Viewing Then Doing?: Problem-Solving Court Coordinators' Perceptions of Medications for Opioid Use Disorders from a Nationally Representative Survey in the United States.

Background. Overdose deaths in the United States (U.S.) surpassed 100,000 in 2021. Problem-solving courts (PSCs), which originally began as drug courts, divert people with nonviolent felonies and underlying social issues (e.g. opioid use disorders (OUDs)) from the carceral system to a community-based treatment court program. PSCs are operated by a collaborative court staff team including a judge that supervises PSC clients, local court coordinators that manage PSC operations, among other staff. Based on staff recommendations, medications for opioid use disorders (MOUDs) can be integrated into court clients' treatment plans. MOUDs are an evidence-based treatment option. However, MOUDs remain widely underutilized within criminal justice settings partially due to negative perceptions of MOUDs held by staff. Objective. PSCs are an understudied justice setting where MOUD usage would be beneficial. This study sought to understand how court coordinators' perceptions and attitudes about MOUDs influenced their uptake and utilization in PSCs. Methods. A nationally representative survey of 849 local and 42 state PSC coordinators in the U.S. was conducted to understand how coordinators' perceptions influenced MOUD utilization. Results. Generally, court coordinators hold positive views of MOUDs, especially naltrexone. While state and local coordinators' views do not differ greatly, their stronger attitudes align with different aspects of and issues in PSCs such as medication diversion (i.e. misuse). Conclusions. This study has implications for PSCs and their staff, treatment providers, and other community supervision staff (e.g. probation/parole officers, court staff) who can promote and encourage the use of MOUDs by clients.

Medication-Assisted Treatment in Problem-solving Courts: A National Survey of State and Local Court Coordinators.

Problem-solving courts (PSCs) are a critical part of a societal effort to mitigate the opioid epidemic's devastating consequences. This paper reports on a national survey of PSCs (N = 42 state-wide court coordinators; N = 849 local court coordinators) and examines the structural factors that could explain the likelihood of a local PSC authorizing medication-assisted treatment (MAT) and MAT utilization. Results of the analyses indicate that MAT availability at the county level was a significant predictor of the likelihood of local courts authorizing MAT. The court's location in a Medicaid expansion state was also a significant predictor of local courts allowing buprenorphine and methadone, but not naltrexone. Problem-solving courts are in the early stages of supporting the use of medications, even when funding is available through Medicaid expansion policies. Adoption and use of treatment innovations like MAT are affected by coordinators' perceptions of MAT as well as structural factors such as the availability of the medications in the community and funding resources. The study has important implications for researchers, policymakers, and practitioners.

Pandemic Procedures: Adapting Problem-Solving Court (PSC) Operations and Treatment Protocols During COVID-19.

With an ongoing pandemic claiming hundreds of lives a day, it is unclear how COVID-19 has affected court operations, particularly problem-solving courts (PSCs) which have goals rooted in rehabilitation for participants in their programs. Even with practical recommendations from national organizations directing courts on how to manage COVID-19, whether and how PSCs met the needs of PSC participants during this time is underexplored. This study, drawn from a larger national study using a survey of PSC coordinators, examines the COVID-19 responses of PSCs to remain safely operational for participants. A sub-sample of survey respondents (n = 82 PSC coordinators) detailed how the COVID-19 pandemic led to changes to their court and treatment operations amidst the constraints of the pandemic. The courts' shifts in policy and practice have important impacts for court participants' treatment retention and success in the PSC program, and these shifts need more in-depth research in the future.

Long-term follow-up of individuals under community supervision who refused rapid HIV testing.

Many criminal justice-involved persons on probation or parole do not receive HIV testing despite being at an increased risk for infection and transmission. Between April, 2011 and May, 2012 in Baltimore, MD and Providence, RI, a two-group randomized controlled trial was conducted in order to examine the uptake of on-site rapid HIV testing compared to off-site referral-based HIV testing at a community clinic. Adults under community supervision were recruited to complete baseline assessments and then offered optional, free rapid-HIV testing. Of the 1263 participants who completed baseline measures, 566 declined HIV testing prior to randomization to the on-site testing at the Probation/Parole office or referral to off-site testing in a community health clinic. Follow-up data from 50 individuals who declined HIV testing were collected from September 2016-June 2017 and are examined in the present study. We describe the long-term outcomes of these 50 individuals in terms of HIV testing, HIV status, and frequencies of drug and sex risk behaviors.

