The properties of sintered calcium phosphate with [Ca]/[P] = 1.50.

In order to obtain the properties of the sintered as-dried calcium phosphate with [Ca]/[P] = 1.50, the characteristics of sintered pellets have been investigated using X-ray diffraction (XRD), inductively coupled plasma-mass spectrometry (ICP-MS), Fourier-transform infrared (FT-IR) spectra, Vickers hardness indentation and scanning electron microscopy (SEM). When the pellet samples were sintered between 700 °C and 1200 °C for 4 h, the hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2), HA) still maintained the major phase, accompanied with the rhenanite (NaCaPO(4)) as the secondary phase and ß-tricalcium phosphate (ß-Ca(3)(PO(4))(2), ß-TCP) as the minor phases. In addition, the HA partially transformed to α-tricalcium phosphate (α-Ca(3)(PO(4))(2), α-TCP) and tetracalcium phosphate (Ca(4)(PO4)(2)O, TTCP), when the pellet samples were sintered at 1300 °C and 1400 °C, respectively, for 4 h. The maximum density and Vickers Hardness (HV) of sintered pellet samples were 2.85 g/cm3 (90.18% theoretical density (T.D.)) and 407, which appeared at 1200 °C and 900 °C, respectively.

Automated framework for digital radiation dose index reporting from CT dose reports.

OBJECTIVE: Radiation exposure from CT studies has increased over the past 30 years in the United States and now constitutes approximately 50% of the radiation dose index administered in the health care setting. Tracking CT dose index (CTDI) is cumbersome because it relies on a manufacturer-generated screen capture, which contains the estimated dose index exposure for the patient. The radiation dose index information is not digital but, rather, is "burned" into the image (i.e., not in numeric form, not as part of the image header or elsewhere associated with the study), making it difficult to automatically share these data with other information systems. The purpose of the dose index reporting application (DIRA) we developed for CT is to extract the radiation dose index information from the CTDI reports to eventually perform automated quality control, promote radiation safety awareness, and provide a longitudinal record of patient-specific health care-related radiation exposure. MATERIALS AND METHODS: A random selection of 518 CTDI reports were processed by the DIRA and the dose index information was extracted. CTDI reports using a standard DICOM C-STORE to the DIRA allow an automated process to compile radiation dose index and patient information in a Web-based framework using a structured query language (SQL) database. RESULTS: Our initial tests showed that the DIRA accurately extracted dose index information from 518 of 518 CTDI reports (100%). Because the extracted CTDI descriptor-dose-length product-is based on standard CTDI measurements obtained using fixed-size cylindric polymethylmethacrylate phantoms, preliminary studies have been performed to correct for patient size by applying correction factors derived from CTDI measurements using a range of phantom sizes from 6 to 32 cm in diameter. Our system provides a way to automatically track CTDI on existing CT scanners and does not rely on the DICOM SR Dose Index Report standard, which is available on only the newest CT scanners. CONCLUSION: A modular and vendor-independent DIRA system can be integrated with any existing CT scanner. This system greatly facilitates digital dose index reporting and makes it possible to provide a longitudinal record of the health care radiation exposure estimate in an individual patient's health record.

Langerhans cell histiocytosis of the lung with probably skeletal involvement.

Langerhans cell histiocytosis is characterized by abnormal accumulations of large mononuclear cells forming granulomas in various organs mainly in the lung, bone, or skin. Adult pulmonary Langerhans cell histiocytosis is rare and almost always associated with cigarette smoking; combination with lung and bone simultaneous involvement is even rare. We present a 41 years old male smoker who was diagnosed with pulmonary Langerhans cell histiocytosis by a lung biopsy and manifestations at high resolution computed tomography of the lung. Later technetium-99m methyl diphosphonate bone scintigraphy showed multiple abnormal tracer accumulation of the radiotracer in the skull and a singular focus in a rib.

Active bleeding in hematoma of the abdominal rectus muscle shown by Tc-99m red blood cell scintigraphy: compared with CT.

A patient with cirrhosis of the liver complicated with left rectus muscle hematoma following paracentesis underwent consecutive noncontrast CT images and a novel Tc-99m red blood cell (RBC) bleeding scan. Six liters of clear yellow fluid were withdrawn. Progressive enlargement of a left rectus muscle hematoma was diagnosed by 3 consecutive CT scans and confirmed by a Tc-99m RBC bleeding scan. Although consecutive CT scans showed progressive enlargement of the hematoma, the radionuclide study showed an active bleeding site.

