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PubMed2005

[Beta-radiation as adjuvant treatment of in-stent restenosis in coronary vessels].

INTRODUCTION: The purpose of this study was to describe our initial "real-world" experience with vascular b-radiation for in-stent restenosis using a simple angioplasty approach without stent implantation. MATERIALS AND METHODS: Thirty-five consecutive patients with in-stent restenosis were treated with balloon angioplasty (n = 28), cutting balloon angioplasty (n = 3), or angioplasty plus stent implantation (only in case of significant dissection: n = 4), followed by catheter-based beta-radiation. Angiographic follow-up was performed after 6 to 10 months. RESULTS: One patient experienced a left main stem occlusion immediately after beta-radiation, which necessitated an acute coronary bypass operation. No other complications related to the radiation procedure were observed. In-stent restenosis recurred in 6 of the 34 patients (18%). DISCUSSION: Our results indicate that catheter-based radiation can be safely introduced at centres without previous experience with this treatment modality. Furthermore, the in-stent restenosis recurrence rates after catheter-based radiation which have been obtained in randomised trials can be reproduced in consecutive patients.

Angioplasty, Balloon, Coronary↗
PubMed2005

Angiographic and intravascular ultrasound findings of the late catch-up phenomenon after intracoronary beta-radiation for the treatment of in-stent restenosis.

We report one-year angiographic and intravascular ultrasound (IVUS) outcomes of in-stent restenosis (ISR) patients treated with intravascular brachytherapy (IVBT). The benefit of IVBT for treating ISR is well documented. However, few data exist on significant angiographic and intravascular ultrasonic in-stent lumen deterioration beyond the habitual 6-month analysis after the index radiation procedure or so-called late catch-up process in the treatment of ISR. Twenty-five consecutive patients with ISR were treated with IVBT using the Beta-Cath System (a 40 mm 90 Sr per 90 gamma source). Quantitative angiographic and IVUS analysis was performed in all of them at 6 and 12 months. IVBT was successful in all patients. Four patients (16%) developed recurrent angiographic binary restenosis at 6-month follow-up, all located within the adjacent reference segments, with 2 being associated with geographical miss. An additional 4 patients (16%) presented with recurrent ISR at 12-month follow-up, all within the stented segment. Significant in-stent lumen loss (0.16 +/- 0.42 mm to 0.34 +/- 0.46 mm; p = 0.008) and in-stent intimal hyperplasia growth (+11.2 +/- 0.48 mm3; p = 0.03) was observed between 6 and 12 months. Intracoronary beta-radiation for the treatment of ISR was associated with significant luminal deterioration (late catch-up) within the stents between 6 and 12 months due to an important late progression of in-stent intimal hyperplasia.

Beta Particles↗
PubMed2005

[Genetic effects of low-dose chronic irradiation of developing seeds of Arabidopsis thaliana Heynh].

A six-year study, starting in 1987, focused on the frequency of embryonic lethals and chlorophyll mutations that arose in developing seeds of Arabidopsis thaliana growing at sites varying in the level of radioactive contamination in the 30-km control region of the Chernobyl Atomic Power Plant. The dose rate of chronic irradiation varied from 200 microR/h to 2.4 R/h. To study the genetic effects of various levels of radioactive contamination, the frequency of mutations arising in a particular generation was determined and the irradiation dose was estimated for the given generation. The dose dependence of the mutation frequency proved to follow a power function with a power less than unity, suggesting a relatively high effect for low-dose irradiation. Possible explanations of this phenomenon are discussed.

Air Pollution, Radioactive↗
PubMed2005

Poor outcome in patients treated with brachytherapy for diffuse in-stent restenosis. The role of additional stenting despite prolonged antiplatelet therapy.

BACKGROUND: Brachytherapy (IBT) has been the first effective treatment of in-stent restenosis (ISR). However, when IBT is associated with additional stenting, high rates of late thrombosis have been observed. Even though prolongation of a double antiplatelet therapy seems to have overcome this problem, studies analyzing whether additional stenting still remains a negative prognostic factor for restenosis are lacking. AIM: To evaluate outcomes of patients treated for ISR with or without additional stenting and IBT followed by prolonged antiplatelet therapy. METHODS: Seventy-seven consecutive patients treated with beta radiation in 89 lesions with ISR were analyzed according to the need for deploying additional stents: 73 lesions were treated without additional stents (Group 1) and 16 lesions with one or more new stents (Group 2) because of suboptimal results or flow-limiting dissections. Double antiplatelet therapy was administered for 12 months. An angiographic follow-up was scheduled after 6 months. P-values < 0.05 were considered significant. RESULTS: Restenosis rates were 31.5% (23/73) and 62.5% (10/16) in Group 1 (G1) and Group 2 (G2), respectively (p = 0.02). The two groups did not differ for late vessel thrombosis (8 in G1 and 2 in G2). In G2, high rates of recurrence were observed in the additional stent (6/16, 37.5%; p = 0.02 versus edge restenosis and in old stent recurrence in both G1 and G2). CONCLUSIONS: The association of additional stenting with brachytherapy in treatment of ISR is characterized by poor outcomes, even if a prolonged antiplatelet therapy has been administered. These results are related to high restenosis rates observed in the additional stent.