The TCU Drug Screen 5: Identifying Justice-involved Individuals with Substance Use Disorders.

The TCU Drug Screen II, a widely used instrument for identifying substance use problems, was originally developed based on Diagnostic and Statistical Manual of Mental Disorders III-R criteria. In 2013, the American Psychiatric Association revised the criteria and classification scheme for substance use disorders (SUDs) with the publication of the DSM-5. Subsequently, the TCU Drug Screen was modified to reflect the updated DSM-5. The current study examines the concordance of the TCU Drug Screen II and TCU Drug Screen 5 with adult and juvenile justice-involved samples. Both versions were administered to 305 adult male and 310 juvenile male justice-involved clients as part of standard intake procedures. Results revealed a high level of agreement between the two versions; however, the TCU Drug Screen 5 detected significantly more cases of SUDs, the majority of which corresponded to a mild SUD. Results documented appropriate discrimination in meeting diagnostic thresholds among both age groups, with fewer adolescents identified as having a disorder. Overall, the results suggest that the TCU Drug Screen 5 is comparable to the TCU Drug Screen II with the added potential benefit of DSM-5 conformity and severity specifiers.

Development and use of a checklist for the implementation of medication for opioid use disorder in jails.

Background: In light of short lengths of stay and proximity to communities of release, jails are well-positioned to intervene in opioid use disorder (OUD). However, a number of barriers have resulted in a slow and limited implementation. Methods: This paper describes the development and testing of a Medication for Opioid Use Disorder (MOUD) Implementation Checklist developed as part of a Building Bridges project, a two-year planning grant which supported 16 US jail systems as they prepared to implement or expand MOUD services. Results: Although initially developed to track changes within sites participating in the initiative, participants noted its utility for identifying evidence-based benchmarks through which the successful implementation of MOUDs could be tracked by correctional administrators. Conclusions: The findings suggest that this checklist can both help guide and illustrate progress toward vital changes facilitated through established processes and supports. Plain Language Summary: People incarcerated in jails are more likely to have opioid use disorder than the general population. Despite this, jails in the United States (U.S.) often offer limited or no access to Medication for Opioid Use Disorder (MOUD). The Building Bridges project was designed to address this gap in 16 U.S. jail systems as they prepared to implement or expand MOUD services. This article addresses the use of a MOUD checklist that was initially designed to help the jails track changes toward evidence-based benchmarks. The findings suggest that this checklist can both help guide and illustrate progress toward vital changes facilitated through established processes and supports.

Effect of Case Management on HIV Outcomes for Community Corrections Population: Results of an 18-Month Randomized Controlled Trial.

BACKGROUND: Evidence-based interventions that engage community-dwelling, justice-involved, people living with HIV (PLWH) in care are urgently needed. Project Bridge, an intensive case management intervention, has demonstrated efficacy for linking PLWH to care transitioning from prison to the community. We assessed whether a modified Project Bridge model was effective for increasing rates of HIV treatment engagement, antiretroviral therapy receipt, and adherence for community-dwelling individuals supervised on probation and parole. SETTING: Baltimore, Maryland. METHODS: In this study, the 18-month outcomes of a randomized controlled trial in which PLWH were also on probation or parole received either Project Bridge (n = 50) or treatment as usual (n = 50) were assessed. HIV treatment engagement (primary outcome), antiretroviral therapy prescription, and adherence (secondary outcomes) are evaluated using the intent-to-treat approach. RESULTS: There were no statistically significant differences in rates of HIV treatment engagement, antiretroviral therapy prescription receipt, or adherence between groups over the 18-month study period. Across groups, participants were 5.6 times more likely to receive HIV care, 5.8 times more likely to receive an antiretroviral therapy prescription, and 4 times more likely to report antiretroviral therapy adherence at each follow-up period. CONCLUSIONS: Future research is needed to identify potentially less-intensive interventions that target the unique needs of PLWH under community supervision.

