Alternative Means of Estimating I Maximum Permissible Activity to Treat Thyroid Cancer.

To protect bone marrow from overirradiation, the maximum permissible activity (MPA) of I to treat thyroid cancer is that which limits the absorbed dose to blood (as a surrogate of marrow) to less than 200 cGy. The conventional approach (method 1) requires repeated γ-camera whole-body measurements along with blood samples. We sought to determine whether reliable MPA values can be obtained by simplified procedures.

Influence of Multigland Parathyroid Disease on 99mTc-Sestamibi SPECT/CT.

Purpose: 99mcTc-sestamibi (MIBI) imaging is performed for preoperative parathyroid lesion localization in patients with primary hyperparathyroidism. Decreased sensitivity in multigland disease (MGD) compared with single-gland disease (SGD) is well recognized for planar and SPECT imaging, but few data are available on MIBI SPECT/CT in MGD.

Methods: We retrospectively analyzed 246 patients with primary hyperparathyroidism who underwent preoperative MIBI SPECT/CT.

Effect of reconstruction algorithms on the accuracy of (99m)Tc sestamibi SPECT/CT parathyroid imaging.

The superiority of SPECT/CT over SPECT for (99m)Tc-sestamibi parathyroid imaging often is assumed to be due to improved lesion localization provided by the anatomic component (computed tomography) of the examination. It also is possible that this superiority may be related to the algorithms used for SPECT data reconstruction. The objective of this investigation was to determine the effect of SPECT reconstruction algorithms on the accuracy of MIBI SPECT/CT parathyroid imaging.

Comparison of criteria to truncate gastric emptying tests.

Purpose: Standardized scintigraphic gastric emptying (GE) protocols to detect gastroparesis (GP) require collecting data for 4 h. This investigation was undertaken to compare seven methods to reduce the duration of the test.

Materials And Methods: This was a retrospective study of GE data collected using a standardized protocol at 0, 1, 2, 3, and 4 h for 602 patients being evaluated for GP.

Sestamibi parathyroid scintigraphy in multigland disease.

Purpose: For sestamibi (MIBI) studies in patients with primary hyperparathyroidism, some investigations found that the test sensitivity is lower in patients with multigland disease (MGD) than in those with single-gland disease (SGD), whereas other investigations reported that the sensitivity of MIBI imaging is similar in MGD and SGD. The objectives of this investigation, therefore, were to determine (a) whether there are differences in the sensitivity and specificity of MIBI imaging for detecting parathyroid lesions in patients with MGD and in patients with SGD, (b) whether there is a relationship between test sensitivity and the number of glands involved, (c) whether there are differences in weight between parathyroid lesions in MGD and SGD, (d) whether there are differences in lesion locations between MGD and SGD, and (e) whether MIBI sensitivity in MGD is related to the number, weight, or location of the lesions.

Materials And Methods: This was a retrospective investigation of data for 651 patients with biochemically confirmed primary hyperparathyroidism limited to the neck, who underwent preoperative parathyroid lesion localization using a dual tracer ⁹⁹mTc-MIBI/TcO₄⁻ protocol that included early and late planar pinhole ⁹⁹mTc-MIBI, pinhole thyroid imaging, image subtraction, and single photon emission computed tomography.

Adenosine triphosphate-binding cassette subfamily C member 2 is the major transporter of the hepatobiliary imaging agent (99m)Tc-mebrofenin.

Unlabelled: The organic anion (99m)Tc-N-[2-[(3-bromo-2,4,6-trimethylphenyl)-amino]-2-oxoethyl]-N-(carboxymethyl)-glycine ((99m)Tc-mebrofenin) and its analogs are widely used for hepatobiliary imaging. Identification of the mechanisms directing bile canalicular transport of these agents will provide insights into the basis of their hepatic handling for assessing perturbations.

Methods: We performed studies in animals, including healthy Fischer 344 rats or rats treated with carbon tetrachloride or intrasplenic cell transplantation and healthy Wistar rats or HsdAMC:TR-Abcc2 mutant rats in Wistar background.

