Is (99m)Tc-labelled pamidronate a better agent than (99m)Tc-medronate for bone imaging?

OBJECTIVE: To evaluate the potential of (99m)Tc-pamidronate ((99m)Tc-APD) against (99m)Tc-medronate ((99m)Tc-MDP) as a new bone-seeking agent using intact bone and fractured femur in a rat model. METHODS: (99m)Tc-APD was prepared by the stannous reduction method. Scintigraphic images were obtained at 2 h and 24 h after intravenous injection of (99m)Tc-APD or (99m)Tc-MDP in rats, then they were culled to estimate activities in various organs. Bone uptake (as percent injected dose/gram weight) was estimated in an intact femur and in 1 week post-fracture model. The urinary excretion dose (as percent injected dose) was also estimated. RESULTS: The bone uptake of (99m)Tc-APD was significantly higher (P<0.05) than (99m)Tc-MDP at 2 h and 24 h post-injection studies. (99m)Tc-APD uptake was further increased (P<0.05) in the fracture model than the intact femur. (99m)Tc-APD uptake in the soft tissues including liver and the kidneys was lower than (99m)Tc-MDP. Renal excretion was faster and the ratios of bone to blood and bone to soft tissues were higher with APD than MDP. APD dose was selected at 1% of MDP, to obviate therapeutic effect, as the former compound is 100 times more potent than MDP. CONCLUSIONS: Our results suggest that (99m)Tc-APD uptake by intact bone and fractured bone was significantly higher than (99m)Tc-MDP. The renal clearance of (99m)Tc-APD was faster and soft tissue uptake was lower than (99m)Tc-MDP. These results suggest that APD has the potential to become an excellent bone-imaging agent.     

Validation of ultrafiltration as a method of measuring free 99mTc-MDP.

Quantitative studies of the kinetics of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) in metastatic and metabolic bone disease require the measurement of free tracer in plasma to derive the input function. Several methods of measuring free (99m)Tc-MDP have been described including ultrafiltration, precipitation using trichloroacetic acid, and a direct in vivo measurement based on the assumption that free MDP is cleared through the kidneys by glomerular filtration. The aim of this study was to validate ultrafiltration as a convenient and accurate method of measuring the free fraction of (99m)Tc-MDP by comparing it with the glomerular filtration rate (GFR) method. A second aim was to measure the percentage of free (99m)Tc-MDP in a cross-section of patients using ultrafiltration to determine the interpatient variability and, therefore, whether individual measurements are required for bone kinetic studies. METHODS: In study 1, 10 volunteers (7 women, 3 men; mean age, 37 y; range, 26-55 y) were injected with 3 MBq (99m)Tc-MDP and 3 MBq (51)Cr-ethylenediaminetetraacetic acid, and multiple blood and urine samples were taken between 0 and 4 h. Plasma samples were spun in 5-, 10-, and 30-kDa filters and counted in a gamma-counter. In study 2, 51 randomly selected patients (26 women, 25 men; mean age, 66 y; range, 31-87 y) attending our department for a routine bone scan were injected with 600 MBq (99m)Tc-MDP, and 4 blood samples were taken between 0 and 4 h and spun in 10-kDa filters. RESULTS: In study 1, the mean percentages (+/-SD) of free (99m)Tc-MDP at 5 min and 4 h after injection measured using the 10-kDa filters were 83.1% +/- 3.4% and 44.0% +/- 10.0%. The mean ratios (+/-SEM) of the free (99m)Tc-MDP in ultrafiltrate compared with the GFR method for the 5-, 10-, and 30-kDa filters were 0.894 +/- 0.010, 0.943 +/- 0.009, and 0.987 +/- 0.010. In study 2, the mean percentages (+/-SD) of free (99m)Tc-MDP at 15 min and 4 h were 75.3% +/- 8.0% and 48.8% +/- 9.5%, with a precision error of 2.3%. The percentages of free MDP at 150 min and 4 h were significantly correlated with GFR but not with serum albumin. CONCLUSION: Ultrafiltration provides an accurate method of evaluating free (99m)Tc-MDP in plasma for bone kinetic studies. The results from both the healthy volunteers in study 1 and the patients in study 2 show that protein binding varied with time and showed significant differences between individuals that were partly dependent on GFR. It is thus necessary to measure individual protein binding values for bone kinetic studies.     

