bluuebunny/crossref_metadata_2025 huggingface dataset:
Design Reuse in Manufacturing and Services*
Authors: Ettlie John E. , Kubarek Matthew
Published: July 2008

Most professionals, actively engaged in design, live in a world of trade‐offs. The most typical compromise is that reducing the cost of design causes quality to suffer, but there are many others as well. This paper summarizes current use of one of the most popular approaches to improving the new offering development process: design reuse. In the present study 42 companies were surveyed, of which 23 were in manufacturing and 19 were in services—but all were actively engaged in technology and design reuse in new offerings. It was hypothesized that policies for design reuse and internal sourcing would promote the complexity and breadth of reuse (here the combination of modular and architectural substitution), which, in turn would dampen the percentage of substitution and reduce the negative impact on innovativeness of new offerings. These predictions were generally supported. Adoption of policies for encouragement or to mandate design reuse were significantly correlated with the extent of reuse (application of both architectural and modular design vs. just one or the other) among manufacturers but not services firms in the sample. Internal sourcing of ideas for design reuse was significantly correlated with extent of reuse for the total sample, and especially for services. Design reuse percentage and extent of design reuse were significantly and inversely associated for manufacturing, as predicted, but not for services. Novelty of new offerings was significantly and inversely related to percentage of reuse, as predicted, for manufacturing, but not for services. It was found that sector also makes a difference in likelihood of adopting higher levels of reuse with service company respondents reporting significantly higher levels (average of 42% reuse for services and 28% for manufacturing applications). Perhaps one of the most interesting preliminary findings to emerge was that the tipping point of negative impact from design reuse percentage on innovativeness for all firms in the sample of new offerings was 43%, beyond which novelty suffers. For manufacturing, the tipping point was lower: Novelty begins to suffer after 33% design reuse, which has important management implications. The conclusion was drawn, based on these preliminary results, that much can be done to relieve some of the negative consequences of the typical trade‐offs commonly encountered in development programs for new offerings, especially when cost, timing, and innovation are the target goals. However, services and manufacturing are quite different in their approach to design reuse and substitution. Further development of the concept of design reuse strategy appears to be warranted based on these preliminary findings. The findings raise the distinct possibility that mesolevel strategic aggregation issues might lead research into areas that help explain how complex systems realize their full self‐organizing potential and why corporate strategy considerations, alone, have failed to explain the success and failure of organizations coping in rugged landscapes.
Photopatch tests: an Italian multicentre study from 2004 to 2006
Authors: Pigatto Paolo Daniele , Guzzi Gianpaolo , Schena Donatella , Guarrera Marcella , Foti Caterina , Francalanci Stefano , Cristaudo Antonio , Ayala Fabio , Vincenzi Colombina
Published: July 2008

Background:  Evaluation of possible photoallergic contact dermatitis in at‐risk populations is often not undertaken, and an agreed methodology for investigation is uncommonly used.

Objectives:  We conducted a retrospective multicentre study to determine the prevalence of photoallergic contact dermatitis in Italy.

Methods:  A total of 1082 patients with histories and clinical features suggestive of photoallergic contact dermatitis were evaluated. All the patients had undergone photopatch testing with allergens proposed for Italy as well as other substances suggested by each patient’s personal history.

Results:  234 patients (21.6%) were positive to at least one test substance of the standard photopatch testing series or to added substances. 234 patients (21.6%) were positive to at least one substance with a total of 290 reactions. 204 of the reactions were typically photoallergic; 68 reactions were allergic and within this group 10 were photoaugmented reactions; 18 reactions were considered to be phototoxic.

Conclusion:  The predominant group of photoallergens was drugs, followed by organic UV filters and antimicrobial agents.
Zinc diethyldithiocarbamate allergenicity: potential haptenation mechanisms
Authors: Chipinda Itai , Hettick Justin M. , Simoyi Reuben H. , Siegel Paul D.
Published: July 2008

Background: Zinc diethyldithiocarbamate (ZDEC) and its disulfide, tetraethylthiuram disulfide (TETD), are rubber accelerators and contact allergens that cross‐react in some individuals.

Objective: This study explored potential protein haptenation mechanisms of ZDEC and its oxidation products.

Methods: ZDEC oxidation/reduction products and sites of protein binding were assessed using high‐performance liquid chromatography and mass spectrometry. The murine local lymph node assay (LLNA) was employed to probe haptenation mechanisms of ZDEC by examining its allergenicity along with its oxidation products and through elimination of oxidation and chelation mechanisms by substituting cobalt for zinc [cobalt (II) dithiocarbamate, CoDEC].

Results: Oxidation of ZDEC by hypochlorous acid (bleach, HOCl), iodine, or hydrogen peroxide resulted in production of TETD, tetraethylthiocarbamoyl disulfide, and tetraethyldicarbamoyl disulfide (TEDCD). Albumin thiols reduced TETD with subsequent mixed disulfide formation/haptenation. ZDEC directly chelated the copper ion on the active site of the superoxide dismutase, whereas CoDEC did not bind to Cu proteins or form mixed disulfides with free thiols. ZDEC, sodium diethyldithiocarbamate, TEDCD, and TETD were all positive in the LLNA except CoDEC, which was non‐allergenic.

