Beta Radiation Treatment Research Articles

Effect of Ionizing Beta Radiation on the Mechanical Properties of Poly(ethylene) under Thermal Stress

It was found in this study, that ionizing beta radiation has a positive effect on the mechanical properties of poly(ethylene). In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. Several types of ionizing radiation are used for crosslinking of polymers. Each of them has special characteristics. Electron beta and photon gamma radiation are used the most frequently. The great advantage is that the crosslinking occurs after the manufacturing process at normal temperature and pressure. The main purpose of this paper has been to determine the effect of ionizing beta radiation on the tensile modulus, strength and elongation of low and high density polyethylene (LDPE and HDPE). These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 99 kGy were compared) and on the test temperature. Radiation cross-linking of LDPE and HDPE results in increased tensile strength and modulus, and decreased of elongation. The measured results indicate that ionizing beta radiation treatment is effective tool for improvement of mechanical properties of LDPE and HDPE under thermal stress.

Beta-90Sr irradiation treatment of silicon wafer coated with extracellular matrix protein to mimic the beta-32P radiation application in intravascular brachytherapy

Wu YP et al. in the International Journal of Cardiology reported that beta-radiation reduced the reactivity of extra cellular matrix proteins in intravascular brachytherapy (IVBT) which resulted in decreased platelet adhesion [1]. Beta-radiation treatment decreases the thrombogenicity of the vessel wall extracellular matrix proteins, in particular, vWF, fibrinogen, fibronectin and collagen, resulting in decreased platelet adhesion and aggregation. The vessel wall becomes lowly prone to thrombosis and might help reduce the onset of acute coronary events and of acute coronary occlusion after intravascular interventions.

The long-term effect of experimental beta-radiation therapy on the human cornea

Background Radiation treatment of the human eye has been utilized in the United States since the early 1900s. Beta-radiation therapy was generally accepted by the medical community as a treatment option for a wide variety of anterior and posterior segment conditions from 1930 to the early 1950s. By the 1960s, beta-radiation therapy had fallen out of favor due to dangerous side effects; however an updated radiation procedure is now in use in ophthalmology to treat anterior and posterior segment disease. Case report A 64-year-old Caucasian female presented for a routine eye examination with a history of experimental beta-radiation treatments to the eyes as a teenager. A high astigmatic refractive error was present and best corrected visual acuity was 20/40 OD, 20/30 OS. Slit lamp examination showed severe disruption throughout the lower third of both corneas, appearing densely calcified with inferior vascularization. The left eye had a central descemetocele. The patient's ocular and visual conditions were relatively stable and required no special treatment as of the writing of this report, decades after her original treatments. Conclusion This patient is one example of the long-term effect of beta-radiation treatment on the eye. Ongoing care is needed to monitor the ocular health and vision of these individuals as radiation effects may necessitate observation and/or care throughout the patient's lifetime. Follow-up on more patients who underwent beta-radiation treatment decades ago, should it be possible to do so, would provide further insight into the long-term anterior segment changes that can occur as a result of such treatment.

Cellular metabolic responses of PET radiotracers to 188Re radiation in an MCF7 cell line containing dominant-negative mutant p53

We investigated the relations between the cell uptakes of metabolic radiotracers and beta-radiation pretreatment using a dominant mutant p53 (p53mt) cell line to evaluate the effects of p53 genes on (18)F labeled positron emission tomography (PET) radiotracer uptakes. pCMV-Neo-Bam (control), which contains a neo-resistance marker, and p53 dominant-negative mutant expression constructs were stably transfected into MCF7 cell line. Cells were plated in 24-well plates at 1.0x10(5) cells for 18 h. Rhenium-188 ((188)Re) (a beta emitter) was added to the medium (3.7, 18.5, 37 MBq) and incubated for 24 h. We performed gamma-counting to determine the cellular uptakes of 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG), o-(2-[(18)F]fluoroethyl)-l-tyrosine (FET) and 2'-[(18)F]fluoro-2'-deoxythymidine (FLT) (370 kBq, 60 min). Cell viabilities were determined by trypan blue staining and flow cytometry. p53mt cells showed 1.5-2-fold higher FDG uptake than wild-type p53 cells in basal condition, and the difference of FDG uptake was greater after (188)Re treatment (P<.01). FET uptake increased with (188)Re dose without a significant difference between p53 statuses. p53mt cells showed lower FLT uptake than wild-type p53 cells in basal condition, and the difference of FLT uptake was greater after (188)Re treatment. By cell viability testing and FACS analysis, p53mt cells showed lower viability and a larger apoptotic fraction (sub-G1) than wild-type p53 cells after (188)Re treatment. We speculate that p53 dysfunction increases glucose and decreases thymidine metabolism in cancer cells and that this may be exaggerated by (188)Re beta-radiation. Our findings suggest that FDG could reflect tumor viability and malignant potential after (188)Re beta-radiation treatment, whereas FLT could be a more useful PET radiotracer for assessing therapeutic response to beta-radiation, especially in cancer cells with an altered function of p53.