^18FDG-PET和^99mTc-MDP骨扫描检测骨转移瘤价值的比较

目的:评价18FDG-PET恶性肿瘤骨转移的作用及与99mTc-MDP-ECT 比较.材料和方法: 经病理证实为恶性肿瘤患者51 例及非肿瘤性疾病5例在本科同时接受18F-FDG-PET和99mTc-MDP-ECT检查(时间间隔不超过2周).骨转移的诊断由病理、X线或CT/MRI、随访超过1年综合决定.结果:99mTc-MDP和18FDG-PET 对骨转移瘤诊断的灵敏度、特异性、准确率率分别为93.7%、93.7%,97.5%、50%,90.8%、62.5%.99mTc-MDP和18FDG-PET均为阳性15例,其中证实骨转移为14例,假阳性1例;均为阴性例数为20例.21例不相符的结果中20例99mTc-MDP-ECT 阳性而18F-FDG-PET 为阴性.18F-FDG-PET和99mTc-MDP-ECT假阴性各1例.均诊断为多发骨转移的12例患者中99mTc-MDP-ECT发现的骨转移病灶数多于18F-FDG-PET.结论:18F-FDG-PET 与99mTc-MDP骨扫描相比较对肿瘤骨转移的探测有较高的特异性,但敏感性较低.     

16-Detector multislice CT in the detection of stress fractures: a comparison with skeletal scintigraphy

AIMS: To test the hypothesis that the improved resolution afforded by 16-detector computed tomography (CT) would translate to better stress fracture detection when compared with skeletal scintigraphy. MATERIALS AND METHODS: Thirty-three cases of suspected stress fractures in 26 patients were investigated using skeletal scintigraphy and 16-detector CT performed on the same day. Planar images of the lower limbs were taken 3h post-injection of 400MBq (99m)Tc-methylene diphosphonate ((99m)Tc-MDP). (99m)Tc-MDP uptake was quantified at suspected fracture sites. CT was performed using a 16-detector multisection machine employing 0.75mm detectors and images reconstructed in 0.5mm increments. Examinations were reported independently and discordant results were compared at follow-up. RESULTS: At initial reporting scintigraphy identified fractures in 13 of the 33 cases and CT identified four of the 33. In one case, on review of the CT images, a fracture was present in the distal fibula that was not initially identified. This resulted in eight scintigraphic-positive CT-negative discordant cases. The (99m)Tc-MDP uptake was significantly lower in the discordant fracture group compared with the concordant group (p<0.01). CONCLUSIONS: Despite technological advances in CT, scintigraphy appeared to detect more stress fractures. As such, multidetector CT should not be used as a routine initial investigation in stress fracture detection. The potential use of (99m)Tc-MDP quantification at fracture sites is of interest and may be worth further investigation.     

Prognostic significance of (18)F-FDG and (99m)Tc-methylene diphosphonate uptake in primary osteosarcoma.

