bluuebunny/crossref_metadata_2025_split huggingface dataset:
Home Asthma Management for Rural Families
Authors: Horner Sharon D. , Fouladi Rachel T. 
Published: February 2007

ISSUES AND PURPOSE. To assess home asthma management among rural families with a school‐age child who has asthma.DESIGN AND METHODS. Exploratory analysis of baseline data of a tri‐ethnic sample of rural families with school‐age children who have asthma.RESULTS. Parents and children enact a moderate amount of asthma management behaviors. Preventive behaviors were correlated with the Asthma Behavior Inventory and treatment behaviors were correlated with the child's asthma severity. Factors that could affect asthma management include no insurance, no visits to providers in 12 months, or no asthma medications.PRACTICE IMPLICATIONS. Nurses must use every contact with families to assess their asthma management and availability of resources, and to determine the fit between asthma severity and the asthma management plan.
Moving into Parenthood: A Program for New Adolescent Mothers Combining Parent Education With Creative Physical Activity
Authors: Sadler Lois S. , Cowlin Ann 
Published: February 2007

ISSUES AND PURPOSE. To describe a school‐based program combining traditional parent education with creative physical activity classes to assist newly delivered adolescent mothers to develop positive parenting behaviors while remaining in school.CONCLUSIONS. The program contains sessions on parenting information, creative coping strategies, fitness, and role modeling of positive parenting behaviors to help young mothers learn healthy parenting skills as they continue in their own adolescent development.PRACTICE IMPLICATIONS. The content and teaching strategies can be adapted for individual or group clinical work with teen mothers and their infants in a variety of community settings as well as in school‐based healthcare programs.
On the use of virtual simulation in radiotherapy of the intact breast
Authors: Tomé Wolfgang A. , Steeves Richard A. , Paliwal Bhudatt P. 
Published: February 2007

In this paper a method of breast cancer treatment planning using virtual simulation implemented at the Department of Human Oncology at the University of Wisconsin is described. All patients in this procedure are placed in a custom vacuum mold in treatment position with both arms up to avoid collision with the CT scanner aperture. For all patients a CT scan of 5‐mm‐slice thickness is acquired. The ipsilateral and contralateral breast, the ipsilateral lung and the heart are delineated and a three‐dimensional plan is generated that tries to minimize the dose to the ipsilateral lung and heart while ensuring adequate coverage of the affected breast. Digitally reconstructed radiographs are used to verify the patient setup on the treatment machine. © 2000 American College of Medical Physics.PACS number(s): 87.53.–j
Preventative maintenance and unscheduled downtime from an economic perspective
Authors: Dunscombe Peter , Roberts Gisele , Valiquette Lianne 
Published: February 2007

A spreadsheet‐based model for economically characterizing the operation of a radiation treatment program has been used to perform a quantitative financial analysis of scheduled and unscheduled downtime. The incremental cost of downtime is broken down into three categories: remuneration of in‐house or third party service technologists, decreased patient capacity, and local operating procedures for dealing with downtime. Different service arrangements and operating procedures are simulated to demonstrate the financial cost of treatment machine unavailability due to either preventative maintenance or unexpected breakdown. Depending on the service arrangement and operating policies for accommodating downtime, the combined cost of scheduled and unscheduled downtime (at 5%) can exceed 10% of the total cost of the radiation treatment program. It has also been demonstrated that the greatest cost component of downtime is decreased patient capacity, which can exceed $400,000 (CAN) when unscheduled downtime reaches 5%. The interpretation of this cost depends on the funding environment. Although the emphasis of this study has been the financial consequences of downtime, there are other factors which must be considered when developing policies and procedures for accommodating downtime such as effects on treatment, patient convenience and quality of life for staff. Even though the numerical results are strictly valid only within the context of the simulations performed, they do provide a broad framework within which medical physicists can make recommendations regarding service support and downtime. © 2000 American College of Medical Physics.PACS number(s): 87.52.–g, 87.90.+y
Preparing a cost analysis for the section of medical physics–guidelines and methods
Authors: Mills Michael D. , Spanos William J. , Jose Baby O. , Kelly Beverly A. , Brill James P. 
Published: February 2007

