Firearm businesses as partners in suicide prevention: a cross-sectional study of the Gun Shop Project in Colorado, USA.

BACKGROUND: The Gun Shop Project aims to reduce firearm suicide and is widely implemented in the USA, yet little is known about the core firearm business practices and behaviours that might contribute to preventing firearm suicide. METHODS: Owners or managers of all firearm businesses identified as participants in Colorado's Gun Shop Project were invited to respond to a questionnaire. Data collection occurred from March to May 2021. Analyses included unweighted descriptive statistics with CIs and Pearson χ2 tests for categorical associations. RESULTS: 54 firearm businesses participated (response rate: 28%). Under half reported practices that are Gun Shop Project core aspects (range: 14%-45%). 22% of businesses frequently engaged customers on the importance of safe firearm storage in suicide prevention while 26% had denied a firearm sale and 14% had assisted with temporary secure storage in the past year with customers perceived to be in suicidal crisis. However, high proportions reported willingness to engage in these behaviours if a customer was in crisis: 74% were willing to refuse a sale of a firearm or ammunition, 70% were willing to discuss temporary secure storage options and 70% were willing to direct customers to mental health services. CONCLUSIONS: This study suggests that efforts to continue educating and involving firearm businesses may have an impact on the adoption of organisational suicide prevention practices and behaviours. Ongoing efforts are needed to understand core components of Gun Shop Project to inform standardised recommendations for effective firearm business practices that prevent firearm suicide.

Inspiratory flow shape clustering: an automated method to monitor upper airway performance during sleep.

We describe an automated method for monitoring airflow dynamics in the upper airway of a sleeping subject. Its main task is to determine a set of inspiratory flow shape representatives and their relative incidence in a given respiratory airflow material. The flow shape clustering aims at reducing redundant information in the data, and thereby decreases the time needed to score overnight sleep recordings. Compared with previous computer-assisted systems, built on a pre-defined classification of prototype shapes, we require no a priori assumptions of the flow shape clusters to be discovered. The intrinsic flow shape clustering is performed with a modification of the Isodata algorithm, and the K-means clustering is used as a reference in comparison studies. The operation of the method is demonstrated on clinical sleep recordings both from patients with nocturnal breathing disorders and from non-symptomatic individuals. The feasible results obtained in the practical research design suggest that application of clustering algorithms to respiratory airflow measurements could give important insights into the subtle flow shape abnormalities underlying obstructive sleep-disordered breathing.

Long-term antipsychotic and benzodiazepine use and brain volume changes in schizophrenia: The Northern Finland Birth Cohort 1966 study.

High doses of antipsychotics have been associated with loss in cortical and total gray matter in schizophrenia. However, previous imaging studies have not taken benzodiazepine use into account, in spite of evidence suggesting adverse effects such as cognitive impairment and increased mortality. In this Northern Finland Birth Cohort 1966 study, 69 controls and 38 individuals with schizophrenia underwent brain MRI at the ages of 34 and 43 years. At baseline, the average illness duration was over 10 years. Brain structures were delineated using an automated volumetry system, volBrain, and medication data on cumulative antipsychotic and benzodiazepine doses were collected using medical records and interviews. We used linear regression with intracranial volume and sex as covariates; illness severity was also taken into account. Though both medication doses associated to volumetric changes in subcortical structures, after adjusting for each other and the average PANSS total score, higher scan-interval antipsychotic dose associated only to volume increase in lateral ventricles and higher benzodiazepine dose associated with volume decrease in the caudate nucleus. To our knowledge, there are no previous studies reporting associations between benzodiazepine dose and brain structural changes. Further studies should focus on how these observations correspond to cognition and functioning.

Antiviral Properties of Chemical Inhibitors of Cellular Anti-Apoptotic Bcl-2 Proteins.

Viral diseases remain serious threats to public health because of the shortage of effective means of control. To combat the surge of viral diseases, new treatments are urgently needed. Here we show that small-molecules, which inhibit cellular anti-apoptotic Bcl-2 proteins (Bcl-2i), induced the premature death of cells infected with different RNA or DNA viruses, whereas, at the same concentrations, no toxicity was observed in mock-infected cells. Moreover, these compounds limited viral replication and spread. Surprisingly, Bcl-2i also induced the premature apoptosis of cells transfected with viral RNA or plasmid DNA but not of mock-transfected cells. These results suggest that Bcl-2i sensitizes cells containing foreign RNA or DNA to apoptosis. A comparison of the toxicity, antiviral activity, and side effects of six Bcl-2i allowed us to select A-1155463 as an antiviral lead candidate. Thus, our results pave the way for the further development of Bcl-2i for the prevention and treatment of viral diseases.

