http://hdl.handle.net/2027.42/78408 Tue, 18 Jun 2013 23:31:36 GMT 2013-06-18T23:31:36Z http://deepblue.lib.umich.edu:80/bitstream/id/280016/216680.gif http://hdl.handle.net/2027.42/78408 http://hdl.handle.net/2027.42/78152 Use of Integrated SPECT/CT Imaging for Tumor Dosimetry in I-131 Radioimmunotherapy: A Pilot Patient Study Dewaraja, Yuni K.; Wilderman, Scott J.; Koral, Kenneth F.; Kaminski, Mark S.; Avram, Anca M. Abstract Integrated systems combining functional (single-photon emission computed tomography; SPECT) imaging with anatomic (computed tomography; CT) imaging have the potential to greatly improve the accuracy of dose estimation in radionuclide therapy. In this article, we present the methodology for highly patient-specific tumor dosimetry by utilizing such a system and apply it to a pilot study of 4 follicular lymphoma patients treated with I-131 tositumomab. SPECT quantification included three-dimensional ordered-subset expectation-maximization reconstruction and CT-defined tumor outlines at each time point. SPECT/CT images from multiple time points were coupled to a Monte Carlo algorithm to calculate a mean tumor dose that incorporated measured changes in tumor volume. The tumor shrinkage, defined as the difference between volumes drawn on the first and last CT scan (a typical time period of 15 days) was in the range 5%-49%. The therapy-delivered mean tumor-absorbed dose was in the range 146-334cGy. For comparison, the therapy dose was also calculated by assuming a static volume from the initial CT and was found to underestimate this dose by up to 47%. The agreement between tracer-predicted and therapy-delivered tumor-absorbed dose was in the range 7%-21%. In summary, malignant lymphomas can have dramatic tumor regression within days of treatment, and advanced imaging methods allow for a highly patient-specific tumor-dosimetry calculation that accounts for this regression. Sat, 01 Aug 2009 00:00:00 GMT http://hdl.handle.net/2027.42/78152 2009-08-01T00:00:00Z http://hdl.handle.net/2027.42/78102 Thyroid Carcinoma Metastasis to Skull with Infringement of Brain: Treatment with Radioiodine Sisson, James C.; Dewaraja, Yuni K.; Wizauer, Eric J.; Giordano, Thomas J.; Avram, Anca M. Background: Infringement by differentiated thyroid carcinoma on the brain is rare but, when suspected, the patient deserves special attention. A patient with an enlarging metastasis of thyroid carcinoma to the skull that was impinging on the brain illustrates diagnostic and therapeutic strategies applicable to the treatment of metastatic carcinoma. Methods: A case study was performed. Computed tomography (CT) and magnetic resonance imaging (MRI) were done, serum thyroglobulin was measured, and tumor responses to thyroxine and 131I treatments were monitored. Tumor dosimetry, enabled by scintigraphy with 131I employing single photon emission tomography fused with CT (SPECT-CT), was performed. Results: The metastasis was from a follicular variant of papillary thyroid carcinoma. During thyrotropin stimulation the tumor enlarged. The tumor decreased in volume after each of two 131I therapies. Dosimetry indicated delivery of 1970 and 2870cGy to the tumor and 35 and 42cGy to the brain, respectively, in the two treatments. The patient has survived for more than 11 years since diagnosis. Conclusions: A metastasis from a follicular variant of papillary carcinoma increased in volume during hypothyroidism producing more infringement on the brain. Beyond the effects of thyroxine therapy, 131I treatments induced recession of tumor volume. In patients with metastases that concentrate 131I, dosimetry with SPECT-CT can predict absorbed doses of radiation to the tumor and to the adjacent organs and thus lay a basis for data-based decisions on 131I therapies. Therapy may induce prolonged survival in patients with metastases infringing on the brain. Sun, 01 Mar 2009 00:00:00 GMT http://hdl.handle.net/2027.42/78102 2009-03-01T00:00:00Z http://hdl.handle.net/2027.42/75749 Proprotein convertase expression and localization in epidermis: evidence for multiple roles and substrates Pearton, David J.; Nirunsuksiri, Wilas; Rehemtulla, Alnawaz; Lewis, S. Patrick; Presland, Richard B.; Dale, Beverly A. Specific proteolysis plays an important role in the terminal differentiation of keratinocytes in the epidermis and several types of proteases have been implicated in this process. The proprotein convertases (PCs) are a family of Ca 2+ -dependent serine proteases involved in processing and activation of several types of substrates. In this study we examined the expression and some potential substrates of PCs in epidermis. Four PCs are expressed in epidermis: furin, PACE4, PC5/6 and PC7/8. Furin is detected in two forms, either with or without the transmembrane domain, suggesting occurrence of post-translational cleavage to produce a soluble enzyme. In addition the furin active site has differential accessibility in the granular layer of the epidermis relative to the basal layer, whereas antibodies to the transmembrane domain stain both layers. These findings suggest that furin has access to different types of substrates in granular cells as opposed to basal cells. PC7/8, in contrast, is detected throughout the epidermis with antibodies to both the transmembrane and active site and no soluble form observed. A peptide PC inhibitor (dec-RVKR-CMK) inhibits cleavage of Notch-1, a receptor important in cell fate determination that is found throughout the epidermis. Profilaggrin, found in the granular layer, is specifically cleaved by furin and PACE4 in vitro at a site between the amino terminus and the first filaggrin repeat. This work suggests that the PCs play multiple roles during epidermal differentiation. Fri, 01 Jun 2001 00:00:00 GMT http://hdl.handle.net/2027.42/75749 2001-06-01T00:00:00Z http://hdl.handle.net/2027.42/75687 Basilar artery aneurysm treated with coil embolization via persistent primitive hypoglossal artery Bapuraj, J. R.; Ojili, V.; Khandelwal, N.; Shanbhogue, A. K. P.; Gupta, Sanjaya K. A saccular aneurysm at the basilar artery bifurcation associated with a persistent primitive hypoglossal artery (PPHA) was successfully treated by endovascular occlusion with Guglielmi detachable coils. As both vertebral arteries were aplasitc, a microcatheter was advanced via PPHA. To the best of our knowledge, this is the first case report describing the treatment of a basilar top aneurysm through the PPHA. Sat, 01 Dec 2007 00:00:00 GMT http://hdl.handle.net/2027.42/75687 2007-12-01T00:00:00Z