linear no-threshold model of radiation carcinogenesis, the risk:benefit ratio models used to calculate the hazards of radiological imaging studies may be grossly inaccurate if the linear no-threshold hypothesis is wrong. Here, we review the myriad inadequacies of the linear no-threshold model and cast doubt on the various studies based on this overly simplistic model. © 2015, © The Author(s) 2015.


Siegel J.A.,Nuclear Physics Enterprises | Stabin M.G.,Vanderbilt University
Health Physics | Year: 2012

Radiation protection recommendations advanced by the International Commission on Radiological Protection and National Council on Radiation Protection and Measurements, and many times adopted into regulations by the United States Nuclear Regulatory Commission, need to be based on scientifically justified assumptions and conclusions. The linear no-threshold model assigns risk to every radiation exposure above zero dose and is the current basis for setting radiation protection standards worldwide. This hypothesis is vigorously challenged by many individuals but just as vigorously defended in spite of the uncertainties surrounding health effects at low dose levels. It is clear that at radiation doses below 100 mSv, the effects, if any, are so low as to be unobservable and perhaps, therefore, unknowable. However, the linear no-threshold hypothesis is used routinely to formulate regulatory dose limits for workers and the general public and to derive stochastic radiogenic risk estimates at low doses. This note will show that while the linear no-threshold hypothesis may play a legitimate role in setting radiation protection standards and operating policies, such as establishing dose limits or as part of an operational "as low as is reasonably achievable" (ALARA) policy, it is inappropriate for use in estimating possible cancer risks associated with low-level radiation exposures. It will also demonstrate that the raising, not lowering, of current regulatory dose limits is more solidly supported by the actual observed data on radiation dose and effects. The authors submit that the misuse of the linear no-threshold model for predicting radiation effects in exposed individuals and populations should be discontinued. Copyright © 2011 Health Physics Society.


De Carvalho Jr. A.B.,Federal University of Sergipe | Stabin M.G.,Vanderbilt University | Siegel J.A.,Nuclear Physics Enterprises | Hunt J.,Brazilian Radiological Protection and Dosimetry Institute (IRD)
Health Physics | Year: 2011

This work compared the predicted dose to an individual due to exposure from a radioactive patient using three models (point, line, and volume), for three therapeutic regimens (hyperthyroidism, thyroid cancer, and non-Hodgkin's lymphoma). For the volume source calculations, Monte Carlo simulations employing the Visual Monte Carlo (VMC) code and the voxel phantom FAX were used. For hyperthyroid patients, the point, line, and volume source models predicted doses to exposed individuals of 54, 24, and 14 mSv, respectively, at a distance of 0.3 m, and 4.8, 4.0 and 3.3 mSv at a distance of 1 m. For thyroid cancer patients, the dose values were 85, 38, and 18 mSv at 0.3 m, and 7.6, 6.4, and 4.4 mSv at 1 m, respectively. For non-Hodgkin's lymphoma (NHL) subjects, the doses were 230, 103, and 36 mSv at 0.3 m, and 21, 17, and 10 mSv at 1 m. These results show that patient release based on point source calculations involves unnecessary conservatism. Copyright © 2011 Health Physics Society.


PubMed | Nuclear Physics Enterprises, U.S. FDA and 2NAC International
Type: | Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine | Year: 2016

Radiological imaging is claimed to carry iatrogenic risk of cancer, based upon an uninformed commitment to the 70-year old linear no-threshold hypothesis (LNTH). Credible evidence of imaging-related low-dose (<100 mGy) carcinogenic risk is nonexistent; it is a hypothetical risk derived from the demonstrably false LNTH. On the contrary, low-dose radiation does not cause, but more likely helps prevent, cancer. The LNTH and its offspring ALARA (as low as reasonably achievable) are fatally flawed, focusing only on molecular damage, while ignoring protective, organismal biological responses. While some grant the absence of low-dose harm, they, nevertheless, advocate the prudence of dose optimization (i.e., using ALARA doses); but this is a radiophobia-centered, not scientific, approach. Medical imaging studies achieve a diagnostic purpose and should be governed by the highest science-based principles and policies. The LNTH is an invalidated hypothesis, and its use, in the form of ALARA dosing, is responsible for misguided concerns promoting radiophobia, leading to actual risks far greater than the hypothetical, carcinogenic risk purportedly avoided. Further, the myriad of imagings benefits are ignored. The present work calls for ending the radiophobia caused by those asserting the need for dose optimization in imaging: medical imagings low-dose radiation has no documented pathway to harm, while the LNTH and ALARA most assuredly do.


PubMed | Nuclear Physics Enterprises and Loyola University Chicago
Type: Journal Article | Journal: Technology in cancer research & treatment | Year: 2016

In the past several years, there has been a great deal of attention from the popular media focusing on the alleged carcinogenicity of low-dose radiation exposures received by patients undergoing medical imaging studies such as X-rays, computed tomography scans, and nuclear medicine scintigraphy. The media has based its reporting on the plethora of articles published in the scientific literature that claim that there is no safe dose of ionizing radiation, while essentially ignoring all the literature demonstrating the opposite point of view. But this reported scientific literature in turn bases its estimates of cancer induction on the linear no-threshold hypothesis of radiation carcinogenesis. The use of the linear no-threshold model has yielded hundreds of articles, all of which predict a definite carcinogenic effect of any dose of radiation, regardless of how small. Therefore, hospitals and professional societies have begun campaigns and policies aiming to reduce the use of certain medical imaging studies based on perceived risk:benefit ratio assumptions. However, as they are essentially all based on the linear no-threshold model of radiation carcinogenesis, the risk:benefit ratio models used to calculate the hazards of radiological imaging studies may be grossly inaccurate if the linear no-threshold hypothesis is wrong. Here, we review the myriad inadequacies of the linear no-threshold model and cast doubt on the various studies based on this overly simplistic model.

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