The purpose of this retrospective analysis was to evaluate the prognostic significance of both initial glucose metabolism as measured by (18)F-FDG PET and osteoblastic activity as measured by (99m)Tc-methylene diphosphonate (MDP) bone scintigraphy in osteosarcoma. METHODS: In 29 patients (18 male, 11 female; age range, 5-41 y) with primary osteosarcoma, (18)F-FDG uptake and (99m)Tc-MDP uptake were measured semiquantitatively (average and maximum tumor-to-nontumor ratios [T/NT(av) and T/NT(max), respectively]) using PET and bone scintigraphy at the time of diagnosis. After chemotherapy, the patients underwent surgery for their primary tumor, and the response was determined histologically. Cumulative overall survival and event-free survival were determined by clinical and imaging follow-up of 7-72 mo (median, 28 mo). RESULTS: Clinical and imaging follow-up revealed that the disease relapsed or failed to achieve complete remission in 9 patients and that 6 patients died of the disease. Both overall and event-free survival were significantly better in patients with a low (18)F-FDG T/NT(max) (less than the median) than in patients with a high (18)F-FDG T/NT(max) (at least the median). The negative relationship of (18)F-FDG T/NT(av), (99m)Tc-MDP T/NT(max), and (99m)Tc-MDP T/NT(av) with overall and event-free survival did not reach a level of significance. (18)F-FDG uptake values correlated moderately and positively with (99m)Tc-MDP uptake values, but a level of significance was reached only between (18)F-FDG T/NT(max) and (99m)Tc-MDP T/NT(av). CONCLUSION: The initial glucose metabolism of primary osteosarcoma as measured by (18)F-FDG PET using T/NT(max) provides prognostic information. High (18)F-FDG uptake correlates with poor outcome. Thus, (18)F-FDG uptake may be complementary to other well-known factors in judging the prognosis in osteosarcoma.     

Quantitative studies of bone using (18)F-fluoride and (99m)Tc-methylene diphosphonate: evaluation of renal and whole-blood kinetics

We report a study of the renal and whole-blood kinetics of (18)F-fluoride and (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) and their effect on the evaluation of the skeletal kinetics of the two bone tracers. Data were obtained during an investigation of postmenopausal women taking hormone replacement therapy who were compared with untreated, age-matched controls. After intravenous injection of 18F-fluoride (1 MBq), (99m)Tc-MDP (1 MBq), (51)Cr-ethylenediaminetetraacetic acid (51Cr-EDTA) (3 MBq) and (125)I-human serum albumin ((125)I-HSA) (0.25 MBq), multiple blood samples and urine collections were taken between 0 and 4 h after injection. (51)Cr-EDTA data were used to evaluate the glomerular filtration rate (GFR) and the completeness of each timed urine collection. (125)I-HSA data were used to evaluate the plasma volume and the red cell uptake of the other three tracers. At 4 h, the cumulative urine excretions (and standard deviations, SDs) were: (99m)Tc-MDP, 58.2% (4.8%); (18)F-fluoride, 36.1% (5.7%); (51)Cr-EDTA, 81.5% (4.5%). Plots of the renal clearance of (18)F-fluoride against urine volume showed that urine flow rates greater than 5 ml.min-1 were necessary to ensure a constant renal clearance of (18)F and hence stable conditions for the evaluation of bone tracer kinetics. In contrast, a low urine flow rate had no effect on the renal kinetics of (99m)Tc-MDP. For MDP, the evaluation of skeletal kinetics requires data on protein binding so that calculations can be performed for free MDP. In the present study, protein binding of MDP was evaluated from the ratio of total (99m)Tc-MDP renal clearance to GFR based on the principle that free (99m)Tc-MDP is a GFR tracer. Between 0 and 4 h after injection, the fractional protein binding of MDP increased linearly with time, changing from 21+/-5% immediately after injection to 58+/-5% at 4 h. Although red cell uptake of (99m)Tc-MDP was negligible, for (18)F-fluoride around 30% of circulating tracer was transported in red cells. In view of the data showing the rapid transport of (18)F-fluoride across the red cell membrane, bone kinetic data for (18)F are more accurately reported as whole-blood clearance rather than plasma clearance.     

Quantitative measurements of bone remodeling using 99mTc-methylene diphosphonate bone scans and blood sampling.