Aged↗
PubMed2005

Intercomparison of activity measurements for beta-emitters in Swiss nuclear medicine laboratories.

OBJECTIVE: The activity of injected radiopharmaceuticals in nuclear medicine, including beta-emitters used for pain palliation, has to be monitored systematically. The objective of the present work was to evaluate the situation and precision of activity monitoring for beta-emitters in Swiss nuclear medicine laboratories. METHODS: A questionnaire about the monitoring methods used was sent to 50 centers. On the basis of the questionnaire results, an intercomparison of activity measurements with 90Y and 169Er sources was organized. RESULTS: This study showed that most laboratories check beta-emitter activity with a dose calibrator measurement in the original vial provided by the producer or in the injection syringe. They therefore need to have calibration factors for the corresponding measurement geometries. The results of the intercomparison were disappointing overall. Sixteen of 27 90Y measurements and 17 of 22 169Er measurements in the original vial deviated from the reference activity by more than 20%. The situation was similar for the syringe. These discrepancies did not stem from the intrinsic limitation of the measuring method but were mainly attributable to the poor quality of the calibration factors provided by the manufacturers, in addition to lack of follow-up and incorrect background subtraction, particularly for 169Er, by the nuclear medicine laboratories. Manufacturers are being contacted to discuss possible improvements for the situation. CONCLUSION: This study showed that commercial dose calibrators are generally adequate for measurement of the activities of beta-emitters. However, in some cases, the measurement of 90Y can lead to errors reaching +/-50%. For 169Er, with its much lower beta-energy, the situation is even worse; the observed differences can be higher than 1 order of magnitude.

Beta Particles↗
PubMed2006

A new method for controlling radiation sterilisation.

A new statistical process control method for gamma and electron-beam sterilisation processes has been established to meet new requirements to take measurement uncertainty into account when product is released. The method, outlined here, uses probability-based data to determine the appropriate target dose for each type of product and thereby avoid unnecessary product rejections.

Beta Particles↗
PubMed2006

Safety of beta radiation exposure to the non-target segment: an intravascular ultrasound dosimetric analysis.

BACKGROUND: The use of longer radioactive seed trains to avoid geographic miss may lead to greater radiation exposure to distal vasculature due to the natural tapering of coronary arteries. The aim of this study was to use IVUS-based dosimetric analysis to evaluate the effect of beta-radiation on angiographically normal, noninjured distal segments. METHODS: We analyzed 17 in-stent restenosis cases (stent length: 20 +/- 8 mm) treated with a 40 mm 90Sr/Y source train. The prescribed dose was 18.4 Gy (reference less than or equal to 3.3 mm) or 23 Gy (reference > 3.3 mm) at 2 mm from the source. Noninjured, but fully radiated, distal reference sites were determined by angiography. Based upon the three-dimensional vessel contours obtained at baseline, the minimum dose delivered to 90% of plaque volume (Dv90) was determined. Vessel, plaque and lumen volumes and Dv90 were computed in every 2 mm subsegment (n = 52). RESULTS: On average, no significant serial change was observed in plaque area (5.0 +/- 2.5 mm3/mm post-treatment to 5.6 +/- 3.1 mm3/mm at 8-month follow up; p = 0.09), vessel area (10.2 +/- 3.7 to 10.3 +/- 4.0 mm3/mm; p = 0.84), or lumen area (5.2 +/- 2.0 to 4.7 +/- 1.8 mm3/mm; p = 0.19). Subsegment analysis, however, revealed a wide range of dose distribution, with a significant positive correlation between Dv90 and plaque increase (p = 0.008), as well as vessel change (p < 0.001), representing dose-dependent positive vessel remodeling following beta radiation. Consequently, no significant relationship was observed between Dv90 and lumen change. CONCLUSIONS: Detailed IVUS-based dosimetric analysis demonstrated that beta radiation promoted positive remodeling, preventing lumen loss despite a mild increase in plaque mass on angiographically normal, noninjured distal segments.

Aged↗
PubMedDate not supplied

Pioneers of nuclear medicine, Madame Curie.