Two-year follow-up after catheter-based radiotherapy to inhibit coronary restenosis.

BACKGROUND: Although early trials indicate the treatment of restenosis with radiation therapy is safe and effective, the long-term impact of this new technology has been questioned. The possibility of late untoward consequences, such as aneurysm formation, perforation, and accelerated vascular disease, is of significant concern. Furthermore, it is not known whether the beneficial effects of radiation therapy will be durable or whether radiation will only delay restenosis. METHODS AND RESULTS: A double-blind, randomized trial was undertaken to compare 192Ir with placebo sources in patients with previous restenosis after coronary angioplasty. Patients were randomly assigned to receive a 0.76-mm (0. 03-in) ribbon containing sealed sources of either 192Ir or placebo. All patients underwent repeat coronary angiography at 6 months. All living patients were contacted 24 months after their index study procedure. Patients were assessed with respect to the need for target-lesion revascularization or nontarget-lesion revascularization, occurrence of myocardial infarction, or death. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192Ir and 29 to placebo. Follow-up was obtained in 100% of living patients at a minimum of 24 months. Target-lesion revascularization was significantly lower in the 192Ir group (15.4% versus 44.8%; P<0. 01). Nontarget-lesion revascularization was similar in 192Ir and placebo patients (19.2% versus 20.7%; P=NS). There were 2 deaths in each group. The composite end point of death, myocardial infarction, or target-lesion revascularization was significantly lower in 192Ir-treated versus placebo-treated patients (23.1% versus 51.7%; P=0.03). No patient in the 192Ir group sustained a target-lesion revascularization later than 10 months. CONCLUSIONS: At 2-year clinical follow-up, treatment with 192Ir demonstrates significant clinical benefit. Although further follow-up (including late angiography) will be necessary, no clinical events have occurred to date in the 192Ir group to suggest major untoward effects of vascular radiotherapy. At the intermediate follow-up time point, vascular radiotherapy continues to be a promising new treatment for restenosis.

Three-year clinical and angiographic follow-up after intracoronary radiation : results of a randomized clinical trial.

BACKGROUND: Although several early trials indicate treatment of restenosis with radiation therapy is safe and effective, the long-term impact of this new technology has been questioned. The objective of this report is to document angiographic and clinical outcome 3 years after treatment of restenotic stented coronary arteries with catheter-based (192)Ir. METHODS AND RESULTS: A double-blind, randomized trial compared (192)Ir with placebo sources in patients with previous restenosis after coronary angioplasty. Over a 9-month period, 55 patients were enrolled; 26 were randomized to (192)Ir and 29 to placebo. At 3-year follow-up, target-lesion revascularization was significantly lower in the (192)Ir group (15. 4% versus 48.3%; P<0.01). The dichotomous restenosis rate at 3-year follow-up was also significantly lower in (192)Ir patients (33% versus 64%; P<0.05). In a subgroup of patients with 3-year angiographic follow-up not subjected to target-lesion revascularization by the 6-month angiogram, the mean minimal luminal diameter between 6 months and 3 years decreased from 2.49+/-0.81 to 2.12+/-0.73 mm in (192)Ir patients but was unchanged in placebo patients. CONCLUSIONS: The early clinical benefits observed after treatment of coronary restenosis with (192)Ir appear durable at late follow-up. Angiographic restenosis continues to be significantly reduced in (192)Ir-treated patients, but a small amount of late loss was observed between the 6-month and 3-year follow-up time points. No events occurred in the (192)Ir group to suggest major untoward effects of vascular radiotherapy. At 3-year follow-up, vascular radiotherapy continues to be a promising new treatment for restenosis.

Effect of intracoronary gamma-radiation therapy on in-stent restenosis: An intravascular ultrasound analysis from the gamma-1 study.