Hashimoto thyroiditis and Takayasu aortitis: visualization of the thyroid gland and ring appearance of the mediastinum on F-18-FDG PET.

A woman with Hashimoto thyroiditis, treated with levothyroxine for 4 years, complained of chest pain that radiated to the neck and had progressively worsened for 2 months. CT of the chest showed circumferential thickening of the ascending aorta and aortic arch, compatible with Takayasu arteritis. She underwent F-18 FDG PET imaging, which revealed an abnormal thyroid gland and a ring-like appearance of the mediastinum.

2-Deoxy-2-[F-18]fluoro-D-glucose positron emission tomography illustrates two visceral tumors in a post kidney transplant patient with multiple cutaneous malignancies.

The success of renal transplantation brings with it the dilemma of managing patients with complications from lifelong immunosuppressive therapy. Immunosuppressed transplant recipients are a special population with significantly increased risk for development of skin cancers. Because malignant tumors are increasing as demonstrated on 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) image, we report the unusual coincidence of multiple cutaneous cancers and two visceral malignancies 20 years after renal transplantation. The malignancies include basal cell and squamous cell carcinomas and malignant fibrous histiocytoma. FDG-PET images show, in this case, visceral masses with increased metabolism: one in the left upper lung and one in the abdomen, corresponding to individual mass lesions observed on computed tomography (CT) images of the chest and abdomen. A fine-needle biopsy of the nodule of the left upper lung lobe yielded a diagnosis of a sarcoma. The mass lesion of the abdomen had caused bowel obstruction, requiring exploratory laparotomy; histopathological findings from the resected mass from the abdomen confirmed the diagnosis malignant fibrous histiocytoma. This long-term immune suppressed transplant recipient developed viscerally located malignant lesions demonstrated by FDG-PET imaging and three types of cutaneous malignancies (skin cancers).

F-18 FDG PET demonstrates crossed cerebellar diaschisis 20 years after stroke.

Stroke produces an area of focal damage and distant areas of reduced blood blow and metabolism termed diaschisis. Tc-99m ECD and HMPAO brain SPECT have demonstrated crossed cerebellar diaschisis (CCD) in patients with cerebral cortical infarct. SPECT findings reflect abnormal cerebral blood flow. CCD as shown on F-18 FDG PET reflects abnormal reflects glucose metabolism. We present the case of a patient with laryngeal cancer who also had a stroke in the left cerebral hemisphere involving the territory of the middle cerebral artery 20 years ago. This patient underwent PET, including the head and neck. A current brain F-18 FDG PET exhibited hypometabolism in the contralateral cerebellum (CCD) as well as hypometabolism of the primary insult in the left cerebral hemisphere. These findings reflect partial impairment or diminished glucose metabolism in the primary insult to the cerebrum and contralateral cerebellum. In addition, this patient illustrates that on PET imaging, CCD could be demonstrated 20 years after a stroke.

Illustrations of abdominal abnormalities on 99mTc tetrofosmin gated cardiac SPECT.

BACKGROUND: 99mTc tetrofosmin is predominantly cleared by the hepatobiliary system and its scan is analogous to a cholescintigraphy. The radiopharmaceutical may be localized in the bone marrow. During cardiac acquisition, when the area being viewed includes the lower thorax and abdomen, abnormalities of the liver, gallbladder and kidneys, and the radioactivity in the oesophagus, stomach and bowel, as well as bone marrow uptake, can be depicted by routine raw data cine images. Excluding the intrathoracic abnormalities, these abdominal abnormalities are illustrated in this paper. METHODS AND MATERIALS: Retrospectively, we reviewed the raw data cine images from 566 patients. These images were 180 degrees or 360 degrees rotation and showed the abdominal organs and thoracic cage, including the ribs, sternum and spine. We found 234 abnormalities, which were correlated with radiography, laboratory and clinical findings. RESULTS: Intra-abdominal abnormalities included bone marrow visualization, 93 occurrences (39.7%); duodeno-gastric (DG) and entero-gastric (EG) reflux, 47 (20.1%); non-visualization of the gallbladder, including possible causes of cholelithiasis, acute cholecystitis, or cholecystectomy, 31 (13.2%); elevation of the right diaphragm and depression of diaphragm, 30 (12.8%); renal abnormalities, including absent kidney, renal atrophy and cyst, 12 (5.1%); splenomegaly, 10 (4.3%); liver, including hepatomegaly and cirrhosis of the liver, eight (3.4%); and breast attenuation resulting in photopenia in the liver, three (1.2%). CONCLUSIONS: (1) The bone marrow uptake of the vertebrae accounts for almost 40% of the abdominal abnormalities, and is usually concordant with anaemia; (2) DG and EG refluxes represent 20% of abdominal abnormalities; they may have a clinical impact and may or may not interfere with SPECT processes and result in artifacts of the inferior wall of the left ventricle; (3) non-visualization of the gallbladder should prompt a search for cholelithiasis; and (4) benign renal cyst or cirrhosis of the liver could also be demonstrated. These coincidental findings may be included in routine cardiac SPECT reports that may have clinical impact because they give the referring physician the chance to pursue further clinical investigation.

