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Contribution to red marrow absorbed dose from total body activity: a correction to the MIRD method.
UNLABELLED: The contribution to red marrow absorbed dose from beta-emitting radionuclides distributed uniformly in the total body can be overestimated using either MIRD 11 or MIRDOSE3. The S value assigned to the red marrow target region from activity distributed in the remainder of the body is of particular concern. The assumption that the specific absorbed fraction for total body irradiating red marrow and other skeletal tissues is the inverse of the total-body mass can result in an inappropriate remainder-of-body contribution to marrow dose. We evaluated differences in the calculation of marrow dose using MIRD 11 and MIRDOSE3 formulations and developed methods to correct the results from either to remove inappropriate contributions. When bone takes up significantly less activity than is predicted from an apportionment of remainder-tissue activity based on mass, the standard remainder-of-body correction may substantially overestimate the electron component of the S value from remainder tissues to red marrow using either MIRD 11 or MIRDOSE3. If bone takes up activity, this contribution is negligible using MIRD 11 S values but remains with MIRDOSE3 S values. This overestimate can be significant, particularly when the residence time of activity in the remainder of the body is much higher than in the red marrow and a different correction is needed. As the ratio of the remainder of body to marrow residence time is lowered, the overestimate becomes less significant. CONCLUSION: In this article, we show the magnitude of this overestimate (which is most important for nuclides with large "nonpenetrating" emission components and for pharmaceuticals that have a large ratio of remainder of body to marrow residence times), show the appropriate corrections to be made in each case, and propose a new method for calculating marrow dose contributions that will avoid this complication in future applications. Because all models give approximate doses for real patients, with uncertainties within those involved in these corrections, we do not suggest that changes be made to existing marrow dose estimates. We suggest only that future calculations be as accurate as possible.
Beta Particles↗
Percutaneous coronary intervention and subsequent endovascular beta-radiation brachytherapy in a 14-year-old with repaired anomalous left coronary artery from pulmonary artery.
Anomalous origin of the left coronary artery from pulmonary artery (ALCAPA) is a rare congenital anomaly. Re-establishment of the dual coronary system is the standard treatment, although the long-term outcome after surgical repair is not well defined. We report a case in which coronary stenting was performed to treat left anterior descending artery lesions eight months after surgical repair of ALCAPA. The patient then developed rapid in-stent restenosis within three months, which was successfully treated by rotational atherectomy, balloon angioplasty, and catheter-based beta-radiation brachytherapy. Follow-up angiograms after three and six months showed no recurrent in-stent restenosis. This represents the first report of coronary stenting in the setting of ALCAPA, and the first report of catheter-based intracoronary radiation therapy in a pediatric patient.
Adolescent↗
A new information system for medical practice.
A data bank containing our clinical experience with more than 3,000 patients with suspected and documented ischemic heart disease is being used to expand our ability to care for patients. This report describes how the experience is documented, stored, and retrieved so that it can be used in patient management. Data acquisition is integrated with patient care by means of forms that are part of the patient record. Follow-up information is obtained at six months, one year, and yearly thereafter. All data are stored in a computer information system that allows the doctor to recall the experience of patients like his new patient. Prognostic information is available on each new patient both on-line and in the form of a printed laboratory report. The data bank represents an initial chapter of a computer textbook of medicine.
Beta Particles↗
[The role of beta-ray induced fibroblasts apoptosis on the inhibition of hypertrophic scar].
OBJECTIVE: To investigate the role of beta-ray induced apoptosis of the fibroblasts on the inhibition of hypertrophic scar. METHODS: A series of patients with hypertrophic scar were grouply treated with a certain dose beta-ray. A liopic sample was taken in each patients. Its was then examined with MTT[3-(4,5-dimethylthiazol.-2-yl)-2,5-dipheny1 terazolium-bromide] technique for deciding the inhibition rate of the fibroblasts, with electron microscope technique, DNA agarose gel electrophoresis and flow cytometry for evaluating the morphological and biochemical characteristics of the fibroblast. RESULTS: The beta-ray radiation resulted in significant inhibition of the fibroblast. The features of fibroblast apoptosis(e.g.: apoptotic bodies, DNA ladders band and hypodiploid DNA peak) could be seen in the group with lower does (10 Gy). The features of fibroblast necrosis could also be found in the group with higher does(20 Gy). CONCLUSIONS: The beta-ray radiation could have the effect for inhibiting the proliferation of scar-derived fibroblast, but with dose dependence. It could be used for the treatment and(or) the prevention of hypertrophic scar.