A clinical protocol of a comparative effectiveness trial of extended-release naltrexone versus extended-release buprenorphine with individuals leaving jail.

This study is a randomized, open label, controlled trial of extended-release buprenorphine (XR-B; BRIXADI™ formulation) versus extended-release naltrexone (XR-NTX) in Maryland jails. A 7-site, open-label, equivalence design will randomly assign 240 adults with a history of opioid use disorder (OUD), stratified by gender and jail, who are nearing release to one of two treatment arms: 1) XR-B in jail or 2) XR-NTX in jail, both followed by 6 monthly injections postrelease at a community treatment program. The primary aim is to determine the rate of pharmacotherapy adherence (number of monthly injections received) of XR-B compared to XR-NTX. The proposed study is innovative because it will be the first randomized clinical trial in the U.S. assessing the effectiveness of receiving XR-B vs. XR-NTX in county jails. The public health impact of the study will be highly significant and far-reaching because most individuals with OUD do not receive treatment while incarcerated, thereby substantially raising their likelihood of relapse to drug use, overdose death, and re-incarceration. Understanding how to expand acceptance of medications for OUD in jails, particularly extended-release medications, and supporting treatment engagement and medication adherence in transition to the community, has far-reaching implications for improving treatment access and success in this population.

A randomized controlled trial of buprenorphine for probationers and parolees: Bridging the gap into treatment.

BACKGROUND: Buprenorphine can be effective in a variety of community substance use treatment settings outside of methadone programs, including outpatient programs and medical practices. In these settings, it has been found to be effective in reducing opioid use and retaining patients in treatment. Despite its effectiveness and safety, it is rarely provided to individuals with opioid use disorders in probation and parole settings. METHODS: Male and female individuals under probation or parole supervision (N = 320) with histories of opioid use disorder will be enrolled in this randomized controlled trial. Participants will be randomized to one of two study arms: Buprenorphine Bridge Treatment (BBT): Participants will begin buprenorphine using the MedicaSafe dispensing device immediately after an on-site intake at a community supervision office and continue such treatment until they are transitioned to a community program; or Treatment as Usual (TAU): Participants will receive a referral to buprenorphine pharmacotherapy treatment in the community. Treatment outcomes will be: (a) illicit opioid oral saliva drug test results; and (b) treatment adherence (i. entered community based treatment; ii. number of days receiving opioid treatment). RESULTS: We describe the background and rationale for the study, its aims, hypotheses, and study design. CONCLUSIONS: If shown to increase compliance rates with conditions of probation and parole, buprenorphine treatment co-located at community supervision field offices could have a major impact on delivery of buprenorphine treatment to the criminal justice population. The public health impact of the proposed study would be widespread because this intervention could be implemented throughout areas of the US.

Expanding low-threshold buprenorphine to justice-involved individuals through mobile treatment: Addressing a critical care gap.