Gastric-emptying scintigraphy of type III hiatal hernia: a case report.

We present the case of a 76-y-old man with mixed (type III) paraesophageal hernia confirmed by endoscopy and CT of the chest who underwent a radionuclide gastric-emptying study that showed accumulation of the radiotracer in the herniated stomach and esophagus in the thorax and accelerated gastric emptying. A scintigraphic gastric-emptying study may be an option for noninvasively demonstrating gastroesophageal accumulation of tracer in patients with hiatal hernia.

2-Deoxy-2-[18F]fluoro-D-glucose positron emission tomography monitoring disease progress in a patient with islet carcinoma of the pancreas.

A woman with islet cell carcinoma of the pancreas proven by biopsy at an exploratory laparotomy underwent six cycles of chemotherapy with paclitaxel and carboplatin. After the chemotherapy to monitor her primary tumor and hepatic metastases, she had three consecutive 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET) determinations that correlated with an In-111 octreotide single photon emission computer tomography. FDG-PET might have utility in monitoring islet cell carcinoma of the pancreas in evaluating metabolic changes following chemotherapy.

Tc-99m depreotide SPECT demonstrates photon-deficiency in the thoracic vertebrae after adjunct radiation therapy of lung cancer: correlation with MRI and bone scintigraphy.

Fifteen months after right lobe lobectomy with adjunctive radiation therapy for squamous cell carcinoma, a patient 53-yr-old man underwent Tc-99m depreotide chest single photon emission tomography (SPECT). In addition to two focal areas of abnormally increased uptake in the right lung, the Tc-99m depreotide SPECT showed cold areas in the middle thoracic vertebrae. Photopenic areas in the 6th and 7th thoracic vertebrae were shown on a bone scintigraphy. T1 weighted magnetic resonance imaging (MRI) of the spine showed fatty replacement of the marrow and Schmorl's nodes involving the 5th to 11th thoracic vertebrae. The vertebrae are normally visualized in Tc-99m depreotide SPECT imaging study, and lung tumor is usually somatostatin receptor positive with demonstrable activity in the lung. Absent uptake in the vertebrae in the fatty replacement of the marrow and multiple and giant vertebral Schmorl's nodes in the correspondent vertebrae in MRI may reflect visualization of vertebrae due to Tc-99m depreotide localizing in the bone marrow. Of the three imaging modalities, MRI showed the widest areas of thoracic vertebral involvement. One should be aware that a cold lesion in the vertebrae on Tc-99m depreotide imaging study may result from irradiation and may indicate the presence of a benign lesion in the bone marrow.

Biodistribution on Tc-99m labeled somatostatin receptor-binding peptide (Depreotide, NeoTec) planar and SPECT studies.

PURPOSE: To determine the biodistribution of Tc-99m labeled somatostatin receptor-binding peptide (Depreotide) on planar and SPECT studies of the thorax and upper abdomen in order to improve diagnostic accuracy. METHODS AND MATERIALS: Retrospectively 29 planar and SPECT studies from 28 patients (all males, average age of 65.79) were reviewed. All the patients had been referred for evaluation of solitary pulmonary nodules. Two to four hours after IV injection of 555- to 740-MBq (15-20 mCi) Tc-99m Depreotide, anterior and posterior total body images, and anterior, posterior, right lateral and left lateral planar images were obtained, and thoracic SPECT was acquired with a three-head gamma camera. The degree of uptake in the lungs, thoracic cage, and organs of the upper abdomen was rated from "0" to "++++". RESULTS: The range of normal activity in the thorax includes cardiac, "0"; pulmonary, "+"; rib, "+/++"; sternum, "++"; vertebrae, "++". The degree of normal activity seen in the upper abdominal organs includes liver and spleen, "+++", and kidneys, "+++/++++". Eight patients with emphysema had diffuse pulmonary uptake graded as "+/++". One patient with left pneumonectomy and radiation therapy to the left hemithorax had photon-deficiency in the left hemithorax and decreased to absent uptake including the vertebrae and ribs. Although some cases had background pulmonary uptake of Tc-99m Depreotide, the bone/ bone marrow activity of the thoracic cage including the ribs, sternum, and thoracic spine is sufficiently great enough to produce a clear distinction between bone and lung in the thoracic cavity that gives high-contrast resolution on SPECT. CONCLUSIONS: The intensity of radioactivity in the sub-diaphragmatic organs such as the liver, spleen, and kidneys provides useful guidance for the categorization of pulmonary lesions. The uptake of land marks such as the sternum, which is anteriorly located, and the thoracic vertebrae, which are posteriorly located in the thoracic cage, can be used in the localization of a Depreotide avid tumor.

