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Nathan C Hall

Publications and source records attributed to Nathan C Hall.

7 recordsLinked to original sources
PubMed2006

Prospective randomized clinical trial comparing intradermal, intraparenchymal, and subareolar injection routes for sentinel lymph node mapping and biopsy in breast cancer.

BACKGROUND: Multiple injection routes, including intradermal (ID), intraparenchymal (IP), and subareolar (SA), are used for 99mTc-sulfur colloid administration for sentinel lymph node (SLN) mapping and biopsy in breast cancer. The aim of this study was to compare localization by ID, IP, and SA injection routes based on preoperative lymphoscintigraphy and intraoperative identification. METHODS: Four hundred prospectively randomized breast cancers underwent SLN mapping and biopsy. RESULTS: Preoperative lymphoscintigraphy demonstrated localization to the axilla in 126/133 (95%) ID, 82/132 (62%) IP, and 96/133 (72%) SA (P < 0.001 ID vs. IP and ID vs. SA; P = 0.081 IP vs. SA), with a mean duration of preoperative lymphoscintigraphy of 139 +/- 18 minutes. Mean time to first localization when localization was demonstrated on preoperative lymphoscintigraphy was 8 +/- 14 minutes for ID, 53 +/- 49 for IP, and 22 +/- 29 for SA (P < 0.001 ID vs. IP and ID vs. SA; P = 0.003 IP vs. SA). Intraoperative identification of a SLN at the time of SLN biopsy was successful in 133/133 (100%) ID, 121/134 (90%) IP, and 126/133 (95%) SA (P < 0.001 ID vs IP; P = 0.014 ID vs. SA; P = 0.168 IP vs. SA), with a mean time from injection of 99mTc-sulfur colloid to start of SLN biopsy of 288 +/- 71 minutes. Mean intraoperative time to harvest the first SLN was 9 +/- 4 minutes for ID, 13 +/- 6 for IP, and 12 +/- 6 for SA (P < 0.001 ID vs. IP and ID vs. SA; P = 0.410 IP vs. SA). CONCLUSIONS: The ID injection route demonstrated a significantly greater frequency of localization, decreased time to first localization on preoperative lymphoscintigraphy, and decreased time to harvest the first SLN. This represents the first prospective randomized clinical trial to confirm superiority of the ID route for administration of 99mTc-sulfur colloid during SLN mapping and biopsy in breast cancer.

Breast Neoplasms↗
PubMed2004

The role of attributional retraining and elaborative learning in college students' academic development.

In the present longitudinal study, the authors examined the impact of attributional retraining (AR) techniques on academic motivation and achievement for college students who are either frequently or infrequently using elaborative learning strategies. During the 1st semester, 203 students completed an initial questionnaire assessing elaborative learning followed by 1 of 3 treatment conditions (No AR, Writing AR, Aptitude Test AR). Results indicated improvements in students' end-of-year perceptions of control, success, and emotions, as well as course-specific and overall academic performance for those receiving either AR format, with "high elaborators" showing higher levels on these measures than "low elaborators." The authors discussed the importance of elaborative and attributional processes underlying the effectiveness of the AR treatment and the potential utility of individualized AR techniques in the college classroom.

Achievement↗
PubMed2004

PET/CT today and tomorrow.

UNLABELLED: Accurate anatomic localization of functional abnormalities seen with PET is known to be problematic. Even though nonspecific tracers such as 18F-FDG visualize certain normal anatomic structures, the spatial resolution is generally inadequate for localization of pathology. Combining PET with a high-resolution anatomic imaging modality such as CT can resolve the localization issue, as long as the images from the two modalities are accurately coregistered. However, software-based registration techniques have difficulty accounting for differences in patient positioning and involuntary movement of internal organs, often necessitating labor-intensive nonlinear mapping that may not converge to a satisfactory result. Acquiring both CT and PET images in the same scanner obviates the need for software registration and routinely provides accurately aligned images of anatomy and function in a single scan. DISCUSSION: A CT scanner positioned in tandem with a PET scanner and with a common patient couch and operating console has recently been explored as a solution to anatomic and functional image registration. Axial translation of the couch between the two modalities enables both CT and PET data to be acquired during a single imaging session. In addition, the CT images can be used to generate noiseless attenuation correction factors for the PET emission data. By minimizing patient movement between the CT and PET scans, and after accounting for the axial separation of the two modalities, accurately registered anatomic and functional images can be obtained. Since the introduction of the first PET/CT prototype a little over 5 years ago, several thousand cancer patients have been scanned on combined PET/CT devices. In the past 3 years, a number of commercial designs have become available featuring multidetector spiral CT scanners and high-performance PET devices. Initial experience has demonstrated an increased level of accuracy and confidence in the interpretation of the combined study compared with separate readings, particularly in the ability to distinguish pathology from normal physiologic uptake and to precisely localize abnormal foci. CONCLUSION: Combined PET/CT scanners represent an important evolution in technology that is helping to bring molecular imaging to the forefront in cancer diagnosis, staging, and therapy monitoring.

