Impact of Single-Time-Point Estimates of Lu-PRRT Absorbed Doses on Patient Management: Validation of a Trained Multiple-Linear-Regression Model in 159 Patients and 477 Therapy Cycles.

Dosimetry after Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) enables estimation of radiation doses absorbed by normal organs and target lesions. This process is time-consuming and requires multiple posttreatment studies on several subsequent days. In a previous study, we described a newly developed multiple-linear-regression model to predict absorbed doses (ADs) from a single-time-point (STP) posttreatment study acquired 168 h after the first infusion and 24 h after the following ones, with similar results to the standard multiple-time-point (MTP) protocol.

Simple model for estimation of absorbed dose by organs and tumors after PRRT from a single SPECT/CT study.

Background: Following each cycle of peptide receptor radionuclide therapy (PRRT), absorbed doses by tumors and normal organs are typically calculated from three quantitative single-photon emission computed tomography (SPECT)/computed tomography (CT) studies acquired at t = 24 h, t = 96 h, t = 168 h after the first cycle of treatment and from a single study at t after the subsequent cycles. In the present study, we have assessed the feasibility of a single SPECT/CT study after each PRRT cycle using a trained multiple linear regression (MLR) model for absorbed dose calculation and have evaluated its impact on patient management. Quantitative [Lu]-DOTA-TATE SPECT/CT data after PRRT of seventy-two consecutive metastatic neuroendocrine tumors patients were retrospectively evaluated.

[RADIONUCLIDE THERAPY OF NEUROENDOCRINE TUMORS - IMPROVEMENTS IN THE PROTOCOL FOR MEASUREMENT OF PATIENT RADIATION EXPOSURE].

Aims: The aim of this study was to evaluate the predictive power of the absorbed dose to kidneys after the first course of treatment with [177Lu]-DOTA-TATE on the cumulative kidney absorbed dose after 3 or 4 cycles of treatment.

Background: Peptide receptor radionuclide therapy (PRRT) with [177Lu]-DOTA-TATE is an effective treatment for somatostatin receptor positive neuroendocrine tumors (NETs). Post-treatment scans (PTS) are required after each cycle of treatment for personalized radiation dosimetry in order to calculate the dose to organs and tumors and to ensure a cumulative absorbed dose to kidneys under a safety threshold of 25 Gy.

Predictive power of the post-treatment scans after the initial or first two courses of [Lu]-DOTA-TATE.

Background: The aim of this study was to evaluate the predictive power of the absorbed dose to kidneys after the first course of treatment with [Lu]-DOTA-TATE for neuroendocrine tumors (NETs) on the cumulative kidney absorbed dose after 3 or 4 cycles of treatment. Post-treatment scans (PTS) are acquired after each cycle of peptide receptor radionuclide therapy (PRRT) with [Lu]-DOTA-TATE for personalized radiation dosimetry in order to ensure a cumulative absorbed dose to kidneys under a safety threshold of 25 Gy. One hundred eighty-seven patients who completed treatment with [Lu]-DOTA-TATE and underwent PTS for dosimetry calculation were included in this retrospective study.

Highly favourable outcomes with peptide receptor radionuclide therapy (PRRT) for metastatic rectal neuroendocrine neoplasia (NEN).

Purpose: Rectal neuroendocrine neoplasia (NEN) is more common than other NEN origins, but is less commonly metastatic. However, when present, distant disease carries a particularly poor prognosis. Evidence guiding optimal treatment of such patients is lacking.

Diagnostic Computed Tomography Coregistration With In-111-DTPA-Octreotide Single Photon Emission Tomography/Low-Dose Computed Tomography.

Objectives: In-111-DTPA-octreotide (OctreoScan) is still pivotal for neuroendocrine tumor imaging, despite the introduction of Ga-68-octreotide tracers. Low-dose computed tomography (LDCT) assists in the localization of SPECT findings but often results in uncertain interpretation. This retrospective study evaluates the impact of coregistration of In-111-DTPA-octreotide SPECT/LDCT with diagnostic CT on interpretation.

Neuroendocrine tumor imaging with 68Ga-DOTA-NOC: physiologic and benign variants.

