Browsing by Subject "Medical"

ABSTRACT

Lori Anne Brown

Duke Divinity School, 2015

Primary Advisor: Esther Acolatse

Assistant Professor of the Practice of Pastoral Theology and World Christianity

Secondary Advisor: Dean Sujin Pak

Assistant Research Professor of the History of Christianity; Associate Dean for Academic Programs

The purpose of this thesis is to examine the challenges that Christian chaplains experience to their authority in secular medical institutions and to explore possible recommendations that can help alleviate them. More specifically, by means of a questionnaire this examination intends to explore if these challenges are both or either personal or institutionally related. Therefore, this examination should be a resource that encourages the Christian chaplain to be an informed interlocutor pertaining to the issues of what his or her God-given authority means. Lastly, this thesis will demonstrate why it is essential for chaplains to know, understand, accept, and embrace the God-given authority bestowed upon them to minister effectively and competently in secular medical institutions.

Key Terms

For the purpose of this study, seven terms require annotation. First, the term “Christian chaplains” refers to individuals who have been baptized, profess Jesus Christ as their Lord and Savior, who ascribe to the orthodoxy and orthopraxis of the Christian faith, and who minister in secular medical institutions. Second, the term “secular medical institution” denotes a public, non-religious institution that provides medical care for people. Thirdly, the term “living human document,” which was coined by Anton Boisen, refers to those to whom Christian chaplains minister. This group includes patients, their families and friends, and the chaplain’s colleagues. Fourth, the term “voices of suffering” refers to the patients who share their narratives while seeking pastoral care. Fifth, the term “bearing witness” refers to the belief that as Christians we are called to develop the skills to bear witness in both word and deed to the gospel of Jesus Christ. Sixth, the term “narratives” refers to the personal stories that patients share. The seventh term “holistic care” is a concept in medical practice that upholds and respects all aspects of a person’s needs: physical, emotional, and spiritual.

I employed three methods in this thesis. The first method was exploratory research to review and study literature to support my argument. The second was to use a method of analogy. In this method, the anecdotal evidence was aggregated in correlation with personal related experiences to help Christian chaplains to learn how to minister effectively in the challenging contexts of the secular medical institution. Moreover, this was done in order to examine how the Christian chaplain can learn to walk competently and effectively with authority between the worlds of religion and medicine. Third, I used a confidential questionnaire to gather additional information from seven Christian chaplains who have ministered or are currently ministering in this context to support the argument of this thesis, as well as to offer recommendations that can help alleviate some of the challenges they experience regarding their authority.

The basic conclusion drawn from the examination and methods employed is that Christian chaplains do experience various types of challenges to their authority than can impact their ministry. However, the conclusion demonstrates that as a result to their commitment to the call of chaplaincy, chaplains recognize that irrespective of the challenges they experience to their authority they are called to compassionately and effectively serve the sick and suffering. Moreover, as a result of their commitment to the call of health care chaplaincy, the chaplains have provided their insight that indicates why some of these challenges exist. Lastly, as a result of the questionnaire the participants provide some practical recommendations that can be implemented into CPE programs, which could possibly help alleviate some of types of the challenges they encounter to their pastoral authority.

Theranostics is an evolving approach in nuclear medicine that aims to combine diagnostic and therapeutic value into a single agent of delivery. With increased interest in alpha-emitting radionuclides for their short effective range and high linear energy transfer, astatine-211 is a promising radionuclide for therapy applications. Previously at Duke University, the ability to image and quantitate images of astatine-211 was investigated and determined to be a challenge due to attenuation and collimation effects on desired photons for imaging, and undesirable high energy emission contributions. This research builds on that previous work to investigate the image quality extent of single photon planar and SPECT imaging for astatine-211 when considering relevant organs that could be at risk for radiation damage based on the distribution of the molecule carrying the At-211. The investigation is broken down into several experiments that provide the basis for understanding the potential of astatine-211 to perform as an imaging radionuclide, and the needed factors for image reconstruction including the appropriate linear attenuation coefficient and k-factor for dual-energy scatter correction. Two phantom designs were created. One was used to provide a baseline image quality comparison of four radionuclides (F-18 for PET, Tc-99m, Lu-177, and At-211 for single photon planar imaging). The other represented the salivary glands in the head and kidneys and tumors in the torso. Imaging the same realistically large phantom showed that only the fluorine-18 PET images 1 cm targets successfully, while technetium-99m and lutetium-177 are comparable in imaging 2 cm and 3 cm targets, and astatine-211 can only image 3 cm targets. This work successfully simulated the salivary glands and kidneys in an anthropomorphic phantom. The results indicated that the use of a k-factor of 1.1 is reasonable in the scatter correction of imaging astatine-211, which effectively reduced downscattered gamma rays in the images. Additionally, the results confirm that the medium energy general purpose collimator is better suited than the low energy high resolution collimator for imaging astatine-211 with improved SNR and comparable noise quality.

The electrical interface to neural medical devices is researched from three perspectives, namely, the electronics within the device, the electrodes on the device, and the electromagnetic fields around the device.

