Nuclear Medicine

With the advent of newly and more reliably designed targeted therapy methods in the past several years, targeted radionuclide therapy has attracted more attentions around the world as a more reliable treatment modality in combination with other well established traditional cancer treatments i.e., external beam radiotherapy and chemotherapy. Alpha particles have a high relative biological effectiveness (RBE) due to their high linear energy transfer (LET). However, to utilize them for therapeutic purposes, precise human body dosimetry calculation is required. The measurement of their uptake and biodistribution can be quite challenging. Also, due to the complex biology of different types of cells, their shapes and functions, there is not a simple and clear understanding of the mechanism of action that fits all. This study aims to estimate and compare the human organ dosimetry of the alpha emitter, 212Pb, from animal data assuming that it is conjugated with three different types of commonly used targeting nanoparticles. For this purpose, the pre-published animal data of three different radionuclide labeled peptide, antibody, and small molecule carriers were selected and converted to human data. Then a compartmental model was designed for each of them to fit the model to the human data with 212Pb, half-life of 10.64 hours. Once each model reached the desired fit, the area under the curves were extracted then the estimated human organ dosimetry calculations took place via the MIRD scheme. The organ dosimetry results for 212Pb + three different carriers are presented in Tables 14, 17, and 20.

We report here the development of a Lewis acid catalyzed method for the dehydrative
coupling of cyclic alcohols and nitriles to form amides with retention of configuration.
By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction)
usually affords racemic product. The present reaction was accomplished by first
converting alcohol starting materials to their corresponding chlorosulfites in situ. Even
after an extensive search, only copper (II) salts were able to produce the desired
conversion of these chlorosulfites to amides though with low catalytic turnover.
Improving the turnover without deteriorating the stereochemical outcome was eventually
accomplished by a careful selection of the reagent addition sequence and through the
removal of gaseous byproducts. This Ritter-like coupling reaction proceeds in good
yields with secondary cyclic alcohols under mild conditions. The stereochemical outcome likely due to fast nucleophilic capture of a non-planar carbocations (hyperconjomers)
stabilized by ring hyperconjugation.

Common methods for commissioning linear accelerators often neglect beam data for small fields. Examining the methods of beam data collection and modeling for commissioning linear accelerators revealed little to no discussion of the protocols for fields smaller than 4 cm x 4 cm. This leads to decreased confidence levels in the dose calculations and associated monitor units (MUs) for Intensity Modulated Radiation Therapy (IMRT).
The parameters of commissioning the Novalis linear accelerator (linac) on the Eclipse Treatment Planning System (TPS) led to the study of challenges collecting data for very small fields. The focus of this thesis is the examination of the protocols for output factor collection and their impact on dose calculations by the TPS for IMRT treatment plans. Improving output factor collection methods, led to significant improvement in absolute dose calculations which correlated with the complexity of the plans.