Quantitative studies of bone using (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) have a potentially valuable role in investigating the treatment of patients with metabolic bone disease. In this study we compared 3 different methods of measuring whole-skeleton (99m)Tc-MDP plasma clearance (K(bone)) in 12 osteoporotic postmenopausal women (mean age, 67.3 y) before participation in a clinical trial of an osteoporosis therapy. The aim was to compare the consistency and accuracy of the 3 methods before their use in evaluating the subjects' response to treatment. METHODS: Subjects were injected with 600 MBq (99m)Tc-MDP and 3 MBq (51)Cr-ethylenediaminetetraacetic acid ((51)Cr-EDTA) and whole-body bone scan images were acquired at 10 min, 1, 2, 3, and 4 h. Two-minute static images of the thighs were acquired immediately after the 1- to 4-h whole-body scans. Six blood samples were taken between 5 min and 4 h, and free (99m)Tc-MDP was measured using ultrafiltration. The glomerular filtration rate (GFR) was estimated from the (51)Cr-EDTA plasma curve. The methods used to evaluate K(bone) were (a) the area-under-the-curve (AUC) method, in which the GFR measurement was subtracted from the total (bone plus renal) clearance (K(total)) measured from the free (99m)Tc-MDP plasma curve; (b) the modified Brenner method, in which (99m)Tc-MDP renal clearance estimated from the whole-body counts was subtracted from the total clearance measured from the rate of elimination of tracer from soft tissue; and (c) the Patlak plot method, which was also used to derive regional values of K(bone) for the skull, spine, pelvis, arms, and legs. RESULTS: There was good agreement between the 3 methods of measuring K(bone). (mean K(bone) +/- SD: AUC method, 30.3 +/- 6.4 mL x min(-1); Brenner method, 31.1 +/- 5.8 mL x min(-1); Patlak method, 35.7 +/- 5.8 mL x min(-1)). The correlation coefficients between the methods varied from r = 0.767 (P = 0.004) to r = 0.805 (P = 0.002). Regional measurements of (99m)Tc-MDP clearance gave the following percentages of the whole-skeleton clearance: skull, 13.3%; spine, 16.6%; pelvis, 17.2%; arms, 11.1%; legs, 23.7%. CONCLUSION: The 3 methods gave consistent and accurate measurements of K(bone). The Patlak method can be used to study regional as well as total-skeleton values of K(bone).     

Scintigraphic imaging of knee synovitis in osteoarthritis after intra-articular injection of technetium-99m pertechnetate in the unilateral knee

A case of left knee synovitis scintigraphic imaging is presented in a 66-year-old patient with bilateral knee osteoarthritis and a right knee Baker's cyst, who had undergone a 74 MBq (99m)Tc-pertechnetate intra-articular injection in the right knee. The findings in this case were compared with the intravenously injected methylene disphosphonate technetium-99m ((99m)Tc-MDP) scintigraphic findings and could be interpreted as the result of (99m)Tc-pertechenate through blood communication from the right to the left knee. This case implies that (99m)Tc-pertechnetate may be useful in imaging the synovitis in multiple arthroses even up to 60 min after its administration, instead of the 5 min imaging after the injection of (99m)Tc-MDP.     

Abundant blood supply and low P-glycoprotein expression on dynamic 99mTc-MIBI imaging predicted better chemotherapy sensitivity for a breast cancer patient: a case report

A patient with a history of breast cancer underwent 3-phase (99m)Tc-methylene diphosphonate (MDP) imaging followed 3 d later by 3-phase (99m)Tc-sestamibi (MIBI) imaging. During the vascular and blood-pool phases, a lymph node over the right clavicle was seen on both the (99m)Tc-MIBI and the (99m)Tc-MDP scans at as early as 30 s and then became hotter. Four months after receiving chemotherapy, the patient achieved a complete response. The lymph node over the right clavicle vanished on ultrasound examination. The similar distribution of the blood-pool phase between the (99m)Tc-MDP and (99m)Tc-MIBI scans indicated that (99m)Tc-MIBI may similarly provide information on vascularization of the lymph node. In addition to indicating vascularization, our (99m)Tc-MIBI protocol may simultaneously provide information on P-glycoprotein expression important for predicting chemotherapy sensitivity. With information on the resistance of a tumor to drugs and the environment in which it dwells, chemotherapy sensitivity might be predicted more precisely.     

Transient splenic uptake of 99mTc-MDP associated with haemolysis

The spleen was visualized in a 32-year-old patient with Hodgkin's disease (IIIB) and autoimmune haemolytic anaemia during a ^99mTc-MDP bone scan. This visualization disappeared within 3 months with the regression of the haemolysis.     