A Brain-Machine Interface may allow paralyzed patients to control robotic limbs with neural signals sensed by fine wires inserted into the brain. The neural signals have an amplitude under one millivolt and must be amplified. A totally integrated amplifier is designed, manufactured, and characterized. The amplifier is fabricated in a standard half-micron CMOS process without capacitors or resistors. Two application issues not previously addressed are solved. First, the topology of the amplifier is shown to be less sensitive to long-term drift of transistor parameters than the standard topology. Second, a neural signal corrupted by 10 millivolts of powerline interference can be recovered. The amplifier has a gain of 58 dB, a bandwidth of 750 to 14k Hz, power consumption of 180 uW, and noise of 1.5 uV RMS. The design techniques proven in this amplifier are suitable for clinical Brain Machine Interfaces.

An implanted electroencephalogram (EEG) recorder may aid the diagnosis of infrequent seizure-like events that are currently diagnosed, without proof, as epilepsy. A proof-of-concept study quantifies the electrical characteristics of the electrodes planned for the recorder. The electrodes are implanted in an ovine model for eight weeks. Electrode impedance is less than 800 Ohm throughout the study. A frequency-domain determination of sedation performs similarly for surface versus implanted electrodes throughout the study. The time-domain correlation between an implanted electrode and a surface electrode is almost as high as between two surface electrodes (0.86 versus 0.92). EEG-certified clinicians judge that the implanted electrode quality is at least adequate and that the implanted electrodes provide the same clinical information as surface electrodes except for a noticeable amplitude difference. No significant issues are found that invalidate the concept of an implanted EEG recorder.

Transcranial stimulation may treat a multitude of neural and psychological illnesses. The stimulation may have higher repeatability and lower patient effort if an implanted device provides the stimulation. The shape of the device, 300 mm long by 1 mm in diameter, is unlike any present implanted device. Five techniques that deliver energy to the device are analyzed using computer simulations. The electrode for the techniques that employ an electric field to deliver the energy is a new design that exploits the anatomy of the scalp and skull. The electric field techniques deliver energy that is likely suitable for some stimulation protocols but not for all. The techniques that employ a magnetic field deliver more than the energy required, especially if the shape of the coil that creates the magnetic field is automatically optimized. However, the magnetic-field techniques heat the brain; the electric-field techniques do not heat the brain. This research validates the new delivery concepts and justifies future research.

Purpose: To investigate the feasibility of the Log-Demons deformable image registration (DIR) method to correct eddy current and Echo Planar Imaging (EPI) distortions while preserving diffusion tensor information.

Methods: A phantom MR scan was conducted using a diffusion phantom scan (Diffusion Phantom Model 128, High Precision Devices, Inc) on a clinical 3T scanner. The scan includes a standard T1-weighted scan and a 20‐direction diffusion tensor imaging (DTI) scan, which consists of one data set with b=0s/mm2 and twenty diffusion-weighted data sets with b=1,000s/mm2. A Log-Demons DIR algorithm was applied to the DTI images for eddy current and EPI distortion correction based on the b=0s/mm2 and T1 weighted data sets and compared the eddy current and EPI distortion corrections along the phase encoding direction by affine and demons DIR algorithms. The Log-Demons framework is optimized based on both similarity and regularization. The registered images were analyzed using Cross-correlation (CC) and mutual information (MI) to assess the performances of distortion corrections by the DIR methods. Quantitative deviations from the original data after correction were also evaluated using the mean, and root mean square error (RMSE) for thirteen regions of interest in the Apparent Diffusion Coefficient (ADC) and Fractional Anisotropy (FA) maps.

The Log-Demons DIR algorithm was then applied to the MASSIVE dataset, which provides diffusion-weighted volumes divided into four sets with both positive (+) and negative(-) diffusion gradient directions and both AP and PA phase encoding directions. The registered images were analyzed using the mutual information (MI) and the absolute mean difference of two images with opposing gradient directions to assess the performances of distortion corrections by the DIR methods. Images with opposing gradient directions were compared when comparing eddy current distortions and images with opposing phase encoding directions were compared for EPI distortions.

Results: In the phantom study, the MI and CC were improved by 2.15%,0.89%, and 39.39% compared to no correction, and affine, and demons algorithm respectively when correction for eddy current distortions. MI and CC were improved by 8.89%, 9.33%, and 9.20% compared to no correction, and affine, and demons algorithm respectively when correction for EPI distortions. Analysis of the tensor metrics using percent difference and the RMS of the ADC and FA found that the Log-Demons algorithm outperforms the other algorithms in terms of preserving diffusion information.

In the MASSIVE study, the Log-demons DIR method outperformed the demons algorithm in terms of MI but underperformed compared to the affine registration for both eddy current and EPI distortions corrections. The absolute mean difference was decreased by 2.94%, 0.44%, and 1.53% compared to no correction, and affine, and demons algorithm respectively when correcting for eddy current distortions, and decreased by 0.39%, 8.03%, and 13.19% compared to no correction, and affine, and demons algorithm respectively when correcting for EPI distortions.

Conclusion: This work indicates that the Log-Demons DIR algorithm is feasible to reduce eddy current and EPI distortions while preserving quantitative diffusion information. Although demonstrated with a DTI phantom study and brain study, this method could be extended for areas in which diffusion-weighted imaging is beneficial.