published_or_final_version / abstract / Surgery / Master / Master of Surgery

In this dissertation, a new reconstruction algorithm to estimate the complete temperature field during hyperthermia is developed which relies upon a limited amount of transient measured temperature data. The predictive capabilities of this new algorithm are then systematically studied; first using one-dimensional simulated treatments, then using three-dimensional simulated treatments, and finally applying it to hyperthermia treatments of normal canine thighs. It was found that this new algorithm predicts the complete temperature fields more accurately and robustly than the steady-state approach. In particular, it can better predict the complete temperature fields in situations where the number of unknown blood perfusion parameters are greater than the number of available temperature sensors. It was also found that the steady-state temperature field could be estimated to within 1°C if there was no measurement noise, no model mismatch, and as few as three measurement locations for seven perfusion zones. The addition of measurement noise degraded the performance of this estimation algorithm especially when the number of measurement locations was small. It was found that use of Tikhonov regularization of order zero significantly improved the performance of the algorithm and that there was an optimal choice for the regularization parameter. For the animal experiments, normal canine thighs were instrumented with one-hundred twelve thermocouples and heated to steady-state using a 6 cm planar ultrasound transducer operating at 0.5 MHz: then the power was turned off and the transient cool down temperature data was stored for later use by the reconstruction algorithm. Only a subset of the one-hundred twelve measurements was used as input to the reconstruction algorithm. The remaining measurements were used to compare the results of the reconstruction algorithm with the true temperatures. The results showed that in general the predicted perfusion and reconstructed temperature field did not change significantly as sensors were removed. However, the error was quite large for some of the situations studied particularly when only twenty-seven piecewise constant regions of perfusion were used. Increasing the number of perfusion regions reduced this error suggesting that model mismatch had contributed significantly to the error.

Two experimental dynamic phantoms have been used for studying temperature distributions induced by interstitial ferromagnetic implant hyperthermia at various blood perfusions, Curie point implants, and input power levels. One of the phantoms is an axially perfused hollow cylinder filled with 3 mm diameter glass beads, and the other is a similar cylinder model that is radially perfused. Analytic models have been developed for evaluating temperature profiles within the two phantoms. Experimental results from the phantoms compare reasonably well with the analytical results. A qualitative comparison is made between thermal profiles derived from both a convection energy equation, for a homogeneous porous medium, and a bioheat transfer equation. The adequacy of using a porous material for simulating living tissue is discussed. Parametric studies showing the effects of various implant parameters such as Curie point and applied power are analyzed.

No description available.

Thesis (doctoral)--Department of Physics, Lund Institute of Technology, 1998. / "October 1998." Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Department of Physics, Lund Institute of Technology, 1998. / "October 1998." Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Kenneth R. Diller. Vita. Includes bibliographical references.

