Evaluation of thyroid scintigraphy in small animals

Thyroid scintigraphy in rats and mice with 99mTc and 123I was attempted to examine whether this modality might be used in small animals and to describe the possibilities of its application in examining experimentally produced thyroid diseases. A human gamma camera with a pinhole collimator improved for small animals was used for imaging. Thyroid images with 99mTc were obtained 20 minutes after injection and those with 123I were 24 hours after administration. All the scintigrams, although those obtained from mice with 99mTc displayed overlapped salivary gland images, demonstrated sufficiently clear images in size and shape, which showed that thyroid scintigraphy in small animals should be applicable in examining experimentally produced thyroid diseases.     

Testing performance of the improved pinhole collimator and its application to small animals

Testing performance of the improved pinhole collimator of 1.5 mm aperture attached to the gamma camera was carried out with three kinds of radionuclides, 99mTc, 67Ga and 131I, using a hand-made phantom. The results obtained in this experiment were compared to those obtained with a human pinhole collimator of 4 mm aperture. Those were nearly understood by taking account of the effective aperture of a pinhole collimator for each effective photon energy. And all scintigrams obtained from rats with various scintigraphy showed high resolution images.     

Control scintigrams of rat organs with 99mTc labeled compounds

The control scintigrams of four kinds of organs in rats with 99mTc were presented by the Kaneko's method using the improved pinhole collimator. All images were high resolutive, and the fine structures of the organs were found in them.     

Evaluation of gamma camera collimator for regional cerebral blood flow measurements using a 133Xe inhalation method

In the measurements of regional cerebral blood flow (rCBF) using inhalation of 133Xe gas, the activity present is generally limited in lower levels than those of usual brain scintigraphy. Measurements with low count-rate are usually resulted in diminishing the accuracies of results obtained. Therefore, it is necessary to make measurements using a high sensitive collimator for getting as much count-rate as possible when a gamma camera is used. The relationships among sensitivity and structures of multi-parallel collimator were mathematically analyzed. The results of analysis suggested that sensitivity usually increased by using a collimator with holes of reduced height and diameter. A prototype multi-parallel collimator with holes of low height and small diameter was made in our laboratory for testing sensitivity and resolution. The collimator possessing 1141 holes of 6 mm phi in hole diameter, 1.5 cm is hole height and septal thickness of 1 mm lead showed 24 times more sensitive than those of a general all purpose collimator supplied by the manufacturer. However, resolution measured in FWHM was of 9 to 14 mm at the collimator face and of 29 to 38 mm at 5 cm from the face. The results indicated that this collimator was useful enough in rCBF measurements with 133Xe inhalation using a gamma camera. The mathematical analysis however, suggested that optimum collimator for rCBF measurements was approximate 4.5 mm phi in hole diameter and 1.0 cm in hole height.     

Prospective study to assess the clinical efficacy of bone scintigraphy--comparative study of the efficacy in breast carcinoma and prostate carcinoma

Prospective study of bone scintigraphy was performed on 414 patients with breast carcinoma and 88 patients with prostate carcinoma. In 468 of them, confirmative diagnoses of bone, whether metastasis was existent or not, were made after the observations over a year. Finally, the incidences of bone metastasis were 11 percent for breast carcinoma and 54 percent for prostate carcinoma respectively. The efficacy of preoperative bone scintigraphy in breast carcinoma was comparable to that in prostate carcinoma with regard to improvement of predictive probability of bone metastasis: raising up the probability in the positive cases and bringing down in the negative cases.     

Quantification in highly scattering/absorbing layered samples using photon time-of-flight measurements and confocal optical geometry

A method for depth-resolved quantification in scattering/absorbing layered samples is described. Confocal optical geometry was used in conjunction with time gated detection for non-invasive quantification of sub-surface absorbing constituents. For analysis, the time-resolved diffuse reflectance intensities from a series of layered absorbing samples were ratioed to that of a similar, non-absorbing specimen. Using this approach, absorbance information sensitive to changing sample composition was obtained. The effect of confocal optical geometry focussing on depth-resolved quantification was characterized using different portions of the time profile. In addition, imaging performance is assessed with varying focal depth, numerical aperture and effective pinhole size. Results indicate that the effect of multiple scattering on the detected signal may be reduced by using a larger numerical aperture objective and small effective pinhole size. Also, the sample absorbance was found to be more linear over a wider concentration range when compared with a large pinhole. When time information was included, the initial rising portion of the time profile was found to enhance sample absorbance linearity when a large pinhole is used. However, little enhancement was observed when the imaging pinhole size was small. Similar effects were seen at each focal depth in the sample. This finding suggests that although including time information may be beneficial, it is not needed when confocal light collection is employed in the analysis of macroscopic scattering samples.     

