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PubMed1999

The LANL model 8823 whole-body TLD and associated dose algorithm.

The Los Alamos National Laboratory Model 8823 whole-body TLD has been designed to perform accurate dose estimates for beta, photon, and neutron radiations that are encountered in pure calibration, mixed calibration, and typical field radiation conditions. The radiation energies and field types for which the Model 8823 dosimeter is capable of measuring are described. The Model 8823 dosimeter has been accredited for all performance testing categories in the Department of Energy Laboratory Accreditation Program for external dosimetry systems. The philosophy used in the design of the Model 8823 dosimeter and the associated dose algorithm is to isolate the responses due to beta, photon, and neutron radiations; obtain radiation quality information; and make functional adjustments to the elemental readings to estimate the dose equivalent at 7, 300, and 1,000 mgcm(-2), representing the required repoting quantities for shallow, lens-of-the-eye, and deep dose, respectively.

Algorithms↗
PubMed1999

Calculations of background beta-gamma radiation dose through geologic time.

Life on earth is exposed to a background level of ionizing radiation from a number of sources, including beta and gamma radiation from geologic and biologic materials. Radiation dose from geologic emitters has changed because of the chemical evolution of the continental crust, changes in the relative abundances of 235U and 238U, and the radioactive decay of uranium, thorium, and 40K with time. The radiation dose from internal 40K has decreased by a factor of about eight because of changes in the activity concentration of 40K in potassium over the past 4 billion years. Radiation exposure from geologic materials has decreased from about 1.6 mGy y(-1) to 0.66 mGy y(-1) over the past 4 billion years, and radiation exposure to an organism with a potassium concentration of 250 mmol L(-1) has decreased from about 5.5 to about 0.70 mGy y(-1). Accordingly, background radiation exposure from these two sources has dropped from about 7.0 to 1.35 mGy y(-1) during the time life has existed on Earth. The conservative nature of mutation repair mechanisms in modern organisms suggest that these mechanisms may have evolved in the distant past and that organisms may retain some of the capability of efficiently repairing damage from higher radiation levels than exist at present.

Beta Particles↗
PubMed2000

Development of an improved dosimetry system for the workers at the Mayak Production Association.

Databases are being created that contain verified and updated dosimetry and worker history information for workers at the Mayak Production Association. Many workers had significant external and internal exposures, particularly during the early years (1948-1952) of operation. These dosimetric and worker history data are to be used in companion epidemiology studies of stochastic and deterministic effects. The database contains both external and internal dose information and is being constructed from other databases that include radiochemical analyses of tissues, bioassay data, air sampling data, whole body counting data, and occupational and worker histories. The procedures, models, methods, and operational uncertainties will be documented and included in the database, technical reports, and publications. The cohort of the stochastic epidemiological study is expected to include about 19,000 persons while the cohort for the deterministic epidemiological study is expected to include about 600 persons. For external dosimetry, workplace gamma, beta, and neutron doses are being reconstructed. The models used for this incorporate issues such as known isotopes, composition, shielding, further analysis of film badge sensitivities, and records of direct measurements. Organ doses from external exposures are also being calculated. Methods for calculating dose uncertainties are being developed. For internal dosimetry, the organ doses have been calculated using the established FIB-1 biokinetic model. A new biokinetic model is being developed that includes more information of the solubility and biokinetics of the different chemical forms and particulate sizes of plutonium that were in the workplace. In addition, updated worker histories will be used to estimate doses to some workers where direct measurements were not made. A rigorous quality control procedure is being implemented to ensure that the correct dosimetry data is entering the various databases being used by the epidemiologists.

Beta Particles↗
PubMed2000

Evaluation of uncertainties in estimates of fetal doses from 59Fe kinetic studies at Vanderbilt University.