Conclusion: The thiol is the critical functional group in ZDEC’s allergenicity, and haptenation is predominantly through chelation of metalloproteins and formation of mixed disulfides.
Seroprevalence of SV40‐like polyomavirus infections in captive and free‐ranging macaque species
Authors: Verschoor E.J. , Niphuis H. , Fagrouch Z. , Christian P. , Sasnauskas K. , Pizarro M.C. , Heeney J.L.
Published: July 2008

Background and methods  To investigate the seroprevalence of polyomavirus infections in macaques, we analyzed 1579 sera from nine different species for antibodies cross‐reactive with simian virus 40 (SV40) in an enzyme‐linked immunosorbent assay. Most samples were collected from captive animals, but we also investigated a colony of free‐ranging Barbary macaques (Macaca sylvanus).

Results  High seropositive rates were found in rhesus macaques (Macaca mulatta; 74.7%), cynomolgus macaques (Macaca fascicularis; 44.8%) and Tonkean macaques (Macaca tonkeana; 41.7%), especially in animals imported from China. Low rates were measured in cynomolgus macaques from Mauritius (8.8%), and in Barbary macaques (1.4%). Seropositivity was age‐dependent increasing to >70% in animals of 5 years and older.

Conclusions  High seroprevalence rates were found in different species of macaques, dependent on their origin. Very low infection rates found in Barbary macaques and cynomolgus macaques from Mauritius suggest that these animals in the wild are not commonly infected by SV40‐like viruses.
Efficacy of three different laser wavelengths for in vitro wound healing
Authors: Evans Denise Hawkins , Abrahamse Heidi
Published: July 2008

Background and objective: Despite contradictory reports on the effect of laser light on cell proliferation, studies have shown that appropriate doses and wavelengths of laser light are therapeutically beneficial in tissue repair and pain control. This study aimed to establish if the dose and/or wavelength influenced the biological responses of irradiated in vitro fibroblasts – 1 h after laser irradiation.

Materials and methods: This study aimed to establish cellular responses of normal and wounded human skin fibroblasts to helium‐neon (632.8 nm), diode (830 nm) and Nd:YAG (1064 nm) laser irradiation using one exposure of 5 or 16 J/cm2 on day 1 and again on day 4.

Results: Wounded cells exposed to 5 J/cm2 using 632.8 nm showed an increase in cell migration and haptotaxis, a stable increase in the release of interleukin‐6 (IL‐6), a decrease in caspase 3/7 activity, an increase in ATP viability and an increase in cell proliferation – 1 h after the final exposure. The results confirm that changes in parameters such as ATP viability, cytokine expression (IL‐6), cell proliferation (alkaline phosphatase enzyme activity) and DNA damage can be observed directly after the laser irradiation. The amount of DNA damage and cytotoxicity may be related to duration of the laser irradiation, which is dependent on the power density (mW/cm2) of each laser.

Conclusion: The results indicate that 5 J/cm2 using 632.8 nm results in a stimulatory effect that is more effective than 830 and 1064 nm. The results suggest possible mechanisms by which the wavelength may potentially influence the cellular responses of wounded cells.
Risk factors for dyslipidemia in Chinese children
Authors: Liao Ying , Liu Ying , Mi Jie , Tang Chaoshu , Du Junbao
Published: July 2008

Aim: Since the mortality rate due to cardiovascular disease continues to increase, research into dyslipidemia has been emphasized in not only adults but also paediatric populations. We aimed to study the risk factors of dyslipidemia in Chinese children.

Methods: Nine hundred and sixty‐two children, aged 6–18 years, in Beijing were enrolled. For each child, data were collected on body height (cm), body weight (kg), sitting height (cm), waist circumference, upper arm circumference, serum lipid levels, as well as familial history of dyslipidemia and early onset cardiovascular disease. Subgroups were determined on the basis of age and sex.

Results: The prevalence rate of dyslipidemia was 11.1% (107/962). Children with dyslipidemia differed significantly from those without, in sitting height, upper arm circumference, body mass index (BMI), waist‐to‐height ratio (WHR) and diastolic and systolic blood pressure (p < 0.05). Logistic regression analysis suggested that WHR, diastolic blood pressure and positive familial history were risk factors for dyslipidemia in children.

Conclusion: Sitting height, upper arm circumference, BMI, WHR, diastolic pressure and systolic pressure were significantly higher in dyslipidemic children than in normal subjects in China. BMI, WHR, diastolic pressure and familial history of dyslipidemia and early‐onset cardiovascular disease were risk factors for dyslipidemia in Chinese children.
Cardiomyopathy in newborns and infants: a broad spectrum of aetiologies and poor prognosis
Authors: Badertscher Andrea , Bauersfeld Urs , Arbenz Urs , Baumgartner Matthias R. , Schinzel Albert , Balmer Christian
Published: July 2008

Aim: This study set out to describe the initial clinical findings, morbidity, mortality and aetiology of infant cardiomyopathy focusing on potential risk factors for an adverse outcome.

Methods: We retrospectively analysed clinical and laboratory findings of all patients diagnosed at our institution from 1995 to 2004 with cardiomyopathy within their first year of life.

