Thoracic radiotherapy treatment planning with cine PET/CT

Purpose: Respiratory motion causes substantial uncertainty in radiotherapy treatment planning. Four-dimensional computed tomography (4D-CT) is a useful tool to image tumor motion during normal respiration. Treatment margins can be reduced by targeting the motion path of the tumor. The expense and complexity of 4D-CT, however, may be cost-prohibitive at some facilities. We developed an image processing technique to produce images from cine CT that contain significant motion information without 4D-CT. The purpose of this work was to compare cine CT and 4D-CT for the purposes of target delineation and dose calculation, and to explore the role of PET in target delineation of lung cancer. Methods: To determine whether cine CT could substitute 4D-CT for small mobile lung tumors, we compared target volumes delineated by a physician on cine CT and 4D-CT for 27 tumors with intrafractional motion greater than 1 cm. We assessed dose calculation by comparing dose distributions calculated on respiratory-averaged cine CT and respiratory-averaged 4D-CT using the gamma index. A threshold-based PET segmentation model of size, motion, and source-to-background was developed from phantom scans and validated with 24 lung tumors. Finally, feasibility of integrating cine CT and PET for contouring was assessed on a small group of larger tumors. Results: Cine CT to 4D-CT target volume ratios were (1.05±0.14) and (0.97±0.13) for high-contrast and low-contrast tumors respectively which was within intraobserver variation. Dose distributions on cine CT produced good agreement (< 2%/1 mm) with 4D-CT for 71 of 73 patients. The segmentation model fit the phantom data with R2 = 0.96 and produced PET target volumes that matched CT better than 6 published methods (-5.15%). Application of the model to more complex tumors produced mixed results and further research is necessary to adequately integrate PET and cine CT for delineation. Conclusions: Cine CT can be used for target delineation of small mobile lesions with minimal differences to 4D-CT. PET, utilizing the segmentation model, can provide additional contrast. Additional research is required to assess the efficacy of complex tumor delineation with cine CT and PET. Respiratory-averaged cine CT can substitute respiratory-averaged 4D-CT for dose calculation with negligible differences.

New library buildings: the Houston Academy of Medicine--Texas Medical Center Library.

A historical account is given of the Houston Academy of Medicine--Texas Medical Center Library within its Texas Medical Center setting in Houston, Texas. Outlined are planning, financing, and construction of the new library, which consists in part of new building and in part of renovated interiors of an old building originally completed in 1954. A concise picture is given of the new library's interiors, showing its functional success for users and employees alike. An architectural summary is appended showing gross and net footages, source of funds, costs and capacities.

