Using technetium-99m (V) dimercaptosuccinic acid to detect malignancies from single solid masses in the lungs.

Fifty patients (43 male, 7 female, age 31-77 years) with single solid masses in their lungs based on the findings of a chest X-radiograph [40 malignancies: 5 small cell carcinoma (Ca), 17 epidermoid Ca, 12 adeno Ca, 6 undifferentiated large cell Ca] and 10 benign lesions underwent technetium-99m (V) dimercaptosuccinic acid [99m-(V)DMSA] scans to evaluate the usefulness of 99mTc-(V)DMSA in the detection of lung Ca with different cell types and benign lesions. Only 43% (17/40) of the malignancies in the lungs were detected by 99mTc-(V)DMSA, including 29% (5/17) epidermoid Ca, 50% (6/12) adeno Ca and 17% (1/6) undifferentiated large cell Ca of the lungs. However, all 5 cases of small cell Ca and 11 cases combined with bone metastasis were revealed by 99mTc-(V)DMSA. In addition, 3 of the 10 benign lesions (2 organizing pneumonias, 1 benign tumor) presented with an uptake of 99mTc-(V)DMSA. The diagnostic sensitivity, specificity and accuracy were 43%, 70% and 48%, respectively, in differentiating malignant from benign lesions for the single solid mass in the lungs. In conclusion, 99mTc-(V)DMSA is of little or no use in the differentiation of lung Ca from single solid masses in the lungs.     

Differentiation of single solid lesions in the lungs by means of single-photon emission tomography with technetium-99m methoxyisobutylisonitrile

The value of technetium-99m methoxy-isobutylisonitrile (MIBI) single-photon emission tomography (SPET) of the chest in differentiating lung carcinomas of various histological types and benign lesions was assessed in 54 patients (47 males and 7 females aged 19–77 years) with single solid lung masses. Chest radiography had indicated that 46 of the lesions were malignant (8 small cell carcinomas, 14 epidermoid carcinomas, 18 adenocarcinomas and 6 undifferentiated large cell carcinomas) and eight, benign. Ten, volunteers who also agreed to undergo ^99mTc-MIBI SPET of the chest served as a control group. The results showed that only 65% (30/46) of the lung malignancies were detected by ^99mTc-MIBI SPECT, including 63% (5/8) of the small cell carcinomas, 64% (9/14) of the epidermoid carcinomas, 72% (13/18) of the adenocarcinomas and 50% (3/6) of the undifferentiated large cell carcinomas. However, 75% (6/8) of the benign lesions were also detected. The diagnostic sensitivity, specificity and accuracy in differentiating malignant and benign lesions were 65%, 57% and 70%, respectively. We conclude that ^99mTc-MIBI is of limited use in the differentiation of single solid lesions in the lungs. Correspondence to: Chia-Hung Kao     

Pentavalent technetium-99m DMSA uptake in pseudofractures of osteomalacia

Tc-99m MDP and Tc-99m (V) DMSA images are described from a 49-year-old woman with chronic renal insufficiency complicated by osteomalacia. Clinical, biochemical, and radiologic bone profiles were compatible with osteomalacia. Osteomalacia is a condition associated with disorders in which mineralization of the organic matrix is defective. All bone lesions visualized with Tc-99m MDP also showed increased uptake of Tc-99m (V) DMSA. Tc-99m (V) DMSA accumulation has been reported in many malignant and some benign conditions. Pseudofractures in osteomalacia could be included in the spectrum of benign lesions that accumulate Tc-99m (V) DMSA.     

The role of Tc-99m (V) DMSA scintigraphy in the diagnosis and follow-up of lung cancer lesions