BACKGROUND: The aim of this study was to use serial volumetric intravascular ultrasound to evaluate the effect of gamma-radiation on recurrent in-stent restenosis. METHODS AND RESULTS: After successful reintervention, patients were randomized to receive either (192)Ir or placebo. Intravascular ultrasound studies with motorized pullback (0.5 mm/s) were performed immediately after irradiation and at 8-month follow-up in 70 patients. Paired volumetric analysis of the stented segment and of 5-mm proximal and distal reference segments was performed; this included measurements of the external elastic membrane, lumen, plaque and media (external elastic membrane minus lumen), stent, and intimal hyperplasia (stent minus lumen). Baseline proximal reference, stent, and distal reference measurements were similar in both groups. The changes in proximal and distal reference measurements of the external elastic membrane, plaque and media, and lumen areas were similar in both groups. However, the decrease in stented segment lumen volume was less in the (192)Ir patients than the placebo patients (-25+/-34 mm(3) versus -48+/-42 mm(3); P:=0.0225), and the increase in the volume of intimal hyperplasia in the stented segment was less in the (192)Ir patients than in the placebo patients (28+/-37 mm(3) versus 50+/-40 mm(3); P:=0.0352). When averaged over the length of the stented segment (32+/-13 mm versus 33+/-14 mm; P:=0.9), the increase in mean area of intimal hyperplasia was 0.8+/-1.0 mm(2) in the (192)Ir group and 1.6+/-1.2 mm(2) in the control group (P:=0.0065). Late stent-vessel wall malapposition was noted in one placebo patient and no (192)Ir patients. CONCLUSIONS: gamma-Radiation therapy can effectively prevent recurrent in-stent restenosis by inhibiting neointimal formation within the stent. At the stent edge, there were no significant differences between (192)Ir and placebo patients.

Particle analysis for the determination of UHMWPE wear.

Three types of ultrahigh molecular weight polyethylene (UHMWPE) acetabular liners were tested against cobalt-chrome (CoCr) femoral heads on a hip simulator to approximately 20 million cycles. The materials included (1) conventional, nonirradiated liners (C-PE); (2) 5 Mrad gamma-irradiated, remelted, and artificially aged liners (5-XPE); and (3) 10 Mrad gamma-irradiated, remelted, and artificially aged liners (10-XPE). Wear was quantified by gravimetric analysis and wear particle characterization. Particle number and morphology were quantified by scanning electron microscopy (SEM) and compared between groups. Atomic force microscopy (AFM) was used to measure particle height in an effort to improve the total wear volume estimation. The wear debris, as characterized by SEM, was predominantly submicron and round, with occasional fibrils documented in the C-PE material. AFM analysis showed that particle height was approximately one-third of the particle equivalent circular diameter for all three materials. This correlation was used to improve the estimation of volumetric wear rate through SEM particle analysis. This technique is particularly useful for high-dose crosslinked UHMWPE, such as 10-XPE, which show weight gain due to fluid absorption during wear testing. This study has shown that particle analysis provides additional particle morphology and quantity information that cannot be obtained through gravimetric analysis.

Endovascular brachytherapy for peripheral vascular disease.

The most common cause of morbidity and mortality in the United States is vascular disease, which afflicts a wide spectrum of organs such as the heart (cardiovascular system), brain (cerebrovascular system), kidney (renal system), liver (hepatic system), and extremities (peripheral vascular system). The most common pathology of vascular diseases is occlusion. Percutaneous Transluminal Angioplasty (PTA) is currently the most common nonsurgical treatment for obstructive arteries. Unfortunately, the long-term effectiveness of PTA is limited by a high restenosis rate. Efforts to reduce post-PTA restenosis, including laser, mechanical atherectomy, intravascular stenting, and pharmacologic agents, have not been successful. With recent advances in the pathogenesis of restenosis, we have learned that the major problem is the intimal hyperplastic reaction in response to vessel injury. Encouraging animal data in the use of various radiotherapeutic approaches to prevent restenosis has led to a large number of multi-national, multicenter, randomized trials on coronary vascular systems. Because early results have been in favor of radiation therapy, and because the basic process of restenosis is similar for coronary and noncoronary vascular systems, many investigators extend the application of radiotherapy to the prevention of restenosis in peripheral vascular systems. However, the clinical scenarios are much different for peripheral vascular systems than for the coronary vascular system. This article discusses the current views of the pathophysiology of restenosis, major clinical trials, and perspectives on future studies. Experimental studies on animal models have documented the profound effects of endovascular brachytherapy in reducing restenosis caused by angioplasty and stenting. Early results of clinical trials are encouraging and confirm these positive results. Long-term follow-up data are needed to show that radiation does prevent, not merely delay, restenosis; Several areas of opportunity exist for both basic science research and clinical studies to enhance our knowledge of the pathophysiology. This would optimize the treatment strategy, maximizing the benefits and minimizing late complications.