Molecular pathway-specific 99mTc-N-(3-bromo-2,4,6-trimethyacetanilide) iminodiacetic acid liver imaging to assess innate immune responses induced by cell transplantation.

Objectives: Inflammatory responses after cell transplantation impair engraftment of transplanted cells. We studied whether perturbations in specific molecular pathways after inflammation in a syngeneic cell transplantation model could be identified by noninvasive imaging.

Methods: After transplanting hepatocytes into the liver of dipeptidyl peptidase IV-deficient Fischer 344 rats, we imaged hepatobiliary excretion of ppmTc-N-(3-bromo-2,4,6-trimethyacetanilide) iminodiacetic acid (99mTc-mebrofenin).

Pinhole versus parallel-hole collimators for parathyroid imaging: an intraindividual comparison.

Unlabelled: This study was undertaken to determine the effects of collimators on the accuracy of preoperative sestamibi parathyroid imaging of the neck.

Methods: Forty-nine patients with primary hyperparathyroidism underwent preoperative (99m)Tc-sestamibi parathyroid imaging. The protocol included early and late pinhole and parallel-hole imaging.

Preoperative parathyroid scintigraphic lesion localization: accuracy of various types of readings.

Purpose: To retrospectively compare the accuracy of various parathyroid scintigraphy readings for single-gland disease (SGD) and multigland disease (MGD) in patients with primary hyperparathyroidism, with histologic analysis as the reference standard.

Materials And Methods: Institutional review board approval was obtained for this HIPAA-compliant study. Records of 462 patients with primary hyperparathyroidism who underwent preoperative imaging with a technetium 99m ((99m)Tc) sestamibi and (99m)TcO4- protocol that consisted of early and late pinhole (99m)Tc sestamibi, pinhole thyroid imaging, image subtraction, and single photon emission computed tomography (SPECT) were retrospectively reviewed.

Systemic and local release of inflammatory cytokines regulates hepatobiliary excretion of 99mTc-mebrofenin.

Objectives: Imaging agents capable of providing cell compartment-specific information will facilitate studies of pathophysiological mechanisms, natural history of diseases, and therapeutic development. To demonstrate the effects of liver injury on the disposal of the organic anion mebrofenin, we performed animal studies.

Methods: Acute liver injury was induced in Fischer 344 rats with 0.

Phantom experiments to improve parathyroid lesion detection.

This investigation tested the hypothesis that visual analysis of iteratively reconstructed tomograms by ordered subset expectation maximization (OSEM) provides the highest accuracy for localizing parathyroid lesions using 99mTc-sestamibi SPECT data. From an Institutional Review Board approved retrospective review of 531 patients evaluated for parathyroid localization, image characteristics were determined for 85 99mTc-sestamibi SPECT studies originally read as equivocal (EQ). Seventy-two plexiglas phantoms using cylindrical simulated lesions were acquired for a clinically realistic range of counts (mean simulated lesion counts of 75 +/- 50 counts/pixel) and target-to-background (T:B) ratios (range = 2.

Diagnosing prosthetic vascular graft infection with the antigranulocyte antibody 99mTc-fanolesomab.

Aim: The objectives of this retrospective investigation were to determine the accuracy of 99mTc-fanolesomab, an antigranulocyte antibody, for diagnosing prosthetic vascular graft infection, ascertain optimum imaging times for this indication, and assess safety of this agent.

Methods: Eighteen patients with 19 prosthetic vascular grafts were included. Indications for graft placement included peripheral vascular disease (8), haemodialysis (7), and aneurysm (4).

Combined labeled leukocyte and technetium 99m sulfur colloid bone marrow imaging for diagnosing musculoskeletal infection.

The use of labeled leukocyte (white blood cell [WBC]) studies in the diagnosis of osteomyelitis can be problematic. A combined study consisting of WBC imaging and complementary bone marrow imaging performed with technetium 99m (99mTc) sulfur colloid is approximately 90% accurate and is especially useful for diagnosing osteomyelitis in situations involving altered marrow distribution. There are limitations and pitfalls associated with a combined study.

PET with FDG-labeled leukocytes versus scintigraphy with 111In-oxine-labeled leukocytes for detection of infection.