Objective To define the role of Tc-99m (V) dimercaptosuccinic acid (DMSA) scanning in the detection of lung cancer (LC) and its metastases, and monitoring the response of LC lesions (LCL) to chemo/radiotherapy (TH). Methods Tc-99m (V) DMSA whole-body scans, planar thorax views, and thorax Single-photon emission computed tomography (SPECT) images were obtained both 30 min (early) and 5 h (late) after Tc-99m (V) DMSA administration in 12 small/nonsmall cell LC patients (11 men, 1 woman; mean age 59 years). Five patients also had bone scans. The same scintigraphic protocol was performed in 7 of 12 patients, 3 weeks after first-line TH. TH response was evaluated visually in all LCL and semiquantitatively in primary tumors (PT) of six patients, by comparing the tumor uptake ratios (TUR) of pre-TH and post-TH Tc-99m (V) DMSA SPECT [TUR = mean counts of region of interests (ROI) in PT/mean counts in contralateral ROI]. In seven patients, a 6-month survival was determined. Results Tc-99m (V) DMSA accumulated in 34 LCL (11 PT, 19 bone metastases, 1 suprarenal mass, 1 axillary node, 2 supraclavicular nodes). A total of 11 patients displayed Tc-99m (V) DMSA uptake in LCL and one patient did not show uptake. In six patients, SPECT imaging showed deeply located PT in the lung parenchyma better than planar views. In five patients, both planar and SPECT views revealed peripherally located PT in the lungs. Early scans showed 18 LCL and late scans displayed all the LCL. Nine bone metastases on pre-TH Tc-99m (V) DMSA scans revealed matched areas of increased Tc-99m methylene diphosphonate (MDP) uptake on bone scans; six bone metastases were additionally detected on Tc-99m (V) DMSA scans when compared with bone scans, and four bone metastases on Tc-99m (V) DMSA scans could not be compared with bone scans because bone scan was not performed. In one patient, Tc-99m (V) DMSA scans became positive for bone metastases on post-TH later than the bone scans for some of the bone metastases. Neither planar nor SPECT imaging showed mediastinal lesions defined on thorax CT in nine patients. On TH monitoring, 17 LCL showed diminished Tc-99m (V) DMSA uptake, one disappeared, four were unchanged, three displayed increased uptake, and five new lesions were established. Of the six patients, TUR in PT increased in two (one survived), decreased in one (exitus), was unchanged in two (two exitus) on post-TH scans, and PT totally disappeared in one (survived) patient. Conclusions Tc-99m (V) DMSA scans are useful in detecting LCL, except for those around the blood pool regions, making it a promising modality to monitor TH response. Obtaining a single fifth hour late Tc-99m (V) DMSA scan is appropriate. SPECT should be applied to all patients for the detection of deeply located lesions.     

Evaluation of Tc-99m(V) DMSA for imaging inflammatory lesions: An experimental study

The present study evaluated^99mTc(V) DMSA as an agent for the visualization of inflammatory lesions in comparison to^99mTc(HI) DMSA and^99mTc-HIG. All three radiopharmaceuticals were prepared with commercial kits.^99mTc(V) DMSA was prepared at neutral pH by the addition of first bicarbonate and then pertechnetate to the kit contents. The labeling efficiency was 99% as determined by ITLC. Abscesses were induced by i.m. injection of 50 μl turpentine into the right thighs of 36 Swiss albino mice. Six days later 3.7 MBq of each radiopharmaceutical was i.v. administered to 12 mice. The mice were sacrificed at 1,3,6 and 24 h later. Scintigrams were obtained with a gamma camera. The abscesses were better visualized on scintigrams with^99mTc(V) DMSA compared to^99mTc(III) DMSA, starting at 1 h. The animals were dissected and the organs were removed, weighed and the radioactivity determined with a gamma counter. The abscess to other tissue ratios were higher with^99mTc(V) DMSA than the other radiopharmaceuticals. The max. abscess/muscle ratios were 9.46 ± 3.20 (24 h), 4.19 ± 1.39 (6 h) and 5.98 ± 1.17 (24 h) and max. abscess/blood ratios were 6.22 ± 1.41, 4.09 ± 0.84 and 0.914 ± 0.351 all at 24 h for^99mTc(V) DMSA,^99mTc(III) DMSA and^99mTc-HIG, respectively. Experimental arthritis was produced in 6 New Zealand white rabbits by intra-articular injection of ovalbumin. Four days later 37 MBq of^99mTc(V) DMSA and^99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h clearly demonstrated arthritic joints. ROFs over arthritic joints were compared to contralateral normal joints (A/C). The max. A/C ratios were 2.10 ± 0.31 (3 h) and 2.92 ± 0.99 (24 h) for^99mTc(V) DMSA and^99mTc-HIG, respectively. Our results indicated the feasibility of imaging inflammatory lesions with^99mTc(V) DMSA.     

