Romanenko, A. Ye., Finch, S. C., Hatch, M., Lubin, J. H., Bebeshko, V. G., Bazyka, D. A., Gudzenko, N., Dyagil, I. S., Reiss, R. F., Bouville, A., Chumak, V. V., Trotsiuk, N. K., Babkina, N. G., Belyayev, Yu., Masnyk, I., Ron, E., Howe, G.;thR. and Zablotska, L. B. The Ukrainian-American Study of Leukemia and Related Disorders among Chornobyl Cleanup Workers from Ukraine: III. Radiation Risks. Radiat. Res. 170, 711–720 (2008). Leukemia is one of the cancers most susceptible to induction by ionizing radiation, but the effects of lower doses delivered over time have not been quantified adequately. After the Chornobyl (Chernobyl) accident in Ukraine in April 1986, several hundred thousand workers who were involved in cleaning up the site and its surroundings received fractionated exposure, primarily from external γ radiation. To increase our understanding of the role of protracted low-dose radiation exposure in the etiology of leukemia, we conducted a nested case-control study of leukemia in a cohor...

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The Ukrainian-American Study of Leukemia and Related Disorders among Chornobyl Cleanup Workers from Ukraine: III. Radiation Risks

Purpose: The linear nonthreshold (LNT) model has been used in radiation protection for over 40 years and has been hotly debated It relies heavily on human epidemiology, with support from radiobiology The scientific underpinnings include NCRP Report No 136 (‘Evaluation of the Linear-Nonthreshold Dose-Response Model for Ionizing Radiation’), UNSCEAR 2000, ICRP Publication 99 (2004) and the National Academies BEIR VII Report (2006) NCRP Scientific Committee 1–25 is reviewing recent epidemiologic studies focusing on dose-response models, including threshold, and the relevance to radiation protectionMethods and materials: Recent studies after the BEIR VII Report are being critically reviewed and include atomic-bomb survivors, Mayak workers, atomic veterans, populations on the Techa River, US radiological technologists, the US Million Person Study, international workers (INWORKS), Chernobyl cleanup workers, children given computerized tomography scans, and tuberculosis-fluoroscopy patients Met

The linear nonthreshold (LNT) model as used in radiation protection: an NCRP update.

Two cohorts of Chernobyl cleanup workers from Estonia (4,786 men) and Latvia (5,546 men) were followed from 1986 to 1998 to investigate cancer incidence among persons exposed to ionizing radiation from the Chernobyl accident. Each cohort was identified from various independent sources and followed using nationwide population and mortality registries. Cancers were ascertained by linkage with nationwide cancer registries. Overall, 75 incident cancers were identified in the Estonian cohort and 80 in the Latvian cohort. The combined-cohort standardized incidence ratio (SIR) for all cancers was 1.15 (95% confidence interval (CI) = 0.98-1.34) and for leukemia, 1.53 (95% CI = 0.62-3.17; n = 7). Statistically significant excess cases of thyroid (SIR = 7.06, 95% CI = 2.84-14.55; n = 7) and brain cancer (SIR = 2.14, 95% CI = 1.07-3.83; n = 11) were found, mainly based on Latvian data. However, there was no evidence of a dose response for any of these sites, and the relationship to radiation exposure remains to be established. Excess of thyroid cancer cases observed may have been due to screening, the leukemia cases included 2 unconfirmed diagnoses, and the excess cases of brain tumors may have been a chance finding. There was an indication of increased risk associated with early entry to the Chernobyl area and late follow-up, though not statistically significant. Further follow-up of Chernobyl cleanup workers is warranted to clarify the possible health effects of radiation exposure.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ijc.21733

Cancer risk among Chernobyl cleanup workers in Estonia and Latvia, 1986-1998.

Chronic lymphocytic leukemia (CLL) is generally considered to be non-radiogenic and is excluded from several programs that compensate workers for illnesses resulting from occupational exposures. Questions about whether this exclusion is justified prompted a Congressional mandate to the National Institute for Occupational Safety and Health (NIOSH) to, further, examine the radiogenicity of CLL. This study revisits the question of CLL radiogenicity by examining epidemiologic evidence from occupationally and medically-exposed populations. A systematic review of radiation-exposed cohorts was conducted to investigate the association between radiation and CLL. Exploratory power calculations for a pooled occupational study were performed to examine the feasibility of assessing CLL radiogenicity epidemiologically. There is a bias against reporting CLL results, because of the disease’s presumed non-radiogenicity. In medical cohort studies that provide risk estimates for CLL, risk is elevated, though non-significantly, in almost all studies with more than 15 years average follow-up. The results of occupational studies are less consistent. Studies with adequate follow-up time and power are needed to better understand CLL radiogenicity. Power analyses show that a pooled study might detect risk on the order of radiation induced non-CLL leukemia, but is unlikely to detect smaller risks.

https://www.jstor.org/stable/pdfplus/29736717.pdf

Chronic lymphocytic leukemia radiogenicity: a systematic review

In preparation for a possible large epidemiological study of radiation-related leukemia in Chernobyl clean-up workers of Ukraine, histologic evaluation of 62 cases of leukemia and related disorders was conducted by a panel of expert hematologists and hematopathologists from the United States, France, and Ukraine. All cases were randomly selected from a surrogate population of men in the general population of 6 regions of Ukraine who were between the ages of 20 and 60 years in 1986 and were reported to have developed leukemia, myelodysplasia, or multiple myeloma between the years 1987 and 1998. The hematologists and hematopathologists on the panel were in agreement with one another and with the previously reported diagnoses and classifications of about 90% of the cases of acute and chronic leukemia in the study. These results suggest that strong reliance can be placed on the clinical diagnoses of acute and chronic forms of leukemia and multiple myeloma that have occurred in Ukrainian Chernobyl clean-up workers providing that the diagnoses are supported by records of the patients having had adequate histologic bone marrow studies. The number of cases in this study with the diagnosis of myelodysplasia, however, was too small to draw firm conclusions.

Histologic Verification of Leukemia, Myelodysplasia, and Multiple Myeloma Diagnoses in Patients in Ukraine, 1987–1998

A machine tool having a rotatable machine tool spindle for performing drilling and tapping operations. The spindle has limited axial movement relative to the spindle carrier. Fluid pressure means may be operated to displace the spindle in opposite directions from a predetermined position in the spindle carrier and to apply a force yieldably opposing return of the spindle to the predetermined position. The position of the spindle in its carrier is sensed by control means and the spindle carrier is translatable toward or away from the workpiece in response to the direction of displacement of the spindle from its predetermined position. The spindle is displaced forwardly to effect translation of the spindle carrier and spindle to engage a tool with a workpiece and the return of the spindle to the predetermined position upon the engagement of the tool with the workpiece is utilized to initiate control means for automatically controlling the depth of drilling or tapping as measured from the surface of the workpiece and the return of the spindle to an automatic repeat position or to a home position. The spindle is allowed to float while a tapping tool is in engagement with the workpiece and the feed and return of the spindle carrier is controlled during this period by sensing the position of the spindle in the carrier. During drilling the spindle is locked against axial movement relative to the carrier while the tool is in engagement with the workpiece. The locking means is engageable over the range of axial movement of the spindle relative to the carrier to locate the spindle in a predetermined position relative to the carrier.

Boice Jd

Papers

Radiation risk estimates for leukemia and thyroid cancer among Russian emergency workers at Chernobyl.