DUAL ENERGY COMPUTED TOMOGRAPHY FOR PROTON THERAPY TREATMENT PLANNING

Proton radiation therapy is gaining popularity because of the unique characteristics of its dose distribution, e.g., high dose-gradient at the distal end of the percentage-depth-dose curve (known as the Bragg peak). The high dose-gradient offers the possibility of delivering high dose to the target while still sparing critical organs distal to the target. However, the high dose-gradient is a double-edged sword: a small shift of the highly conformal high-dose area can cause the target to be substantially under-dosed or the critical organs to be substantially over-dosed. Because of that, large margins are required in treatment planning to ensure adequate dose coverage of the target, which prevents us from realizing the full potential of proton beams. Therefore, it is critical to reduce uncertainties in the proton radiation therapy. One major uncertainty in a proton treatment is the range uncertainty related to the estimation of proton stopping power ratio (SPR) distribution inside a patient. The SPR distribution inside a patient is required to account for tissue heterogeneities when calculating dose distribution inside the patient. In current clinical practice, the SPR distribution inside a patient is estimated from the patient’s treatment planning computed tomography (CT) images based on the CT number-to-SPR calibration curve. The SPR derived from a single CT number carries large uncertainties in the presence of human tissue composition variations, which is the major drawback of the current SPR estimation method. We propose to solve this problem by using dual energy CT (DECT) and hypothesize that the range uncertainty can be reduced by a factor of two from currently used value of 3.5%. A MATLAB program was developed to calculate the electron density ratio (EDR) and effective atomic number (EAN) from two CT measurements of the same object. An empirical relationship was discovered between mean excitation energies and EANs existing in human body tissues. With the MATLAB program and the empirical relationship, a DECT-based method was successfully developed to derive SPRs for human body tissues (the DECT method). The DECT method is more robust against the uncertainties in human tissues compositions than the current single-CT-based method, because the DECT method incorporated both density and elemental composition information in the SPR estimation. Furthermore, we studied practical limitations of the DECT method. We found that the accuracy of the DECT method using conventional kV-kV x-ray pair is susceptible to CT number variations, which compromises the theoretical advantage of the DECT method. Our solution to this problem is to use a different x-ray pair for the DECT. The accuracy of the DECT method using different combinations of x-ray energies, i.e., the kV-kV, kV-MV and MV-MV pair, was compared using the measured imaging uncertainties for each case. The kV-MV DECT was found to be the most robust against CT number variations. In addition, we studied how uncertainties propagate through the DECT calculation, and found general principles of selecting x-ray pairs for the DECT method to minimize its sensitivity to CT number variations. The uncertainties in SPRs estimated using the kV-MV DECT were analyzed further and compared to those using the stoichiometric method. The uncertainties in SPR estimation can be divided into five categories according to their origins: the inherent uncertainty, the DECT modeling uncertainty, the CT imaging uncertainty, the uncertainty in the mean excitation energy, and SPR variation with proton energy. Additionally, human body tissues were divided into three tissue groups – low density (lung) tissues, soft tissues and bone tissues. The uncertainties were estimated separately because their uncertainties were different under each condition. An estimate of the composite range uncertainty (2s) was determined for three tumor sites – prostate, lung, and head-and-neck, by combining the uncertainty estimates of all three tissue groups, weighted by their proportions along typical beam path for each treatment site. In conclusion, the DECT method holds theoretical advantages in estimating SPRs for human tissues over the current single-CT-based method. Using existing imaging techniques, the kV-MV DECT approach was capable of reducing the range uncertainty from the currently used value of 3.5% to 1.9%-2.3%, but it is short to reach our original goal of reducing the range uncertainty by a factor of two. The dominant source of uncertainties in the kV-MV DECT was the uncertainties in CT imaging, especially in MV CT imaging. Further reduction in beam hardening effect, the impact of scatter, out-of-field object etc. would reduce the Hounsfeld Unit variations in CT imaging. The kV-MV DECT still has the potential to reduce the range uncertainty further.

Conceptual Bases of the Planning Process in Family Preservation/Family Support State Plans

Congress and the Department of Health and Human Services (DHHS) intend for the Family Preservation and Support Act of 1993 (P.L. 103-66) to catalyze major reforms in state human services systems. DHHS and numerous other institutions developed conceptual and procedural guidance for the states' planning processes. Review of the planning dimensions of participation and expertise reveals that major emphases on stakeholder participation and technical planning processes obscure the need for expertise in family preservation and family support.

A novel treatment planning methodology for high dose 166Ho-DOTMP therapy in patients with multiple myeloma

Bone marrow ablation, i.e., the complete sterilization of the active bone marrow, followed by bone marrow transplantation (BMT) is a comment treatment of hematological malignancies. The use of targeted bone-seeking radiopharmaceuticals to selectively deliver radiation to the adjacent bone marrow cavities while sparing normal tissues is a promising technique. Current radiopharmaceutical treatment planning methods do not properly compensate for the patient-specific variable distribution of radioactive material within the skeleton. To improve the current method of internal dosimetry, novel methods for measuring the radiopharmaceutical distribution within the skeleton were developed. 99mTc-MDP was proven as an adequate surrogate for measuring 166Ho-DOTMP skeletal uptake and biodistribution, allowing these measures to be obtained faster, safer, and with higher spatial resolution. This translates directly into better measurements of the radiation dose distribution within the bone marrow. The resulting bone marrow dose-volume histograms allow prediction of the patient disease response where conventional organ scale dosimetry failed. They indicate that complete remission is only achieved when greater than 90% of the bone marrow receives at least 30 Gy. ^ Comprehensive treatment planning requires combining target and non-target organ dosimetry. Organs in the urinary tract were of special concern. The kidney dose is primarily dependent upon the mean transit time of 166 Ho-DOTMP through the kidney. Deconvolution analysis of renograms predicted a mean transit time of 2.6 minutes for 166Ho-DOTMP. The radiation dose to the urinary bladder wall is dependent upon numerous factors including patient hydration and void schedule. For beta-emitting isotopes such as 166Ho, reduction of the bladder wall dose is best accomplished through good patient hydration and ensuring a partially full bladder at the time of injection. Encouraging the patient to void frequently, or catheterizing the patient without irrigation, will not significantly reduce the bladder wall dose. ^ The results from this work will produce the most advanced treatment planning methodology for bone marrow ablation therapy using radioisotopes currently available. Treatments can be tailored specifically for each patient, including the addition of concomitant total body irradiation for patients with unfavorable dose distributions, to deliver a desired patient disease response, while minimizing the dose or toxicity to non-target organs. ^