In vitro and in vivo evaluation of the influence of type III NaPi co-transporter activity during apoptosis on <Superscript>99m</Superscript>Tc-(V)DMSA uptake in the human leukaemic cell line U937

Purpose Pentavalent ^99mTc-dimercaptosuccinic acid [^99mTc-(V)DMSA or (V)DMSA] is a marker of phosphate transport, entering cells specifically through type III NaPi co-transporters. Phosphate ion is known to be involved in cell metabolism, including the apoptotic cell death process. As phosphate accumulation decreases during apoptosis, we investigated the influence of type III NaPi co-transporter activity on (V)DMSA uptake during this type of cell death.Methods Uptake of (V)DMSA and phosphate was compared in a leukaemic cell line (U937) in vitro model after induction of apoptosis by a chemotherapeutic agent, etoposide (VP16). (V)DMSA biodistribution in nude mice during apoptosis was also investigated in a U937 xenograft in vivo model. The percentage of apoptosis in vitro and ex vivo was determined with annexin V fluorescein by flow cytometry.Results The in vitro results showed that, in parallel with the decrease in phosphate uptake during apoptosis, (V)DMSA accumulation is negatively correlated with the percentage of apoptosis. Biodistribution studies showed decreased accumulation of (V)DMSA in tumours after treatment with VP16. Animal studies also confirmed an inverse correlation between percentage of apoptosis in tumours and (V)DMSA uptake.Conclusion The activity of type III NaPi co-transporter is inhibited during the early stages of apoptosis, leading to differential incorporation of (V)DMSA in viable cells and apoptotic cells both in vitro and in vivo.     

Solitary muscular sarcoidosis: CT,MRI, and scintigraphic characteristics

Scintigraphy using gallium-67 (⁶⁷Ga) citrate and penvaralent technetium-99m dimercaptosuccinic acid {[^99mTc(V)]DMSA} and other radiological examinations were performed in three patients with solitary muscular sarcoidosis who had tumor-like muscular lesions. Although distinction from other invasive soft tissue tumors was difficult using plain and enhanced computed tomography and magnetic resonance imaging, marked uptake of⁶⁷Ga and moderate uptake of [^99mTc(V)]DMSA were shown at the sites of granulomatous inflammatory lesions of sarcoidosis. Both⁶⁷Ga and [^99mTc(V)]DMSA scintigraphy could be of value in the diagnosis and detection of distribution of granulomas of sarcoidosis in the soft tissue and in determining the appropriate region for biopsy.     

Oxygen bubbling can improve the labelling of pentavalent technetium-99m dimercaptosuccinic acid

It has previously been reported that almost all of the trivalent technetium-99m dimercaptosuccinic acid (^99mTc (III) DMSA) present in the labelling product of pentavalent technetium-99m DMSA (^99mTc (V) DMSA) can be changed into^99mTc (V) DMSA by bubbling with pure oxygen. We therefore performed studies in animals (mice) and humans to investigate the effect of such oxygen bubbling on the labelling efficiency of and on the renal uptake of^99mTc. The method of labelling of^99mTc (V) DMSA was that of Hirano. It was found that oxygen bubbling oxidized the contaminated^99mTc (III) DMSA into^99mTc (V) DMSA in vitro and decreased the uptake of radioactivity in the kidney in both animals and humans.     

Scintimammographic detection of usual ductal breast hyperplasia with increased proliferation rate at risk for malignancy

OBJECTIVES: To estimate whether breast uptake of (99m)Tc-(V)DMSA and (99m)Tc-sestamibi in usual ductal epithelial breast hyperplasia (UDH) and apocrine metaplasia is related to cell proliferation rate (Ki-67) and oestrogen receptor (ER) expression, both of which are associated with the potential risk of evolving to malignancy. METHODS: Among patients referred for suspicious breast findings on palpation and/or mammography and evaluated preoperatively with both radiopharmaceuticals, we retrospectively studied 17 (10 with UDH: group I; and seven with apocrine metaplasia: group II). Lesion-to-background (L/B) ratios in early and late acquisitions were calculated for both radiotracers in both groups, as well as their retention ratios. Ki-67 and oestrogen receptor expression were determined immunohistochemically. The late L/B ratios between the two tracers were compared, as were the late ratios for each tracer between Ki-67 < or = 3% and > 3%, and between ER < or = 15% and > 15%. Linear regression analysis was also performed between L/B and retention ratios and Ki-67 expression. RESULTS: There was a significant increase of the (99m)Tc-(V)DMSA L/B ratio in late images as compared to the early images in group I (P<0.05), while in group II it was not significantly increased (P=0.084). (99m)Tc-sestamibi ratios did not demonstrate variability over time in either group (P=0.156 and 0.274, respectively). Significant coefficient correlation was found between the (99m)Tc-(V)DMSA L/B(late) ratios and retention ratios and Ki-67 levels only for group I (r=0.889, P<0.001 and r=0.802, P<0.01, respectively). The (99m)Tc-(V)DMSA L/B(late) ratios in group I were significantly higher when Ki-67 > 3% than when Ki-67 < or = 3% (P=0.016) but did not differ considerably between ER > 15% and < or = 15% (P=0.732). CONCLUSION: (99m)Tc-(V)DMSA uptake in UDH correlates with Ki-67 expression. This could prove useful in identifying women with benign but high-risk breast pathologies who might benefit from chemoprophylaxis.     