In a 1997 paper, Stabin et al. published estimates of the fetal radiation doses for women who received oral administrations of 59Fe at Vanderbilt University in the 1940's. These authors concluded that there was "considerable uncertainty... in the amount of radioactive material administered to these subjects." In an effort to quantify this uncertainty, the underlying factors in the input data used in the Stabin et al. dose estimates have been examined in detail. Such factors include (a) an absence of detailed information on, and discrepancies in, the amounts of 59Fe reported to have been administered; (b) the probability that the radioactive iron included 55Fe as well as 59Fe; (c) uncertainties as to the period of time that elapsed between the administration of the radioiron and the taking of the maternal blood samples, and the accompanying impacts of radioactive decay; (d) possible losses of 59Fe in the procedures used in preparing the blood samples; and (e) questions as to the reported efficiency of the counting equipment. Our principal conclusion is that, due to the significant uncertainties and the lack of key information, it is not possible to estimate the doses accurately. An ancillary conclusion, however, is that the doses were probably significantly higher than previously estimated. This latter possibility should be carefully considered by any investigators who subsequently seek to use these estimates to quantify the relationship between the doses to the fetus and the resulting health effects.

Beta Particles↗
PubMed2002

Radiation dose implications of airborne contaminant deposition to humans.

In nuclear accident consequence assessment, dose contributions from radionuclide deposition on the human body have in the past generally been either ignored or estimated on the basis of rather simple models. Recent experimental work has improved the state of knowledge of relevant processes and parameter ranges. The results presented in this paper represent a first approach to a detailed assessment of doses from radiopollutant deposition on the human body, based on contaminant-specific data. Both the dose to skin from beta-emitters and the whole-body dose from gamma-emitters on body surfaces were found to give potentially significant contributions to dose. Further, skin penetration of some contaminants could lead to significant internal doses.

Air Pollutants, Radioactive↗
PubMed2004

Considerations for applying VARSKIN mod 2 to skin dose calculations averaged over 10 cm2.

VARSKIN Mod 2 is a DOS-based computer program that calculates the dose to skin from beta and gamma contamination either directly on skin or on material in contact with skin. The default area for calculating the dose is 1 cm2. Recently, the U.S. Nuclear Regulatory Commission issued new guidelines for calculating shallow dose equivalent from skin contamination that requires the dose be averaged over 10 cm2. VARSKIN Mod 2 was not filly designed to calculate beta or gamma dose estimates averaged over 10 cm2, even though the program allows the user to calculate doses averaged over 10 cm2. This article explains why VARSKIN Mod 2 overestimates the beta dose when applied to 10 cm2 areas, describes a manual method for correcting the overestimate, and explains how to perform reasonable gamma dose calculations averaged over 10 cm2. The article also describes upgrades underway in Varskin 3.

Beta Particles↗
PubMed2004

Radioactivity in cathode ray tubes.

While surveying used computer equipment out of a zone posted as a Contamination Area, 100% of the computer monitors surveyed had levels of radioactivity that were significantly above background. The radioactivity was primarily on the front face of the cathode ray tube and was not amenable to decontamination. Hot spots were found also along the edges and seals of the cathode ray tube. Similar surveys of computer monitors that were never in Contamination Areas confirmed that radioactivity was incorporated into the monitor. Surveys were made of recently manufactured television sets with similar results. Gamma spectroscopy indicates that the radioactivity is due to naturally occurring radioactive materials. Since most surveys of cathode ray tubes in the literature were made while the units were energized and indicated low-energy x-rays, the use of naturally occurring radioactive materials in the manufacture of cathode ray tubes has not been widely recognized. This paper presents the results of these surveys, the results of gamma spectroscopy, and a method for releasing existing computer equipment having naturally occurring radioactive materials.

Beta Particles↗
PubMed2001

Effects of radiation therapy on vascular responsiveness.