Purpose: To compare prospectively the accuracy of positron emission tomography (PET) with leukocytes labeled in vitro with (18)F fluorodeoxyglucose (FDG) versus that of conventional scintigraphy with leukocytes labeled in vitro with (111)In oxine in patients suspected of having infection.

Materials And Methods: This HIPAA-compliant study had institutional review board approval; informed consent was obtained from all patients. Patients were 25 men and 26 women aged 32-86 years.

111Indium pentetreotide imaging in the evaluation of head and neck tumors.

Objectives/hypothesis: Peptide receptor imaging with Indium pentetreotide is useful in the diagnosis of diffuse neuroendocrine system tumors (DNEST) of the head and neck. Uses of Indium pentetreotide scintigraphy include tumor and metastases detection, familial tumor screening, and surveillance for recurrence. Using target to background ratios (TBR) could generate a comparative scale for these tumors.

FDG PET of infection and inflammation.

Nuclear medicine plays an important role in the evaluation of infection and inflammation. Fluorine 18 fluorodeoxyglucose (FDG) is a readily available radiotracer that offers rapid, exquisitely sensitive high-resolution tomography. In patients with acquired immunodeficiency syndrome, FDG positron emission tomography (PET) accurately helps localize foci of infection and is particularly useful for differentiating central nervous system lymphoma from toxoplasmosis.

Radionuclide imaging of the parathyroid glands.

The parathyroid glands, which usually are situated behind the thyroid gland, secrete parathyroid hormone, or PTH, which helps maintain calcium homeostasis. Primary hyperparathyroidism results from excess parathyroid hormone secretion. In secondary hyperparathyroidism, the normal PTH effect on bone calcium release is lost.

Regulation of hepatobiliary transport activity and noninvasive identification of cytokine-dependent liver inflammation.

Unlabelled: Many diseases are associated with cytokine release after inflammatory infiltration, which perturbs organ function. Radioligands capable of noninvasive tracking to assess the integrity of specific biochemical pathways offer potent ways to establish such perturbing mechanisms.

Methods: To demonstrate regulation of hepatobiliary transport in disease, we used (99m)Tc-mebrofenin in a carbon tetrachloride-induced liver injury model in Fischer 344 rats.

Coincidence-detection FDG-PET versus gallium in children and young adults with newly diagnosed Hodgkin's disease.

Unlabelled: Coincidence-detection 18F-FDG-PET (PET) and 67Ga whole-body and SPECT (Ga) were compared in children and young adults with newly diagnosed Hodgkin's disease (HD).

Materials And Methods: Thirty patients with histologically confirmed HD underwent PET with attenuation correction 1 h after injection of 150-220 MBq 18F-FDG and whole-body and SPECT imaging 72 h after injection of 250-370 MBq 67Ga citrate. Two experienced readers retrospectively reviewed PET and Ga scans, grading 13 anatomic regions from one (normal) to five (abnormal).

Diagnosing infection in the failed joint replacement: a comparison of coincidence detection 18F-FDG and 111In-labeled leukocyte/99mTc-sulfur colloid marrow imaging.

Unlabelled: The objectives of this study were to investigate (18)F-FDG imaging, using a coincidence detection system, for diagnosing prosthetic joint infection and to compare it with combined (111)In-labeled leukocyte/(99m)Tc-sulfur colloid marrow imaging in patients with failed lower extremity joint replacements.

Methods: Fifty-nine patients--with painful, failed, lower extremity joint prostheses, 40 hip and 19 knee--who underwent (18)F-FDG, labeled leukocyte, and bone marrow imaging, and had histopathologic and microbiologic confirmation of the final diagnosis, formed the basis of this investigation. (18)F-FDG images were interpreted as positive for infection using 4 different criteria: criterion 1: any periprosthetic activity, regardless of location or intensity; criterion 2: periprosthetic activity on the (18)F-FDG image, without corresponding activity on the marrow image; criterion 3: only bone-prosthesis interface activity, regardless of intensity; criterion 4: semiquantitative analysis--a lesion-to-background ratio was generated, and the cutoff value yielding the highest accuracy for determining the presence of infection was determined.