Scarred atrophic thyroid after I-131 therapy for Graves' disease documented at autopsy.

Radioiodine is used as the definitive treatment of choice in most patients with Graves' hyperthyroidism. Most patients with Graves' disease eventually develop hypothyroidism following I-131 therapy and require thyroid hormone replacement therapy. We present a patient with aortic stenotic cardiac disease and coronary artery disease who suffered from fatigue, weight loss and atrial fibrillation. The patient's radionuclide study, as well as the T4 and TSH, confirmed Graves' disease and he received I-131 therapy. Our patient's development of hypothyroidism following 5 mCi I-131 therapy after seven days later was considered as unusual; in addition, our patient, at autopsy, had documented histopathologic changes confirming atrophy and fibrosis of the thyroid gland.

Diffusely increased uptake by thoracic vertebrae on bone scintigraphy in midcourse of lung cancer irradiation: a case report.

Bone scintigraphy performed on a patient during the middle of radiation therapy for an inoperable left lung malignancy showed diffusely increased uptake in the thoracic vertebrae and relatively increased uptake in the ribs of the left thorax. This bone scan finding is apparently a transient phenomenon that occurs in response to irradiation and eventually leads to photon deficiency or photopenia of the vertebrae. However, this transiently increased uptake of the thoracic spine, compared with uptake in the lumbar spine, mimics diffusely decreased uptake or photopenia of the lumbar vertebrae and may be misinterpreted as an effect of irradiation of the abdominal region. In the case of asymmetric uptake between the thoracic and lumbar spine, a carefully taken history of the timing and location of irradiation is necessary to avoid misinterpretation.

Electronic off-peak status of one head of a dual-head gamma camera resulted in bone scintigraphy artifacts and faulty findings on gated myocardial SPECT.

OBJECTIVE: Gamma cameras contain energy discriminators that allow only those photons within a specified energy range to be recorded. A spontaneous shift in peak of 1 head of a dual-head gamma camera may cause artifacts. We present our experience with the incidental occurrence of off-peak status in 1 head of a dual-head gamma camera that resulted in subsequent artifacts and poor-quality images. METHODS: Four patients had been scheduled to undergo imaging on a newly installed dual-head gamma camera on the same morning. The first patient underwent (201)Tl-chloride anterior and posterior total-body imaging to check for metastatic thyroid cancer, and the images were of adequate quality for interpretation. The next 2 patients underwent dual-isotope rest (201)Tl-chloride and gated dipyridamole (99m)Tc-tetrofosmin myocardial SPECT. The rest (201)Tl myocardial SPECT images of both patients showed normal perfusion in the left ventricular wall, but the dipyridamole (99m)Tc SPECT images showed virtual absence of perfusion in the apical, anterior, and lateral walls. These findings might suggest myocardial ischemia. In addition, 1 of 2 patients' cardiac gated SPECT findings led to inaccurate left ventricular ejection fractions. Technologists did not become aware of the artifacts until the fourth patient underwent total-body bone scanning, which showed faint activity with loss of contrast in the entire anterior body. One of the camera heads was then found to have off-peak status. Thus, we abandoned use of 1 detector of the dual-head gamma camera and repeated the anterior bone scanning of the 4th patient and the dipyridamole SPECT of 1 of the 2 cardiac patients. RESULTS: Gated cardiac SPECT abnormalities resulting from off-peak status were difficult to identify and included abnor-mal left ventricular wall perfusion and an inaccurate left ventricular ejection fraction. It was determined later that the off-peak status was caused by malfunction of a photomultiplier tube. CONCLUSION: Degraded planar images resulting from the off-peak status of a camera head are easily identified. The presence of the same pattern of abnormalities in 2 consecutive myocardial SPECT examinations should alert technologists to the possibility that the abnormalities are, in fact, artifacts.

99mTc-Depreotide chest SPECT demonstrates pulmonary metastases from renal cell carcinoma.

