Use In Treatment Planning Research Articles

Poster #51 CANNABIS USE AND BRAIN STRUCTURAL ALTERATIONS OF CINGULATE CORTEX AND HIPPOCAMPUS IN FIRST EPISODE PSYCHOSIS PATIENTS AND AT RISK MENTAL STATE SUBJECTS

The aim of this study was to investigate the psychometric properties of Internet administered questionnaires used in panic research. Included were 494 people who had registered for an Internet-based treatment program for panic disorder (PD). Participants were randomly assigned to fill in the questionnaires either on the Internet or the paper-and-pencil versions, and then to fill in the same questionnaires again the next day using the other format. The questionnaires were the body sensations questionnaire [BSQ; Chambless, D. L., Caputo, G. C., Bright, P., & Gallagher, R. (1984). Assessment of fear of fear in agoraphobics: the body sensations questionnaire and the agoraphobic cognitions questionnaire. Journal of Consulting and Clinical Psychology, 52, 1090–1097], agoraphobic cognitions questionnaire [ACQ; Chambless, D. L., Caputo, G. C., Bright, P., & Gallagher, R. (1984). Assessment of fear of fear in agoraphobics: the body sensations questionnaire and the agoraphobic cognitions questionnaire. Journal of Consulting and Clinical Psychology, 52, 1090–1097], mobility inventory [MI; Chambless, D. L., Caputo, G., Jasin, S., Gracely, E. J., & Williams, C. (1985). The mobility inventory for agoraphobia. Behaviour Research and Therapy, 23, 35–44], beck anxiety inventory [BAI; Beck, A. T., Epstein, N., Brown, G., & Steer, R. A. (1988). An inventory for measuring clinical anxiety: psychometric properties. Journal of Consulting and Clinical Psychology, 56, 893–897], beck depression inventory II [Beck, A. T., & Steer, R. A. (1996). Beck Depression Inventory. Manual, Svensk version (Swedish version). Fagernes, Norway: Psykologiförlaget, AB], quality of life inventory [QOLI; Frisch, M. B., Cornell, J., Villanueva, M., & Retzlaff, P. J. (1992). Clinical validation of the quality of life inventory. A measure of life satisfaction for use in treatment planning and outcome assessment. Psychological Assessment, 4, 92–101], and montgomery Åsberg depression rating scale [MADRS; Svanborg, P., & Åsberg, M. (1994). A new self-rating scale for depression and anxiety states based on the comprehensive psychopathological rating scale. ACTA Psychiatrica Scandinavica, 89, 21–28]. Results showed largely equivalent psychometric properties for the two administration formats (Cronbach’s α between 0.79 and 0.95). The results also showed high and significant correlations between the Internet and the paper-and-pencil versions. Analyses of order effects showed an interaction effect for the BSQ and the MI (subscale Accompanied), a main effect was identified for ACQ, MI-Alone, BAI and BDI II. However, in contrast to previous research, the Internet version did not consistently generate higher scores and effect sizes for the differences were generally low. Given the presence of an interaction effect, we recommend that the administration format should be stable in research across measurement points. Finally, the findings suggest that Internet versions of questionnaires used in PD research can be used with confidence.

The Peabody Treatment Progress Battery: History and Methods for Developing a Comprehensive Measurement Battery for Youth Mental Health

There is increased need for comprehensive, flexible, and evidence-based approaches to measuring the process and outcomes of youth mental health treatment. This paper introduces a special issue dedicated to the Peabody Treatment Progress Battery (PTPB), a battery of measures created to meet this need. The PTPB is an integrated set of brief, reliable, and valid instruments that can be administered efficiently at low cost and can provide systematic feedback for use in treatment planning. It includes eleven measures completed by youth, caregivers, and/or clinicians that assess clinically-relevant constructs such as symptom severity, therapeutic alliance, life satisfaction, motivation for treatment, hope, treatment expectations, caregiver strain, and service satisfaction. This introductory article describes the rationale for the PTPB and its development and evaluation, detailing the specific analytic approaches utilized by the different papers in the special issue and a description of the study and samples from which the participants were taken.