Megavoltage radiation field matching on uneven surface.

Large radiation fields adjacent to each other require proper field matching to avoid overdosage at their junction. Various methods of determining optimum field separation have been discussed in the literature. However, these methods consider a perfectly flat surface of incidence throughout the irradiated area. In reality, it is more common for the patient thickness to vary within large fields, thus creating an uneven surface of incidence. In this paper, we have discussed the approach to gap calculation for an uneven surface of incidence. Dose measurements were made at the junction of two fields for 60Co, and 4, 6, and 24 MV X ray beams to verify this approach. Beam profiles measured under uneven surfaces indicated that the 50 percent dose decrement line did not shift towards the central axis for frequently encountered variations in patient thickness. Thus, careful geometric considerations could provide an optimum field separation. Ignoring the surface inhomogeneity may lead to field overlap and overdose at the junction.

Alopecia associated with unexpected leakage from electron cone.

Excessive irradiation due to unexpected leakage was found on a patient receiving electron beam therapy. The cause of this leakage was analyzed and the amount of leakage was measured for different electron beam energies. The highest leakage occurred with a 6 x 6 cm cone using a 12 MeV electron beam. The leakage dose measured along the side of the cone could be as great as 40%. Until the cones are modified or redesigned, it is advised that all patient setups be carefully reviewed to assure that no significant patient areas are in the side scatter region.

Extended field irradiation for carcinoma of the uterine cervix with positive periaortic nodes.

Forty-three patients were treated with extended field irradiation for periaortic metastasis from carcinoma of the uterine cervix (FIGO stages IB-IV). Twelve patients (28%) remained continuously free of disease to the time of analysis or death from intercurrent disease, 20 (46%) had persistent cancer within the pelvis, 11 (26%) had persistent periaortic disease, and 23 (53%) developed distant metastasis. The actuarial 5-year survival rate was 32%. The results correlated well with the periaortic tumor burden at the time of irradiation. None of 19 patients (0%) with microscopic or small (less than 2 cm) periaortic disease had periaortic failures, compared to 29% (4/14) of those with moderate-sized (2-5 cm) disease and 70% (7/10) of those with massive (greater than 5 cm) periaortic metastasis. Similarly, the 5-year survival rates were 50% (6/12) with microscopic disease, 33% (2/6) with small gross disease, 23% (3/13) with moderate-sized disease, and 0% (0/10) with massive periaortic metastases. Only 10% (1/10) of patients whose tumor extended to the L1-2 level survived 5 years, compared with 31% (9/29) of those whose disease extended no higher than the L3-4 level. The periaortic failure rates correlated to some extent with the dose delivered through extended fields, although the difference was not statistically significant. Only 8% (1/13) of those who had undergone extraperitoneal lymphadenectomies developed small bowel complications, compared with 25% (7/29) of those who had had transperitoneal lymphadenectomies. The incidence of small bowel obstruction was 8% (1/13) following periaortic doses of 4000-4500 cGy, 10% (1/10) after 5000 cGy, and 32% (6/19) after approximately 5500 cGy. From this, we concluded that the subset of patients who would benefit most from extended field irradiation are those in whom the residual disease in the periaortic area measures less than 2 cm in size at the time of treatment, whose disease extends no higher than L3, and whose cancer within the pelvis has a reasonable chance of control with standard radiation therapy techniques.

A comparison of the roles of surgery and radiation therapy in the management of craniopharyngiomas.

