bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐A‐BRA‐01: Commissioning and Implementation of New Equipment or Treatment Paradigms
Authors: Soen J , Pankuch M 
Published: November 2011

A fundamental responsibility of the Clinical Medical Physics is to assist in the project management and commissioning of new equipment. The undertaking of such responsibilities may appear overwhelming when added to the routine clinical physics responsibilities of an operational center. In addition, the unique challenge of effective implementation requires extensive collaborative efforts from the entire staff, including physicians, therapists, nursing and administration. Methods for successful cooperation typically fall outside the realm of formal training programs. It is the responsibility of the onsite medical physicist to first understand the functionality, the capabilities, and the limitation of their new equipment and then to productively pass this information along to the clinical staff.Several simple strategies can be considered before, during and after the commissioning duties. These include creating a clear, well defined plan with transparent expectations of the physicians, the clinical staff and administration. While this is obvious, it is not always clear how this is accomplished and what pitfalls one may encounter in the process. A new modality often requires the use of the latest, possibly less familiar tools. The physicist must ensure proper access and appropriate training for these tools often leading to unanticipated problems and unfamiliar results. A key component is to realistically estimate the amount of time it will require and to communicate that to the whole team. A comprehensive awareness of the complete system by entire planning team must be a fundamental beginning product of the project and should be permitted to be flexible enough to process unexpected complications exposed in the commissioning process.The use of these tactics will be discussed in two clinical cases: 1) The implementation of 4‐D CT in a proton therapy environment and 2) the commissioning of an Elekta accelerator for both CMS‐XIO and CMS Monaco. While specific vendors will be used in the examples, the tactics discussed will be generally applicable to any vendor or equipment.Learning Objective:1. Understand basic strategies, processes and techniques employed in safe and effective execution of a project plan.2. Examine the described strategies used by the speakers in two actual clinical examples.3. Understand organizational issues that one may have to address prior to and during the commissioning and implementation of new equipment.
WE‐A‐BRB‐03: X‐Ray Guided Targeting of Nanoparticles to Cancer
Authors: Ferraro D , Hallahan D 
Published: November 2011

Purpose: X‐irradiation induces the expression of novel receptors on the surface of cancer cells. Peptide ligands that bind specifically to these receptors are now used to retarget liposomes and nanoparticles containing chemotherapy for cancer. Here we show that radiolabeling of nanoparticles will be used to image the spatial and temporal distribution of nanoparticles targeted to radiation inducible receptors during planned clinical trials. Methods: Biodegradable nanoparticles were manufactured by use of cross linking reagents with nanoparticle albumin. Peptide ligands that target radiation inducible receptors, HVGGSSV and GIRLRG were conjugated to nanoparticles using bifunctional PEG linkers. Radiolabeling with radioiodine was conjugated to nanoparticles by use of iodigen while Zr86 was conjugated by use of DFO as a chelator. Near infrared imaging was also used when Alexafluor750 fluorophore was conjugated to nanoparticles. Radiolabeled nanoparticles were injected by tail vein into mice bearing irradiated cancers. The biodistribution was imaged by PET, SPECT and NIR imaging. Results: Cancer specific binding of targeted nanoparticle was achieved by both the HVGGSSV and GIRLRG peptide ligands that bind to radiation inducible TIP‐1 and GRP‐78 receptors respectively. PEGylated nanoparticles have a circulation time greater than 24 hours which necessitated internal emitters with long half lives. Radiolabeled nanoparticles imaged by PET and gamma camera maintained cancer specific binding in mouse models of cancer. Nanoparticles and liposomes that were targeted to radiation inducible proteins bind selectively and for 7 to 9 days respectively. Anti‐cancer drugs including doxorubicin in liposomes and paclitaxel in nanoparticle enhanced radiation‐induced tumor control in mouse models of cancer. Conclusions: Radiation inducible receptors on cancer are suitable for targeted drug delivery. Long half lived radionuclides are needed to monitor the biodistribution in these PEGylated nanoparticles. PET and SPECT imaging are planned for upcoming clinical trials.National Cancer Institute R01 and R21 grants.
WE‐A‐211‐02: An Analysis of Recent Literature regarding Radiation Risk
Authors: Wagner L , Boice J 
Published: November 2011