Among those who have made important discoveries in the field of radioactivity and thus helped in the development of nuclear medicine as an identical entity are: Heinrich Hertz who in 1886 demonstrated the existence of radiowaves. In 1895 Wilhelm Röntgen discovered the X-rays. In 1896 H. Becquerel described the phenomenon of radioactivity. He showed that a radioactive uranium salt was emitting radioactivity which passing through a metal foil darkened a photographic plate. An analogous experiment performed by S.Thomson in London was announced to the president of the Royal Society of London before the time H.Becquerel announced his discovery but Thomson never claimed priority for his discovery. Muarie Sklodowska Curie (1867-1934) was undoubtedly the most important person to attribute to the discovery of radioactivity. In 1898 she discovered radium as a natural radioactive element. This is how she describes the hard time she had, working with her husband Pierre Curie (1859-1906) for the discovery of radium and polonium: "During the first year we did not go to the theater or to a concert or visited friends. I miss my relatives, my father and my daughter that I see every morning and only for a little while. But I do not complain...". In presenting her discovery of radium, Madame Curie said: " ...in the hands of a criminal, radium is very dangerous. So we must often ask ourselves: will humanity earn or lose from this discovery? I, myself belong to those who believe the former...". The notebooks that Madame Curie had when she was working with radium and other radioactive elements like polonium, thorium and uranium are now kept in Paris. They are contaminated with radioactive materials having very long half-lives and for this reason anyone who wishes to have access to these notes should sign that he takes full responsibility. There are some more interesting points in Madame Curie's life which may not be widely known like: Although her full name is Maria Sklodowska-Curie, she is not known neither by that full name nor as Maria Sklodowska but as Marie Curie. Madame Curie was the second of five children. At the age of 24 she went to Sorbonne-Paris after being invited by her sister Bronja to study for about 2-3 years; instead she stayed in Paris for her whole life. Her doctorate was on the subject: "Research on radioactive substances" which she completed in six years under the supervision of H. Becquerel. Pierre Curie was Director of the Physics Laboratory of the Ecole Municipale of Physics and Industrial Chemistry when he married M. Curie in 1895. Pierre Curie left his other research projects and worked full time with his wife. In this laboratory M. Curie and her husband Pierre discovered radium and polonium. In 1901 Pierre Curie induced a radiation burn on his forearm by applying on his skin radiferous barium chloride for 10 hours. During World War I, M.Curie organized for the Red Cross a fleet of radiological ambulances each with X-ray apparates which were called "Little Curies". The X-ray tubes of these apparates were unshielded and so M.Curie was exposed to high doses of radiation. Once an ambulance fell into a ditch and M.Curie who was inside the ambulance was badly bruised and stayed at home for 3 days. M. Curie with her daughters, Irene and Eve, was invited and visited America in 1921. She led a successful campaign to collect radium for her experiments. Before leaving America, President Harding donated through her to the Radium Institute of Paris 1 g of radium for research purposes. At that time the process to obtain 0.5 g of pure radium bromide required 1 ton of ore and 5 tons of chemicals. No measures of radiation protection were taken back then. In 1929 Madame Curie visited the United States for a second time. She met with President Hoover and with the help of the Polish women's association in America collected funds for another gram of radium. Madame Curie died of leukemia on July 4, 1934. Sixty years after her death her remnants were laid to rest under the dome of the Pantheon. Thus she became the first woman under her own merit, to rest in the Pantheon. In 1934 at the Institute of Radiology in Paris, Frederique Joliot and Irene Curie-Joliot discovered artificial radiation. They studied alpha particles and beta;-radiation.

Editorial↗
PubMed1992

Chronic exposure to ionizing radiation as a tumor promoter in mouse skin.

We have tested chronic exposure to 90Y beta radiation for its action as a complete tumor promoter, a stage I tumor promoter, or a stage II tumor promoter in SENCAR mouse skin. In skin initiated with a single application of 7,12,dimethylbenz[a]anthracene (DMBA, 10 nmol), chronic exposure to beta radiation as a complete promoter (0.5 Gy, twice/week, 13 weeks) produced no tumors and, when added to a complete chemical promoter (TPA), reduced tumor frequency about 30%. A similar result was observed when beta radiation was tested as a stage II promoter. DMBA-initiated mice that received chemical (12-O-tetradecanoylphorbol-13-acetate, TPA) stage I promotion followed by 13 weeks of beta-radiation exposure (0.5 Gy, twice/week) as stage II promotion produced essentially no tumors, and combining the same chronic beta-radiation exposure with chemical (mezerein) stage II promotion reduced tumor frequency about 20% when compared to a similar group that was not irradiated. Chronic beta-radiation exposure was tested two ways as a stage I tumor promoter in initiated skin that was subsequently treated with mezerein as a stage II promoter. Stage I promotion was shown to proceed with the passage of time, indicating this process occurs naturally in the absence of chemical or physical stimulation. Hyperthermia, previously shown to be a potent inhibitor of chemically stimulated stage I promotion, had no effect on the natural process, indicating at least some differences in mechanism between the two processes. The natural process was, in fact, inhibited by chemical tumor promoters, but not by radiation. In addition to the increase resulting from this natural process, tumor frequency was further increased slightly but significantly (12-15%, P less than or equal to 0.05) when chronic radiation exposure was given as a stage I promoter (0.5 Gy, twice/week, 13 weeks) subsequent to initiation, in spite of the expected 20% reduction resulting from this dose. Exposure of initiated animals to radiation (0.5 or 1.0 Gy, twice/week, 2 weeks) in addition to TPA as stage I promotion produced a similar increase in tumor frequency (P less than 0.02). At higher radiation doses, however, tumor frequency was reduced compared to unirradiated controls. In a third test as a stage I promoter, beta radiation (0.5 Gy twice/week, 4 weeks) was given prior to initiation with N-methyl-N'-nitro-N-nitrosoguanidine in animals subsequently promoted by TPA (twice/week, 13 weeks), and again the radiation slightly but significantly (P less than 0.03) increased tumor frequency compared to the unirradiated control group.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Dot-blot hybridization: quantitative analysis with direct beta counting.