Results: Of the 35 patients, cardiomyopathy was classified as dilated in 18, hypertrophic in 14 and unclassified in 3. The aetiologies were genetic syndromes (8), metabolic diseases (5), familial isolated cardiomyopathy (3) and myopathy (1). During a median follow‐up of 1.5 years (range 0–9 years), 13 patients died from progressive heart failure and two underwent heart transplants. Estimated survival and freedom from transplant was 69, 66, 58 and 50% after 0.5, 1, 2 and 6 years, respectively. Patients with severe heart failure symptoms within the first month of life had significantly worse outcomes than patients without heart failure symptoms.

Conclusion: High morbidity and poor prognosis result through progressive heart failure. Aetiology and clinical course are especially heterogeneous in infants. The most commonly identified aetiologies are genetic syndromes and metabolic diseases. A multidisciplinary approach is recommended for defining the aetiology and developing individual treatment strategies.
Denture contamination by yeasts in the elderly
Authors: Vanden Abbeele Astrid , De Meel Hèlène , Ahariz Mohamed , Perraudin Jean‐Paul , Beyer Ingo , Courtois Philippe
Published: July 2008

Objectives:  The aim of this study was to investigate yeast carriage in healthy denture wearers by swabbing and to evaluate the effect of denture hygiene habits.

Materials and methods:  Denture wearers (n = 87) without evidence of denture stomatitis or any other oral disease were investigated by separately swabbing the fitting surface of the upper denture and the corresponding palatal mucosa in contact with the appliance. In a group of volunteers, a gel without any active compound was spread on the palatal side of the denture once in every morning for 2 weeks.

Results:  Screening showed Candida colonisation of upper prosthesis in 75.9% of individuals. The most frequent species isolated were Candida albicans (77.9% of the positive cultures), Candida glabrata (44.1%) and Candida tropicalis (19.1%). Carriage of more than one yeast species was found in 48.5% of the contaminated dentures. There was a statistically significant association between denture contamination and palatal mucosa colonisation (chi‐squared test: p < 0.0001). Repeated swabbings after 1 week as well as during a weekly follow‐up for 1 month confirmed the denture contamination and its degree of severity. A daily gel application produced a yeast‐count decrease to 10% of the initial value after 2 weeks (chi‐squared test: p = 0.0134 and p = 0.2841 for prosthesis and palatal mucosa, respectively).

Conclusion:  This study documented the reliability of oral swabbing when investigating yeast carriage in healthy denture wearers. Moreover, just a diagnostic tool, sampling upper dentures for Candida could be the opportunity to verify the patient’s compliance to hygiene advice.
INCIDENCE OF CAMPYLOBACTER IN PROCESSED POULTRY: IS IT A CONCERN FOR HUMAN HEALTH?
Authors: KING STUART , ADAMS MICHELLE C.
Published: July 2008

In Australia, over 15,000 cases of campylobacteriosis occur annually; however, recent findings from case‐control studies suggest that poultry may not be the primary etiological agent. To determine the incidence of Campylobacter species on Australian poultry, a qualitative and quantitative survey of different poultry products was undertaken. The qualitative study examined 428 poultry carcasses from 42 processors. Overall, 93.7% of the carcasses were found to be positive for Campylobacter species, of which 84.1% were identified as Campylobacter jejuni by hippurate hydrolysis, and 9.6% as other Campylobacter species. A longitudinal study over 6 weeks on 27 broiler carcasses from a single processor found an average Campylobacter species count of 163 cfu/cm2, with a range of 5–1,850 cfu/cm2 excluding one carcass that was negative. The real health risk of this carriage, however, cannot be determined accurately without further investigation of the presence of virulence factors and more accurate species identification.

PRACTICAL APPLICATIONS

This article identifies that the incidence of Campylobacter species on processed poultry remains at levels recognized to be potentially infectious to humans. This suggests that current changes in processing control in the Australian poultry industry primarily established for Salmonella species may not necessarily reduce all potential human pathogens to safe levels.

Using current literature, this article also debates whether the simple identification of presence and absence of a particular pathogen is sufficient for assumptions to be drawn on risk of infection. The discussion questions the real role of poultry in cases of campylobacteriosis, and suggests that based on case‐history data, poultry may be not be the common cause of the disease.
Growth, Condition, and Size Distribution of Paddlefish, Polyodon spathula, Juveniles Reared in Ponds at Three Densities
Authors: Onders Richard J. , Mims Steven D. , Dasgupta Siddhartha
Published: July 2008

Abstract.— A study was conducted to determine the effect of increasing density on growth and size distribution of paddlefish, Polyodon spathula, juveniles reared in ponds. Feed‐trained paddlefish of mean weight (±SE) 25.8 ± 1.1 g were randomly stocked into nine 0.02‐ha ponds at 12,355, 18,533, and 24,710 paddlefish/ha, three replications per treatment. The fish were fed daily in excess of what they would eat for 97 d, beginning with a floating trout diet containing 45% protein and 16% lipid and then transferring to a floating catfish diet containing 32% protein and 4.5% lipid. Survival at harvest was not significantly different (P > 0.05) among treatments and averaged 90%. Mean final weights (±SD) for the low‐, middle‐, and high‐density treatments were 205.2 ± 54.1, 174.8 ± 53.2, and 178.6 ± 51.4 g, respectively. Best‐fit distributions centered on these means were lognormal. The low‐density distribution was significantly different (P < 0.05) from the two higher densities, which were not significantly different from each other (P > 0.05). Paddlefish weight at the minimum target length of 35 cm was estimated to be 100 g by regression analysis. The probability of paddlefish reaching or exceeding 100 g was 90% for the low‐density treatment. For the two higher densities, probabilities were 79 and 78%, respectively. Mean Fulton’s condition factors (FCFs) (±SD) were 250 ± 19, 242 ± 4, and 256 ± 37 for the low‐, middle‐, and high‐density treatments, respectively. The FCF for the middle‐density treatment was significantly lower than for the low‐ and high‐density treatments (P < 0.05), which were not significantly different from each other (P > 0.05). CV, feed conversion ratio, and relative growth were not significantly different (P > 0.05) among treatments and averaged 0.43, 1.50, and 5.45, respectively. Monoculture of paddlefish juveniles in ponds results in a hierarchic size structure when density is at least greater than 12,355 paddlefish/ha. The effect is enhanced with increasing density but becomes asymptotic as density approaches 18,533 paddlefish/ha. Feeding in excess does not ameliorate the effect.
Inbreeding Effects on Hatchery and Growout Performance of Pacific White Shrimp, Penaeus (Litopenaeus) vannamei
Authors: Moss Dustin R , Arce Steve M , Otoshi Clete A , Moss Shaun M
Published: July 2008