Apoptosis↗
[Soft extravascular model (SEM) with beta-radioactive ray inhibits smooth muscle cell proliferation and intimal hyperplasia in autogenous vein graft].
OBJECTIVE: To investigate the effects of the soft extravascular model (SEM) with 32P on intimal hyperplasia and smooth muscle cell preliferation in autogenous vein grafts. METHODS: We transplanted the femoral veins to the co-lateral femoral arteries in rabbits. The animals were divided into three groups of Aspirin group, 32P group and control group. We observed the expression density of endothelin type A receptor cDNA (ETAcDNA) and intimal relative thickness by using in situ molecular hybridization of ETAcDNA by computerized image analysis technology. RESULTS: SEM with beta-ray obviously inhibited SMC preliferation from 1 W to 12 W postoperation, and notably restrained intimal hyperplasia at early to middle stage of graft. Aspirin could not inhibit SMC proliferation and intimal hyperplasia under the condition of this experiment.
Animals↗
Use of the beta-imager for rapid ex vivo autoradiography exemplified with central nervous system penetrating neurokinin 3 antagonists.
The neurokinin 3 (NK3) receptor antagonists represent a novel class of pharmacological agents, which are currently under evaluation for the treatment of psychiatric disorders. An efficient brain penetration is one of the main prerequisites to further evaluate compounds displaying high potency to bind the NK3 receptor. The present report describes a method for determining the in vivo occupancy of central NK3 receptors after peripheral administration of drugs. An ex vivo measurement of NK3 receptor occupancy by quantitative autoradiography employing [3H]senktide as the radioligand has been developed. The speed of the method, which is usually considered low due to the time dedicated to film exposure (from weeks to months), has been considerably increased by the use of the beta-imager. The high sensitivity of this new radioimager was used to visualize and quantitatively analyze the [3H]senktide binding sites in brain sections within hours. Using this method, we have demonstrated that the reference NK3 antagonist SR142801 dose dependently occupied the NK3 receptors in the gerbil brain after subcutaneous administration with an ED50 of 0.85 mg/kg. The less active enantiomer SR142806 occupied the NK3 receptors only by 25% at the highest used dose of 10 mg/kg. These values are in accordance with the reported behavioral effects of the compounds. Our results indicate that ex vivo receptor occupancy measurements can be dependently used to predict the central activity of NK3 antagonists. More generally, the combination of ex vivo receptor autoradiography with the beta-imager detection constitutes a new and fast method to evaluate the brain penetration of drug candidates.
Animals↗
Treatment of long, diffuse, in-stent restenotic lesions with beta radiation using strontium 90 and sequential positioning "pullback" technique: procedural details and clinical outcomes.
BACKGROUND: Long, diffuse, in-stent restenotic lesions have been problematic for many patients, necessitating the need for multiple repeat percutaneous coronary interventions (PCI). The need for repeat PCI has been significantly reduced in patients since the advent of vascular brachytherapy. In-stent restenosis resulting in long lesions (> 30 mm) presents even more of a challenge. The interventional injury length created during PCI is usually greater than 30 mm and the vascular brachytherapy systems available in most hospitals are 30 mm or 40 mm in length. The purpose of this paper is to define "pullback technique" and to report the Montreal Heart Institute (MHI) data to show that the pullback technique using the Novoste system seems to be a safe and effective method for using vascular brachytherapy to treat long, diffuse, in-stent restenotic lesions. METHODS: We reviewed the database of patients enrolled in the Compassionate Use Registry between August 1999 and July 2000. The data are reported on 23 consecutive patients treated with the pullback technique. RESULTS: The mean lesion length was 49.4 +/- 19.8 mm. Three patients (13%) underwent target vessel revascularization. Angiographic follow-up was obtained in 18 patients (78%). Seven patients (38.8%) showed angiographic restenosis (> 50% luminal re-narrowing). No aneurysms or zones of ectasia were noted. CONCLUSION: This angiographic and clinical evaluation of the MHI Compassionate Use Registry data show the pullback technique to be safe from both a dosimetric and clinical point of view.
Beta Particles↗
Design philosophy of air quality surveillance systems.