Radiation oncology is a highly complex medical specialty, involving many varied routine and special procedures. To assure cost‐effectiveness and maintain support for the medical physics program, managers are obligated to analyze and defend all aspects of an institutional billing and cost‐reporting program. Present standards of practice require that each patient's radiation treatments be customized to fit his/her particular condition. Since the use of personnel time and other resources is highly variable among patients, graduated levels of charges have been established to allow for more precise billing. Some radiation oncology special procedures have no specific code descriptors; so existing codes are modified or additional information attached in order to avoid payment denial. Recent publications have explored the manpower needs, salaries, and other resources required to perform radiation oncology “physics” procedures. This information is used to construct a model cost‐based resource use profile for a radiation oncology center. This profile can be used to help the financial officer prepare a cost report for the institution. Both civil and criminal penalties for Medicare fraud and abuse (intentional or unintentional) are included in the False Claims Act and other statutes. Compliance guidelines require managers to train all personnel in correct billing procedures and to review continually billing performance. © 2000 American College of Medical Physics.PACS number(s): 87.90+y, 87.53.–j
Potential therapeutic misadministration due to inappropriate electron beam field shaping
Authors: Olch Arthur J. , Fallen Robert , Conrad Jill , Lavey Robert S. 
Published: February 2007

Lead or cerrobend blocking strips are used to shape electron treatment fields when an appropriate custom insert is not available. For the Varian 2100C accelerator, the structural supports of the electron applicators impede the free placement of these field‐shaping strips on the open custom insert frame while placement at the top of the applicator is unimpeded. We have investigated the dosimetric ramifications of placing field shaping strips at the top level of the applicator for 6, 9, and 16 MeV electrons. Our results demonstrate as much as a 30% dose decrease and 2 cm penumbral increase when this is done compared to field shaping at the insert level. The magnitude of this dosimetric error qualifies as a therapeutic misadministration in many states depending on how many treatments are delivered in this manner. Based on this finding, we recommend that routine use of lead strip blocking be discouraged in favor of custom inserts due to the potential for inappropriate placement on some linear accelerators.PACS number(s): 87.53.–j, 87.52.–g
Entrance dose measurements for in‐vivo diode dosimetry: Comparison of correction factors for two types of commercial silicon diode detectors
Authors: Zhu X. R. 
Published: February 2007

Silicon diode dosimeters have been used routinely for in‐vivo dosimetry. Despite their popularity, an appropriate implementation of an in‐vivo dosimetry program using diode detectors remains a challenge for clinical physicists. One common approach is to relate the diode readout to the entrance dose, that is, dose to the reference depth of maximum dose such as for the field. Various correction factors are needed in order to properly infer the entrance dose from the diode readout, depending on field sizes, target‐to‐surface distances (TSD), and accessories (such as wedges and compensate filters). In some clinical practices, however, no correction factor is used. In this case, a diode‐dosimeter‐based in‐vivo dosimetry program may not serve the purpose effectively; that is, to provide an overall check of the dosimetry procedure. In this paper, we provide a formula to relate the diode readout to the entrance dose. Correction factors for TSD, field size, and wedges used in this formula are also clearly defined. Two types of commercial diode detectors, ISORAD (n‐type) and the newly available QED (p‐type) (Sun Nuclear Corporation), are studied. We compared correction factors for TSDs, field sizes, and wedges. Our results are consistent with the theory of radiation damage of silicon diodes. Radiation damage has been shown to be more serious for n‐type than for p‐type detectors. In general, both types of diode dosimeters require correction factors depending on beam energy, TSD, field size, and wedge. The magnitudes of corrections for QED (p‐type) diodes are smaller than ISORAD detectors.PACS number(s): 87.66.–a, 87.52.–g
Applying the equivalent uniform dose formulation based on the linear‐quadratic model to inhomogeneous tumor dose distributions: Caution for analyzing and reporting
Authors: McGary John. E. , III Walter Grant , Woo S. Y. 
Published: February 2007