BACKGROUND: Opioid use disorder (OUD) is highly prevalent among justice-involved individuals. While risk for overdose and other adverse consequences of opioid use are heightened among this population, most justice-involved individuals and other high-risk groups experience multiple barriers to engagement in opioid agonist treatment. METHODS: This paper describes the development of Project Connections at Re-Entry (PCARE), a low-threshold buprenorphine treatment program that engages vulnerable patients in care through a mobile van parked directly outside the Baltimore City Jail. Patients are referred by jail staff or can walk in from the street. The clinical team includes an experienced primary care physician who prescribes buprenorphine, a nurse, and a peer recovery coach. The team initiates treatment for those with OUD and refers those with other needs to appropriate providers. Once stabilized, patients are transitioned to longer-term treatment programs or primary care for buprenorphine maintenance. This paper describes the process of developing this program, patient characteristics and initial outcomes for the first year of the program, and implications for public health practice. RESULTS: From November 15, 2017 through November 30, 2018, 220 people inquired about treatment services and completed an intake interview, and 190 began treatment with a buprenorphine/naloxone prescription. Those who initiated buprenorphine were primarily male (80.1%), African American (85.1%), had a mean age of 44.1 (SD = 12.2), and a mean of 24.0 (SD = 13.6) years of opioid use. The majority of patients (94.4%) had previous criminal justice involvement, were unemployed (72.9%) and were unstably housed (70.8%). Over a third (32.1%) of patients had previously overdosed. Of those who began treatment, 67.9% returned for a second visit or more, and 31.6% percent were still involved in treatment after 30 days. Of those who initiated care, 20.5% have been transferred to continue buprenorphine treatment at a partnering site. CONCLUSIONS: The PCARE program illustrates the potential for low-threshold buprenorphine treatment to engage populations who are justice-involved and largely disconnected from care. While more work is needed to improve treatment retention among vulnerable patients and engaging persons in care directly after release from detention, offering on-demand, flexible and de-stigmatizing treatment may serve as a first point to connect high-risk populations with the healthcare system and interventions that reduce risk for overdose and related harms.

Longitudinal analysis of HIV-risk behaviors of participants in a randomized trial of prison-initiated buprenorphine.

BACKGROUND: It has been estimated that approximately 15% of people who are incarcerated in the US have histories of opioid use disorder. Relapse to opioid use after release from prison poses a serious risk of HIV infection. Prison-initiated buprenorphine may help to reduce HIV infection given the association between opioid use and HIV-risk behaviors. METHODS: The present study is a secondary analysis of longitudinal data gathered from a randomized controlled trial of buprenorphine-naloxone for people who were incarcerated (N = 211) between 2008 and 2012. It compares the impact of assignment to initiate buprenorphine in prison (N = 106 randomized, N = 104 analyzed) versus in the community (N = 107 randomized, N = 107 analyzed) and whether or not participants entered community treatment on the frequency of HIV-risk behaviors in the 12 months following release from prison. Data were analyzed hierarchically and for each outcome variable, a multilevel, over-dispersed Poisson model was fit to the data. Outcome variables were the number of times the following behaviors occurred in the last 30 days: (1) having sex without a condom (2) injecting drugs (3) using unsterilized needles, and (4) sharing injection paraphernalia. RESULTS: Participants assigned to begin buprenorphine in the community experienced a greater decrease in injection drug use over time compared to participants assigned to begin buprenorphine in prison. There were no significant associations between treatment assignment or community treatment entry and instances of having sex without a condom, sharing injection paraphernalia, or using unsterilized needles. CONCLUSIONS: Overall, the present study did not find support for the initiation of buprenorphine in prison (as opposed to the community) as a means to reduce incidences of HIV-risk behaviors. Avenues for future research in the nexus of HIV-risk reduction, criminal justice, and pharmacotherapy are discussed. Trial registration This study was supported by the National Institute on Drug Abuse (NIDA), Buprenorphine for Prisoners (PI: Kinlock; R01DA021579). ClinicalTrials.gov identifier: NCT00574067.

Molecular targeting and treatment of an epidermal growth factor receptor-positive glioma using boronated cetuximab.