This paper discusses the design philosophy of the air quality surveillance systems which Kennecott is installing in the vicinity of its copper smelters in Arizona, Nevada, New Mexico, and Utah. These monitoring systems are part of supplementary control systems (SCS) that are utilized to ensure that short-term ambient air quality standards are met. These systems utilize minicomputers as remote terminals. The interface between a terminal and the primary sensors is via specially designed input/output circuitry. The system is controlled by a centralized host minicomputer, which is connected to each of the remote stations via a telephone line communication network. Real time data is displayed on cathode ray tubes located at strategic locations in the plants. This paper will discuss the system design philosophy from both a hardware and software point of view. The actual experience in design, development, and installation of the system will also be discussed.
Air Pollutants↗
[An investigation on morphology of experimental corneal neovascularization].
OBJECTIVE: To observe the morphologic character of the corneal neovascularization in experimental rabbits and also compare it with the morphology of that after irradiation with beta-rays. METHODS: A model of new blood vessels on the corneas of New Zealand rabbits was established with silver nitrate burning. The growth character of the neovascularization was compared between the irradiated and non-irradiated groups. The casting of the new blood vessels in different periods was made and the morphologic differences between the two groups were compared under a scanning electron microscope. RESULTS: The corneal new blood vessels occurred and continuously proliferated with the typical method of budding. The formation of buds was obviously inhibited and damaged after irradiation with  or  beta-rays, and the irradiated new branches were also atrophic and necrotic. CONCLUSIONS: Stopping the budding procedure of the corneal neovascularization may inhibit the formation and development of the corneal new blood vessels.
Animals↗
A particular structure associated to the nucleoid of cyanobacteria.
Regressive staining as well as beta-radiations or trypsin treatment on Synechocystis PCC6803 and Spirulina platensis (Gom,-Geilteri.) whole cells or permeaplasts, respectively, have demonstrated the presence of a particular structure associated to the nucleoid of cyanobacteria. This structure with a tridimensional network aspect has been called scaffold-like. We presume that it represents the cellular-molecular support for the supercoiling of the nucleoid of cyanobacteria.
Beta Particles↗
SIC, an intracerebral beta(+)-range-sensitive probe for radiopharmacology investigations in small laboratory animals: binding studies with (11)C-raclopride.
UNLABELLED: Our aim was to show the ability of a recently developed beta(+)-range-sensitive intracerebral probe (SIC) to measure, in vivo, the binding of radioligands in small animals. METHODS: The potential of the device for pharmacokinetic studies was evaluated by measurement of the dynamic striatal binding of (11)C-raclopride, a well-documented D(2) dopaminergic receptor ligand, in rat brain after intravenous injection of the labeled compound. The effects of preinjection of the unlabeled ligand (raclopride, 2 mg/kg intravenously) and of increasing the synaptic dopamine level (amphetamine treatment, 1 mg/kg intravenously) or of depleting synaptic dopamine (reserpine pretreatment, 5 mg/kg intraperitoneally) on in vivo (11)C-raclopride binding were monitored by SIC. RESULTS: The radioactivity curves measured as a function of time were reproducible and consistent with previous studies using PET imaging (ratio of striatum to cerebellum, 2.6 +/- 0.3 after 20 min). Further studies showed significant displacement of (11)C-raclopride by its stable analog. Finally, the device proved its capacity to accurately detect changes in (11)C-raclopride binding after a sudden (amphetamine) or a gradual (reserpine) modulation of endogenous dopamine levels. CONCLUSION: These results show that the new device can monitor binding of PET ligands in anesthetized rodents in vivo, with high temporal resolution.
Animals↗
[The role of beta irradiation on neointimal formation and apoptosis in vein grafts model].
OBJECTIVE: To evaluate the effect of beta irradiation on intimal proliferation and apoptosis in vein grafts. METHODS: Autogenous vein graft model was established in 80 rats by transplanting the internal branch of the jugular vein to the carotid artery by end to end anastomosis. The veins were irradiated by (32)P solution before anastomosis. Two dose schedules were studied: control group (graft, nonirradiated) and radiation group (20 Gy). The grafted veins were harvested at 3, 1, 2 and 4 week respectively after the operation. intimal hyperplasia (IH), smooth muscle cell (SMC), proliferation, p53, bcl-2 and bax were observed pathologically and immunohistochemically. They were analyzed by a computerized system. The presence of apoptotic VSMC was demonstrated by TUNEL method. RESULT: There was a significant decrease in the average intimal thickness at 7, 14 and 28 days (t = 15.694, P < 0.05) in the radiation group. Immunohistochemical analysis of PCNA indicated decreased positive cells in the radiation group compared with the controls at 1 and 2 weeks (t = 60.157, P < 0.01). Apoptosis of VSMC was higher in the radiation group than in the control group at 2 weeks (t = 56.176, P < 0.01). There was no significant difference in expression of P(53) between the two groups, and there was a significant increase in bax/bcl-2 in the radiation group at 2 weeks (t = 9.783, P < 0.05). CONCLUSION: These preliminary results demonstrated that low dose of beta irradiation in the vein graft inhibits SMC proliferation and induces the apoptosis of VSMC in rats.
