| dc.description.abstract |
<p>Numerous studies have shown that the combination of radiation therapy and hyperthermia,
when delivered at moderate temperatures (40°-45°C) for sustained times (30-90 minutes),
can help to provide palliative relief and augment tumor response, local control, and
survival. However, the dependence of treatment success on achieved temperature highlights
the need for accurate thermal dosimetry, so that the prescribed thermal dose can be
delivered to the tumor. This can be achieved noninvasively with MR thermometry.
However, there are many challenges to performing MR thermometry in the breast, where
hyperthermia of locally advanced breast cancer can provide a benefit. These include
magnetic field system drift, fatty tissue, and breathing motion.</p>
<p>The purpose of this research was to develop a system for the hyperthermia treatment
of LABC while performing MR thermometry. A hardware system was developed for performing
the hyperthermia treatment within the MR bore. Methods were developed to correct
for magnetic field system drift and to correct for breath hold artifacts in MR thermometry
of the tumor using measurement of field changes in fat references. Lastly, techniques
were developed for measuring temperature in the fatty tissue using multi-echo fat
water separation methods, reducing the error of performing MR thermometry in such
tissues. All of these methods were characterized with phantom and in vivo experiments
in a 1.5T MR system. </p>
<p>The results of this research can provide the means for successful hyperthermia
treatment of LABC with MR thermometry. With this thermometry, accurate thermal doses
can be obtained, potentially providing improved outcomes. However, these results
are not only applicable in the breast, but can also be used for improved MR thermometry
in other areas of the body, such as the extremities or abdomen.</p>
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