A report on the incidence of intestinal 99mTc-methylene diphosphonate uptake of bone scans and a review of the literature

BACKGROUND: In addition to well-known specific conditions for soft-tissue uptake of bone-seeking radiotracers, there is a limited number of reports on intestinal uptake of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) on bone scans. AIM: To describe the incidence of intestinal accumulation of (99m)Tc-MDP on bone scans in adult patients, define the patterns of this unusual finding and review the literature on its causes. METHODS: Two thousand, one hundred and forty-four consecutive patients have been evaluated for intestinal (99m)Tc-MDP uptake on bone scans. Intestinal uptake was observed visually 3-4 h after the administration of the radiopharmaceutical. A whole-body bone scan and various spot views of the abdomino-pelvic region were obtained with a dual-headed gamma camera to evaluate the intestinal uptake. Delayed scans were also obtained as well as co-relative imaging and/or colonoscopic studies in some of intestinal uptake patients. Six patients had delayed scans of the abdomino-pelvic region. Fourteen patients had comparable scans either a year before or a year later. The positive intestinal uptake scans were further grouped according to the localization and intensity (mild uptake: lower than iliac bone; moderate uptake: equal to iliac bone; significant uptake: higher than iliac bone). RESULTS: Twenty-two (17 female, five male) patients out of 2144 with a mean age of 57 years showed intestinal (99m)Tc-MDP uptake. The localization was mainly (20/22) in the right abdomino-pelvic region projecting on and in the configuration of ascending colon while one patient showed intestinal uptake all over the abdomen and one displayed diffuse intestinal radioactivity in his right hemithorax. The majority of the cases showed moderate to intense intestinal uptake (18/22). Six patients showed a decrease, disappearance or alteration in the intestinal uptake on the delayed images. Re-evaluation bone scans in five patients 1 year later showed no intestinal uptake this time. Among nine patients with prior bone scans 1 year before, intestinal uptake was negative in seven at that time. No significant pathology was obtained on the correlative images. CONCLUSION: (99m)Tc-MDP uptake can be observed in the intestines in 1% of bone scans with a prominent localization in the ascending colon and rarely all over the intestines or in thorax due to Chilaiditi's syndrome, as well. The mechanism of intestinal uptake is still unclear in some of the patients. Delayed imaging, additional spot views and SPECT studies help in the differentiation of this finding from possible misinterpretation. Intestinal (99m)Tc-MDP uptake on bone scan could be an intermittent process and should be included among other well-known reasons of soft-tissue uptake.     

The value of quantitative uptake of (99m)Tc-MDP and (99m)Tc-HMPAO white blood cells in detecting osteomyelitis in violated peripheral bones

Our objective in this study was to evaluate whether measurement of quantitative uptake of (99m)Tc-methylene diphosphate (MDP) and (99m)Tc-hexamethylpropyleneamine oxime (HMPAO) white blood cells (WBCs) is useful in detecting osteomyelitis in peripheral bony lesions. METHODS: Twenty-four patients (12 men and 12 women; age range, 25-72 y) were referred for imaging because of clinically suspected osteomyelitis. They had a traumatic fracture (n = 10), knee prosthesis (n = 5), hip prosthesis (n = 2), diabetic foot (n = 4), or chronic osteomyelitis (n = 3). Three-phase bone scanning and (99m)Tc-HMPAO WBC studies were performed on all patients within the same week. Regions of interest were drawn over the abnormal bony sites and the contralateral normal sites, and the abnormal-to-normal uptake ratios (A/N ratios) were obtained for both studies. RESULTS: All patients had abnormal findings on 3-phase bone scanning, whereas 17 (71%) had abnormal findings on (99m)Tc-HMPAO WBC studies, of which 15 were confirmed to be true-positive. In those 15 patients, the mean A/N ratios for (99m)Tc-MDP and (99m)Tc-HMPAO WBC were 3.0 +/- 1.6 (range, 1.3-6.2) and 1.8 +/- 0.3 (range, 1.4-2.2), respectively. In the other 9 patients, whose scan results were clinically confirmed to be true-negative, the mean A/N ratios for (99m)Tc-MDP and (99m)Tc-HMPAO WBC were 2.1 +/- 1.2 and 1.2 +/- 0.2, respectively. In the group with a (99m)Tc-MDP A/N ratio greater than 2 (n = 15), 87% (13/15) had a high (99m)Tc-HMPAO WBC A/N ratio (>1.5), including 2 that were false-positive. In the remaining 2 patients, one with chronic osteomyelitis and the other with a recent hip prosthesis, (99m)Tc-HMPAO WBC ratios were normal. In the group with a bone A/N ratio of less than 2 (n = 9), only 4 patients (44%) were true-positive for acute osteomyelitis. CONCLUSION: (99m)Tc-MDP bone scanning alone, with an A/N ratio of more than 2, is useful in detecting osteomyelitis in violated bone except in the case of a recent hip prosthesis or chronic osteomyelitis.     