Influence of Pi3-K and PKC activity on 99mTc-(V)-DMSA uptake: correlation with tumour aggressiveness in an in vitro malignant glioblastoma cell line model

Purpose Intensive proliferation and a high degree of migration and invasion are characteristic features of malignant glioblastomas, associated with a poor prognosis. Phosphatidylinositol-3-kinase (Pi3-K) and protein kinase C (PKC) are two phosphorylated proteins involved in glioblastoma cell progression. Phosphorylated focal adhesion protein kinase (FAK) has also been reported to be involved in tumour progression. In a recent study, we demonstrated a correlation between phosphorylated FAK, proliferation rate and ^99mTc-(V)-dimercaptosuccinate [(V)-DMSA] uptake. We hypothesised that ^99mTc-(V)-DMSA could be a potential imaging agent to evaluate glioblastoma aggressiveness. The aim of the present study was to assess the relationship between ^99mTc-(V)-DMSA incorporation rate and modulation of Pi3-K and PKC activity.Methods Proliferation, migration and invasion capacities in the presence of protein kinase modulators—staurosporine (PKC inhibitor), 4-phorbol 12-myristate 13-acetate (PMA; PKC activator) and LY294002 (Pi3-K inhibitor)—were correlated with ^99mTc-(V)-DMSA cell accumulation in an in vitro model of several malignant glioma cells: G111 (grade II), U-87-MG (grade III) and G152 (grade IV).Results In all cell lines tested, LY294002 and staurosporine treatment inhibited cell proliferation, migration and invasion. In contrast, treatment with PMA stimulated tumour aggressiveness. ^99mTc-(V)-DMSA uptake was strongly correlated with the % of cellular proliferation (r=0.8462) and the % of cellular migration (r=0.9081), and to a lesser extent with the % of cellular invasion (r=0.7761).Conclusion Our results clearly demonstrated that ^99mTc-(V)-DMSA reflects Pi3-K and PKC activity and is correlated with tumour aggressiveness. ^99mTc-(V)-DMSA could be a reliable in vivo marker providing additional information on the biological status of malignant glioblastoma.     

Scintimammographic findings of in situ ductal breast carcinoma in a double-phase study with Tc-99m(V) DMSA and Tc-99m MIBI value of Tc-99m(V) DMSA

The authors present a case of in situ ductal carcinoma of the breast (DCIS) with no associated mass in a 46-year-old woman examined with Tc-99m MIBI and Tc-99m(V) DMSA scans, which were acquired in separate sessions 10 minutes and 60 minutes after injection. Histologic analysis revealed a small (<1 cm) infiltrating ductal carcinoma located within the DCIS. Mammography showed a cluster of microcalcifications on a very dense parenchymal background. Tc-99m(V) DMSA was characterized as positive for DCIS, especially in the delayed image. Tc-99m MIBI failed to identify the lesions previously noted. In conclusion, Tc-99m(V) DMSA scintimammography seems to have an advantage and could improve the detection of nonpalpable in situ breast carcinomas.     