Humans↗
PubMed2003

Minimally invasive parathyroidectomy: how effective is preoperative sestamibi scanning?

Minimally invasive parathyroidectomy (MIP) guided by preoperative sestamibi scanning has been shown to reduce operative time, hospital stay, and cost in treating primary hyperparathyroidism. However, controversy exists over routine preoperative sestamibi scanning. The purpose of this study was to determine the utility of sestamibi scanning at our institution as part of the MIP protocol and to analyze calcium and parathyroid hormone levels as possible predictors of successful sestamibi scanning. Charts of 37 consecutive patients undergoing MIP at our institution were reviewed, and age, sex, preoperative calcium, and parathyroid (PTH) levels, invasiveness of procedure, and pathologic diagnosis were recorded. Sestamibi scans were reviewed and scored by 4 nuclear medicine faculty based on the level of suspicion for parathyroid adenoma. Neither calcium nor PTH correlated significantly with sestamibi scan score (Spearman coefficient, r = 0.075, P = 0.67 and r = 0.277, P = 0.10, respectively). Receiver-operating-characteristic (ROC) analysis showed sestamibi scanning to have sensitivity and specificity in predicting MIP completion (87% and 68%). Logistic regression showed only sestamibi scan (P = 0.038), not calcium or PTH (P = 0.977 and P = 0.767) to be predictive of MIP completion. In conclusion, sestamibi scanning effectively predicted the ability to perform MIP. However, preoperative calcium and PTH predicted neither sestamibi scan results nor completion of MIP.

Adenoma↗
PubMed2002

Protein oxidation and heme oxygenase-1 induction in porcine white matter following intracerebral infusions of whole blood or plasma.

Spontaneous or traumatic intracerebral hemorrhage (ICH) in the white matter of neonates, children and adults causes significant mortality and morbidity. The detailed biochemical mechanisms through which blood damages white matter are poorly defined. Presently, we tested the hypothesis that ICH induces rapid oxidative stress in white matter. Also, since clot-derived plasma proteins accumulate in white matter after ICH and these proteins can induce oxidative stress in microglia in vitro, we determined whether the blood's plasma component alone induces oxidative stress. Lastly, since heme oxygenase-1 (HO-1) induction is highly sensitive to oxidative stress, we also examined white matter HO-1 gene expression. We infused either whole blood or plasma (2.5 ml) into the frontal hemispheric white matter of pentobarbital-anesthetized pigs ( approximately 1 kg) over 15 min. We monitored and controlled physiologic variables and froze brains in situ between 1 and 24 h after ICH. White matter oxidative stress was determined by measuring protein carbonyl formation and HO-1 gene expression by RT-PCR. Protein carbonyl formation occurred rapidly in the white matter adjacent to both blood and plasma clots with significant elevations (3- to 4-fold) already 1 h after infusion. This increase remained through the first 24 h. HO-1 mRNA was rapidly induced in white matter with either whole blood or plasma infusions. These results demonstrate that not only whole blood but also its plasma component are capable of rapidly inducing oxidative stress in white matter. This rapid response, possibly in microglial cells, may contribute to white matter damage not only following ICH, but also in pathophysiological states in which blood-brain-barrier permeability to plasma proteins is increased.

Animals↗
PubMedDate not supplied

Image-guided cancer therapy using PET/CT.

Functional imaging with positron emission tomography (PET) is playing an increasingly important role in the diagnosis and staging of malignant disease, image-guided therapy planning, and treatment monitoring. PET scanning with the radiolabeled glucose analogue (18)F-fluorodeoxyglucose ((18)FDG) is a relatively recent addition to the clinically available technology for imaging cancer, complementing the more conventional anatomical imaging modalities of computed tomography (CT) and magnetic resonance (MR). These modalities are complementary in the sense that CT provides accurate localization of organs and lesions while PET maps both normal and abnormal tissue function. When combined, the two modalities can identify and localize functional abnormalities. Attempts to align CT and PET data sets with fusion software are generally successful in the brain, whereas the remainder of the body is more challenging owing to the increased number of possible degrees of freedom between the two scans. Recently these challenges have been addressed by the introduction of the combined PET/CT scanner, a hardware-oriented approach to image fusion. With this device, accurately registered anatomical and functional images can be acquired for each patient in a single scanning session. Currently, over 400 combined PET/CT scanners are installed in medical institutions worldwide, almost all of them for the diagnosis and staging of malignant disease. However, the real impact of this technology undoubtedly will be for cancer therapy, where PET/CT images will be used to guide biopsies and assist in surgical intervention, to define target volumes for radiation therapy and optimize dose, and to monitor response to chemotherapy and establish individualized patient treatment strategies.

Fluorodeoxyglucose F18↗