Objective: Imaging with (68)Ga-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-octreotide analogs has become an important modality in patients with neuroendocrine tumors (NETs). In addition to high uptake in NET lesions, prominent physiologic radiotracer activity has been reported in the pituitary gland, pancreas, adrenal glands, liver, and spleen, and faint activity has been reported in the thyroid and gastrointestinal tract. This article describes previously unknown sites of 68Ga-DOTA-1-NaI3-octreotide (NOC) uptake unrelated to NETs.

Localization of parathyroid adenoma by ¹¹C-choline PET/CT: preliminary results.

Purpose: This prospective pilot study was aimed to evaluate ¹¹C-choline PET/CT (choline) as a tool for localization of parathyroid adenoma (PTA).

Methods: Forty patients with biochemical hyperparathyroidism underwent choline and ⁹⁹mTc-MIBI imaging within a median interval of 56 days. Choline and MIBI images were analyzed and correlated with each other, with additional modalities such as ultrasound, CT, MRI, and with surgical findings, when available.

Ga-68 DOTA-NOC uptake in the pancreas: pathological and physiological patterns.

Objective: Gallium-68 (Ga-68) DOTA-1-NaI3-octreotide (DOTA-NOC) positron emission tomography (PET)/computed tomography (CT) is increasingly used for neuroendocrine tumors (NETs), often found primarily in the pancreas. However, physiologic uptake of DOTA-NOC has been described in the uncinate process of the pancreas. We studied DOTA-NOC uptake in this organ.

68Ga-DOTA-NOC PET/CT imaging of neuroendocrine tumors: comparison with ¹¹¹In-DTPA-octreotide (OctreoScan®).

Purpose: Recent data have indicated that ⁶⁸Ga-DOTA-NOC positron emission tomography/X-ray computed tomography (PET/CT) may yield improved images in a shorter acquisition protocol than ¹¹¹In-DTPA-octreotide (OctreoScan®, OCT). Therefore, we performed a prospective comparison of ⁶⁸Ga-DOTA-NOC and OCT for the detection of neuroendocrine tumors (NETs).

Methods: Nineteen patients (eight carcinoid, nine pancreatic NETs, and two NE carcinoma of unknown origin) with previous positive OCT scans underwent ⁶⁸Ga-DOTA-NOC PET/CT and OCT single-photon emission computed tomography imaging for staging or follow-up.

Cerebral perfusion after a 2-year remission in major depression.

Although patients suffering from major depression respond to antidepressant treatment within several weeks, full reinstatement of premorbid capabilities requires much longer. Nevertheless, most research in major depression seeking the pathophysiological correlates of remission has focused upon the acute post-treatment period. Brain imaging research offers no exception.

Added value of SPECT/CT for correlation of MIBG scintigraphy and diagnostic CT in neuroblastoma and pheochromocytoma.

Objective: In pheochromocytoma and neuroblastoma, pathologic findings on metaiodobenzylguanidine (MIBG) scintigraphy (planar and SPECT) and on diagnostic CT are sometimes difficult to correlate. Furthermore, CT reading may be impaired by anatomic distortion after surgery or irradiation and if contrast agent is not injected. The present study evaluates the impact of SPECT/CT fusion images on correlation and image analysis of both techniques.

99mTc-HMPAO SPECT study of cerebral perfusion after treatment with medication and electroconvulsive therapy in major depression.

Unlabelled: Compromised regional cerebral blood flow (rCBF) in major depressive disorder may be partly reversed by successful antidepressant treatment. However, it is not known if the reversal of rCBF compromise is dependent on the mode of antidepressant treatment. The current study aimed to address this question.

Single-photon emission computed tomography/computed tomography in endocrinology.

The introduction of fusion of functional and anatomical imaging modalities into the field of endocrinology led to a major breakthrough in diagnosis, staging, and follow-up of patients with endocrine tumors. The management of endocrine tumors is based on a wide variety of conventional techniques, including computed tomography, ultrasound, or magnetic resonance imaging, and on scintigraphic functional techniques, associated with unique uptake and transport mechanisms and with the presence of high density of membrane receptors on some of these tumors. Anatomical modalities provide accurate detection and localization of morphological abnormalities, whereas nuclear medicine studies reflect the pathophysiological status of the disease process.