In vitro and in vivo studies with pentavalent technetium-99m dimercaptosuccinic acid

The purpose of this investigation was to characterise the in vivo chemistry and binding mechanisms of technetium-99m dimercaptosuccinic acid [^99mTc(V)DMSA]. Biodistribution was studied in mice by frozen section whole-body autoradiography and microautoradiography in selected tissues. Binding to bone mineral analogues was studied in vitro using various forms of calcium phosphate and hydroxyapatite under varied conditions. Similar studies with^99mTc-hydroxymethylene diphosphonate (HDP) were also carried out for comparison. The in vivo stability of^99mTc(V)DMSA was monitored by high-performance liquid chromatographic analysis of blood and urine samples taken over 24 h from patients injected with the tracer. Whole-body autoradiography shows that^99mTc(V)DMSA has highest affinity for bone (cortical rather than medullary) in mice. Substantial uptake of the tracer was also observed in the kidney (cytoplasm of cortical renal tubular cells). No specific localisation was observed in the liver at either the microscopic or the macroscopic level. While^99mTc-HDP bound strongly to calcium phosphates under all conditions,^99mTc(V)DMSA binding was inhibited in the presence of phosphate and was stronger at pH 6.0 than at pH 7.4. In non-phosphate buffers, however, the binding of^99mTc(V)DMSA remained high across the pH range 4–7.4.^99mTc(V)DTVISA binds to calcium phosphates chemically unaltered, and no radioactive species other than the three isomers of^99mTc(V)DMSA were detected in blood or urine samples taken from patients up to 24 h after injection.^99mTc(V)DMSA is stable in vivo, and no conversion of the complex to other chemical species needs to be invoked to explain its uptake in bone metastases or soft tissue tumour. Bone affinity may be due to reversible binding of the unaltered complex to the mineral phase of bone.     

A comparison of the tumor-seeking agent Tc-99m(V) dimercaptosuccinic acid and the renal imaging agent Tc-99m dimercaptosuccinic acid in humans

Being aware of the ideal nuclear properties of Tc-99m, our interest has been focused on the design of the (+5) oxidation state Tc-99m(V) dimercaptosuccinic acid (Tc(V)-DMSA) as a tumor-seeking agent. Tc-99m(V) DMSA holds a TcO4(3-) core and, like PO4(3-), has excellent characteristics for tumor uptake, but has a different distribution than the well-known renal scanning agent, Tc-99m DMSA. The differences in chemical behavior of Tc-99m(V) DMSA and Tc-99m DMSA are discussed. Three cases in which neoplasms were studies with Tc-99m(V) DMSA and Tc-99m DMSA are presented. Tc-99m DMSA and Tc-99m(V) DMSA, having a common ligand and tracer but, with the metal ion core in a different oxidation state, the uptake characteristics are altered markedly.     

Tc-99m(V) DMSA imaging. A new approach to studying metastases from breast carcinoma.

Combined Tc-99m MDP skeletal imaging and Tc-99m(V) DMSA whole body scans to detect metastases were performed during the follow-up of 30 patients who underwent surgery for breast carcinoma. Eight patients had normal Tc-99m MDP and Tc-99m(V) DMSA scans and were declared free of metastatic disease, further confirmed by no change in symptomatology over a 1-year follow-up period. Twenty-two patients had positive Tc-99m MDP scans with varied skeletal involvement. Tc-99m(V) DMSA scans showed matched areas of increased radiotracer concentration in bony metastases in 20 of these patients. Tc-99m(V) DMSA concentration was not seen in traumatic vertebral collapse or in coexistent osteoarthritic disease in vertebral metastatic involvement. Interestingly, Tc-99m(V) DMSA showed increased concentration in brain and liver metastases. Pentavalent Tc-99m(V) DMSA appears useful for detecting skeletal and soft-tissue metastases in breast carcinoma, and can improve the specificity of Tc-99m MDP bone scans in screening for bone metastases.     

The value of Tc-99m (V) dimercaptosuccinic acid in detecting intra-abdominal infection: compared with gallium scan