The suitability of using direct beta counting (DBC) for quantitating radioactivity of the probe:target complex in dot-blot hybridization was evaluated using a Packard Matrix 96. A comparison of blots analyzed using autoradiography followed by densitometry scanning (film/densitometry) with those analyzed using direct beta counting revealed similar data trends with the two methods. However, direct beta counting quantitated the amount of radioactivity in the dot blots directly (without film exposure or additional sample preparation), which significantly reduced the time required to obtain results. Blots analyzed first with direct beta counting and then liquid scintillation counting exhibited similar data trends with both methods. Despite a decreased counting efficiency, analysis with direct beta counting has the following advantages compared with liquid scintillation counting: 1) no additional sample preparation is required (no vials or cocktail are used), 2) no sample destruction occurs due to analysis and 3) quantitative results are obtained more rapidly (since the radioactivity for all 96 samples in a dot blot is simultaneously determined in real time). Analysis with direct beta counting was also shown not to interfere with the successful reprobing of stripped dot blots with either unique sequence or total genomic probes. Overall, direct beta counting provides quick, quantitative results for dot blots while saving considerable time and effort.

Animals↗
PubMed1991

[Effect of xiao banxia-fuling decoction on the amplitude of gastric electrical spike wave in rats after irradiation of the gastric region].

The effect of xiao banxia-fuling decoction on the amplitude of gastric electrical spike wave in rats after irradiation of the gastric region was investigated in this study. The result proved: by using the medicine every day, the amplitude of spike wave, which was reduced by irradiation, was significantly raised at the 10th, 14th day in the corpus and 7th, 10th, 14th, 21st day in the antrum after 15Gy irradiation (P less than 0.01). Since the altitude of spike wave correlated with the intensity of the gastric motility. The authors believe that this compound Chinese herbs may have some beneficial effects on preventing the inhibition of gastric motility and reducing the radiation reaction of digestive system.

Animals↗
PubMed1991

Ponderable indices in the offspring and nucleic acids quantity in endocrine glands of rats exposed to real and sham VDU screens.

Adult female and male Imp: DAK rats were exposed beneath a real VDU screen (Erl groups) loaded with light-green characteristics due to computation of trigonometric functions in a loop program from a microcomputer. The control animals were exposed beneath a sham screen (Esh groups), being the front glass of vacuum devoid cathode ray tube covered with a transparent celluloid sheet printed with light-green characteristics. The difference in body weight of foetuses from autopsied Erl and Esh females was due mainly to a one-day delay in the fecundation of Esh females. In other groups of Erl females, a prolongation of the oestrous cycle was found in comparison to that of the Esh females. In both Erl females and Erl males, a nonsignificant decrease of weight of anterior pituitary and adrenals was found. RNA quantity was augmented in the anterior pituitary of Erl females and DNA quantity was diminished in the hypothalamus of Erl males. The obtained results suggest the suppression of hypothalamo-hypophyseal function in rats exposed to a real VDU screen.

Animals↗
PubMed1991

Treatment of keloids by 90Sr-90Y beta-rays.

The use of radiations for the treatment of keloids was the topic of debate for years. Because of the benign nature of the keloids, surgery (keloidectomy) was treatment of choice. However, the use of surgery alone for arresting the keloids growth does not give satisfactory results due to the high frequency of recurrences. In this study 110 symptomatic cases were treated with 90Sr-90Y beta-radiation either alone for flat keloids or in combination with surgery for thick keloids. The results obtained with this method were found to be quite satisfactory. Patients were given four fractions of 5 Gy per fraction either as weekly or twice weekly schedules. Radiation dose of 2000 cGy given twice weekly in four fractions showed response in 86% of the cases as compared to 73% in those receiving four fractions of 5 Gy weekly. Further observations on different time dose fractionation schedules would open up newer dimensions in the radiotherapy of keloids.

Adolescent↗