Brain SPECT study of common ground between hypothyroidism and depression.

Hypothyroidism and major depressive disorder (MDD) share neuropsychiatric features. Cerebral perfusion deficits are found in both disorders. We compared regional cerebral blood flow (rCBF) in hypothyroidism and MDD to determine if clinical similarities are mediated by common neurocircuitry.

Technetium-99m-MIBI SPECT/CT in primary hyperparathyroidism.

The novel trend toward focused parathyroidectomy requires precise preoperative localization of the parathyroid adenoma in patients with primary hyperparathyroidism (PHPT). The present study evaluated the impact of hybrid single photon emission computed tomography/computed tomography (SPECT/CT), using 99mTc-sestamibi (MIBI), on the surgical management of these patients. In a retrospective study of 36 patients with PHPT, SPECT/CT was undertaken when planar 99mTc-MIBI scintigraphy was negative or when an ill-defined focus in the neck or an ectopic site on planar views was visualized.

Short- and long-term outcome of lung volume reduction surgery. The predictive value of the preoperative clinical status and lung scintigraphy.

The NETT study assessed the benefits of lung volume reduction surgery (LVRS) versus medical treatment. However, data is available only on the early outcome of LVRS (24 months). We evaluate the factors affecting the outcome at one-year and up to 6 years after LVRS.

In vivo measurement of brain monoamine oxidase B occupancy by rasagiline, using (11)C-l-deprenyl and PET.

Unlabelled: In recent years, monoamine oxidase B (MAO-B) inhibitors have become widely used in the treatment of early-stage Parkinson's disease. (11)C-l-deprenyl PET has been used by others to characterize MAO-B ligands in terms of their in vivo potency toward MAO-B and duration of action. In this study, we used (11)C-l-deprenyl PET to demonstrate the specific binding characteristics of the new irreversible selective MAO-B inhibitor rasagiline in 3 healthy volunteers.

Regional cerebral blood flow in patients with mild hypothyroidism.

Unlabelled: Emotional and cognitive abnormalities are common in adult hypothyroidism. Few studies, however, have evaluated cerebral perfusion and metabolism in this disorder. The aims of this study were to compare regional cerebral blood flow (rCBF) between hypothyroid patients and healthy subjects and assess flow during the euthyroid state after treatment.

Cerebral blood flow in chronic symptomatic mild traumatic brain injury.

Patients with mild traumatic brain injury (MTBI) challenge physicians' skills and test their patience. Their manifold symptomatology is often not supported by objective neurological findings. We sought to compare regional cerebral blood flow (rCBF) between symptomatic subjects with longstanding MTBI and healthy controls, and to examine the correspondence between neuropsychological deficit and rCBF compromise.

SPECT/CT hybrid imaging with 111In-pentetreotide in assessment of neuroendocrine tumours.

Objective: Somatostatin receptor scintigraphy (SRS) of neuroendocrine (NE) tumours is often challenging because of minute lesion size and poor anatomic delineation. This study evaluates the impact of sequentially performed single-photon emission computed tomography (SPECT)/CT fusion on SRS study interpretation and clinical management of these tumours.

Patients And Design: Seventy-two patients were studied with routine SRS and SPECT/CT at 4, 24 and optionally 48 h after injection of 222 MBq 111In-pentetreotide.

SPECT/CT in tumor imaging: technical aspects and clinical applications.

Diagnostic imaging has gained a major role in the management of patients with cancer and has made a further step forward with the introduction of fusion techniques into the field. This technology provides hybrid images of two independent modalities, a functional scintigraphic technique and an anatomical procedure, yielding a superior imaging study. Scintigraphy is based on the use of single photon or positron emitting tracers providing a description of function or processes, whereas computed tomography (CT), ultrasound, or magnetic resonance imaging (MRI) depict the precise localization and type of morphological changes that have occurred in the lesions.

Cerebral blood flow in depressed patients: a methodological comparison of statistical parametric mapping and region of interest analyses.

Functional brain imaging has assumed a leading role in neuropsychiatric research. However, findings reported for mental disorders often vary. Whether this reflects diversity in pathophysiology or heterogeneity of imaging techniques and data-analytic procedures is still unknown.