PURPOSE: The purpose of the present study was to evaluate the anti-epidermal growth factor monoclonal antibody (mAb) cetuximab (IMC-C225) as a delivery agent for boron neutron capture therapy (BNCT) of a human epidermal growth factor receptor (EGFR) gene-transfected rat glioma, designated as F98(EGFR). EXPERIMENTAL DESIGN: A heavily boronated polyamidoamine dendrimer was chemically linked to cetuximab by means of the heterobifunctional reagents N-succinimidyl 3-(2-pyridyldithio)-propionate and N-(k-maleimido undecanoic acid)-hydrazide. The bioconjugate, designated as BD-C225, was specifically taken up by F98(EGFR) glioma cells in vitro compared with receptor-negative F98 wild-type cells (41.8 versus 9.1 microg/g). For in vivo biodistribution studies, F98(EGFR) cells were implanted stereotactically into the brains of Fischer rats, and 14 days later, BD-C225 was given intracerebrally by either convection enhanced delivery (CED) or direct intratumoral (i.t.) injection. RESULTS: The amount of boron retained by F98(EGFR) gliomas 24 h following CED or i.t. injection was 77.2 and 50.8 microg/g, respectively, with normal brain and blood boron values <0.05 mug/g. Boron neutron capture therapy was carried out at the Massachusetts Institute of Technology Research Reactor 24 h after CED of BD-C225, either alone or in combination with i.v. boronophenylalanine (BPA). The corresponding mean survival times (MST) were 54.5 and 70.9 days (P = 0.017), respectively, with one long-term survivor (more than 180 days). In contrast, the MSTs of irradiated and untreated controls, respectively, were 30.3 and 26.3 days. In a second study, the combination of BD-C225 and BPA plus sodium borocaptate, given by either i.v. or intracarotid injection, was evaluated and the MSTs were equivalent to that obtained with BD-C225 plus i.v. BPA. CONCLUSIONS: The survival data obtained with BD-C225 are comparable with those recently reported by us using boronated mAb L8A4 as the delivery agent. This mAb recognizes the mutant receptor, EGFRvIII. Taken together, these data convincingly show the therapeutic efficacy of molecular targeting of EGFR using a boronated mAb either alone or in combination with BPA and provide a platform for the future development of combinations of high and low molecular weight delivery agents for BNCT of brain tumors.

StaySafe: A self-administered android tablet application for helping individuals on probation make better decisions pertaining to health risk behaviors.

This paper describes the development and protocol for feasibility and efficacy testing of a risk reduction intervention designed to improve behavioral health outcomes among drug offenders on probation under community supervision or in residential substance abuse treatment centers. StaySafe is a self-administered tablet-based intervention for teaching better decision-making skills regarding health risk behaviors, especially those involving HIV risks. We are using pre/post, experimental/control group randomized clinical trial (RCT) in both community and residential probation settings with goals to 1) assess the feasibility and acceptance of StaySafe by examining participation rates and satisfaction measures, and 2) examine the impact of StaySafe on decision-making skills, confidence and motivation to avoid sex and drug risks, willingness to discuss health risks and concerns with helpful others, and engagement in health risk behaviors. StaySafe consists of 12 brief sessions and utilizes an evidence-based decision-making schema, called WORKIT, which guides participants through steps for identifying the problem and options, evaluating the options and making a decision about which option to carry out. Multiple sessions of StaySafe provide a practice effect so that the WORKIT steps become easily accessible to participants when making decisions. Three of the sessions provide participants a choice of activities designed to provide additional information about HIV and reinforce lessons learned during the WORKIT sessions. Preliminary data demonstrate feasibility and high levels of satisfaction with StaySafe.

Initiating buprenorphine treatment prior to versus after release from prison: Arrest outcomes.

BACKGROUND: This secondary analysis of a randomized trial examines the association between initiation of buprenorphine treatment prior to, versus post-release, and rearrests during the 12-months following release. METHODS: Official rearrest data (N = 199) for the 12-months post-release were examined. Four outcomes were measured: (1) rearrested (yes/no), (2) time to rearrest, (3) number of rearrests, and (4) severity of charges (less severe vs. severe). RESULTS: A minority (43.1%) of the sample were rearrested (N = 91). There were no significant differences between study conditions in the proportion of rearrested participants [P = 0.28] nor in the mean number of arrests [P  = 0.15]. Likewise, the condition was not a significant predictor of the hazard of rearrest [p = 0.10]. The mean number of days until rearrest for the in prison vs. post-release buprenorphine conditions were not significantly different (205.8 days (SD  = 104.6) vs. 170.8 days (SD  = 113.1), respectively; P  = 0.13]. Treatment condition was not a significant predictor of the likelihood of rearrest for a severe crime compared to a less severe crime [P  = 0.09]. CONCLUSION: Despite the parent study finding of higher rates of post-release drug treatment entry in the group assigned to start buprenorphine treatment prior to, compared to post-release, there were no significant differences in the proportion of individuals arrested, the mean number of arrests, the time to first arrest, or the severity of their charges.