TH‐C‐220‐02: Development of Binary Micro MLCs for an Open Source Small Animal Imaging and Therapy System with IMRT Capability

Purpose: Current micro‐RT systems use either stationary collimators or dynamic hexagonal collimators. Even though dynamic multileaf collimators (MLCs) offer superior target conformity and beam modulation, no such system is currently available for small animal systems. This study aims to develop binary micro MLCs (bmMLCs) to be incorporated into an open source combined micro‐PET/CT/RT system with IMRT capability. Methods: A bmMLC system was designed using Flexinol actuator wire which features muscle‐like contraction when electrically driven. An assembly was constructed by attaching brass leaves to supporting steel tubes with springs which can translate within larger concentric steel tubes on a customized collimator support structure. The actuator wires were connected to the inner steel rods. When electricity was passed through the wire, it contracted pulling the assembly against the spring on supporting rod to open the leaves. Individual collimator leaves were arranged to move in opposing directions and stacked in an interleaved position. Results: A proof of concept prototype has been successfully tested using a two leaf‐system. In order to get a treatment width of 0.25cm at isocenter, brass leaves that are 2cm long, 0.05cm wide and 2.4cm thick (for 99.99% attenuation of 250kVp X‐ray) were used. The full scale collimation system was designed using 20 leaves on each side. Leaves were designed to translate 1cm producing a maximum field size of 5×10cm2 at the isocenter of the RT system. Opening and closing time of collimator leaves was less than a second which is sufficient for the expected low dose rate from the X‐ray source. Conclusions: The first dynamic bmMLC system for a micro‐RT system is being developed to enable IMRT applications. The mechanical characteristics of the bmMLC system are currently being evaluated and optimized. Future work will include development of software to drive the collimator movement for use in treatment planning.

Patient perspectives on a treatment plan and summary program in community oncology care.

6027 Background: Routine use of treatment plans and summaries has been recommended as an important step in improving the quality of cancer care. However, limited data exist about their impact on qu...

Aspects of simulator cone-beam CT for radiotherapy treatment planning

AbstractBackground and purpose: Following a recent major upgrade in cone-beam computed tomography (CBCT) software and functionality, we have reassessed aspects of our Varian Acuity simulator performance for use in treatment planning. The feasibility of using CBCT for treatment planning has been assessed and here we report specifically on Hounsfield number (HN) accuracy and related dose errors, and digitally reconstructed radiograph (DRR) image quality.Methods: Using a Catphan® 600 CT phantom, HN accuracy and uniformity were investigated for a range of CBCT imaging modes. This included the variation in HNs with scan length and phantom position. Results were compared with those acquired from conventional CT. Treatment plans for three sites were generated using the Rando phantom, and results from CBCT-based data were compared to that from CT-based data using a gamma analysis. Image quality of DRRs based on CBCT data were compared with those from CT data both quantitatively, by calculating the modulation transfer function (MTF) and qualitatively, by counting the number of line pairs visible on a phantom.Results and conclusions: Catphan data showed that for certain cases, the HN calibration of the Acuity CBCT was out of tolerance and could lead to errors in dose calculation of >2%. HNs were only acceptable for scan lengths >10 cm. In multi-scan mode, geometric shifts and differences in HNs were seen on CT slices on either side of the interface between the two acquisitions. However, comparisons between treatment plans calculated using CBCT data and conventional CT data from Rando phantoms showed that head, pelvis and thorax plans were acceptable. CBCT DRR image quality compared favourably with a conventional CT scanner in some respects; however, image uniformity and low contrast resolution were poorer due to the ‘cupping’ artefact obtained with CBCT scans.

Achieving adolescent adherence to treatment of major depression.

When treatments are ordered for adolescent major depression, or for other adolescent medical illnesses, adherence and clinical outcomes are likely to be unsatisfactory, unless 4 basic principles of the medical treatment of adolescent illness are implemented. These comprise providing effective patient and parent/caregiver education, establishing effective patient and caregiver therapeutic alliances, providing effective treatment, and managing other factors associated with treatment adherence as indicated. The goals of treatment are to achieve the earliest possible response and remission. Failure to treat adolescent major depression successfully has potentially serious consequences, including worsened adherence, long-term morbidity, and suicide attempt. Accordingly, prescribed treatment must be aggressively managed. Doses of an antidepressant medication should be increased as rapidly as can be tolerated, preferably every 1-2 weeks, until full remission is achieved or such dosing is limited by the emergence of unacceptable adverse effects. A full range of medication treatment options must be employed if necessary. Treatment adherence, occurrence of problematic adverse effects, clinical progress, and safety must be systematically monitored. Adolescents with major depression must be assessed for risk of harm to self or others. When this risk appears significant, likelihood of successful outcomes will be enhanced by use of treatment plans that comprehensively address factors associated with treatment nonadherence. Abbreviated and comprehensive plans for the treatment of potentially fatal adolescent illnesses are outlined in this review.