Objective Gallium-67 (Ga-67) and labeled leukocytes are useful in the detection of an unknown infectious source. However, the delay in the diagnosis of a Ga-67 citrate scan (gallium scan) and the complicated labeling technique of a leukocyte scan are major drawbacks to their clinical use. Recently, Tc-99m (V) dimercaptosuccinic acid (DMSA) has been found to be very useful in the detection of infection. Tc-99m (V) DMSA is inexpensive, easy to prepare, and provides a result within hours. In this study, we evaluated the potential of Tc-99m (V) DMSA scan (DMSA scan) in the detection of intra-abdominal infection. Methods A total of 33 patients who suffered from an unknown cause of fever after colorectal surgery were enrolled in this study. All patients received both a gallium scan and a DMSA scan. DMSA scintigraphy was performed 3–4 h after an injection of 740 MBq (20 mCi) of Tc-99m DMSA. After completion of the DMSA image, 111 MBq (3 mCi) of Ga-67 citrate was injected intravenously. Gallium scintigraphy was performed after 24 h and later as needed. Results Of the 33 patients, 17 (51.5%) were diagnosed with intra-abdominal abscesses. For DMSA scans, the sensitivity, specificity, and overall accuracy were 88.2%, 93.7%, and 90.9%, respectively. For gallium scans, the diagnostic sensitivity, specificity, and accuracy were 100%, 87.5%, and 93.9%, respectively. No statistical difference was found in the diagnostic accuracy between these two diagnostic modalities using Fisher's exact test. Conclusions DMSA scan is a useful alternative to gallium scan in the detection of intra-abdominal infection in patients with colorectal surgery because Tc-99m DMSA is inexpensive, easy to prepare, and most importantly the result can be obtained within hours.     

Pentavalent rhenium-188 dimercaptosuccinic acid for targeted radiotherapy: synthesis and preliminary animal and human studies

Pentavalent rhenium-188 dimercaptosuccinic acid [¹⁸⁸Re(V)DMSA] is a β-emitting analogue of ^99mTc(V)DMSA, a tracer that is taken up in a variety of tumours and bone metastases. The aim of this study was to develop the kit-based synthesis of the agent on a therapeutic scale, to assess its stability in vivo, and to obtain preliminary biodistribution and dosimetry estimates, prior to evaluation of its potential as a targeted radiotherapy agent. The organ distribution of ¹⁸⁸Re in mice was determined 2 h after injection of 3 MBq ¹⁸⁸Re(V)DMSA prepared from eluate from a ¹⁸⁸W/¹⁸⁸Re generator. Three patients with cancer of the prostate and three with cancer of the bronchus, all with bone metastases confirmed with a standard ^99mTc-hydroxymethylene diphosphonate (^99mTc-HDP) scan, were given 370 MBq ¹⁸⁸Re(V)DMSA and imaged at 3 h and 24 h using the 155-keV γ-photon (15%). Blood and urine samples were collected to determine clearance and to analyse the speciation of ¹⁸⁸Re. Organ residence times were estimated from the scans, and used to estimate radiation doses using MIRDOSE 3. In mice, ¹⁸⁸Re(V)DMSA was selective for bone and kidney. In patients, it showed selectivity for bone metastases (particularly those from prostate carcinoma) and kidney, but uptake in normal bone was not significantly greater than in surrounding soft tissues. Of the normal tissues the kidneys received the highest radiation dose (0.5–1.3 mGy/MBq). The images were strongly reminiscent of ^99mTc(V)DMSA scans in similar patients. High-performance liquid chromatography analysis of blood and urine showed no evidence of ¹⁸⁸Re in any chemical form other than ¹⁸⁸Re(V)DMSA up to 24 h. In conclusion, ¹⁸⁸Re(V)DMSA and its ¹⁸⁶Re analogue warrant further clinical assessment as generator/kit-derived agents for treatment of painful bone metastases. These agents should also be assessed in medullary thyroid carcinoma and other soft tissue tumours which have been shown to accumulate ^99mTc(V)DMSA. Received 8 January and in revised form 28 February 1998     

The role of Tc-99m (V) DMSA scintigraphy in the evaluation of superscan on bone scintigraphy

PURPOSE: This study evaluated the biodistribution of Tc-99m (V) DMSA in patients with superscans on bone imaging and defined its role in differentiating the underlying cause. METHODS: Nine patients (five with metastatic and four with metabolic bone disease) with classical superscans were entered into the study. All patients had the necessary radiologic and biochemical studies and a final diagnosis was reached accordingly. Tc-99m (V) DMSA scintigraphy was performed 1 week after Tc-99m MDP whole-body bone imaging. RESULTS: In four of five patients with widespread skeletal metastases, Tc-99m (V) DMSA scan showed diffusely increased bone uptake. In the remaining patient, the Tc-99m (V) DMSA scan showed a normal distribution pattern. All patients with metabolic bone disease had increased bone uptake on Tc-99m (V) DMSA scans. CONCLUSION: Tc-99m (V) DMSA shows increased bone uptake in patients having a superscan appearance in metastatic or metabolic bone disease. Tc-99m (V) DMSA imaging may play a role in the evaluation of patients with equivocal bone scan findings for a superscan.     