Fifty-two patients with craniopharyngioma were seen between January 1961 and July 1986. Of these, 40 were treated with surgery alone, 8 with surgery and postoperative radiotherapy, and 3 with radiotherapy alone. One patient received no treatment. For the group treated with surgery alone, 33% (13/40) had local tumor control, 42.5% (17/40) developed major complications, and 71% (25/35) survived 5 years. With surgery and postoperative radiotherapy, 100% (8/8) had local tumor control, 25% (2/8) developed major complications, and 100% (7/7) survived 5 years. Two of the three patients treated with radiotherapy alone had local tumor control and the third was salvaged with surgery. The "complete resection" rate for 32 patients treated with radical surgery was 63% (20/32). Tumor control was achieved in 50% (10/20) of the patients treated with "complete resection" without radiotherapy, in 15% (3/20) of the patients treated with "incomplete resection" without radiotherapy, and in 100% (8/8) of the patients treated with "incomplete resection" and postoperative radiotherapy. In this series, doses of 5000-5500 cGy were as effective in achieving control as 5500-6000 or 6000-7000 cGy.

A subgroup analysis of the Scripps Coronary Radiation to Inhibit Proliferation Poststenting Trial.

INTRODUCTION: In the Scripps Coronary Radiation to Inhibit Proliferation Poststenting (SCRIPPS) Trial, 192Ir significantly reduced angiographic, ultrasonographic, and clinical endpoints of restenosis. The objective of this analysis was to quantitate the impact of patient, lesion and technical characteristics on late angiographic outcome. METHODS: Patients with restenotic, stented coronary lesions were randomized to receive either 192Ir or placebo sources. Late luminal loss and loss index were calculated for several patient subgroups, including patients with diabetes, in-stent restenosis, multiple previous percutaneous transluminal coronary angioplasty (PTCA) procedures, longer lesion lengths, saphenous vein grafts, small vessel diameters, and minimum dose exposures < 8.00 Gy. Two-factor analysis of variance was used to test for an interaction between patient characteristics and treatment effect. RESULTS: In the treated group, late loss was particularly low in patients with diabetes (0.19 mm), in-stent restenosis (0.17 mm), reference vessel diameters < 3.0 mm (0.07 mm), and patients who received a minimum radiation dose to the entire adventitial border of at least 8.00 Gy. The loss index in each of these subgroups was similarly low at -0.02, 0.03, -0.02, and 0.03, respectively. By 2-factor analysis of variance, a significant interaction between subgroup characteristic and treatment effect (late loss) was found in patients with in-stent restenosis (p = 0.035), and patients receiving a minimum dose of 8.00 Gy to the adventitial border (p = 0.009). CONCLUSION: In this pilot study, patient characteristics associated with a more aggressive proliferative response to injury appeared to confer an enhanced response to radiotherapy. Furthermore, a dose threshold response to 192Ir was found with an enhanced response occurring when the entire circumference of the adventitial border was exposed to at least 8.00 Gy.

Quantitative angiographic analysis of stent restenosis in the Scripps Coronary Radiation to Inhibit Intimal Proliferation Post Stenting (SCRIPPS) Trial.

To identify luminal dimension changes occurring within the stent alone and within the stent + margin segment, we reviewed the quantitative angiographic results obtained from the Scripps Coronary Radiation to Inhibit Proliferation Post Stenting (SCRIPPS) trial, a prospective randomized trial assessing the effect of iridium-192 (Ir-192) on the prevention of stent restenosis. Fifty-five patients were randomly assigned to receive Ir-192 or placebo sources after successful intervention. Procedural and 6-month follow-up cineangiograms were quantitatively reviewed in 52 patients to identify changes within the stent and the stent + margin segment. The percent diameter stenosis was lower within the stent than within the stent + margin segment after the procedure (6 +/- 22% vs 21+/- 15%, p <0.0001) and at follow-up (28 +/- 29% vs 42 +/- 21%, p <0.0001). As a result, a lower restenosis rate was found within the stent than within the stent + margin (25% vs 37%, p <0.0001); isolated stent margin restenosis occurred in 11.5% of lesions. Treatment with Ir-192 reduced restenosis within the stent (8% vs 39%; p = 0.010) and within the stent + margin segment (17% vs 54%; p = 0.010); the reduction in restenosis at the margin only (8.3% vs 14.3%, p = 0.503) was not significant. The lowest relative risk for restenosis resulting from Ir-192 occurred within the stent (0.21; 95% confidence interval [CI] 0.05 to 0.86) compared with the stent + margin segment (0.31; 95% CI 0.12 to 0.81) or the stent margin (0.58; 95% CI 0.12 to 2.91). In the SCRIPPS trial, 32% of restenosis occurred at the stent margins. Treatment with Ir-192 reduced restenosis primarily within the stent rather than the margin. Whether extending the treatment length to fully include the stent margins will further reduce restenosis requires further study.