Unilateral pulmonary metastases from Ewing's sarcoma shown in a technetium-99m-methylene-diphosphonate bone scan

A 32-year-old man with a history of painful swelling of the right ankle underwent bone scintigraphy, which showed increased uptake in the right ankle and also unexpected diffuse uptake throughout the right hemithorax. A single photon emission tomography scan performed after the intravenous injection of 740 MBq of technetium-99m methylene-diphosphonate ((99m)Tc-MDP) showed abnormal uptake throughout the right lung. Computed tomography (CT) revealed a large mass in the right lower lobe. CT-guided biopsy of this mass led to a diagnosis of metastatic Ewing's sarcoma. Although lung uptake on bone scans has been noted in various occasions (such as: pulmonary alveolar microlithiasis, Pneumocystis carinii pneumonia, and various tumoral lesions), increased uptake of (99m)Tc-MDP in lung metastases of Ewing's sarcoma has not been reported according to our knowledge until now. We report such a case.     

The rabbit biodistribution of a therapeutic dose of zoledronic acid labeled with Tc-99m

The aim of the present study was to label a therapeutic dose of zoledronic acid (ZOL) with Tc-99m, evaluate its in vitro stability and compare its biodistribution to ^99mTc-methylene biphosphonate (^99mTc-MDP) in normal rabbits. Preparation of 0.50 mg of ^99mTc-ZOL was carried out by the reduction of ^99mTc-pertechnetate in the presence of stannous chloride. The radiolabeling efficiency was found to be greater than 99%. The labeled complex was stable at least up to 6 h at room temperature determined by paper chromatography. ^99mTc-ZOL and ^99mTc-MDP were administered intravenously to the rabbits for scintigraphic studies. Between ^99mTc-ZOL and ^99mTc-MDP, there were no significant differences in the ratios of femur/BG and lumbar vertebrae/BG, whereas epiphysis/BG and the kidney/BG ratios of ^99mTc-MDP were higher than ^99mTc-ZOL at the static studies.     

(99m)Tc-interleukin-8 for imaging acute osteomyelitis.