The use of radiation therapy to inhibit vascular proliferative diseases has produced encouraging results in several clinical trials. However, little is known about the possible side effects of radiation on vascular responsiveness. Our goal was to study the in vitro vascular responses of the rabbit aorta to various agonists immediately after several regimens of radiation therapy administered at doses prescribed in clinical protocols and at two different dose rates. High-dose-rate radiation was administered either by brachytherapy, using a gamma source, iridium 192, or an external electron beam producing beta radiation. Low-dose-rate radiation was administered by brachytherapy using a liquid-filled balloon with the beta emitter 32P. Vascular reactivity after the various regimens of irradiation was determined using the organ bath pharmacology assay. Various agonists were applied to the rabbit aorta to produce full cumulative concentration-response curves. Radiation, administered using an external electron beam, did not alter endothelium-dependent relaxation of the aorta induced by acetylcholine. However, the use of a catheter-based system to deliver radiation disrupted the endothelial cell lining of the vessel, causing a lack of relaxation by acetylcholine. Therefore, to compare all modalities of radiation therapy on vascular responsiveness, the agonists used in this study are known to act directly on the smooth muscle. Radiation therapy had no effect on the contractile responses induced by the following agonists: phenylephrine and potassium chloride. Vascular dilatation induced by nitroglycerin, a nitric oxide donor, was unaffected by radiation therapy. The contractile response induced by des-Arg9-bradykinin, a kinin B1 receptor agonist, was significantly increased twofold to threefold by all types of irradiation under study. This enhanced response is attributable to an increase of mRNA levels coding for this receptor. In all cases, radiation therapy did not alter the effective concentration producing 50% of maximal responsiveness (EC50) and did not reduce the vascular responsiveness induced by agonists. Taken together, we conclude that radiation therapy does not hinder endothelium-independent vascular responsiveness and increases the kinin B1 receptor-mediated vasoconstriction.

Acetylcholine↗
PubMed1997

Biodistribution in tumour-bearing mice of two 90Y-labelled biotins using three-step tumour targeting.

Tumour pretargeting techniques based on a three-step approach with the avidin/biotin system and associated with the high-energy beta-emitter yttrium-90 (90Y) have been applied with encouraging results in cancer therapy. While in-vivo stable binding of 90Y through a chelating agent like DOTA is essential for directly labelled monoclonal antibodies in the labelling of a fast clearing molecule like biotin, this may not be so important, since the time for catabolic processes to occur is drastically reduced. In this study, the biodistribution of 90Y bound to biotin through DTPA or DOTA was evaluated. Tumour-bearing mice received biotinylated antibody on day 1, avidin on day 2 and 90Y-labelled biotin on day 3. The biodistribution was determined 4 and 24 h after the injection of radiolabelled biotin. The majority of the injected dose was recovered in the urine 4 h after injection of both radiolabelled compounds. Higher bone uptake of 90Y was observed in animals administered 90Y-DTPA-biotin. In general, all organs including tumour showed higher accumulation of activity following the injection of 90Y-DAPA-biotin. Despite the lower levels of accumulation in the tumour after injection of 90Y-DOTA-biotin, the tumour-to-liver and tumour-to-bone ratios for the DOTA ligand were higher compared to DTPA. The higher tumour uptake observed after injection of 90Y-DTPA-biotin may be attributed to the presence of two biotin molecules in its dimeric structure. Our results indicate that the ideal 90Y-labelled biotin derivative for therapy studies should be formed from a DOTA core with two non-cleavable spacers, each ending with a biotin molecule.

Adenocarcinoma↗
PubMed2001

Physical and biological dosimetry in patients undergoing radiosynoviorthesis with erbium-169 and rhenium-186.

Physical and biological dosimetry were investigated in 45 rheumatoid arthritis patients treated by radiosynoviorthesis (RSO) with 186Re-sulphide (medium-sized joints) and 169Er-citrate (digital joints). Biological dosimetry involved scoring dicentrics in lymphocytes, cultured from blood samples withdrawn just before and 6 h, 24 h and 7 days after treatment. Physical methods included repeated blood sample counts and scintigraphy data. For erbium-169 (pure beta emitter), only bremsstrahlung could be measured and solely in the injection area. For rhenium-186 (both beta and gamma emitter), whole body scans and static images of joints and locoregional lymph nodes were performed. Dosimetry calculations were in accordance with the MIRDOSE 3 software and tables. For erbium-169 (21 patients), either metacarpophalangeal (30 MBq) or proximal interphalangeal (20 MBq) joints of the hands were treated (one joint per patient); 18 patients (out of 21) were interpretable for biological dosimetry, 10 (out of 11) for physical dosimetry and six (out of 10) for both. For rhenium-186, 23 wrists, nine elbows, three shoulders and two ankles were injected in 24 patients, with a maximum of three joints per patient (70 MBq per joint); 20 patients (out of 24) and 10 (out of 10) were interpretable for biological and physical dosimetry, respectively, and eight (out of 10) for both methods. Erbium-169 biological dosimetry was negative in all interpretable patients, and physical dosimetry gave a blood dose of 15 +/- 29 microGy and an effective dose lower than 1 mSv/30 MBq. For rhenium-186, biological results were negative in 16 patients (out of 20), but showed a blood irradiation around 200 mGy in the last four. A significant cumulative increase of dicentrics 7 days after injection (16/10,000 instead of 5/10,000 prior to treatment; p < 0.04) was also noted. Gamma counts gave a blood dose of 23.9 +/- 19.8 mGy/70 MBq and the effective dose was found to be 26.7 +/- 5.1 mGy/70 MBq, i.e. about 380 microGy.MBq-1. Erbium-169 RSO is very safe from both physical and biological dosimetry standpoints. Rhenium-186 leak is greater, as demonstrated by the higher blood activity and the measurable, although limited, dicentrics induction in blood lymphocytes. However, the effective dose remains moderate, i.e. 30 times lower than in 131I therapy in benign thyroid diseases.