Animals↗
CRTs pose health problems for operators.
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Asthenopia↗
Update on radiation for restenosis.
Coronary stenting is now used in most coronary interventions and reduces the restenosis rate to 20% or less. However, repeat in-stent restenosis occurs in 40%-60% of these patients. Radiation therapy, guided by intravascular ultrasound, can further reduce the incidence of repeat in-stent restenosis, and clinical trials have shown that all patient subgroups benefit from it. The mechanism appears to be reduction in neointimal hyperplasia. Studies are now evaluating use of medication with stents and radiotherapy, implantation of radiation-eluting stents, longer radiation sources to adequately cover lesions, and catheter balloons inflated with radioisotope solution. Intravascular radiation may soon be the standard of treatment for patients with in-stent restenosis and has the potential to reduce the recurrence rate to below 10%.
Beta Particles↗
Evaluation of the effectiveness of post-operative beta-irradiation in the management of pterygium.
A retrospective review of cases of pterygium excision using the bare sclera method followed by application of 2500-3500 rads of Sr 90 beta-radiation carried out between 1994 and the year 2000 at Ojulowo Eye clinic Ibadan and St Mary's Catholic Specialist Eye Hospital Ago-Iwoye, Nigeria. Follow up period was between six months and six years. A total of 124 eyes from 95 patients were operated. 58 (61.1%) were males and 37 (38.9%) were females. The youngest patient was 10 years old while the oldest was 89 years mean 46.1 +/- 2 STD of 13.5. Most pterygia were unilateral and nasal in location. Improvement in visual acuity of between 2-6 lines on snellen chart occurred in 6 (4.8%) of operated eyes. Recurrence necessitating repeat surgery and additional radiation occurred in 8 eyes (6.9%). The complications of surgery and beta radiation consisted of conjunctiva inflammation 10 (8.6%), cornea opacities 4 (3.2%), gritty sensation 3 (2.6), cataract 1 (0.8%). No case of sclera necroses was observed. Post-operative beta-radiation is safe and effective in preventing recurrence of pterygium.
Adolescent↗
Determination of the efficiency of commercially available dose calibrators for beta-emitters.
OBJECTIVES: The goals of this investigation are to determine whether commercially available dose calibrators can be used to measure the activity of beta-emitting radionuclides used in pain palliation and to establish whether manufacturer-supplied calibration factors are appropriate for this purpose. METHODS: Six types of commercially available dose calibrators were studied. Dose calibrator response was controlled for 5 gamma-emitters used for calibration or typically encountered in routine use. For the 4 most commonly used beta-emitters ((32)P, (90)Sr, (90)Y, and (169)Er) dose calibrator efficiency was determined in the syringe geometry used for clinical applications. Efficiency of the calibrators was also measured for (153)Sm and (186)Re, 2 beta-emitters with significant gamma-contributions. Source activities were traceable to national standards. RESULTS: All calibrators measured gamma-emitters with a precision of +/-10%, in compliance with Swiss regulatory requirements. For beta-emitters, dose calibrator intrinsic efficiency depends strongly on the maximal energy of the beta-spectrum and is notably low for (169)Er. Manufacturer-supplied calibration factors give accurate results for beta-emitters with maximal beta-energy in the middle-energy range (1 MeV) but are not appropriate for use with low-energy ((169)Er) or high-energy ((90)Y) beta-emitters. beta-emitters with significant gamma-contributions behave like gamma-emitters. CONCLUSION: Commercially available dose calibrators have an intrinsic efficiency that is sufficient for the measurement of beta-emitters, including beta-emitters with a low maximum beta-energy. Manufacturer-supplied calibration factors are reliable for gamma-emitters and beta-emitters in the middle-energy range. For low- and high-energy beta-emitters, the use of manufacturer-supplied calibration factors introduces significant measurement inaccuracy.
Beta Particles↗
Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria.
An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the D10 value of B. cereus at 4 degrees C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 degrees C. The gamma irradiation of the bacteria without incubation at 4 degrees C before irradiation was more effective than that of the bacteria with incubation overnight at 4 degrees C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 degrees C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation.
Bacteria, Aerobic↗