The influence of ideological interest groups on congressional financial support of international family planning

The World Health Organization estimates there are about 585,000 maternal deaths each year, with 98% of the maternal deaths in developing countries. Access to family planning methods is one method to decrease maternal mortality and morbidity. ^ The U.S. was the leader in providing financial and technical assistance to developing countries to enable women to have this access. The election of Ronald Regan changed the course of U.S. support; abortion became a central factor in the political decision-making with regards to the financial support of international family planning. ^ One factor that may sway policy-makers' decisions is the influence of ideological interest groups, Political Action Committees funding of candidates in relation to votes on bills that impacted on financial support of international family planning and the amount spent by these groups on lobbyist was reviewed. Pro-choice funding of candidates was greater for the four of the fives votes supporting family planning. Pro-Choice lobbyist spending was $185,000 vs. $8,184,000 spent by Pro-Life ideological groups. ^

Everyone is; should healthcare? Outsourcing: Issues in strategic planning, organizational culture, and organizational ethics

Expenditures for personal health services in the United States have doubled over the last decade. They continue to outpace the growth rate of the gross national product. Costs for medical care have steadily increased at an annual rate well above the rate of inflation and have gradually outstripped payers' ability to meet their premiums. This limitation of resources justifies the ongoing healthcare reform strategies to maximize utilization and minimize costs. The majority of the cost-containment effort has focused on hospitals, as they account for about 40 percent of total health expenditures. Although good patient outcomes have long been identified as healthcare's central concern, continuing cost pressures from both regulatory reforms and the restructuring of healthcare financing have recently made improving fiscal performance an essential goal for healthcare organizations. ^ The search for financial performance, quality improvement, and fiscal accountability has led to outsourcing, which is the hiring of a third party to perform a task previously and traditionally done in-house. The incomparable nature and overwhelming dissimilarities between health and other commodities raise numerous administrative, organizational, policy and ethical issues for administrators who contemplate outsourcing. This evaluation of the outsourcing phenomenon, how it has developed and is currently practiced in healthcare, will explore the reasons that healthcare organizations gravitate toward outsourcing as a strategic management tool to cut costs in an environment of continuing escalating spending. ^ This dissertation has four major findings. First, it suggests that U.S. hospitals in FY2000 spent an estimated $61 billion in outsourcing. Second, it finds that the proportion of healthcare outsourcing highly correlates with several types of hospital controlling authorities and specialties. Third, it argues that healthcare outsourcing has implications in strategic organizational issues, professionalism, and organizational ethics that warrant further public policy discussions before expanding its limited use beyond hospital “hotel functions” and back office business processes. Finally, it devises an outsourcing suitability scale that organizations can utilize to ensure the most strategic option for outsourcing and concludes with some public policy implications and recommendations for its limited use. ^

Planning and implementation efficacy as a determinant of health risk communication outcomes: Case studies of the U.S. Public Health Service (PHS)