We apply the concept of equivalent uniform dose (EUD) to our data set of model distributions and intensity modulated radiotherapy (IMRT) treatment plans as a method for analyzing large dose inhomogeneities within the tumor volume. For large dose nonuniformities, we find that the linear‐quadratic based EUD model is sensitive to the linear‐quadratic model parameters, α and β, making it necessary to consider EUD as a function of these parameters. This complicates the analysis for inhomogeneous dose distributions. EUD provides a biological estimate that requires interpretation and cannot be used as a single parameter for judging an inhomogeneous plan. We present heuristic examples to demonstrate the dose volume effect associated with EUD and the correlation to statistical parameters used for describing dose distributions. From these examples and patient plans, we discuss the risk of incorrectly applying EUD to IMRT patient plans.PACS number(s): 87.53.Tf
A clinical evaluation of setup errors for a prostate immobilization system
Authors: McGary John E. , Grant Walter 
Published: February 2007

A prostate treatment immobilization system was evaluated with respect to setup errors and efficiency for a specific treatment setup. Prostate patients were treated in the prone position with a rectal catheter using the NOMOS intensity modulated radiotherapy system. Immobilization and setup consisted of a Vac‐Lok™ bag (MED‐TEC, Orange City, IO) fitted within a registration carrier box where patients were aligned to the bag using skin marks along the lower leg. Daily setup errors were analyzed using lateral portal films, registration plates mounted to the carrier box, and the pubic symphasis as a bony reference. Two studies were conducted to evaluate setup technique. In the first study, patient setup required 3–5 minutes for patient positioning and the corresponding superior/inferior errors were found to have a standard deviation of 3.5 mm. In the second study, the technique standards were reduced to allow for faster setup times and, consequently, larger errors; setup times were 1–2 minutes and the mean and standard deviation errors were and 5 mm, respectively.PACS number(s): 87.53.–j, 87.90.+y
Use of a radioactive check device for redundancy check of ionization chambers
Authors: Sidhu N. P. S. , Rouvas Alkis , Cadman Patrick 
Published: February 2007

The use of a radioactive check device containing Strontium 90 was investigated to carry out the redundancy checks of Farmer‐type ionization chambers. It was not possible to meet the recommended tolerance limits of the redundancy checks without taking into account the angular response of the ionization chambers. The ionization chambers exhibited a maximum variation of 1% in the angular response in this check device. After accounting for the angular response the maximum variation of the short‐term repeatability was 0.14% with a standard deviation of . The long‐term constancy checked over a period of nine months was less than for measurements, taking into account the angular response of the ionization chambers. No significant effect of the background radiation levels was observed on the measurements.PACS number(s): 87.53.–j, 87.52.–g
Fast verification of Gamma Knife™ treatment plans
Authors: Zhang Pengpeng , Dean David , Wu Q. Jackie , Sibata Claudio 
Published: February 2007

The Leksell stereotactic Gamma Knife™ uses radiation from 201 sources that are focused to the center of a collimator helmet to deliver a high dose of radiation with minimal irradiation of proximal structures. This paper presents a method for fast verification of the irradiation time as calculated by the Leksell Gamma Knife™ treatment planning software GammaPlan®. To obtain the irradiation time for each shot in the treatment plan, one must first accurately calculate the tissue maximum ratio (TMR) for each of the individual 201 beams. The algorithm presented in this paper begins with the determination of the geometrical relationship between the Gamma Knife™ collimator helmet and the stereotactic frame. A group of reference points is measured to build a head model simulating the patient skull geometry. During radiosurgery, the isocenter of the collimator helmet is moved to the shot center. A group of spatial vectors describing the reference points at the skull surface is obtained by converting the Cartesian coordinates to Polar coordinates. For each individual beam, the three nearest reference vectors are found by ranking the relative angles. The depth that each beam penetrates the patient's skull to the isocenter is obtained via linear interpolation. The TMR for each beam then is compared with the TMR for the calibration setup, which is done using a spherical 8 cm radius phantom. This algorithm is applied to verify the treatment time calculated in GammaPlan® Version 5.2. The results are shown to agree with GammaPlan® within 3%.PACS number(s): 87.52.–g, 87.66.–a
Comparison of commercially available three‐dimensional treatment planning algorithms for monitor unit calculations in the presence of heterogeneities
Authors: Butts Joseph R. , Foster Alvis E. 
Published: February 2007