The peer review process screens scientific articles for merit prior to acceptance or rejection for publication. After publication the process continues with scrutiny by other researchers as expressed in letters to the editor and other scientific research that either affirms or denies findings. Research into radiation effects directly affects the use of ionizing radiations in medicine. The quality of peer review of articles on radiation effects is therefore critical to the practice of medicine. This presentation will examine adequacy of peer review regarding recent articles on radiation effects that have appeared in the peer‐reviewed literature. The purpose is to examine what factors in research techniques and analyses contribute to the quality and believability of the findings.Learning objectives:1. To gain insight into the critical evaluation of scientific literature on bioeffects2. To understand how to distinguish causation from correlation or association
WE‐A‐211‐03: BEIR VII: What It Does and Doesnˈt Say
Authors: OˈConnor M 
Published: November 2011

Background: Over the last 2 years, there has been considerable attention focused on the potential cancer risks from medical imaging procedures, particularly with the widespread use of multislice CT. Almost all studies rely upon the BEIR VII report (Biological Effects of Ionizing Radiation panel formed under the auspices of the National Academy of Sciences) to generate an estimate of the risk of cancer from a given procedure. In doing so, most studies treat the BEIR VII report as a solid basis of scientific evidence for estimation of cancer risk. In reality, a close reading of this report shows that there are a large number of assumptions inherent in all aspects of the estimates of cancer risk — a fact that is often and clearly stated in the report.This presentation will review some of the assumptions used by the BEIR panel to calculate cancer risk, including the impact of different models (excess absolute risk vs. excess relative risk), the dose and dose rate effectiveness factor (DDREF) and relative biological effectiveness (RBE), on cancer estimates.Often lost in the discussion on medical exposure is a reference level by which exposure levels can be compared to something that unavoidable and impacts everyone on earth — background radiation. This presentation will review the consequences of applying the BEIR model to background radiation and known variations in levels of background radiation throughout the U.S., and how the cancer rate from background compares with that from medical imaging.Learning Objectives1. Understand the assumptions underlying the BEIR VII report2. Be able to compare the relative risks of medical imaging procedures to that from background radiation
WE‐A‐301‐06: Adaptive Prior Image Constrained Compressed Sensing‐Based CBCT Reconstruction Algorithm
Authors: Lee H , Xing L , Lee R 
Published: November 2011

Purpose: Cone‐beam CT (CBCT) images are acquired repeatedly during a course of radiation therapy and a natural question to ask is whether CBCT images obtained earlier in the process can be utilized as prior knowledge to reduce patient imaging dose in subsequent scans. The purpose of this work is to develop an adaptive prior image constrained compressed sensing (APICCS) method to solve this problem. Methods: The smoothed prior images are utilized as an initial guess and are incorporated into the objective function under the PICCS framework. The clustered prior images are additionally employed to detect any possible mismatched areas compared with the current images that are classified by the k‐means algorithm at each iteration step. A distance transformation is then introduced to convert the mismatched information into a weighted relaxation map for an adaptive update. In constructing the relaxation map, the matched regions between the prior and current images are assigned with smaller values and thus are much less influenced by the sparse projections, thereby leading to fewer streaking artifacts. On the other hand, mismatched regions are associated with larger values and the regions are updated more by the new projections, thus avoiding any possible adverse effects of prior images. The APICCS approach was assessed by using patient data acquired under standard‐ and low‐dose protocols. Results: The APICCS method provides an effective way to enhance the image quality at the matched regions between the prior and current images compared to the existing PICCS algorithm. In addition, the APICCS algorithm allows an imaging dose reduction of 10 to 40 times due to the greatly reduced number of projections and X‐ray tube current. Conclusions:The APICCS technique allows us to effectively take advantage of previously obtained CBCT images and provides high quality CBCT images with sparse projections.This work was supported in part by Mid‐career Researcher Program (2009‐0085999) through NRF grant funded by the MEST and in part by the Industrial Strategic Technology Development Program (10035495) funded by the Ministry of Knowledge Economy (MKE, Korea).
WE‐A‐301‐08: In Vivo Evaluation of a Strategy to Reduce Partial Scan Reconstruction Artifacts in Myocardial Perfusion Computed Tomography
Authors: Ramirez‐Giraldo J C , Jorgensen S M , Ritman E L , Kantor B , McCollough C H. 
Published: November 2011