Significance of renal high uptake in bone marrow scintigraphy with 111In-chloride

The significance of high renal uptake found in patients with hematological disease who underwent bone marrow scintigraphy with 111In-chloride was investigated. In patients with a high renal uptake, the uptake in bone marrow was low, suggesting a reflection of erythropoietic activity. The reversal relationship, however, was not necessarily present. With regard to correlation with iron metabolism, significantly higher uptake of serum Fe and lower UIBC were found among those with high renal uptake, suggesting that the level of free trans ferrin in the serum is largely involved in the high uptake in the kidney.     

Usefulness of bone imaging in diagnosis of sternocostoclavicular hyperostosis

Sternocostoclavicular hyperostosis (SCCH) is a rare disease that is characterized by hyperostosis and soft tissue ossification between the clavicles and the anterior part of the upper ribs. There have been few published reports of 99mTc-MDP bone imaging findings in this disease. Thirty-three patients who were suspected to have SCCH were studied with 99mTc-MDP bone imaging. Bone images were abnormal in 31 (94%) of 33 patients. Chest radiographs were available in 30 patients, but negative in 14 (46%) of them. Bone imaging revealed also radionuclide accumulations in other bones such as the vertebrae, femur or sacroiliac joints in ten (14 sites) of 33 cases. Bone scintigraphy was useful in the diagnosis of sternoclavicular hyperostosis.     

Recent advances in the targeted fluorescent probes for the detection of metastatic bone cancer

Tumors of the breast, prostate, and lung are most likely to metastasize to the bone and typically indicates a poor cure and survival rate in cancer patients. Detection of metastatic bone cancer in early stage would save many lives and greatly improve patients' quality of life. Clinically, bone scintigraphy is often utilized to visualize bone metastases due to its relatively low cost and high sensitivity. Recently, a growth number of analytical researches aimed at developing targeted fluorescent probes to noninvasively image bone metastases with improved spatial resolution and specificity has been reported. In this review, we will summarize and discuss the recent published fluorescent probes on the accurate detection of metastatic bone cancer. First, the design principles of various targeted probes for imaging bone metastases will be presented, highlighting the signal moieties, targeting ligands, and physicochemical properties of the bone-specific probes. Next, the up-to-date bone-targeting fluorescent probes will be summarized and overviewed. Finally, future perspectives and challenges confronting the researchers in this field will be discussed.We believe this review will encourage novel ideas to develop smart targeted molecular probes for bone metastasis imaging,image-guided surgery, and therapeutic imaging materials.     

模板法合成金银核壳纳米线及电化学表征

采用氧化铝模板由交流电沉积制备纯银纳米线.然后借助化学还原法,在已制备好的银线表面包裹不同厚度的金壳层,得到具有核壳结构的AgcoreAushell复合纳米线.电子显微镜(SEM,TEM)显示该复合结构纳米线表面形貌与加入的金盐量有关,而且包裹层较薄的复合纳米线表面存在大量的孔洞.循环伏安测试表明,具有孔洞效应的复合纳米线经多次循环扫描后即可过渡到无孔洞效应的表面.以对巯基苯胺(PATP)作为探针分子的表面增强拉曼光谱,可用于表征纳米材料的表面结构.     

硫醇自组装膜对金电极上吡咯电化学聚合的影响

用电化学聚合法在多种烷基硫醇自组装膜修饰金电极上制备了聚吡咯.通过计时安培法、循环伏安法和交流阻抗技术研究了自组装膜的烷基链长和端基功能团对吡咯聚合过程和性质的影响.当自组装膜较完美时,聚吡咯沉积在自组装膜表面;而当自组装膜有一定缺陷时,吡咯在针孔处成核,然后继续生长并完全覆盖在自组装膜表面.研究结果表明,烷基硫醇的链越短,吡咯聚合越容易;疏水的烷基硫醇自组装膜有利于聚吡咯在电极表面的生长.     