This study was conducted under the auspices of the Subcommittee on Risk Communication and Education of the Committee to Coordinate Environmental Health and Related Programs (CCEHRP) to determine how Public Health Service (PHS) agencies are communicating information about health risk, what factors contributed to effective communication efforts, and what specific principles, strategies, and practices best promote more effective health risk communication outcomes.^ Member agencies of the Subcommittee submitted examples of health risk communication activities or decisions they perceived to be effective and some examples of cases they thought had not been as effective as desired. Of the 10 case studies received, 7 were submitted as examples of effective health risk communication, and 3, as examples of less effective communication.^ Information contained in the 10 case studies describing the respective agencies' health risk communication strategies and practices was compared with EPA's Seven Cardinal Rules of Risk Communication, since similar rules were not found in any PHS agency. EPA's rules are: (1) Accept and involve the public as a legitimate partner. (2) Plan carefully and evaluate your efforts. (3) Listen to the public's specific concerns. (4) Be honest, frank, and open. (5) Coordinate and collaborate with other credible sources. (6) Meet the needs of the media. (7) Speak clearly and with compassion.^ On the basis of case studies analysis, the Subcommittee, in their attempts to design and implement effective health risk communication campaigns, identified a number of areas for improvement among the agencies. First, PHS agencies should consider developing a focus specific to health risk communication (i.e., office or specialty resource). Second, create a set of generally accepted practices and guidelines for effective implementation and evaluation of PHS health risk communication activities and products. Third, organize interagency initiatives aimed at increasing awareness and visibility of health risk communication issues and trends within and between PHS agencies.^ PHS agencies identified some specific implementation strategies the CCEHRP might consider pursuing to address the major recommendations. Implementation strategies common to PHS agencies emerged in the following five areas: (1) program development, (2) building partnerships, (3) developing training, (4) expanding information technologies, and (5) conducting research and evaluation. ^

THE DECLINE OF ISCHEMIC HEART DISEASE MORTALITY IN TEXAS: HEALTH PLANNING IMPLICATIONS

This is a report on an empirical study of the decline of ischemic heart disease mortality in the State of Texas. The study period was from 1970 to 1977. The data was collected and analyzed at three different levels of analysis: state, health service area (HSA), and county. The study was designed to test five main hypotheses. They serve to test the role of the medical care system as a possible factor associated with the changing ischemic heart disease mortality trends.^ The principal findings of the study were that a reasonable relationship could be found between the number of emergency medical care personnel, the number of icu-ccu beds, the number of medical specialists and the percent of hospitals with icu-ccu and the decline in ischemic heart disease mortality for the State of Texas. However, non significant relationships were found between variables in the medical care system and ischemic heart disease mortality trends, at the health service area level of analysis. More specifically, the number of coronary care unit beds was found to be negatively correlated with the decline in ischemic heart disease mortality at the county level.^ While being limited in its scope, the study suggests that certain factors (emergency medical service, icu-ccu beds, percent of icu-ccu units, and medical specialists) have been shown to be associated with the observed decline in ischemic heart disease mortality. The study also suggests many avenues of future research that need to be explored. ^

THE APPLICATION OF CIRRHOSIS MORTALITY AND SUICIDE MORTALITY AS INDICATORS FOR ALCOHOLISM PLANNING

This study provides a review of the current alcoholism planning process of the Houston-Galveston planning process of the Houston-Galveston Area Council, an agency carrying out planning for a thirteen county region in surrounding Houston, Texas. The four central groups involved in this planning are identified, and the role that each plays and how it effects the planning outcomes is discussed.^ The most substantive outcome of the Houston-Galveston Area Council's alcoholism planning, the Regional Alcoholism/Alcohol Abuse Plan is examined. Many of the shortcomings in the data provided, and the lack of other data necessary for planning are offered.^ A problem oriented planning model is presented as an alternative to the Houston-Galveston Area Council's current service oriented approach to alcoholism planning. Five primary phases of the model, identification of the problem, statement of objectives, selection of alternative programs, implementation, and evaluation, are presented, and an overview of the tasks involved in the application of this model to alcoholism planning is offered.^ A specific aspect of the model, the use of problem status indicators is explored using cirrhosis and suicide mortality data. A review of the literature suggests that based on five criteria, availability, subgroup identification, validity, reliability, and sensitivity, both suicide and cirrhosis are suitable as indicators of the alcohol problem when combined with other indicators.^ Cirrhosis and suicide mortality data are examined for the thirteen county Houston-Galveston Region for the years 1969 through 1976. Data limitations preclude definite conclusions concerning the alcohol problem in the region. Three hypotheses about the nature of the regional alcohol problem are presented. First, there appears to be no linear trend in the number of alcoholics that are at risk of suicide and cirrhosis mortality. Second, the number of alcoholics in the metropolitan areas seems to be greater than the number of rural areas. Third, the number of male alcoholics at risk of cirrhosis and suicide mortality is greater than the number of female alcoholics.^