In animal breeding programs, selection coupled with a narrow genetic base can cause high levels of inbreeding to occur rapidly (in one or two generations). Although the effects of inbreeding have been studied extensively in terrestrial animals and to a lesser extent in aquaculture species, little is known about the effects of inbreeding on penaeid shrimp. The objective of this study was to investigate the effects of inbreeding on hatchery and growout performance of the Pacific white shrimp, Penaeus vannamei. The experiment was conducted over 2 yr, and data from two successive generations (G2 and G3) of inbred (sibling–sibling mating) and outbred families were analyzed. There were 11 inbred and 12 outbred families in G2 and 9 inbred and 10 outbred families in G3. Inbreeding coefficients (F) for outbred and inbred families were 0.00 and 0.25, respectively, for G2 and 0.00 and 0.375, respectively, for G3. Growth rates for outbreds and inbreds were similar in both G2 and G3. Hatch rate for inbred families was 33.1% lower than for outbred families in G2 and 47.1% lower in G3. Inbreeding depression (IBD) (relative change in phenotype per 0.1 increase in F) ± 95% CI for hatch rate was −12.3 ± 10.1%. Hatchery survival for inbred families was 31.4% lower than for outbred families in G2 and 38.8% lower in G3. IBD for hatchery survival was −11.0 ± 5.7%. Growout survival was 1.9% lower for inbred families than for outbred families in G2 and 19.6% lower in G3. IBD for growout survival was −3.8 ± 2.9%. There was also a significant linear relationship between IBD estimates for survival traits and mean outbred survival. At high outbred survival, IBD was low (e.g., growout survival in G2), but IBD appeared to become more severe when outbred survival was lower. This suggests that stress (related to environment and/or life stage) may worsen IBD for survival traits. Results also indicate that moderate to high levels of inbreeding (>10%) should be avoided in commercial shrimp hatcheries because the cumulative effect of IBD on hatch rate and hatchery survival will significantly reduce postlarvae production. Thus, IBD can be significant enough to justify the use of inbreeding as a germplasm protection strategy (under certain scenarios) for genetic improvement programs.
Early intervention in bipolar disorder, part I: clinical and imaging findings
Authors: Salvadore Giacomo , Drevets Wayne C. , Henter Ioline D. , Zarate Carlos A. , Manji Husseini K.
Published: July 2008

The concept of prevention is not new to psychiatry and has long been recognized in general medicine. Recent evidence has highlighted that early pharmacological and psychosocial treatment dramatically ameliorates poor prognosis and outcome for individuals with psychotic disorders, reducing conversion rates to full‐blown illness and decreasing symptom severity. Nevertheless, despite the many recent advances in our thinking about early intervention, the need for early intervention in bipolar disorder (BPD) is an area that has been relatively neglected.

This review attempts to synthesize what is currently known about early intervention in BPD. We discuss methodological issues pertaining to this topic, review clinical studies that focus on high‐risk subjects as well as first‐episode patients and review findings from brain imaging studies in the offspring of individuals with BPD as well as in first‐episode patients.

A companion paper discusses the cellular and molecular mechanisms of action of agents with neurotrophic and neuroplastic properties, with a particular emphasis on lithium and valproate.
Motives for substance use among young people seeking mental health treatment
Authors: Hides Leanne , Lubman Dan I. , Cosgrave Elizabeth M. , Buckby Joe A. , Killackey Eoin , Yung Alison R.
Published: July 2008

Aims: To explore substance use motives among young people seeking mental health treatment.

Methods: Participants consisted of 103 young people seeking mental health treatment, who had used drugs or alcohol in the past year. The young people completed a 42‐item substance use motives measure based on the Drinking Motives Measure for their most frequently used substance in the past year.

Results: Exploratory factor analysis of the substance use motives scale indicated the young people reported using substances for positive and negative drug effects, to socialize with their peers, and to cope with a negative affect. They did not report using substances for enhancement or conformity motives. Coping motives predicted the presence of a current substance use disorder.