Evaluation by using radionuclide uptake of bone in Paget's disease of bone: special reference to treatment with calcitonin

Bone scintigraphy using 99mTc-MDP was performed on 2 patients with Paget's disease of bone before and after the treatment with a synthetic eel calcitonin analogue [Asu1,7)-eel calcitonin, ECT] at a dose of 40 U per day. All pagetic lesions showed markedly the increased accumulation of the radionuclide. The uptake ratio, defined as the count rate of 99mTc-MDP over each bone lesion to that over the control bone, was calculated. The response to the calcitonin therapy was evaluated with the uptake ratio of the radionuclide. The uptake ratio decreased markedly within the first 3 months of the treatment, in association with a palliation of bone pain, while the serum alkaline phosphatase activities which had been within the normal range or slightly high before the treatment did not show any significant change or did not reflect a clinical feature (e.g. bone pain) with the treatment. Thus, the uptake ratio on the bone scintigram seemed to offer the most sensitive and most reliable information for the evaluation of calcitonin treatment of Paget's disease of bone.     

Characterization of a new external neutron beam facility at the Ohio State University

A thermal neutron beam facility has been designed and implemented at the Ohio State University Research Reactor. A project is underway to construct a large vacuum chamber such that the facility could have neutron depth profiling and neutron radiography capabilities as intended. The neutron beam is extracted from the reactor through a neutron collimator emplaced in Beam Port #2. The neutron spectrum entering the neutron collimator was unfolded from foil activation analysis results and also simulated with a full reactor core model in the MCNP Monte Carlo code. The neutron collimator uses polycrystalline bismuth as a gamma ray filter and single-crystal sapphire as a fast neutron filter. The beam is defined by multiple 3.0 cm diameter apertures made of borated aluminum. Characterization of the beam was performed using foil activation to find the flux and a low-budget neutron imaging apparatus to see the beam profile. The modulation transfer function was calculated to offer insight into the resolution of the imaging system and the collimation of the beam. The neutron collimator delivers the filtered thermal neutron beam with a ~4 cm diameter and a thermal equivalent flux of (1.27 ± 0.03) × 10⁷ n/(cm²s) at 450 kW power at the end of the collimator.     

Evaluation of geometries appropriate for 125I in vivo bone strontium X-ray fluorescence measurement

Summary In this study, we present a significant improvement in the minimum detection limit (MDL) for strontium measurement in bone with X-ray fluorescence using ¹²⁵I as the excitation source. The improvement was achieved thanks to a new collimator in the 90 degree geometry and a different source positioning in the 180 degree geometry. The achieved MDL in the 90 degree geometry is 0.0426±0.0006 mg Sr/g Ca, which is 5.5 times better than the one previously reported. In the 180 degree geometry, the new source positioning improved the MDL from 0.118±0.004 to 0.0446±0.0009 mg Sr/g Ca.     

Scintigraphic imaging of autotransplanted splenic grafts by 99mTc-labeled heat-damaged erythrocytes

Splenectomy is known to increase the risk of bacterial infection. Recently splenic autotransplantation has been suggested as a method of preserving splenic function. In order to demonstrate the viability of transplanted tissue, spleen scintigraphy using 99mTc labeled heat damaged erythrocytes were carried out. So far 21 studies have done in 12 patients. Spleen scans were positive 1 month after surgery, though images showed poor contrast against considerable background of bone marrow and blood pool. The quality of the images much improved five to twelve months after surgery. Functioning splenic autografts could be also shown by scintigraphy using 99mTc sulfur colloid, but the image quality was poorer, particularly within the early stage after operation. Labeling yields were 79.8% on the average, ranging from 45.6-92.3%, that affected little the quality of images. Important techniques in the splenic autotransplantation imaging include a thorough elimination of free 99mTcO4- before injection and to use comparatively small volume of damaged erythrocytes.     