Adult↗
PubMed1993

Type III hyperlipoproteinemia acquired by liver transplantation.

A case of type III hyperlipoproteinemia (HLP) (dysbetalipoproteinemia) acquired by liver transplantation is reported. The 50-year-old female patient was referred to the Frankfurt University Hospital for orthotopic liver transplantation. She had suffered from ethylic liver cirrhosis. The donor liver showed discrete signs of steatosis. The postoperative course of the patient was satisfactory. Enzyme levels and blood coagulation tests returned to normal within thirty days. However, both cholesterol and triglycerides gradually increased from approximately 2.00 g/L to values ranging from 2.50 to 3.50 g/L within 200 days after transplantation. Cutaneous xanthomas did not develop. The patient's lipoprotein pattern met the criteria of type III HLP: the cholesterol to triglyceride ratio in very low-density lipoproteins (VLDL) was 0.64. Intermediate-density lipoprotein(IDL) cholesterol was 0.48 g/L. Lipoprotein electrophoresis showed a broad beta-band, and beta-migrating particles were present in VLDL. Immunoblotting of apolipoprotein (apo) E from the patient's plasma revealed an E2/2 phenotype. However, restriction isotyping of an in vitro amplified apoE gene fragment showed the genotype of the patient to be epsilon 3/epsilon 4. These data suggest that the development of type III HLP in this patient was due to a change in the apoE phenotype from E3/4 to E2/2 after liver transplantation.

Apolipoproteins E↗
PubMed2004

The role of brachytherapy and Cutting Balloon angioplasty in the current treatment of stent restenosis.

The Gamma I, START and INHIBIT trials conclusively demonstrate the feasibility, safety and efficacy of intracoronary radiation as the treatment of choice for stent restenosis. Further reports confirm this finding and extend the indications. Vascular brachytherapy should be made available for all patients with diffuse stent restenosis. Specific devices such as cutting balloons may improve the procedure but does not seem to have an impact alone on the evolution.

Angioplasty, Balloon, Coronary↗
PubMed2006

Intraoperative electron radiotherapy for extremity sarcomas does not increase acute or late morbidity.

UNLABELLED: Intraoperative electron radiotherapy is used to treat surgical sites that potentially harbor occult tumor immediately after limb-sparing surgical resection of extremity soft tissue sarcomas. It is unknown whether single-fraction, high-dose intraoperative electron radiotherapy at the time of surgery increases wound morbidity when combined with preoperative or postoperative external beam radiotherapy. In a retrospective study, we evaluated whether intraoperative electron radiotherapy increased 90-day and late (> 90 days) wound complication rates by comparing patients who had adult extremity soft tissue sarcomas treated by limb-sparing surgery and preoperative (n = 14) or postoperative (n = 13) external beam radiotherapy. The median followup was 36 months. Seven (26%) patients had wound complications occurring within 90 days postoperatively and completion of radiotherapy. Late wound complication rates were similar. Two patients in each of the external beam radiotherapy groups required late subtotal limb amputations for prolonged wound complications. Our findings suggest intraoperative electron radiotherapy during limb-sparing surgery allows radiation dose escalation without increased 90-day or late-wound complication rates when combined with preoperative or postoperative external beam radiotherapy for patients with extremity soft tissue sarcomas. LEVEL OF EVIDENCE: Prognostic Study, Level II (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2005

Radiation protection in radiosynovectomy of the knee.