This study uses an anthropomorphic phantom and its computed tomography (CT) data set to evaluate monitor unit (MU) calculations using the CMS Focus Clarkson, the CMS Focus Multigrid Superposition Model, the CMS Focus FFT Convolution Model, and the ADAC Pinnacle3 Collapsed Cone Convolution Superposition Algorithms. Using heterogeneity corrections, a treatment plan and corresponding MU calculations were generated for several typical clinical situations. A diode detector, placed in an anthropomorphic phantom, was used to compare the treatment planning algorithms' predicted doses with measured data. Differences between diode measurements and the algorithms' calculations were within reasonable levels of acceptability as recommended by Van Dyk et al. [Int. J. Rad. Onc. Biol. Phys. 26, 261–273 (1993)], except for the CMS Clarkson algorithm, which predicted too few MU for delivery of the intended dose to chest wall fields.PACS number(s): 87.53.Bn, 87.53.Dq
A simple method for electron energy constancy measurement
Authors: King R. Paul , Anderson R. Scott 
Published: February 2007

A device is described for use in confirming the energy constancy of clinical electron beams. A wedge shaped absorber is placed over an ionization chamber leading to an energy dependent response. A measurement under the energy filter is divided by a measurement in air to correct for the inherent energy dependence of the chamber. A nearly linear response is demonstrated.PACS number(s): 87.52.–g, 87.53.–j, 87.66.–a
Verification of tangential breast treatment dose calculations in a commercial 3D treatment planning system
Authors: Baird Christopher T. , Starkschall George , Liu H. Helen , Buchholz Thomas A. , Hogstrom Kenneth R. 
Published: February 2007

The accuracy of the photon convolution/superposition dose algorithm employed in a commercial radiation treatment planning system was evaluated for conditions simulating tangential breast treatment. A breast phantom was fabricated from machineable wax and placed on the chest wall of an anthropomorphic phantom. Radiographic film was used to measure the dose distribution at the axial midplane of the breast phantom. Subsequently, thermoluminescent dosimeters (TLDs) were used to measure the dose at four points within the midplane to validate the accuracy of the film dosimetry. Film measurements were compared with calculations performed using the treatment planning system for four types of treatment: optimized wedged beams at 6 and 18 MV and two‐dimensional compensated beams at 6 and 18 MV. Both the film‐ and TLD‐measured doses had a precision of approximately 0.6%. The film‐measured doses were approximately 1.5% lower than the TLD‐measured doses, ranging from 0–3 % at 6 MV and 0.5–1 % at 18 MV. Such results placed a high level of confidence in the accuracy and precision of the film data. The measured and calculated doses agreed to within for both the film and TLD measurements throughout the midplane exclusive of areas not having charged particle equilibrium. Good agreement was not expected within these regions due to the limitations in both film dosimetry and the dose‐calculation algorithm. These results indicated that the treatment planning system calculates doses at the midplane with clinically acceptable accuracy in conditions simulating tangential breast treatment.PACS number(s): 87.53.–j, 87.66.–a
Comparison of two planning systems for HDR brachytherapy gynecological application
Authors: Elhanafy Osman A. , Migahed Mostafa D. , Sakr Hanim A. , Ellithy Mostafa , Das Rupak K. , Odau Heath J. , Thomadsen Bruce R. 
Published: February 2007