Fundamental study for SPECT imaging with 123I produced by (p, 5n) reaction

The effects of higher-energy photon from 123I (p, 5n) on the SPECT image quality were evaluated. The quality was evaluated by image contrast and %rms. Image contrast had similar tendency to planar and SPECT FWHM value. %rms was affected by septal penetration. Using 140 keV high resolution collimator (140 keV HR), image contrast was superior to that for 300 keV medium energy collimator (300 keV ME), but septal penetration rate (SPR) was 18% and %rms was 10.5. When quantitation is required, the collimator with less SPR than 18% is recommended for SPECT imaging. Using 300 keV ME, SPR was 0.05%, but spatial resolution and image contrast were inferior to that for 140 keV HR.     

Bone marrow scintigraphy with 111In-chloride--a clinical value for the hematological diseases

Bone marrow scintigraphy with indium chloride (111In) was performed in fifty-one patients with the hematological diseases. The results of the investigation were that 1. in all patients, as well as in patients with aplastic anemia, no correlation was there between the degree of the indium chloride accumulation and peripheral blood counts, 2. in patients with aplastic anemia and pure red cell aplasia (PRCA) a tendency to reduction in uptake of indium chloride in bone marrow, 3. in patients with these two good correlation between the degree of indium chloride accumulation and histology of the erythroid bone marrow, but in patients with chronic myelocytic leukemia (CML) and atypical leukemia no correlation between the two, so it seemed unlikely that indium chloride should reflect the effective production of erythrocytes, 4. four patients with leukemia were studied with indium chloride bone marrow imaging two times to evaluate their responses to chemotherapy, and peripheral expansion was no change or reduced in two patients with acute myelocytic leukemia (AML) and one patient with acute lymphocytic leukemia (ALL) who obtained complete remission, but on the other hand, it enlarged in one patient with acute myelocytic leukemia who obtained partial remission, and 5. in two patients with chronic myelocytic leukemia it enlarged up to the ankle joints, which was considerably specific.     

Design and simulation of neutron radiography system based on 241Am–Be source

Neutron imaging is extended rapidly as a means of non-destructive testing (NDT) of materials. Various effective parameters on the image quality are needed to be studied for neutron radiography system with good resolution. In the present study a portable system of neutron radiography has been designed using ²⁴¹Am–Be neutron source. The effective collimator parameters were calculated to obtain relatively pure, collimated and uniform neutron beam. All simulations were carried out in two stages using MCNPX Monte Carlo code. In the first stage, different collimator configurations were investigated and the appropriate design was selected based on maximum intensity and uniformity of neutron flux at the image plane in the outlet of collimator. Then, the overall system including source, collimator and sample was simulated for achieving radiographic images of standard samples. Normalized thermal neutron fluence of 2.61×10^?5 cm^?2 per source particle with n/γ ratio of 1.92×10⁵ cm^?2 μSv^?1 could be obtained at beam port of the designed collimator. Quality of images was assessed for two standard samples, using radiographic imaging capability in MCNPX. The collimated neutron beam in the designed system could be useful in a transportable exposure module for neutron radiography application.     

Gonadal dose measurement in diagnostic nuclear medicine using thermoluminescent dosimeters

Instead of using the Medical Internal Radiation Dose Committee (MIRD) concept to calculate the gonadal dose during diagnostic examination using radiopharmaceuticals, measurements of gonadal doses using thermoluminescent dosimeters were studied. The results obtained are comparable with that calculated using the MIRD concept. Five frequently used examinations were investigated, viz., liver, brain, thyroid, bone scintigraphy and cholescintigraphy. The calibration of thermoluminescent dosimeters are fully described, and the experimental techniques are also fully presented.     

Technical study for SPECT of the head using slant hole collimator

The performance of a 160 keV slant hole collimator (160 keV SH) was compared with that of a 140 keV high resolution collimator (140 keV HR) for SPECT imaging of the head using 99mTc. The minimum radius of revolution was reduced from about 23 cm to 13 cm using 160 keV SH. Relative sensitivity of the 160 keV SH was 108% of that of the 140 keV HR. Compared with SPECT using 140 keV HR, 160 keV SH SPECT yielded approximately a 15% increase in resolution. The 160 keV SH SPECT images of phantom were superior in resolution and contrast to that of 140 keV HR SPECT. We concluded that high quality SPECT images of the head can be obtained from rotating gamma cameras equipped with slant hole collimators.