Power Doppler sonography versus Tc-99m DMSA scintigraphy for diagnosing acute pyelonephritis in children: are these two methods comparable?

PURPOSE This study assessed the role of renal power Doppler ultrasonography (PDU) to identify acute pyelonephritis (APN) and to determine whether PDU can replace Tc-99m DMSA renal scintigraphy in the diagnosis of APN in children.METHODS A prospective study was conducted in 40 infants and young children (78 kidneys were evaluated) with a mean age of 25.9 months (range, 1 to 68 months) who were hospitalized with a first episode of high fever and bacteruria, possibly APN. All children were examined by PDU and Tc-99m DMSA within the first 3 days after admission. Patients with congenital abnormalities, hydronephrosis, and urinary reflux were excluded.RESULTS Twenty-seven of the 78 kidneys appeared abnormal on Tc-99m DMSA, and 20 of them were abnormal on PDU. Fifty-one of 78 kidneys were normal on Tc-99m DMSA, and 3 of 51 appeared diseased on PDU. The accuracy of PDU was 87%, sensitivity was 74%, and specificity was 94%. The positive predictive and negative predictive values were both 87%. When considering the numbers of lesions in 27 kidneys with positive Tc-99m DMSA studies (38 lesions), PDU did not disclose 16 lesions (false-negative results). Thus, the sensitivity of PDU for diagnosing lesions of APN decreased to 58%.CONCLUSIONS A positive PDU finding should obviate the use of Tc-99m DMSA in patients thought to have possible APN. However, because of a large number of false-negative results (26%) and underestimation of the number of pyelonephritic lesions (low sensitivity of 58%), PDU cannot replace Tc-99m DMSA in the diagnosis of APN in children.     

Correlation between 99mTc-(V)-DMSA uptake and constitutive level of phosphorylated focal adhesion kinase in an in vitro model of cancer cell lines

Purpose Although a number of prognostic indicators have been developed, it is still difficult to predict the biological behaviour of all cancer types. ^99mTc-(V)-DMSA (V DMSA) uptake and focal adhesion kinase (FAK) expression and activation level could be potential agents for this purpose. We hypothesised the existence of a correlation between V DMSA, whose uptake is linked to phosphate ions, essential compounds for tumour growth and cell proliferation, and the adhesion protein FAK, whose elevated expression and level of constitutive activation are implicated in cancer progression. The aim of this study was to assess the relationship between V DMSA incorporation rate and FAK expression and activation by phosphorylation on tyrosine 397 residue.Methods We determined V DMSA uptake in six different cancer cell lines and we measured FAK expression and activation by using Western Blotting analysis. Correlations with factors known to be associated with poor prognosis, such as invasive potential, resistance to chemotherapy and proliferation rate, were also investigated. Results The cell lines exhibited different V DMSA incorporation rates. In addition, these cells showed the same FAK expression, but various degrees of activation. A correlation was observed between V DMSA uptake and level of FAK phosphorylation and between V DMSA or constitutive FAK activation and proliferation rate. However, no correlation was shown between these parameters and the other factors tested, i.e. invasive potential and anticancer drug resistance.Conclusion The results of this in vitro study clearly demonstrate that phosphorylation of FAK, proliferation rate and V DMSA uptake are closely related. Because proliferation and a high level of constitutive FAK activation are linked to cancer progression, it can be assumed that in vivo V DMSA uptake reflects tumour aggressiveness.     

Synthesis and characterization of [186Re]rhenium(V)dimercaptosuccinic acid: A possible tumour radiotherapy agent

[¹⁸⁶Re]Re(V)DMSA, a β-emitting analogue of the tumour imaging radiopharmaceutical pentavalent [^99mTc]Tc(V)DMSA of possible value in tumour therapy, is readily prepared by stannous reduction of [¹⁸⁶Re]ReO₄⁻ in the presence of dimercaptosuccinic acid at 100°C using a commercial DMSA kit as used for renal imaging with ^99mTc, and purified using a disposable sample preparation column. The complex has been identified as [ReO(DMSA)₂]⁻ by NMR, optical and i.r. spectroscopy and elemental analysis.