M.Tech. (Chiropractic) / Introduction: Myofascial pain syndrome is often seen in clinical practice as a cause for pain. It is characterized as a dull ache to a burning pain that can cause referral of pain to other areas of the body (Travell and Simons, 1999). One method used to treat this, is by dry-needling therapy (DNT). DNT has proved to be effective in the treatment of myofascial pain, but it has shown to cause post needling soreness. This soreness discourages many patients from receiving further dry-needling or treatment (Kamanli et al. 2005). Ways to help alleviate post-soreness are heat, stretching, ultrasound and application of pressure (Fleckenstein et al. 2010). All these modalities are done after the needle has been removed. This then adds an extra modality to the treatment as well as increased treatment time; therefore these modalities are often skipped by practitioners (Hong, 1994). Another factor to look at is that many of these modalities have not been researched objectively for effectiveness on relieving the post-needling soreness (Kamanli et al. 2005). Using a moxi cigar, placed on top of the acupuncture needle whilst inserted into the active trigger point is a way in which heat as a modality to treat post-needling soreness can be combined into the needling time. Aim of study: The aim was to investigate if heat conduction using a moxi cigar is an effective modality in alleviating post-needling soreness when treating myofascial pain syndrome with DNT. Methodology: The trial comprised of 90 participants divided randomly into three equal groups. Group 1 received DNT of active trigger point 1 of the trapezius muscle only. Group 2 received DNT of active trigger point 1 of the trapezius muscle, with the addition of the burning moxi cigar to conduct heat through the acupuncture needle to the trigger point. Group 3 received DNT of active trigger point 1 of the trapezius muscle, followed by 5 minutes of ultrasound therapy over the acupoint. Each participant was treated once with readings being recorded pre-treatment, post-treatment and then final readings were taken 24 hours post-treatment. Subjective data was in the form of a numerical pain scale questionnaire and a pain diary. Objective data was CROM and algometer readings. Data analysis: data collected by the researcher was analyzed with the help of a statistician at STATKON at the University of Johannesburg. After consultation, it was concluded that results would be analyzed using Shapiro-Wilk test for normality and Levene’s test for equal variances. For all objective data collected, parametric testing would be used on objective data. The parametric tests used were: One way Anova and Post Hoc test. For subjective data, non-parametric testing was used on subjective data namely: Kruskal Wallis, Wilcoxon-signed rank and Mann-Whitney U test. Conclusion: Based on the results, clinically, the study showed that dry needling with the addition of ultrasound or moxibustion, as a treatment for post-needling soreness did appear to have better results. The use of these two added modalities did ease post-needling soreness which for many patients is the reason they don’t wish to receive further dry-needling treatment. When using moxibustion the post-needling soreness is eased. This added treatment can be used during the dry needling and does not require additional treatment time for the practitioner or for the patient. To conclude, the efficacy of using a moxibustion to alleviate post-needling soreness has been seen clinically. This treatment can be used with minimal addition treatment time and could be used in clinical practice.

Glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults and has a median survival of 13.4 months. Convection enhanced delivery (CED) has shown promise for the treatment of GBM by allowing intratumoral delivery of therapeutics, bypassing the blood brain barrier. A fiberoptic microneedle device (FMD) CED catheter enables simultaneous delivery of laser energy and therapeutic. The laser allows for heating of tissue in the region of infusion, called thermotherapy. Thermotherapy offers the advantages of increasing the volume of distribution (Vd) of the infusate, as well as facilitating intracellular penetration of the therapeutic. We hypothesize that heating of brain tissue will increase infusate Vd in ex vivo CED brain infusions. Methods: Formalin fixed mouse brains were infused by FMD-CED with Evans blue for 1 hour at 0.1 μl/min, at 22°C, 37°C and 42°C (n=4 brains/group). The Vd was determined and compared using one-way ANOVA. Results: FMD-CED performed at 42°C resulted in significantly higher mean Vd (4.90+2.2mm3; p =0.03) than those at 22°C (1.49+0.4 mm3), although no differences in Vd were observed between the other temperature groups. 42°C brains demonstrated interstitial and intracellular distribution, while rare intracellular distribution was noted in the other groups. Discussion: The Vd of FMD-CED infusions is facilitated by sub-lethal thermotherapy. This study indicates that thermotherapeutic enhancement of infusate Vd does not occur exclusively via vascular mechanisms. Thermotherapy facilitates advective-diffusion by decreasing interstitial fluid pressure and increasing transcellular fluid transport. These results were validated in a companion in vivo FMD-CED study in the rodent brain. / Master of Science

Surgically implanted thermoregulating ferromagnetic seeds as a mean of inducing hyperthermia in malignant tumors has been successfully introduced in a clinical environment at the University of Arizona. This work covers topics in quality assurance for the method on two levels. The first level deals with the magnetic induction system where magnetic and electric fields are measured. A discussion on safety levels for patients and treatment personnel is given, and an optically coupled probe for magnetic field measurements is described. The second level treats the electrical characteristics of the ferromagnetic seeds. Systems to measure the permeability and conductivity of the seeds are presented with some typical results. Finally, hysteresis power loss in a seed is measured and compared to losses due to eddy currents.