Purpose: The quantitative accuracy of CT numbers in myocardial perfusion computed tomography (MPCT) is degraded by artifacts arising from the use of partial scan reconstruction (PSR), which is used in cardiac CT to improve temporal resolution. PSR artifacts appear because of inconsistencies in the angular range of projection data used for PSR. The purpose of this study was to demonstrate the ability of targeted spatial frequency filtration (TSFF) to reduce PSR artifacts in animal studies. Methods: TSFF superposes the high frequency information from a PSR, which contains optimal temporal resolution, with the low frequency information from a full (360‐deg) scan, which contains optimal CT number accuracy. We scanned 4 pigs with an MPCT protocol that had x‐rays continuously on, using 120kVp and 90mAs/rotation. Animals were scanned under two conditions: locked and unlocked. In the locked condition, the animalˈs heart was paced in synchrony with gantry rotation, guaranteeing consistent angular ranges in the projection data for the desired position in the RR interval. This avoids PSR artifacts. In the unlocked condition, cardiac pacing was not used, leading to variations in the angular projection range associated with any specific point in the RR interval. Filtered backprojection was used to reconstruct partial and full scans at 70% of the RR interval. Time attenuation curves (TACs) were calculated in the myocardium and back muscle. Results: TACs in the back muscle, which should have been flat, had a mean standard deviation of 13.9HU, 2.29HU and 1.12HU over all 4 animals, for the unlocked, locked and unlocked+TSFF conditions, respectively. For the myocardium, the root mean squared error was 5.9HU and 2.45HU for the unlocked and unlocked+TSFF corrected images with respect to the gold standard (locked condition). Conclusions: The TSFF algorithm effectively suppressed PSR artifacts in vivo, improving the accuracy of CT numbers in MPCT.This work was supported in part by the American Heart Association Predoctoral Fellowship No. 10PRE2560028 and by the NIH Opus CT Imaging Resource Construction Grant No. R018898.
WE‐B‐110‐02: Diagnostic Exposure Tracking in the Medical Record
Authors: Seibert JA 
Published: November 2011

The Electronic Medical Record (EMR) represents the collection of diagnostic tests and procedural test information related to an individual patientˈs history of care at a health center. In the context of medical diagnostic imaging, this relates to the access to imaging procedures, the written diagnoses from the imaging experts, and of increasing relevance and importance, the radiation dose reports for the procedures. The EMR is also emerging as the gateway for computerized order entry for imaging exams, in which the imaging history and accumulated radiation dose will be made available for the referring physician from various imaging procedures, such as interventional radiology and cardiology, computed tomography, and nuclear medicine. Integrating the Healthcare Enterprise (IHE) Radiation Exposure Monitoring (REM) profile specifies how information related to dose can be extracted from modalities that are compliant with the DICOM Radiation Dose Structured Report (RDSR). However, once the information is collected via the RDSR, appropriate steps must be taken to parse the data according to exam types, body area scanned, and dose metrics provided in order to apply conversion factors to estimate an effective dose for a procedure. Effective dose estimates can be considerably under or overestimated, depending on the modality, the patient size, machine calibration errors, and a host of issues that are under current investigation. In this presentation, a review of the various dose metrics for the modalities is discussed, as are current methods to calculate the effective dose. Ultimately, to post the dose information in the EMR, a dose‐management actor described by the IHE REM profile captures the pertinent dose information from each modality and study, parses the data and computes the effective dose according to defined conversion methods. Each individual dose report message transmitted to the EMR is stored in the patient dose report file defined by medical record number, which updates the dose index raw data (e.g., DAP in Interventional radiology, CTDIvol, DLP in CT), the calculated effective dose per procedure, and total cumulative effective dose for the patient.Learning objectives:1. Understand the various dose metrics produced by the imaging modalities.2. Determine how effective dose can be estimated for a given procedure with the dose index values provided by a modality.3. Understand limitations of effective dose calculations, the wide range of under/over estimates that can occur for a specific procedure, and the limitations of the total cumulative patient effective dose.
WE‐B‐220‐03: Treatment of Localized Prostate Cancer Using Magnetic Resonance Imaging‐Controlled Ultrasound Therapy
Authors: Chopra R 
Published: November 2011