Angiographic and clinical outcomes at 8 months of cutting balloon angioplasty and β‐brachytherapy for native vessel in‐stent restenosis (BETACUT): Results from a stopped randomized controlled trial

The objective of this study was to assess angiographic and clinical outcomes of cutting balloon (CB) angioplasty and concomitant Sr/Y-90 beta-brachytherapy as a treatment modality for patients with native vessel in-stent restenosis (ISR). Procedural advantages over the standard balloon (SB) have been claimed for the CB. Intracoronary brachytherapy preceded by SB angioplasty is regarded as the treatment of choice in patients with ISR. In an interim analysis of a prospective randomized trial designed for 652 patients, 100 consecutive patients with ISR were assigned to treatment with SB angioplasty (n = 51) or CB angioplasty (n = 49), followed in either case by Sr/Y-90 beta-brachytherapy. Quantitative coronary angiography at baseline, postintervention, and at 8 months was performed by an independent central laboratory. More than 90% of target lesions in the overall patient population were diffuse, with 14% of stents totally occluded. Procedural parameters and immediate angiographic outcomes were essentially the same in either study arm. At 8 months, no statistically significant differences were observed in recurrent angiographic restenosis (SB = 26.1%; CB = 29.5%; P = 0.82), target lesion revascularizations (SB = 13.7%; CB = 8.2%; P = 0.53), and major adverse cardiac events (SB = 15.7%; CB = 8.2%; P = 0.36). In this interim analysis, there was no indication of a beneficial effect of CB use over SB use in terms of angiographic or clinical outcomes at 8-month follow-up. CB angioplasty appears to be as safe and efficacious as SB angioplasty in beta-radiation treatment of patients with predominantly diffuse native vessel ISR. It was decided to discontinue the trial.

Efficacy of long radiation treatment in native in-stent restenosis: a subanalysis from the RENO registry

Background: The effectiveness of intracoronary radiation therapy of diffuse in-stent restenosis (ISR) with Strontium-90 Beta sources is unknown. Methods: The RENO registry is a post market prospective surveillance study enrolling consecutive patients with ISR at 46 European centers using the Novoste Beta-Cath™ system. Patients were treated with approved interventional devices, followed by Strontium-90 Beta-radiation treatment. Of the 1098 patients enrolled in the trial, 139 had diffuse native coronary ISR treated with a stepping technique using a 30, 40, or 60mm source train or a single 60mm source train. The historical control group was the placebo arm of the WRIST and LONG WRIST studies (N=94). Results: Baseline characteristics were similar between two groups except for more diabetics in placebo. Brachytherapy success ( 96%. The results are shown in the table. Conclusion: Beta-radiation with Sr-90 using either a stepping (pullback) technique or a single 60mm source train to treat patients with diffuse, long native ISR lesions is effective and results in significant reductions in TVR by 75% and MACE by 72% without any increase in the late thrombosis rates compared to historical controls .

Use of localised intracoronary β radiation in treatment of in-stent restenosis: the INHIBIT randomised controlled trial

In-stent restenosis is a major limitation of intracoronary stenting. Ionising gamma radiation has been shown to reduce recurrence of restenosis after stent placement. We aimed to compare the effects of intracoronary beta radiation treatment with those of placebo for clinical and angiographic outcomes of patients with diffuse in-stent restenosis. 332 patients with in-stent restenosis underwent successful coronary intervention, and were then randomly allocated to intracoronary beta radiation with a phosphorus-32 source (n=166) or placebo (166) delivered into a centreing balloon catheter through an automatic afterloader. Longer lesions (>22 mm of dilated length) were treated with tandem positioning of the study wire. The primary safety endpoint was major adverse cardiac events, defined as death, myocardial infarction, and repeat target-lesion revascularisation at 9 months. The primary efficacy endpoint was binary angiographic restenosis rate in the analysis segment during 9-months' follow-up. Analysis was by intention to treat. Procedural success, and in-hospital and 30-day complications were similar among the two groups. 24 (15%) patients in the radiated group had the primary safety endpoint of death, myocardial infarction, or repeat target-lesion revascularisation over 290 days compared with 51 [corrected] (31%) in the placebo group (difference 16% [95% CI 7-25], p = 0.0006). Binary angiographic restenosis rate was lower in the radiated group than the placebo group for the entire analysed segment (difference 25% [14--37], p < 0.0001). Vascular brachytherapy using pure beta-emitter 32P delivered into a centreing catheter via an automatic afterloader can be used to reduce overall revascularisation in patients undergoing treatment for diffuse in-stent restenosis.

Postoperative beta radiation treatment of pterygium

A retrospective analysis of 69 patients with diagnosis of pterygium who underwent surgical removal of the pterygium and postoperative beta radiation from a Strontium-90 (Sr-90) applicator from January, 1973, to December, 1977, is presented. The radiation treatment was delivered 2–48 hrs postoperatively after surgical removal of the pterygium. Those few patients who received beta radiation after more than 56 hours postoperatively were not included in the analysis because of the small number of patients in this group. Thirty-two patients had bilateral pterygium; 18 patients from this group received radiation treatment to one eye only. A total of 83 eyes have been irradiated in the whole group. A total dose of 1800–2200 rad equivalent of beta radiation was delivered to the edge of the cornea and surgical bed of the pterygium in the conjunctiva. Measurement by phantom showed that the dose to the anterior surface of the lens will be approximately 70–90 rad, and the dose to the retina will be 4–8 rad during a single dose of 1800–2200 rad equivalent of beta radiation to the conjunctiva and pterygium bed. Thirty-nine percent of the nonirradiated eyes after removal of the pterygium developed recurrence, whereas only 5% of the irradiated eyes developed recurrence. Nineteen percent of the irradiated eyes developed cataract as well as 10% of the nonirradiated eyes. These include all detectable cataracts, some of which did not require lens removal. Local cortisone therapy reduced the progression of the recurrent disease for a few months and partial regression was seen in four eyes, but there was no complete regression of any recurrent pterygium with topical cortisone therapy. This retrospective study showed that postoperative 1800–2200 rad beta radiation from a Strontium-90 applicator, if delivered 2–48 hours postoperatively, is effective in reducing the recurrence rate. It has acceptable range of complication if it is administered by an experienced radiation therapist and calculation and calibration are done precisely. The immediate and late side effects and complications of beta radiation from a Strontium applicator are discussed, and the dose delivered to the cornea, sclera, lens, and retina with this radiation treatment are shown.