Boron neutron capture therapy of cancer: current status and future prospects.

BACKGROUND: Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when boron-10 is irradiated with low-energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Clinical interest in BNCT has focused primarily on the treatment of high-grade gliomas and either cutaneous primaries or cerebral metastases of melanoma, most recently, head and neck and liver cancer. Neutron sources for BNCT currently are limited to nuclear reactors and these are available in the United States, Japan, several European countries, and Argentina. Accelerators also can be used to produce epithermal neutrons and these are being developed in several countries, but none are currently being used for BNCT. BORON DELIVERY AGENTS: Two boron drugs have been used clinically, sodium borocaptate (Na(2)B(12)H(11)SH) and a dihydroxyboryl derivative of phenylalanine called boronophenylalanine. The major challenge in the development of boron delivery agents has been the requirement for selective tumor targeting to achieve boron concentrations ( approximately 20 microg/g tumor) sufficient to deliver therapeutic doses of radiation to the tumor with minimal normal tissue toxicity. Over the past 20 years, other classes of boron-containing compounds have been designed and synthesized that include boron-containing amino acids, biochemical precursors of nucleic acids, DNA-binding molecules, and porphyrin derivatives. High molecular weight delivery agents include monoclonal antibodies and their fragments, which can recognize a tumor-associated epitope, such as epidermal growth factor, and liposomes. However, it is unlikely that any single agent will target all or even most of the tumor cells, and most likely, combinations of agents will be required and their delivery will have to be optimized. CLINICAL TRIALS: Current or recently completed clinical trials have been carried out in Japan, Europe, and the United States. The vast majority of patients have had high-grade gliomas. Treatment has consisted first of "debulking" surgery to remove as much of the tumor as possible, followed by BNCT at varying times after surgery. Sodium borocaptate and boronophenylalanine administered i.v. have been used as the boron delivery agents. The best survival data from these studies are at least comparable with those obtained by current standard therapy for glioblastoma multiforme, and the safety of the procedure has been established. CONCLUSIONS: Critical issues that must be addressed include the need for more selective and effective boron delivery agents, the development of methods to provide semiquantitative estimates of tumor boron content before treatment, improvements in clinical implementation of BNCT, and a need for randomized clinical trials with an unequivocal demonstration of therapeutic efficacy. If these issues are adequately addressed, then BNCT could move forward as a treatment modality.

Synthesis of a small library of 3-(carboranylalkyl)thymidines and their biological evaluation as substrates for human thymidine kinases 1 and 2.

A small library consisting of two series of thymidine derivatives containing o-carboranylalkyl groups at the N-3 position was prepared. In both series, alkyl spacers of 2-7 methylene units were placed between the o-carborane cage and the thymidine scaffold. In one series, an additional dihydroxypropyl substituent was introduced at the second carbon atom of the carborane cage. In the series of N-3-substituted carboranyl thymidines without additional dihydroxypropyl substituent, three steps were required to obtain the target compounds in overall yields as high as 75%, while in the series of N-3-substituted carboranyl thymidines with additional dihydroxypropyl substituent, 9-10 steps were necessary with significantly lower overall yield. All target compounds were good substrates of human cytosolic thymidine kinase 1 while they were, if at all, poor substrates of the mitochondrial thymidine kinase 2. There was only a minor difference in phosphorylation rates between N-3-substituted carboranyl thymidines with additional dihydroxypropyl substituents with thymidine kinase 1 (range: 13-49% relative to thymidine) and their counterparts lacking this group (range: 11-57% relative to thymidine). Tether lengths of two and five methylene groups in both series gave the highest enzyme activities in the present study. A hypothesis for this result is presented.

Calculating an unknown source activity using modeled and experimental results.