The current status of image-guided external beam radiotherapy for prostate cancer

To assess the current status and technological advances in image-guided external beam radiotherapy for prostate cancer. Modern imaging has improved the ability to define radiotherapy target volumes. Specifically, treatment margins have been reduced through the use of treatment planning and image-guidance technology. Increasing dose has led to increased disease control. Concurrent technological advances may improve treatment-related toxicity. Data continues to emerge on patient selection, treatment schedule, and use of additional systemic therapy in conjunction with radiation. In the present article, we review recent developments in radiation planning, image guidance, patient selection and fractionation, dose escalation, toxicity, systemic therapy, and follow-up.

Evolving the Dose Volume Histogram (DVH) Concept for use in Treatment Planning of Moving Structures using 4DCT

Evolving the Dose Volume Histogram (DVH) Concept for use in Treatment Planning of Moving Structures using 4DCT

A CT‐based analytical dose calculation method for HDR brachytherapy

This article presents an analytical dose calculation method for high-dose-rate 192Ir brachytherapy, taking into account the effects of inhomogeneities and reduced photon backscatter near the skin. The adequacy of the Task Group 43 (TG-43) two-dimensional formalism for treatment planning is also assessed. The proposed method uses material composition and density data derived from computed tomography images. The primary and scatter dose distributions for each dwell position are calculated first as if the patient is an infinite water phantom. This is done using either TG-43 or a database of Monte Carlo (MC) dose distributions. The latter can be used to account for the effects of shielding in water. Subsequently, corrections for photon attenuation, scatter, and spectral variations along medium- or low-Z inhomogeneities are made according to the radiological paths determined by ray tracing. The scatter dose is then scaled by a correction factor that depends on the distances between the point of interest, the body contour, and the source position. Dose calculations are done for phantoms with tissue and lead inserts, as well as patient plans for head-and-neck, esophagus, and MammoSite balloon breast brachytherapy treatments. Gamma indices are evaluated using a dose-difference criterion of 3% and a distance-to-agreement criterion of 2 mm. PTRAN_CT MC calculations are used as the reference dose distributions. For the phantom with tissue and lead inserts, the percentages of the voxels of interest passing the gamma criteria (Pgamma > or = 1) are 100% for the analytical calculation and 91% for TG-43. For the breast patient plan, TG-43 overestimates the target volume receiving the prescribed dose by 4% and the dose to the hottest 0.1 cm3 of the skin by 9%, whereas the analytical and MC results agree within 0.4%. Pgamma > or = 1 are 100% and 48% for the analytical and TG-43 calculations, respectively. For the head-and-neck and esophagus patient plans, Pgamma > or = 1 are > or = 99% for both calculation methods. A correction-based dose calculation method has been validated for HDR 192Ir brachytherapy. Its high calculation efficiency makes it feasible for use in treatment planning. Because tissue inhomogeneity effects are small and primary dose predominates in the near-source region, TG-43 is adequate for target dose estimation provided shielding and contrast solution are not used.