Widespread PSA screening and transrectal biopsy has led to an increase in the diagnosis of localized prostate cancer in younger men, and at an earlier stage of disease. While treatment at this stage is associated with good long‐term survival rates, existing therapies are burdened with high complication rates to sexual, urinary and bowel function. Furthermore, diagnosis of prostate cancer is based on sampling of less than 1% of the glandular volume, and many men are overtreated for a disease that is clinically insignificant. Improvements to the localization of prostate cancer within the gland would lead to better decisions with respect to treatment. The introduction of minimally‐invasive treatments for localized prostate cancer with reduced complications would also be an attractive option for patients and healthcare providers.Our group has been exploring the role of MRI in both the diagnosis and treatment of localized prostate cancer for over a decade. Multi‐parametric MRI has been shown to provide good spatial localization of disease through a combination of multiple complementary tissue parameters. In this realm, our group has been exploring the potential of integrating tissue stiffness measurements through a technique known as MR elastography. Current efforts are focused on translating endorectal MRE into preliminary human evaluation. With respect to treatments, our focus for the past 10 years has been on the development of MRI‐guided transurethral ultrasound therapy, a minimally‐invasive approach for the delivery of high‐intensity ultrasound to the gland. This technology has been translated from concept to clinic by our research group, and preliminary results indicate the approach is feasible, and has the potential for precise thermal destruction of the whole prostate, or sub‐volumes within the gland.This seminar will describe our efforts to exploit MRI for both diagnostic and therapeutic applications in prostate cancer management.
WE‐C‐BRA‐03: Acceptance Testing and Commissioning of a Commercial 3D Surface Matching Video System
Authors: Al‐Hallaq HA 
Published: November 2011

Non‐invasive 3D surface matching systems have become commercially available forinitial patient positioning and real‐time monitoring during radiotherapy treatment. Some systems are capable of providing surface motion surrogates that can be used for respiratory gating. All systems must undergo commissioning and acceptance prior to clinical use. First, clinical implementation of these systems requires the establishment of routine quality control proceduresthat range from phantom studies to monitoring clinical setups.In particular, the congruence of the surface imaging isocentermust be compared to both the imaging and treatment radiation isocenters. Isocenter congruence accuracy limitations may need to be tailored to the treatment site. For example, tighter accuracy is expected of isocenter congruence for treatment monitoring ofstereotactic radiosurgery patients compared to monitoring of breast patients due to the smaller planning target volume margins. For clinical commissioning studies, the correlation of 3D surface matching compared to the routinely‐used image‐guided procedures should be well characterized. Furthermore, understanding the accuracy, robustness, and limitations of the algorithms used to register two 3D surfaces is key to understanding the expected clinical results. We will summarize our institutional experience with acceptance testing and commissioning the AlignRT (VisionRT Ltd., London, UK) 3D surface matching system and its clinical implementation for positioningpatients receiving whole breast radiotherapy.Learning Objectives:1. List some acceptance testing procedures for surface imaging systems2. Understand the commissioning process of surface imaging systems for whole breast radiotherapy3. Understand how surface imagingisocenter congruence testing must be incorporated into ongoing quality assurance of image‐guided RT (IGRT)
WE‐C‐BRB‐06: Analyzing the Impact of Intra‐Fraction Motion: Correlation of IMRT QA Metrics with D95%
Authors: Waghorn B , Meeks S , Langen K 
Published: November 2011