A method is presented that provides a way to calculate the unknown activity of a source by using experimental exposure rate measurements from an ion chamber and exposure rates calculated using the MCNP radiation transport code. The method consists of fitting experimental data to MCNP results with both data sets in the form of (Equation is included in full-text article.)where r is the distance from the source at which the measurement was taken, X˙ is the exposure rate, and An is an assumed nominal activity of the source. The fit is done by calculating a correction factor for the nominal activity that shifts the experimental data to match the MCNP results. The actual activity of the source in question is found by multiplying the assumed nominal activity by the activity correction factor. The method was used to calculate the activities of the three Cs sources used in the Ohio Emergency Management Agency's instrument calibration range. It was found that the activities were less than the decay-corrected nominal activities by factors ranging from 3% to 10%.

Evaluation of the effects of scattered radiation on dosimeter calibration in a calibration range.

ISO standard 4037 specifies limits for scattered radiation for "gamma reference radiation" for the calibration of "protection-level dosemeters and rate dosemeters." More specifically, it specifies that scattered radiation should contribute less than 5% to the total exposure rate for source-center-to-dosimeter-center distances (henceforth called downrange distances) over which dosimeters are calibrated. In a previous paper by the authors, the results of an MCNP analysis of a calibration range with a Cs irradiator (henceforth called Cs calibration range) were reported. In that paper, simulations of the singly differential photon fluence rate (i.e., flux) energy spectra (henceforth called photon flux energy spectra) from the Cs (an ISO standard 4037 gamma reference radiation) irradiator were reported. In that paper, the spectra were examined to determine the contribution of scattered photons to the exposure rate in the Cs calibration range for various downrange distances. In this paper, the simulations of the photon flux energy spectra for the Cs irradiator photons for various downrange distances are convolved with response functions, creating an ideal exposure meter and two commercially available ion chamber survey meters, in order to predict the meters' response rates versus downrange distance. The simulated response rates indicate that the Cs calibration range satisfies an operational check of the contribution of scattered radiation to the exposure rate that is specified in the ISO standard 4037, although as shown in the previous paper by the authors, the Cs calibration range does not satisfy the ISO standard 4037 specification that scattered radiation should contribute less than 5% to the total exposure rate for downrange distances over which dosimeters are calibrated. The ISO standard 4037 operational check is that the measured exposure rate varies from an inverse square dependence by less than 5% for the downrange distances over which dosimeters are calibrated.

A Comparison of Measurements and Calculations of the Effects of Scattered Radiation on Dosimeter Calibration in a Calibration Range.

The method presented provides an alternative to the shadow shield method for experimentally measuring the contribution due to scattering radiation in a calibration range. Scattering of 0.6616 MeV photons from a Cs irradiator in a calibration range does not only occur due to the walls and floor of the range. It also occurs due to the source material itself, its encapsulation, the brass cup that holds the source, the two stainless tubes that surround the source capsule and the brass cup, and the irradiator structure that surrounds the aforementioned objects. The shadow shield method underestimates this scattering radiation that originates in the irradiator. By measuring the uncollided effective activity using a CZT detector and a total effective activity using a survey meter, the contribution of scattered radiation (including all of the abovementioned sources of scatter) to the effective source activity is able to be measured. In this paper, the measured mean effective source activities for a Cs irradiator in a calibration range are reported for a CZT detector and a survey meter. The measured activities are compared among themselves and with the results of MCNP calculations. From these comparisons, the new alternative method for measuring the scatter contribution was validated by agreement in both the MCNP calculations and experimental measurements that scattering contributed about 28% to the overall effective activity of the range.

Evaluation of scattered radiation in a calibration range using exposure rate energy spectra.

ISO standard 4037 specifies that for calibrating protection level dosimeters, scattered radiation should contribute less than 5% of the exposure. In previous work, the authors reported the results of an MCNP analysis of the shadow shield technique that was performed for a calibration range with a Cs irradiator. This paper examines the energy distribution of the photons contributing to the exposure percent scatter (S%) and the detailed origin of the scatter that originates in the irradiator. In summary, it reports that: 1) the majority of S% is due to photons with energies that are significantly below the source energy, 2) a significant percentage of S% is due to photons that scatter within the source and source capsule walls, and 3) S% due to scatter within the irradiator is even more significant than previously reported.