Early and accurate diagnosis of osteomyelitis remains a clinical problem. Acute osteomyelitis often occurs in infants and most often is located in the long bones. Radiologic images show changes only in advanced stages of disease. Scintigraphic imaging with (99m)Tc-methylene diphosphonate (MDP), or bone scanning, is much more sensitive in detecting acute osteomyelitis but lacks specificity. We evaluated the performance of (99m)Tc-interleukin-8 (IL-8) in an experimental model of acute osteomyelitis. METHODS: Acute pyogenic osteomyelitis was induced in 10 rabbits by inserting sodium morrhuate and Staphylococcus aureus into the medullary cavity of the right femur. The cavity was closed with liquid cement. A sham operation was performed on the left femur. Routine radiographs were obtained just before scintigraphy. Ten days after surgery, the rabbits were divided into 2 groups of 5 animals, received an injection of either 18.5 MBq (111)In-granulocytes or 18.5 MBq (67)Ga-citrate, and were imaged both 24 h after injection and 48 h after injection. On day 12, the rabbits received either 18.5 MBq (99m)Tc-MDP or 18.5 MBq (99m)Tc-IL-8, and serial images were acquired at 0, 1, 2, 4, 8, 12, and 24 h after injection. Uptake in the infected femur was determined by drawing regions of interest. Ratios of infected femur (target) to sham-operated femur (background) (T/Bs) were calculated. After the final images were obtained, the rabbits were killed and the right femur was dissected and analyzed for microbiologic and histopathologic evidence of osteomyelitis. RESULTS: Acute osteomyelitis developed in 8 of 10 rabbits. All imaging agents correctly detected the acute osteomyelitis in these animals. The extent of infection was optimally visualized with (67)Ga-citrate and delayed bone scanning, whereas diaphyseal photopenia was noted with both (99m)Tc-IL-8 and (111)In-granulocytes. In 1 rabbit with osteomyelitis, imaging results were falsely negative with (111)In-granulocytes and falsely positive with (99m)Tc-MDP. Quantitative analysis of the images revealed that the uptake in the infected region was highest with (67)Ga-citrate (4.9 +/- 0.8 percentage injected dose [%ID]) and (99m)Tc-MDP (4.7 +/- 0.7 %ID), whereas the uptake in the infected area was significantly lower with (99m)Tc-IL-8 (2.2 +/- 0.2 %ID) and (111)In-granulocytes (0.8 +/- 0.2 %ID) (P < 0.0042). In contrast, the T/Bs were significantly higher for (99m)Tc-IL-8 (T/B, 6.2 +/- 0.3 at 4 h after injection) than for (67)Ga-citrate, (99m)Tc-MDP, and (111)In-granulocytes, which had ratios of 1.5 +/- 0.4, 1.9 +/- 0.2, and 1.4 +/- 0.1, respectively (P < 0.0001). Radiography correctly revealed acute osteomyelitis in only 2 of 8 rabbits. CONCLUSION: In this rabbit model of osteomyelitis, (99m)Tc-IL-8 clearly revealed the osteomyelitic lesion. Although the absolute uptake in the osteomyelitic area was significantly lower than that obtained with (99m)Tc-MDP and (67)Ga-citrate, the T/Bs were significantly higher for (99m)Tc-IL-8 because of fast background clearance. The ease of preparation, good image quality, and lower radiation burden suggest that (99m)Tc-IL-8 may be a suitable imaging agent for the scintigraphic evaluation of acute osteomyelitis.     

99Tc-亚甲基二膦酸盐与153Sm-乙二胺四亚甲基膦酸对骨侵袭和骨质溶解抑制作用的对比研究

目的 对比观察99c-亚甲基二膦酸盐(99Tc-MDP)与153Sm-乙二胺四亚甲基膦酸(153Sm-EDTMP)对Walker256癌细胞引起的大鼠骨侵袭和骨质溶解的抑制作用及二者对移植瘤细胞的影响.方法 建立Walker 256癌大鼠骨侵袭和骨质溶解模型.设空白对照组、99Tc-MDP治疗组、153Sm-EDTMP治疗组、99Tc-MDP+153Sm-EDTMP治疗组,采用99Tcm-MDP全身骨显像、骨骼X线片及胫骨病理切片方法观察两种药物单独或联合应用对荷瘤大鼠骨侵袭和骨质溶解的抑制作用,并通过流式细胞仪分析两种药物对移植瘤细胞的影响.结果 与对照组相比,99Tc-MDP治疗组、153Sm-EDTMP治疗组、99Tc-MDP+153Sm-EDTMP治疗组均能明显抑制荷瘤大鼠骨侵袭和骨质溶解(确切概率法:P<0.05).两种药物联合应用与单独应用相比未见明显差异.各治疗组移植瘤细胞的凋亡率明显高于对照组,S期的细胞比例明显下降,二者联合应用的作用更明显.结论 ①99Tc-MDP及153Sm-EDTMP对荷Walker 256癌大鼠均有抑制骨侵袭和骨质溶解的作用;②两种药物在诱导移植瘤细胞凋亡、抑制移植瘤细胞增殖方面均有一定作用,二者联合应用的作用更明显.     