Purpose: Motion‐encoded dose distributions, taking into account intra‐fraction motion during intensity modulated radiation therapy (IMRT), can be determined both computationally and experimentally, with a number of analysis techniques available to quantify the dosimetric changes. The analysis results can provide important information regarding the clinical impact of motion and the appropriateness of a given treatment plan. This study provides a comparison of different analysis techniques performed on computationally predicted motion‐encoded dose distributions. Methods: A total of 3,768 motion‐encoded dose distributions were calculated computationally for 38 step‐and‐shoot and 38 compensator IMRT plans across 9 lung patients. The motion‐encoded dose distributions were compared to static dose distributions using four analysis techniques: 2D and 3D gamma, histogram (looking at the fraction of voxels with a dose deviation exceeding 3% of the prescription dose) and dose volume histogram (DVH) analyses. Tests were also implemented to separate failing voxels caused by either over‐dosing or under‐dosing. In addition tests were performed both globally (not taking into account the planning regions of interest) and within restricted regions of interest, such as the target volume. Results: Global analysis techniques did not accurately predict clinically relevant dosimetric changes in the target D<sub>95%</sub>. Three‐dimensional gamma and histogram analyses, localized within the target and considering only voxels experiencing decreased doses due to motion, provided the strongest correlations with changes in D<sub>95%</sub> (r,2</sup>=0.68 and r,2</sup>=0.71 respectively). A global 2D gamma analysis correlated less well with changes in D<sub>95%</sub> (r,2</sup>=0.44), and was both less specific and sensitive. Conclusions: This study suggests that any clinical decisions based solely on 2D or global measurement techniques may not provide adequate dosimetric information about the effect of motion on IMRT delivery. Care needs to be taken in determining the appropriate analysis technique and in interpreting the results in order to understand the relevant dosimetric changes caused by motion.This work was supported in part by .decimal, Inc.
WE‐C‐BRB‐08: Independent Dose Calculation Followed by Dynalog File Analysis as an Alternative for Measurement Based IMRT QA
Authors: Sun B , Boddu S , Goddu S , Yang D , Rangaraj D , Mutic S 
Published: November 2011

Purpose: Experimental methods are commonly used for patient‐specific IMRT verification. The aim of this work is to investigate the possibility of substituting the time and labor intensive IMRT QA with calculation based dose verification and log file analysis. Method: 11 IMRT plans (5 head and neck plans, 3 rectum plans, 3 breast plans and 5 prostate plans) made using Pinnacle were recalculated using a QA phantom. All the plans were verified by ICs and 2D MapCheck measurements and compared to the independent dose calculation using Eclipse. The deviations between dosimetric measurements and independent dose calculation in a QA phantom were evaluated. The plans with patient anatomy were imported to Eclipse for 3D dose calculations. The DVHs and point doses calculated by Pinnacle and Eclipse are evaluated for PTV and critical structures. To verify data transfer and performance of the delivery unit dynalog file analysis was performed.Results: Average deviation between IC measurements and point dose calculations with Pinnalce and Eclipse for Head and Neck were 1.1±1.3% and 1.4±1.6%, respectively. For MapCheck measurement, the mean gamma value with 3% dose difference and 3 mm distance‐to‐agreement were within 1.5% for most plans. The mean 3D dose differences calculated from two different treatment systems are with 3 % for Head‐and‐Neck cases and are within 2% for other plans. The dynalog analysis shows that the gantry angle, jaw position, collimator angle and MLC positions have the passing rate of above 97%. The independent dose calculation with the dynalog analysis takes only 37 minutes, while experimental approach, which takes up to 3 hours. Conclusion: Independent dose calculation followed by dynalog file analysis is a reliable tool to verify the IMRT treatment. With the IMRT QA program becoming more mature, independent dose calculations and dynalog analysis may be used to replace experimental based verification methods.