Radiosynovectomy is a widely available therapeutic option that involves radiopharmaceutical injections into joints to treat rheumatoid arthritis. However, data on the beta-radiation dose equivalents for the staff performing such treatments are limited. The aim of this study was to determine the personal dose equivalents H(P)(0.07) to the skin of the hands of the treating physician under several exposure scenarios. An activity of 185 MBq (90)Y was used. Thermoluminescence detectors were attached at the finger tip of the thumb, forefinger, and middle finger of the treating physician. Measurements of beta-exposures were made during treatment of 70 knees with (90)Y under the following exposure scenarios: group 1, the radiosynovectomy was performed with syringe shield with Perspex (Plexiglas, Röhm GmbH, Germany) (thickness of 5 mm); group 2, additionally a manipulator was used for fixation of the needle; group 3, radiation-resistant gloves were added to the measures in groups 1 and 2. For group 1, the highest beta doses were measured at the forefinger (22.1 microSv MBq(-1)) (22,100 microrem/27 microCi) and thumb with 16.5 microSv MBq(-1) (16,000 microrem/27 microCi) at the left hand, which holds the needle (right-handed physician). In group 2, the radiation doses were reduced to 0.6 microSv MBq(-1) (60 microrem/27 microCi) at the left forefinger and 0.5 microSv MBq(-1) (50 microrem/27 microCi) at the left thumb. The use of a manipulator and special radiation resistant gloves reduced the radiation dose to 0.4 microSv MBq(-1) (40 microrem/27 microCi) at the left forefinger and to 0.3 microSv MBq(-1) (30 microrem/27 microCi) at the left thumb in group 3. It was concluded that while performing radiosynovectomy without a manipulator for fixation of the needle, the dose measured at the left forefinger could exceed the German limit of 500 mSv (50 rem) per year for the official dosimetry at the skin. Using holding forceps allows compliance with the legal limit and could considerably reduce the beta dose. The use of radiation-resistant gloves reduced the beta dose at the skin only slightly.

Beta Particles↗
PubMed2004

Intracoronary brachytherapy with beta-radiation for the treatment of long diffuse in-stent restenosis.

OBJECTIVE: To assess the efficacy of intracoronary brachytherapy with beta-radiation (Sr/Y) for the treatment of long diffuse in-stent restenosis (ISR). METHODS: As recurrent ISR depends on intimal injury after coronary angioplasty, long in-stent restenotic lesions were defined as lesions with a treatment length >26 mm (lesion length >20 mm plus a treatment margin of 3 mm at each end). Seventy-eight patients with long ISR were treated at our institution with beta-brachytherapy after coronary angioplasty. Patients were irradiated with either an approximate dose of 12 Gy at 1 mm vessel wall depth or with 18 Gy at 1 mm vessel wall depth. Clinical follow-up was available for 69 patients and angiographic follow-up for 65 patients. Late lumen loss (LLL), binary restenosis (stenosis >50%), target lesion revascularization (TLR) and major adverse cardiac events (MACE) were assessed for a follow-up time of 6.6+/-2.2 months. RESULTS: Mean interventional treatment length was 46+/-18 mm. TLR was performed in all 23 patients with binary restenosis (33%). Death of cardiac cause was reported for two patients, one of whom did not undergo TLR. Thus, overall MACE rate was 35%. Recurrent ISR was significantly more frequent in patients with geographic miss. Comparison of the different radiation dose regimens revealed significantly lower LLL in patients irradiated with the higher dose (0.20+/-0.68 mm compared with 0.65+/-0.96 mm, P=0.03). CONCLUSION: Intracoronary brachytherapy with beta-radiation (Sr/Y) is a safe and effective therapeutic option for the reduction of recurrent ISR in long diffuse lesions. We recommend a high-dose irradiation with 18 Gy at 1 mm vessel wall depth.

Aged↗