99mTc-Depreotide has been used on single pulmonary nodules to identify somatostatin receptor-positive lung cancer. We report that pulmonary metastases of a 78-y-old man with postradical nephrectomy for renal cell carcinoma were detected by (99m)Tc-depreotide chest SPECT. Thus, (99m)Tc-depreotide chest SPECT can be used to diagnose secondary lung cancer, such as pulmonary metastases from renal cell carcinoma with somatostatin receptor-positive tumor, other than primary lung cancer. Depending on whether the (99m)Tc-depreotide was positive for pulmonary metastases, the patient underwent an appropriate therapy without further invasive procedures.

Tc-99m depreotide detecting malignant pulmonary nodules: histopathologic correlation with semiquantitative tumor-to-normal lung ratio.

Tc-99m depreotide is a synthetic somatostatin analog with a low molecular weight of 1358 and binding domains for somatostatin receptors (SSTRs) subtypes 2, 3, and 5. This agent has been used for imaging pulmonary nodules in an effort to differentiate malignancies from infectious processes. To investigate whether there is significant ratio variability predicting a specific lung cancer type, we undertook this study. We analyzed the semiquantitative tumor-to-normal lung ratios among 23 patients with histopathologically proven lung carcinoma. Eleven patients with squamous cell carcinoma had 14 nodular lesions (n = 14); the ratios ranged from 6.0 to 1.4; the mean was 3.500. Nine patients with adenocarcinoma had 9 nodular lesions (n = 9); the ratios ranged from 3.2 to 1.0; mean was 1.89. Three patients with large cell carcinoma had 3 nodular lesions (n = 3); mean was 1.2. There were significantly different ratio values between squamous cell carcinoma and nonsquamous cell carcinoma. On a statistical analysis by t test, this difference proved to have a statistically significant value of P < 0.038. For patients with lung cancer, we could predict the tumor most likely to be squamous cell carcinoma if the uptake ratio was greater than 3.5. Otherwise, the lower ratio appeared to be either the result of large cell carcinoma or adenocarcinoma. High tumor uptake of Tc-99m depreotide reflecting abundant SSTRs of a tumor and/or peritumoral neovasculature such as squamous cell carcinoma could be potentially useful in diagnostic and therapeutic guidance.

Intrathoracic and intra-abdominal Tl-201 abnormalities seen on rotating raw cine data on dual radionuclide myocardial perfusion and gated SPECT.

PURPOSE: The lower thorax and upper abdomen are visualized during cardiac acquisition of rest Tl-201 and stress Tc-99m tetrofosmin gated SPECT. Thus, abnormal Tl-201 localization in these areas and in organs such as parts of the lungs, liver, spleen, and kidneys can be observed, including rotating raw cine data. MATERIALS AND METHODS: Other than cardiac images, the authors retrospectively reviewed Tl-201 rotating (raw data) images of 235 patients. Abnormal findings in the lungs, liver, spleen, and kidneys were identified that correlated with the patients' clinical information; radiographic findings, including computed tomography and ultrasonography of the abdomen; other scintigraphic studies; and laboratory findings. RESULTS: In 53 patients, 54 abnormalities were detected. Intrathoracic abnormalities included focal areas of increased uptake, one in the right lower lung and another in the right upper lung that confirmed lung cancer, in 2 patients; diffuse uptake in both lungs in 11 patients; photopenia in the lung bases, which had resulted from pleural effusions, in 3 patients; and abnormal right liver configuration caused by elevation of the right hemidiaphragm in 1 patient. Of the intra-abdominal abnormalities, 12 patients with splenomegaly were identified. Six patients had focal areas of increased uptake in the gastric area. Nonvisualization of one kidney resulted from a congenitally absent right kidney in 1 patient, from right nephrectomy in 1 patient, from end-stage renal disease in another, and from a lower position of the left or right kidneys in 5 patients. Small and decreased uptake of both kidneys resulted from end-stage renal disease in 1 patient. Small and decreased uptake of one kidney was noted in 1 patient with renal scarring, in 1 patient with a renal stone, in 3 patients with chronic pyelonephritis, and in 5 patients with renal cyst(s). CONCLUSIONS: Discernible intrathoracic and intra-abdominal abnormalities using rotating raw cine data from imaging in three-dimensional displays include diffuse or focal pulmonary uptake, pleural effusion, elevation of a hemidiaphragm, splenomegaly, increased uptake in the gastric area, renal abnormalities including absent or small kidneys, end-stage renal disease, renal scarring, renal cyst(s), and lower position of a kidney. The incidental finding of such abnormalities may prompt further clinical investigation.