WE‐A‐BRC‐02: IMRT for Prostate Cancer

The prostate is a mobile structure compared to the surrounding bony anatomy. Daily setup, immobilization and localization uncertainties can be addressed by increasing the PTV but may result in additional dose to surrounding normal structures. At FCCC we attempt to reduce the uncertainty by employing daily localization using ultrasound, implanted fiducials or through target tracking using implanted Calypso beacons. We currently use an 8mm growth in all directions except posteriorly where 5mm is typical. Patients with fiducials and those being irradiated in the post‐prostatectomy setting undergo localization via an in‐room CT scanner or CBCT. We have recently begun target tracking on post‐prostatectomy patients as well. All patients are simulated and treated supine without a thermoplastic immobilizer to minimize respiratory related prostatic motion. Patients undergo MR and CT simulations with the rectum empty. These data are fused for target and normal structure delineation for use in treatment planning. Emphasis on soft tissue structures is important to avoid potential systematic localization errors due to the time difference between scans for patients with implanted fiducials or beacons. Dose limiting structures primarily include the rectum, bladder, and femoral heads, but may also include bowel and erectile tissues. We have developed “plan acceptance criteria” based on published data with respect to rectal complications. DVH analysis is used to ensure that the rectal volumes receiving 65Gy and 40Gy are less than 17% and 35%, respectively. Additionally, the bladder volumes receiving 65Gy and 40Gy are less than 25% and 50%, respectively. The volume of either femoral head receiving 50Gy should be less than 10%. PTV coverage should result in at least 95% of the volume receiving the prescription dose. It should be noted that the 3D dose distribution itself plays an important role in IMRT delivery and DVH analysis alone may not be sufficient. The isodose distribution should be such that the 90% and 50% lines do not traverse the half or full width of the rectum on any CT slice, respectively. Dose escalation and hypofractionation regimes continue to be of interest in the treatment of this disease site. However, most delivery techniques require PTV reductions to avoid increased normal tissue toxicity. A quantitative analysis of uncertainties contributing to PTV margins is addressed. Additionally, treatment methods that may not require margin consideration, are discussed. These include fiducial tracking using the Cyberknife and the use of high intensity focused ultrasound (HiFU) ablation.Learning Objectives:1. To understand the practical steps associated with IMRT of the prostate2. To understand the numerical values presented for plan acceptance3. To be aware of MR‐CT fusion issues for patients with implanted fiducials or beacons4. To be aware of issues related to PTV reduction

Cone-beam volumetric imaging in dental, oral, and maxillofacial medicine. Fundamentals, diagnostics, and treatment planning (2008)

Authors: Joachim E. Zoller, and Jorg Neugebauer. Publisher: Quintessence Publishing Company Limited, New Malden, Surrey, UK Price: £118.00 ISBN: 978-3-938947-46-3 The authors have produced an atlas based on the understanding and interpretation of Cone-Beam Volumetric Imaging (CBVI). The book is divided into three sections; the first part describes the technology of CBVI, the second describes and illustrates the diagnostics of this three-dimensional imaging technique, and the third, its use in treatment planning. An accompanying DVD provides dynamic assessment of some of the illustrated cases. The first section details the fundamental differences between conventional computed …

Automatic registration using implicit shape representations: applications in intraoperative 3D rotational angiography to preoperative CTA registration

A solution for automatic registration of 3D Rotational Angiography (XA) to CT/MR of the liver. Targeted for use in treatment planning of liver interventions. A shape-based approach to registration is proposed that does not require specification of landmarks nor is it prone to local minima like purely intensity-based registration methods. Through the use of vessel characteristics, accurate registration is possible even in the presence of deformations induced by catheters and respiratory motion. Registration was performed on eight pairs of multiphase CT angiography and 3D rotational digital angiography datasets. Quantitative validation of the registration accuracy using vessel landmarks was performed on these datasets. The validation study showed that the method has a registration error of 9.41 +/- 4.13 mm. In addition, the computation time is well below 60 s making it attractive for clinical application. A new method for fully automatic 3DXA to CT/MR image registration was developed and found to be efficient and accurate using clinically realistic datasets.

Who knows they have a treatment plan?

Background: Guidelines for the effective care of chronic and complex conditions increasingly recommend developing treatment plans in collaboration with patients as one strategy in a coordinated approach to management. We examined the socio-demographic characteristics associated with the development of treatment plans for patients with asthma, diabetes or a cardiovascular condition to establish what proportion of patients with these conditions recalled being consulted in the plan's preparation. Method: Serial, cross-sectional population based surveys using computer assisted telephone interviews (CATI) with 2,296 randomly selected adult participants with asthma, diabetes or a cardiovascular condition living in Queensland in 2006 and 2,203 adults with these conditions in 2008. Results: The proportion of patients with asthma, diabetes or a cardiovascular condition aware of having a treatment plan for their chronic condition increased almost two-fold between 2006 and 2008. Approximately half the respondents did not recall being asked for their input into the plan. Patients with a cardiovascular condition, older patients, and early school leavers were less likely to recall having a treatment plan. There were some variations when each condition was examined separately. Conclusion: Overall, the use of treatment plans and engagement of patients in their development remains low, particularly in those subgroups of the community who are most likely to benefit.