Conclusions: The findings support the need for integrated treatment approaches within mental health settings, particularly targeted at young people with co‐occurring mental health and substance use problems.
Family‐based interpersonal psychotherapy for depressed preadolescents: an open‐treatment trial
Authors: Dietz Laura J. , Mufson Laura , Irvine Holly , Brent David A.
Published: July 2008

Aim:To conduct an open‐treatment trial to evaluate the feasibility, acceptability and clinical outcomes of using a family‐based adaptation of Interpersonal Psychotherapy for Depressed Adolescents with a sample of preadolescents (ages 9–12) presenting for outpatient treatment for depression.

Methods:Sixteen preadolescents who met criteria for a depressive disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition participated in this open‐treatment trial of family‐based interpersonal psychotherapy (FB‐IPT). Parents chose whether their preadolescents should receive FB‐IPT only (n = 10) or FB‐IPT with antidepressant medication (n = 6). Pre‐ and post‐treatment assessments included clinician‐administered measures of depression and global functioning, and parent‐ and child‐reported anxiety symptoms.

Results:FB‐IPT was associated with high treatment compliance rates (88%) and was associated with significant decreases in preadolescents' depressive and anxiety symptoms. Preadolescents who received FB‐IPT only were as likely as those receiving FB‐IPT and medication to have significant reductions in depressive symptoms and anxiety symptoms, and to experience significant improvement in global functioning. Parents were more likely to choose combination treatment when their depressed preadolescents had a comorbid anxiety disorder.

Conclusions:Further research on FB‐IPT is needed to establish its efficacy as compared with usual outpatient treatment, its ability to be disseminated to child clinicians with varying levels of training and in adequately powered randomized controlled trials that can detect group differences.
Early intervention with difficult to engage, ‘high‐risk’ youth: evaluating an intensive outreach approach in youth mental health
Authors: Schley Carsten , Ryall Victoria , Crothers Leanne , Radovini Sandra , Fletcher Karen , Marriage Karen , Nudds Simon , Groufsky Catherine , Yuen Hok Pan
Published: July 2008

Background: Although intensive outreach (IO) models such as assertive community treatment and intensive case management have a strong evidence base in adult psychiatry, their effectiveness in the early intervention sector is unknown.

Aim: To explore client characteristics and treatment effects in a group of difficult to engage, ‘high‐risk’ young people, seen by the Intensive Mobile Youth Outreach Service (IMYOS, ORYGEN Youth Heath) in Western Metropolitan Melbourne.

Methods: The clinical files of 47 clients were audited, targeting demographic and treatment outcome data prior to and during IMYOS involvement.

Results: Clients typically presented with traumatic childhoods, disrupted education, repeated treatment dropout, poor mental health and ‘high‐risk’ behaviours. Results showed a significant reduction in risk to self and others between referral and discharge, and significantly lower admissions rates and inpatient days compared with the 9 months prior to referral.

Conclusions: IO might be an effective early intervention strategy to minimize risk of harm and decrease hospitalization in young people. However, conclusions are provisional as there was no control group included in this study. Further study is required, perhaps with a waiting list control.
A theoretical approach to using human footprint data to assess landscape level conservation efforts
Authors: Haines Aaron M. , Leu Matthias , Svancara Leona K. , Scott J. Michael , Reese Kerry P.
Published: July 2008

Conservation organizations are increasingly being held accountable for identifying and documenting measures of conservation success. We propose the use of human land‐use spatial data to aid in the assessment of conservation efforts by monitoring qualitative change in the human footprint (i.e., spatial land‐use measures of negative anthropogenic activity) within a hypothesis‐driven framework to assess the effects of conservation efforts (i.e., positive anthropogenic activity). If human footprint data show that implemented conservation strategies mitigated or reduced negative anthropogenic influences, then a potential conservation approach is working. In contrast, if the implementation of conservation strategies did not mitigate or reduce the human footprint, then new conservation approaches may need to be developed or old ones refined. Human footprint data may offer great potential for assessing conservation efforts when used as part of a larger conservation monitoring strategy.
SU‐DD‐A2‐04: A Comparison of Doses Calculated by Commonly Used Algorithms in Eyeplaque Implant
Authors: Zhang H , Law A , Wang J , Li K , Gupta N , Zhang D , Kong X , Weldon M , Mayr N , Martin D , Meigooni A
Published: July 2008

Purpose: To verify the deviation of dose calculation based on commonly used TG43U1‐based algorithms from Monte Carlo simulations in eyeplaque implants, and to evaluate the dose perturbation introduced by eyeplaque. Method and Materials: Monte Carlo technique was used to generate 3D dose distributions of single IsoAid™ I‐125 brachytherapy sources. A novel computer code EyeMC was developed to utilize the single‐source 3D dose distribution to generate dose distributions of multiple‐source implants for COMS eye‐plaques, through rotating, superposing, displacing and interpolating methods. In addition, Monte Carlo simulations were performed for the 8‐seed implant to verify the accuracy of the EyeMC and treatment planning system, and to verify the magnitude seed‐eyeplaque effects. Eight seeds were placed as two isocentric squares at the same plane, with the inner square width of 0.6 cm and outside square width of 1.1 cm. The treatment planning system Brachyvision™ was also used to calculate the doses at points of interest with point‐ and line‐source approximations. Results: The point‐source approximation used in the treatment planning system agreed with line‐source approximation within 10%. Compared to the Monte Carlo simulation, the treatment planning system using line‐source approximation significantly underestimated the dose values at the eyeplaque axis, by 13% at 2 mm, 18% at 1.0 cm, 20% at 2.0 cm, and 24% at 3 cm. The eyeplauqe‐seed effect was small but noticeable. The presence of the eyeplaque could reduce dose up to 10% at the distance of interest up to 3 cm. The data from EyeMC agreed with multiple‐seed full Monte Carlo simulation within 3%. Conclusion: Our comparison of commonly used TG43U1‐based algorithm shows that neither point‐source nor line‐source approximations provides accurate dose calculations for multiple‐seed implant eyeplaques at short distances. Our study suggests that a Monte Carlo‐aided code, such as EyeMC, is needed to increase the accuracy of dose calculation.
SU‐DD‐A2‐05: Uncertanity of Real Time in Vivo Dosimetry with MOSFET Linear Array in I‐125 Prostate Permanent Implant Brachytherapy
Authors: Takahashi Y , Tachibana H , Sumida I , Kozuka T , Ito A , Ogata T , Yoshioka Y , Koizumi M , Yamashita T , Inoue T
Published: July 2008