Depth dose characteristics of 24-MV x-ray beams at extended SSD.

Depth dose characteristics of 24-MV beams from a medical linear accelerator at various SSDs have been measured. The dose buildup, percent depth dose (PDD), and output were measured using ionization chambers and a diode detector under full scatter. Surface dose ranged from 8% to 51% depending upon the collimator setting at 100-cm SSD. It decreased by 10%-15% as distance was increased to 200 cm, but remained unchanged beyond this distance. The dmax migrated rapidly toward the surface with increasing field size at 100-cm SSD. At extended SSD, the dmax occurred at greater depths and shifted a little toward the shallow depths with increasing field size. Large field PDDs measured at extended SSD agreed well with those predicted from 100-cm data. The output followed the 1/(distance)2 relationship quite well. The extended SSD beam data are clinically useful when treating hemibody or performing total body irradiation (TBI) procedures.

Tissue compensators with use of vinyl lead sheets for head and neck portals on 4-MV x rays.

Tissue compensators made with a high atomic number material are compact and retain the skin-sparing effect of megavoltage beams. In this note, we have described the use of a commercially available vinyl lead as a material for tissue compensators for use with 4-MV beams on a Clinac-4/80. The dosimetric data obtained included the sheet's lead equivalence, thickness ratios, surface dose and buildup region, and transmission factors. The presence of a compensator did not alter the beam's skin-sparing effects. It was concluded that the vinyl lead sheets allowed an easy and rapid fabrication of a tissue compensator for head and neck portals of up to 15 X 15 cm.

Leakage radiation from electron applicators on a medical accelerator.

The leakage characteristics of electron applicators on our Clinac 2500 linear accelerator have been measured. The leakage radiation in the patient plane and at the surface of the electron applicators has been measured for applicator sizes from 6 cm X 6 cm to 25 cm X 25 cm and beam energies from 6 to 22 MeV. For certain applicator/energy combinations the leakage radiation was significant. The leakage radiation, relative to the central axis dose, was found to be up to 7% in the patient plane and up to 39% at the applicator surface. Reducing the collimator setting or adding lead at select locations on the applicator surface was effective in reducing the magnitude of the radiation leakage.

Evaluation of optically projected x-ray images from an elastomer-based ionographic system.

In ionographic imaging, the ions produced in a high-pressure, high-Z gas are normally collected on an insulating foil. If a deformable dielectric gel is used as a collecting electrode, then the electrostatic image can be visualized by optically projecting the gel deformation onto a screen. In the present work, we have evaluated the imaging performance of such an ionographic system in terms of its sensitivity and resolution capabilities. X-ray images of a sharp lead edge formed on a thin silicone elastomer were optically projected and recorded on x-ray films. The edge profiles were obtained at different values of x-ray exposure, elastomer thickness, gas pressure, and collecting voltage across the chamber. These profiles were processed to obtain the sensitivity and resolution of the system at different operating conditions. Images of some test objects are shown using this system in order to demonstrate its clinical potential.

Dose anisotropy around an Au-198 seed source.

For interstitial implants with radioactive Au-198 seeds, the dosimetric calculations usually ignore the finite source size and employ a point source approximation, resulting in a computed isotropic dose distribution. However, the measured radiation fluence from Au-198 seeds is reported to be anisotropic, suggesting some amount of dose anisotropy in tissue. We have measured this dose anisotropy around Au-198 seeds (2.5 X 0.8 mm2) using Kodak X-OMAT XV-2 films placed in contact with individual seeds in a phantom. Autoradiographs obtained for various exposure times were digitized and studied with an image analysis computer network. The network's overall spatial resolution was about 0.01 cm. The optical isodensity contours around the seed were obtained. The useful range of optical density (OD) for the system was found to be 1 to 2 OD units. Within this range, the shape of an optical isodensity contour would be identical to an isodose contour. Proximal to the source, the contours were elliptical in shape, elongated along the seed axis. However, further away, the elongation was in the direction normal to the seed axis. This was in agreement with the reported data on the radiation fluence around Au-198 seeds. It was concluded that measurable dose anisotropy existed around Au-198 seeds. However, it was too small to be of any clinical significance.