SU-FF-J-67: Tomotherapy MVXCT Numbers Versus RLSP for Various Ions and Materials

Purpose: Optimization of ion radiotherapy and spacecraft shielding is critically dependent upon the relative linear stopping power (RLSP) of each material through which an ion would pass. In radiotherapy, RLSPs for patient tissues are usually obtained by converting kilovoltage x ray computed tomography (KVXCT) numbers; however, some registration and immobilization devices, implant materials, and dosimetry phantoms do not lie on the standard KVXCT number to RLSP conversion curve. KVXCT imaging is also prone to artifacts created by high atomic number and density materials. Ion computed tomography (ICT) could reduce these problems but these systems currently exist only in the research stage and, for abdominal scanning, would require energies and field sizes greater than available with current therapy accelerators and beam delivery systems. Megavoltage x ray computed tomography (MVXCT) may offer an alternative imaging scheme. Methods and Materials: The RLSPs for twenty-two materials were measured using a parallel plate ionization chamber and scanning water phantom in proton, carbon ion, and iron ion beams. These same materials were scanned using both KVXCT and MVXCT. Results and Discussion: The MVXCT versus RLSP functions for the three ions were almost identical. The functions were approximately bi-linear but the change in slope was smaller than for the KVXCT curves and deviations between measured and fit data were smaller. Conclusions: An MVXCT number to ion RLSP conversion function has been generated for use in treatment planning. Although the function does not account for the effect of ion nuclear interactions, MVXCT numbers can be used to predict the range of ions and may serve as an intermediate step until ICT is developed. Experiments may now be performed to compare KVXCT and MVXCT based treatment planning in the presence of artifacts and non-tissue like materials. This work was partially supported by NASA grant NAG-1943 and NMTB grant DAMD17-97-2-7016.

Magnetic resonance imaging of primary vaginal carcinoma

To describe the magnetic resonance imaging (MRI) features of vaginal carcinoma and to suggest a role for MRI in its management. Twenty-five patients with primary vaginal carcinoma treated at our institution between 1996 and 2005 were included in the study. The MRI examinations were reviewed and tumour dimensions, signal characteristics and involvement of pelvic structures were documented, as were sites of enlarged lymph nodes and metastases. Details of patient treatment and outcome were obtained from the clinical notes. The median patient age was 54 years (range 31-86 years). Tumour maximum diameter ranged from 1.6-11.3 cm (mean 3.7 cm). Most tumours were of iso-intense signal to muscle on T1-weighted images and hyper-intense to muscle on T2-weighted images. Eighty-eight percent of patients had tumour extending beyond the vagina and 56% of patients had Figo stage III or above tumours. Sixteen patients were treated with radiotherapy (two with chemoradiotherapy), five with surgery and four with supportive care. Ten patients (40%) died of their disease during the study period. The MRI stage of the tumour correlated with survival. MRI identified over 95% of primary vaginal tumours in the present study, enabled radiological staging, which correlated with outcome, and provided information of use in treatment planning.

The MIRECC Version of the Global Assessment of Functioning Scale: Reliability and Validity

This study examined the reliability and convergent, discriminant, and predictive validity of the Mental Illness Research, Education, and Clinical Center (MIRECC) version of the Global Assessment of Functioning (GAF) scale. The MIRECC GAF measures occupational functioning, social functioning, and symptom severity on three subscales. MIRECC GAF ratings were obtained for 398 individuals with schizophrenia or schizoaffective disorder who were receiving treatment at three Veterans Affairs mental health clinics. Assessments were completed by using the Positive and Negative Syndrome Scale and the Quality of Life Interview at baseline and nine months later. All three MIRECC GAF subscales exhibited very high levels of reliability. The occupational and symptom subscales showed good convergent and discriminant validity. The social subscale was related to measures of social functioning and, to a greater degree, symptom severity. The occupational and social subscales significantly predicted their respective domains at the nine-month follow-up. The symptom subscale predicted negative symptoms at follow-up; however, it did not predict positive symptoms or cognitive disorientation. Instead, the social subscale was predictive of cognitive disorientation at follow-up. When the standard GAF was routinely administered by clinicians, scores demonstrated little validity. The three MIRECC GAF subscales can be scored reliably, and they have good concurrent and predictive validity. Further work is needed on brief measures of patient functioning, especially measures of social functioning.