Trapping of technetium-99m albumin macroaggregate and other four radiopharmaceuticals by blood clots in vitro

Radiopharmaceuticals are known to interact with the blood components (i.e. the red blood cells, serum proteins etc) but so far, there have been no data regarding their purely mechanical trapping in thrombi. The experiments presented in this communication provide evidence that the technetium-99m labeled albumin macroaggregate ((99m)Tc-MAA), apparently due to its particle size, can be almost quantitatively retained in the in vitro model described. These results can be extrapolated in vivo and offer a plausible explanation for either the "hot spot" artifact, occasionally seen in lung perfusion imaging or for the partial trapping of (99m)Tc-MAA by a thrombus at the tip of a subclavian catheter, as has been recently reported. Control experiments were also run using (99m)Tc-methylene diphosphonate ((99m)Tc-MDP), (99m)Tc(III)-dimercaptosuccinic acid ((99m)Tc(III)-DMSA), (99m)Tc-methoxyisobutyl isonitrile ((99m)Tc-MIBI) and sodium pertechnetate (Na(99m)TcO(4)), in order to study the extent of trapping of these radiopharmaceuticals under identical incubation conditions. (99m)Tc-MDP and (99m)Tc(III)-DMSA exhibited the lowest blood clot uptake (partially non-specific and partially mechanical trapping), while in the case of (99m)Tc-MIBI and Na(99m)TcO(4), besides mechanical and non-specific clot-trapping, transport and retention inside the red blood cells was also observed.     

Unusual extraosseous tumoral accumulation of 99mTc-MDP

Three cases (rhabdomyosarcoma, lymphoma, and metastatic malignant melanoma) of unexpected increased uptake of methylenediphosphonate labelled by technetium 99m sodium pertechnetate (^99mTc-MDP) are described. The possible mechanisms of the extraosseous tumoral accumulation of ^99mTc-MDP in these malignancies are discussed. The usefulness of this method for the diagnosis, localization, and follow-up of some extraosseous tumors is evaluated.     

Localization of Tc-99m MDP in epiphyseal growth plates of rats

The distribution and localization of Tc-99m methylene diphosphonate (Tc-MDP) in the epiphyseal growth plates of the rat were elucidated by contact and microautoradiography. The uptake of the tracer was found to be especially high in the calcified cartilage bars at the end of the vascular loops. In addition to areas of mineralization, increased uptake was found in the Howship's lacunae on the resorbing surfaces. This labeling corresponded with the fluorescence of tetracycline, which labeled both forming and resorbing surfaces, when given with short labeling interval. Distribution of Tc-MDP did not coincide with new production of collagen, as judged by H-3 proline labeling; nor was the uptake localized within cells with high alkaline phosphatase activity. The affinity of the tracer for the mineral phase was confirmed by decalcification of in vivo labeled sections with EDTA, which showed loss of radioactivity in contrast to sections incubated in water. By chromatography the activity in the decalcification medium could not be distinguished from that of Tc-MDP.     

99mTc-MDP retention in osteoporosis: Relationship to other indices of bone cell activity and response to calcium and vitamin D therapy

Serum calcium, albumin, phosphorus, and alkaline phosphatase, urinary creatinine and retention of ^99mTc-methylene bisphosphonate (^99mTc-MDP) were measured in 61 subjects with osteoporosis and the values compared with those obtained in normal subjects. ^99mTc-MDP retention was inversely related with urinary creatinine output in normal subjects. In osteoporotic subjects urinary creatinine output was lower and ^99mTc-MDP retention higher even when urinary creatinine output was taken into account. Other measurements were similar. In 21 subjects these measurements together with urinary hydroxyproline were performed before and after treatment with calcium and vitamin D. ^99mTc-MDP and alkaline phosphatase fell; urinary hydroxyproline was unchanged. A single 24 h urine measurement after ^99mTc-MDP injection is a valuable method of predicting whether calcium and vitamin D therapy will be useful in a particular case of osteoporosis.