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The identification and preservation of parathyroid glands (PGs) during thyroid surgery can be challenging. Many techniques have been developed to help surgeons find PGs. We have developed a novel mitoxantrone hydrochloride injection that can be used for lymphatic targeting. After local application during surgery, mitoxantrone hydrochloride injection for tracing (MHI) helps surgeons better identify and preserve PGs and helps pathologists find more lymph nodes. We conducted an open-label, multicenter, randomized clinical trial (CTR20171137) in six centers in China from 08/2017 to 12/2018. Patients with thyroid carcinoma were randomized to the MHI group or the control group. All patients received total thyroidectomy and bilateral central compartment lymph node dissection. The primary outcomes were the PG resection rate and lymph node staining rate. The full analysis set (FAS) included 461 patients, of which 228 were assigned to the MHI group, and 233 were assigned to the control group. The PG resection rates of the MHI group and the control group were 6.6% (15/228) and 26.6% (62/233), respectively, with a significant difference (P < 0.001). No PGs were stained blue with MHI. The central lymph nodes were stained blue with MHI, and the staining rate was 90.5%±12.0%. More lymph nodes were detected in the MHI group than in the control group (13.0±7.3 vs. 10.1±6.4 nodes/patient, P < 0.001). No adverse events related to MHI were observed. MHI is a safe and effective tracer that may help to preserve PGs and identify more central lymph nodes in patients with thyroid cancer.

It has been appreciated for some time that low oxygen activity is required for effective steel desulphurization, and recently this has been recognized for hot metal desulphurization. In the present experiments, calcium carbide was injected into 70 kg melts of iron during which desulphurization and deoxidation were studied by continuously measuring oxygen activity and frequently sampling for sulphur content. In some experiments, carbon dioxide was used either as a carrier gas or as generated from calcium carbide/limestone mixtures. The experiments confirmed that the oxygen activity in hot metal was controlled by the silicon-silica equilibrium, except when aluminum was added. It was found that the rate of desulphurization was associated with the oxygen activity. The desulphurization rate increased as oxygen activities decreased in order from carbon dioxide-containing injections into iron-carbon-silicon melts, to calcium carbide/nitrogen injections into iron-carbon-silicon melts, to finally calcium carbide/nitrogen injected into iron-carbon-aluminum melts. The dependence of the incubation period with the melt oxygen activity was recognized. The incubation times coincide with periods of deoxidation before desulphurization proceeds. In order to interpret the experimental results, a kinetic model was developed that takes simultaneous desulphurization and deoxidation into account. This model demonstrates clearly that the rate of desulphurization is controlled by the melt oxygen activity and the powder feed rate. Thus, low oxygen is required for effective hot metal desulphurization. In a log h$\sb{\rm o}$-log h$\sb{\rm s}$ diagram, the refining trajectories determined from the kinetic model were found to be consistent with those obtained from the experiments. From the model calculations, it was found that the commercial calcium carbide which normally contains 30 per cent of lime can be employed for the melts pre-deoxidized with silicon or aluminum, without causing significant delay of desulphurization. Another aspect of this work is the particle-liquid contact. The contact was measured by monitoring the melt temperature during injection, and applying calorimetric principles to analyze the results. It was found that a significant fraction of particles does not come in contact with the melt during their rise through it. The particle-liquid contact fraction is approximately 30-50 per cent. The same conclusion was obtained by analyzing the experimental rate constants of desulphurization on the basis of mass transfer theory. Doctor of Philosophy (PhD)