Four-dimensional computed tomographic analysis of esophageal mobility during normal respiration

Chemo-radiotherapy for thoracic tumors can result in high-grade radiation esophagitis. Treatment planning to reduce esophageal irradiation requires organ motion to be accounted for. In this study, esophageal mobility was assessed using four-dimensional computed tomography (4DCT). Thoracic 4DCT scans were acquired on a 16-slice CT scanner in 29 patients. The outer esophageal wall was contoured in two extreme phases of respiration in 9 patients with nonesophageal malignancies. The displacement of the center of contour was measured at 2-cm intervals. In 20 additional patients with Stage I lung cancer, the esophagus was contoured in all 10 phases of each 4DCT at five defined anatomic levels. Both approaches were then applied to 4DCT scans of 4 patients who each had two repeat scans performed. A linear mixed effects model was constructed with fixed effects: measurement direction, measurement type, and measurement location along the cranio-caudal axis. Measurement location and direction were significant descriptive parameters (Wald F-tests, p < 0.001), and the interaction term between the two was significant (p = 0.02). Medio-lateral mobility exceeded dorso-ventral mobility in the lower half of the esophagus but was of a similar magnitude in the upper half. Margins that would have incorporated all movement in medio-lateral and dorso-ventral directions were 5 mm proximally, 7 mm and 6 mm respectively in the mid-esophagus, and 9 mm and 8 mm respectively in the distal esophagus. The distal esophagus shows more mobility. Margins for mobility that can encompass all movement were derived for use in treatment planning, particularly for stereotactic radiotherapy.

Variations in orthodontic treatment planning decisions of Class II patients between virtual 3-dimensional models and traditional plaster study models

Study models provide invaluable information in treatment planning. Digital models have proved to be an effective measurement tool, but their use in treatment planning has not been studied. Ten sets of records of Class II malocclusion subjects (dental study models, lateral cephalograms/tracings, panoramic radiographs, intraoral and extraoral photographs) were used for treatment planning by 20 orthodontists on 2 separate occasions. Digital models were used to evaluate the patients at 1 session and plaster models were used at the other session. Treatment recommendations were scored and compared for agreement. Eleven orthodontists served as the control group, looking at the records on 2 occasions with plaster models for agreement. Good agreement was noted for surgery (P = 1.00, kappa = 0.549), extractions (P = .360, kappa = 0.570), and auxiliary appliances (P = 1.00, kappa = 0.539) for the digital/plaster group. Agreement in the plaster/plaster group for surgery (P = 1.00, kappa = 0.671), extractions (P = 1.00, kappa = 0.626), and auxiliary appliances (P = .791, kappa = 0.672) was also good. Overall proportions of agreement ranged between 0.777 and 0.870 for digital/plaster and 0.818 and 0.873 for plaster/plaster. There was no statistical difference in intrarater treatment-planning agreement for Class II malocclusions based on the use of digital models in place of traditional plaster models. Digital orthodontic study models (e-models) are a valid alternative to traditional plaster study models in treatment planning for Class II malocclusion patients.

Principal component, Varimax rotation and cost analysis of volume effects in rectal bleeding in patients treated with 3D-CRT for prostate cancer

We investigate the utility of principal component analysis as a tool for obtaining dose–volume combinations related to rectal bleeding after radiotherapy for prostate cancer. A direct implementation of principal component analysis reduces the number of degrees of freedom from the patient's dose–volume histograms that are associated with bleeding. However, when low-variance principal components are strongly correlated to outcome, their interpretation is problematic. A Varimax rotation is employed to aid in interpretability of the low-variance principal components. This procedure brings us closer to finding unique dose–volume combinations related to outcome but reintroduces correlation, requiring analysis of the overlap of information contained in such modes. Finally, we present examples of cost–benefit analyses for candidate dose–volume constraints for use in treatment planning.

Enhancing the Utility of ProstaScint SPECT Scans for Patient Management

This project investigated reducing the artifact content of In-ill ProstaScint SPECT scans for use in treatment planning and management. Forty-one patients who had undergone CT or MRI scans and simultaneous Tc-99m RBC/In-111 ProstaScint SPECT scans were included. SPECT volume sets, reconstructed using Ordered Set-Expectation Maximum (OS-EM) were compared against those reconstructed with standard Filtered Back projection (FBP). Bladder activity in Tc-99m scans was suppressed within an ellipsoidal volume. Tc-99m voxel values were subtracted from the corresponding In-111 after scaling based on peak activity within the descending aorta. The SPECT volume data sets were merged with the CT or MRI scans before and after processing. Volume merging, based both on visual assessment and statistical evaluation, was not affected. Thus iterative reconstruction together with bladder suppression and blood pool subtraction may improve the interpretation and utility of ProstaScint SPECT scans for patient management.