Purpose: This report compares the Nucletron NPS and PLATO planning system for patients treated for cervix cancer.Materials and Methods: This study compares calculations generated using the older NPS (version 11.43) planning system and the more recent PLATO (version 14.1) system for two cases: 1) a single dwell position and 2) an actual patient application using a tandem and ovoid.Results: For one dwell position: for NPS planning the dose for points along the source axis forward of the cable was 9.85% more than for symmetrically placed points in the cable direction. For PLATO, the same test gave rise to a difference of 10.2%. Comparing the two systems, NPS calculated doses for points in the forward direction 14% greater than those calculated by PLATO. The entry of points using the digitizer accounted for less than 1% of any difference. For the patient case: the dose difference between NPS and PLATO planning for all patient reference points entered from films ranged from 1 to 4%. The difference in dose between optimized and nonoptimized planning was approximately 0.5% for prescription points (points A), while for the bladder and rectum the differences were 6% and 20%, respectively with NPS, and with PLATO, 8% and 22%, respectively.Conclusion: This study highlighted the effects of the differences in the calculational algorithm between the older and newer planning systems from Nucletron. While the differences were minimal on the perpendicular bisector of the source, along the axis they become considerable. In a practical gynecological case, these differences mostly affect the dose to the rectum, since that organ receives the greatest proportion of its dose from rays near the same axis. Overall, the PLATO system plan required about 2.5% less integrated reference air kerma than the NPS plan for the same dose to point A. For either planning system, optimization is crucial in decreasing dose to bladder and rectal points. © 2001 American College of Medical Physics. [DOI: 10.1120/1.1384528]PACS number(s): 87.53.–j
The overshoot phenomenon in step‐and‐shoot IMRT delivery
Authors: Ezzell Gary A. , Chungbin Suzanne 
Published: February 2007

The control loop in the Varian DMLC system (V4.8) requires msec to monitor and halt the irradiation of a segment, causing an “overshoot” effect: the segment ends on a fractional monitor unit larger than that planned. As a result, the actual MU delivered may differ from that planned. In general, for step‐and‐shoot treatments, the first segment receives more, the last receives less, and intermediate segments vary. The overshoot for each segment (ΔMU) is small, approximately 0.6 MU at 600 MU/min Our IMRT planning system (Corvus) produces plans often having more than 20% of the segments with less than 1 MU/segment. Such segments may be skipped if the ΔMU exceeds the segments’ planned MU. Furthermore, QA filming often requires reducing the total MU by a factor of 4–6, increasing the potential for dosimetric error. This study measured ΔMU over a range of MU/min and MU/segment. At MU/segment, the ΔMU was stable, corresponding to a delay of 62 msec. ΔMU became larger and more variable at MU/segment. The behavior was modeled in a computer program that predicted the change in delivered MU/segment and total change in delivered MU to each beamlet. Beams were analyzed for patients receiving 5 field prostate or 9 field head and neck treatments. At 400 MU/min, 28% and 16%, respectively, of the planned segments were skipped. For QA filming, up to 75% of the segments were skipped. The cumulative error averaged MU/beamlet, but individual beamlets had errors exceeding 200%. The effect is most significant for low dose regions. Recommendations are given for deciding when to treat or do QA studies with lower MU/min. In general, treatments are not significantly affected, but QA films taken at reduced MU may be improved if irradiated at lowered MU/min.PACS number(s): 87.53.–j, 87.90.+y
Shielding assessment of a mobile electron accelerator for intraoperative radiotherapy
Authors: Daves Jodi L. , Mills Michael D. 
Published: February 2007

A new approach to intraoperative radiotherapy makes use of a mobile electron linear accelerator delivering therapeutic radiation doses in an operating room suite. This unconventional technology has raised questions concerning protection for personnel and the necessity of shielding the adjoining areas. In this study, the leakage and scatter radiation from the mobile electron accelerator is measured and characterized in a series of spherical projections. An analysis is performed to determine the need for shielding or, alternatively, patient‐based load restrictions in the operating room. This investigation provides a resource to assess shielding and/or patient load restrictions for any facility performing intraoperative radiotherapy with a similar unit. The data presented indicates that the mobile electron accelerator may be operated in an area with little or no shielding under nominal patient load expectations.PACS number(s): 87.52.–g, 87.53.–j