Real‐time dose monitoring is important to improve the accuracy of prostate permanent implant brachytherapy (PI). However, few data about in vivo dosimetry in PI have been reported because dosimetry of low energy photons from I‐125 sources is challenging. The purpose of this study is to estimate the dosimetric uncertainty in I‐125 permanent implant brachytherapy using 5‐linear array MOSFET. We evaluated the physical characteristics including angular response variability, linearity, calibration factor, and detector response variability for photon beams from I‐125 seed. All experiments were performed using I‐125 seeds to eliminate the energy dependence. Furthermore phantom study was performed to estimate the dosimetric uncertainty in preclinical settings. For isotropic analysis, the response of 270 and 90 degrees were 8 to 15 % lower than 0 degree and in another angle, the differences of responses were within 5%. However, the deviation of each angle was within 6%. The linearity of the readings is excellent (R2=0.098). The fading effect of MOSFET was not observed. Calibration factor was obtained with the standard deviation within 4%. We found that calibration factor was changed by seed‐detector distance (SDD) by 10% in shorter distance (5mm and 7mm) and 4% in greater distance compared with SDD 10mm. The same tendency was observed by Monte Carlo Simulation. Monte Carlo simulation showed that the beam hardening effect occurred as the SDD increased, which can increase additional deviation. In phantom study, treatment planning was performed with 47 seeds in a modified peripheral loading manner. We measured the urethral dose at base, midland, and apex positions during 20 minutes. In mid grand and base regions, measure dose agreed within 6% and in apex region less than 15% differences were observed. These data suggest that in vivo dosimetry in permanent implant brachytherapy with the appropriate correction can be performed within 15%.
SU‐DD‐A3‐01: Integration of KV Image‐Guidance with Arc Therapy for Radiotherapy of the Prostate
Authors: Moseley D , Sharpe M , Craig T , Jaffray D
Published: July 2008

Purpose: To assess the feasibility of on‐line kV image‐guidance and fluoroscopic monitoring during arc therapy. Method and Materials: A pelvis phantom with anthropomorphic prostate and seminal vesicles was implanted with 3 gold fiducial markers. CBCT imaging was performed before and during delivery of a prostate treatment plan using volumetric modulated arc therapy (VMAT). Both CBCT images were assessed for image quality based on noise. The gold fiducials were segmented in the guidance CBCT volume and subsequently localized in each projection image taken during the VMAT delivery. Since the phantom is rigid and was not moved between images, no movement of fiducials in each projection image is expected. Any movement was defined as tracking error. A clinical action level of 3 mm was used to designate if the tracking error was significant. Results: CBCT image noise (1 S.D.) increased from 10.4 HU to 20.6 HU due to increased scatter onto the kV detector as well as interference patterns induced by the MV beam pulses. The frame‐by‐frame tracking error below a 3mm clinical action level was 96.6% for the CBCT acquired for setup correction before the VMAT delivery. This value decreased to 88.7% for the CBCT volume captured concurrently with the VMAT delivery. Conclusion: Arc therapy promises to deliver highly conformal dose distributions quickly and efficiently. Simultaneous kV imaging allows for the capture of a residual image as well as an opportunity for fluoroscopic monitoring of the patient's position during treatment. CBCT image quality is degraded during VMAT delivery but image quality is still suitable for assessment of residual setup error as well as intra‐fraction motion.

Research sponsored by Elekta Synergy Research Group.
SU‐DD‐A3‐05: Experimental Investigation of a Monoscopic Real‐Time Tumor Tracking Method Combining Occasional X‐Ray Imaging and Continuous External Respiratory Monitoring
Authors: Cho B , Poulsen P , Suh Y , Dieterich S , Sloutsky A , Mostafavi H , Keall P
Published: July 2008

Purpose: To demonstrate the feasibility of a monoscopic method for real‐time tumour tracking, combining occasional x‐ray imaging and continuous external respiratory monitoring, which incorporates two correlations; (1) the correlation between the two projected components of 3D tumour positions on the imager plane (xp, yp) and the external respiratory signal (R), (2) the correlation between (xp, yp) and the unresolved component (z∥) along the monoscopic view direction using a prior 3D tumour trajectory that can be obtained by either MV/kV imaging or 4DCBCT. Method and Materials: A lung tumor trajectory acquired by a CyberKnife system was fed into 3D motion platform with a marker‐embedded phantom. The associated external respiratory signal was also fed into a separate 1D motion platform. The moving phantom was imaged by MV and kV imagers simultaneously. The 1D motion was also monitored by RPM system. The marker positions from images were extracted by Varian RPM‐Fluoro application. The performance of the proposed method was compared with stereoscopic estimation under various imaging frequencies. Results: The overall estimation error for continuous kV/MV imaging was 0.1±0.3 mm, which reflects the mechanical uncertainty of imaging systems and the marker extraction uncertainty. The error was 0.2±0.7 mm for stereoscopic estimation with 10‐s interval imaging and 0.6±0.7mm for monoscopic estimation with the same update interval. Conclusion: The proposed method can effectively estimate target position and thus be used for tumor tracking with gantry‐mounted single x‐ray imagers that major linac manufacturers offer. Conflict of Interest: Research supported by Varian Medical Systems.
SU‐DD‐A4‐05: An Analysis of Signal‐To‐Noise Ratio Differences Between the New High‐Sensitivity, Microangiographic Fluoroscope (HSMAF) and a Standard Flat‐Panel Detector (FPD)
Authors: Jain A , Kuhls‐Gilcrist A , Rudin S , Bednarek D
Published: July 2008

Purpose: To explain the difference in the measured signal‐to‐noise ratio (SNR) for a new high‐resolution detector with that for a standard FPD. Method and Materials: We measured a ratio of 4.3 between the SNR2 of an FPD (194 μm pixels) and HSMAF (35 μm pixels). This ratio cannot be explained by the pixel areas alone since the FPD pixel area is 30.7x larger than that of the HSMAF. To explain this disparity, we investigated the role of instrumentation‐noise and the x‐ray conversion phosphor (600 and 300 μm thick CsI:Tl for the FPD and HSMAF, respectively) considering differences in absorption efficiency, Swank factor and blur. Point spread functions (PSF's) were derived from measured presampled line spread functions (assuming isotropic blur), and the effect was analyzed by convolving with a simulated Poisson‐distributed x‐ray image. The calculated SNR2 ratio was compared to the measured SNR2 ratio for a practical range of exposures (1–100μR). Results: The difference between SNR2 of the detectors was largely accounted for by considering detector characteristics in addition to pixel size. The increase in SNR2 from optical blur was about 8 times greater for the HSMAF than for the FPD, since the signal was spread across more of the smaller pixels for the HSMAF. With consideration of the effect of absorption efficiency and Swank factor on SNR, the calculated SNR2 ratio agreed well with that measured (4.6 versus 4.3, respectively). Conclusion: The measured SNR depends not only on pixel area, but also to a large extent on phospher characteristics. Despite having a much lower number of incident x‐ray photons per pixel, the SNR2 of the HSMAF was much closer to that of the FPD because of a greater spread of light quanta over a larger number of pixels.

(Support: NIH Grants R01‐NS43924, R01‐EB002873, Toshiba Medical Systems Corporation).
SU‐DD‐A4‐06: Instrumentation Noise Equivalent Exposure (INEE): An Investigation of Spatial Frequency Effects
Authors: Kuhls‐Gilcrist A , Jain A , Bednarek D , Rudin S
Published: July 2008

Purpose: To expand on previous development of the instrumentation‐noise equivalent exposure (INEE) metric which directly quantifies the quantum‐limited performance range of a detector in terms of entrance exposure, by investigating spatial frequency dependence. Method and Materials: The INEE formalism assumes the total noise of an x‐ray detector is proportional to the incident number of quanta, with an additive term representing contributions resulting from instrumentation‐noise sources. The INEE then represents the threshold exposure below which the detector's performance is no longer driven by quantum statistics, becoming instrumentation‐noise‐limited and is measured using output signal variance plot versus exposure, fitted to . Similarly, to provide a spatial frequency dependent INEE, INEE(u,v), the two‐dimensional NPS (i.e. the variance of image intensity divided among the various frequency components of the image) was measured and plot as a function of exposure at each spatial‐frequency and fit with NPS(u,v)=k(u,v)(Exposure+INEE(u,v)). Output signal variance and NPS were measured using 90 flat‐field images on a digital x‐ray detector according to IEC guidelines and using the RQA 5 spectrum. Results: The measured INEE(u,v) was radially symmetric with the lowest INEE values at low spatial‐frequencies with an increasing INEE at higher spatial‐frequencies. The frequency behavior was determined to be largely dependent on the blur and scattering of the phosphor as described by the detector MTF. Frequency independent INEE was determined to be the weighted mean of INEE(u,v) with k(u,v), over all spatial frequencies. Conclusion: The INEE metric addresses the need for a direct, quantitative measure of the quantum‐noise‐limited exposure range of x‐ray detectors by providing the threshold exposure at which the detector instrumentation‐noise exceeds the quantum‐noise. Frequency dependence was investigated to provide a greater understanding of this promising new metric.

(Support: NIH Grants R01‐NS43924, R01‐EB002873, Toshiba Medical Systems Corporation).
SU‐EE‐A1‐05: A Real‐Time Feedback Control Algorithm to Compensate 2D Target Motion with a Dynamic Multileaf Collimator
Authors: Tacke M , Nill S , Oelfke U
Published: July 2008

Purpose: The aim of the work is to develop a real‐time control algorithm for a dynamic dose delivery with a multileaf collimator (MLC) that accounts for 2D target motion and deformation. Method and Materials: The multithreaded real‐time feedback control receives the target's position and deformation in real‐time from an independent localization device and approximates the future target position to calculate the next leaf positions. For lateral shifts, the leaves either include the entire target, exclude any healthy tissue, or utilize a percental trade‐off between surrounding tissue and target. Furthermore, the leaves can be placed so that an adjacent organ‐at‐risk (OAR) is not irradiated. For leaf positions and velocities, the physical constraints of the 160 MLC, Siemens, were obeyed. Theoretical simulations with different motion models were first performed to test the feedback algorithm. Experiments with a modified MLC demonstrate the feasibility of the method and the delay times within the feedback control loop were assessed. Results: The adaptive sequencer allows to compensate in real‐time for anatomically feasible target motion by adapting the radiation field to the new target position. Simulations indicate a significant improvement in conformity. Depending on the selected tracking mode, either an underdosage of the target edges, an overdosage of the adjacent tissue or a percental trade‐off occurs. First experiments proved the feasibility of the tracking algorithm combined with the dynamically adapted MLC though further developments to reduce the MLC control system latency are required to improve the feedback control loop. Conclusion: The simulations indicate an accurate application of the dose to moving targets if the real‐time feedback control is applied. The developed sequencer provides in real‐time the required new leaf positions to the MLC control system which then adapts the treatment field to the target motion. Conflict of Interest: Research supported by Siemens Medical Solutions.
SU‐EE‐A2‐04: Verification of the Rotational Accuracy of the Brainlab Robotics 6D Couch and the ExacTrac X‐Ray 6D Fusion System
Authors: Chen Q , Ryu S , Liu Y , Chetty I , Ouyang I , Wen N , Liu D , Movsas B , Jin J
Published: July 2008

Purpose: The Brainlab's Robotics 6D couch is integrated with ExacTrac X‐ray 6D system to compensate the rotational deviations in patient positioning. The purpose of this study is to quantitatively demonstrate the magnitude of improving the rotational accuracy by the 6D system. Method and Materials: Two tests were conducted. A self‐made tool was first used to verify that the rotation angles given by the ExacTrac matched with the actual rotation angles measured by geometry calculation and a level. A wedge was used to raise one side of the test tool for various rotational angles. A Rando head phantom with four BBs implanted was used for the second test. One BB was at the isocenter, with two others 5cm laterally, and the fourth 5cm superior. The relative rotational angles of each BB to the isocenter were calculated from CT images. The phantom was randomly setup within 5° rotations. Portal films were taken after each Robotics 6D couch corrections. BBs positions in the portal films were measured and the rotations were calculated and compared with that in the simulation. Results: The difference between the results determined by X‐ray 6D fusions and actual angels for various setups were 0.113°±0.06° and 0.05°±0.09°, according to level measurement or geometry calculation, respectively, for the pitch direction. The corresponding differences were 0.23°±0.09° and 0.08°±0.09° for the roll. After the Robotics 6D couch correction, the actual rotation was 0.03°±0.05°. and 0.13°±0.04° for the pitch and roll directions. For the second test, the final setup rotation angles compared with the Simulations were 0.42°±0.24°, 0.30°±0.16° and 0.06°±0.02° for pitch, roll and yaw rotations, respectively. Conclusion: The study demonstrated that the rotational accuracy was in the acceptable limit to use in the clinic. This has a great potential to improve the clinical targeting accuracy of radiosurgery.
SU‐EE‐A3‐06: Dose Reduction in CBCT Via Intensity Weighted Region of Interest Imaging
Authors: Pearson E , Cho S , Pan X , Pelizzari C
Published: July 2008

Purpose: Reporting preliminary evaluation results of an intensity weighted region of interest (IWROI) imaging technique that utilizes recent developments in cone‐beam CT (CBCT) reconstruction theory to reduce patient exposure and detected scattered radiation. Method and Materials: Patient dose can be reduced by decreasing the x‐ray source fluence, however this comes with the cost of a decreased signal‐to‐noise‐ratio in the resulting images. IWROI imaging introduces filters into the x‐ray beam such that the central ROI receives the full beam intensity, and thus maintains SNR level while the periphery of the field‐of‐view (FOV) is illuminated by a reduced intensity, filtered beam. Reconstruction is done with the recently developed chord‐based BPF algorithm, which has been shown to be robust against some forms of truncation and to have favorable noise propagation properties. This algorithm enables IWROI to be used more flexibly and yields higher image quality. Experimental studies were carried out by constructing aluminum and copper filters which could be attached directly to the CBCT source. Scans were taken with 125 kVp, 80 mA and 15 ms pulse length exposure setting. Dose measurements were made using LiF TLDs 10cm deep in a 20cm stack of 30cm×30cm solid water slabs. Results: For the 3mm copper filter case the measurements showed a 7% dose reduction for the central ROI and a 37% reduction for the low intensity region of the image. The coefficient of variation for the full intensity ROI after BPF reconstruction was 0.053 and 0.100 in the filtered region indicating relative noise levels. Conclusion: IWROI imaging can reduce radiation exposure to sensitive regions of the anatomy while still producing high image quality in the region of interest. The filtered region also contains enough information for comparison of the gross anatomy with the planning scan. Conflict of Interest: Work supported by Varian Medical Systems, Inc.