Development of a battery of tests to measure attitudes and intended behaviours of dental students towards people with disability or those in marginalised groups.

INTRODUCTION: Recommended curricula in Special Care Dentistry (SCD) outline learning objectives that include the domain of attitudes and behaviours, but these are notoriously difficult to measure. The aims of this study were (i) to develop a test battery comprising adapted and new scales to evaluate values, attitudes and intentions of dental students towards people with disability and people in marginalised groups and (ii) to determine reliability (interitem consistency) and validity of the scales within the test battery. MATERIALS AND METHODS: A literature search identified pre-existing measures and models for the assessment of attitudes in healthcare students. Adaptation of three pre-existing scales was undertaken, and a new scale was developed based upon the Theory of Planned Behaviour (TPB) using an elicitation survey. These scales underwent a process of content validation. The three adapted scales and the TPB scale were piloted by 130 students at 5 different professional stages, from 4 different countries. RESULTS: The scales were adjusted to ensure good internal reliability, variance, distribution, and face and content validity. In addition, the different scales showed good divergent validity. DISCUSSION: These results are positive, and the scales now need to be validated in the field. CONCLUSIONS: It is hoped that these tools will be useful to educators in SCD to evaluate the impact of teaching and clinical exposure on their students.

Construction and identification of a model for HJURP gene defect expression in human embryo villus cells.

OBJECTIVES: To construct a lentiviral vector for RNA interference (RNAi) of the HJURP gene and to identify the silencing efficiency in the human embryo villus cells and to provide a human embryo villus cells multiplication and chromosome segregation. MATERIALS AND METHODS: In accordance with the study, three specific sequences of siRNA targeting HJURP gene were designed, synthesized, then the complementary DNA containing both sense and antisense oligonucleotides of the targeting sequences were annealed and inserted into the lentiviral vector.The correct clonings were confirmed by PCR and sequencing. The most effective recombinant lentivirus vector was screened, and the recombinant plasmids with the lentivirus packaging mixes were co-transfected into 293T cells to obtain packaged lentivirus particles. Then viral titer was determined. The silencing efficiency of target gene in human embryo villus cells was detected by Real-Time PCR. RESULTS: DNA sequencing showed that the shRNA sequence was successfully inserted into the lentivirus vector. The recombinant lentiviral vector was successfully transfected into 293T cells. The recombinant lentivirus had a titer of 108 PFU/ml. After silencing HJURP gene in human embryo villus cells, the expression level of HJURP mRNA decreased significantly and the RNAi efficiency was greater than 70%. CONCLUSION: A lentiviral shRNA expression vector targeting the HJURP gene was successfully constructed and may effectively silence the target gene at a cellular level, which provides a experimental model for the influence of HJURP gene expressing inhibition on human embryo villus cells multiplication and chromosome segregation.

Guidance for the core content of a Curriculum in Special Care Dentistry at the undergraduate level.

Given the rapidly changing demography of populations worldwide, dental professionals of the future need to be able to meet the challenge posed by the evolving landscape in health care needs. Leading institutions are now embedding teaching and learning in special care dentistry (SCD) within their curricula, to provide students with the knowledge, skills and attitudes to meet the oral health needs of vulnerable groups within their communities. The International Association for Disability and Oral Health (iADH) has initiated the development of undergraduate curriculum guidance in SCD through a consensus process. The curriculum in SCD is defined in statements of learning outcomes with many of the skills being transferable across the undergraduate course. This curriculum includes examples of teaching and assessment, designed to enhance critical thinking in relation to SCD and to promote positive attitudes towards disability and diversity. The learning outcomes are designed to be readily adapted to conform to the generic profiles and competencies, already identified in undergraduate frameworks by global educational associations, as well as meeting the requirements of professional regulatory bodies worldwide. Suggestions for teaching and learning are not intended to be prescriptive; rather, they act as a signpost to possible routes to student learning. Ideally, this will require that students have a sufficiently diverse patient case mix during their undergraduate studies, to achieve the required levels of confidence and competence by the time they graduate. Clinical care competencies in SCD emphasise the need for learners to broaden their theoretical knowledge and understanding through practical experience in providing care for people with special health care needs. It is crucial to the development of equitable dental services for all members of a community, that these learning outcomes are embedded into evolving curricula but most importantly, that they are evaluated and refined in a dynamic way with shared learning for all teachers.

Combined acetaminophen and ibuprofen for pain relief after oral surgery in adults: a randomized controlled trial.

BACKGROUND: Acetaminophen is often used with a non-steriodal anti-inflammatory drug for acute pain. Hitherto, these drugs have had to be given separately, typically at different time intervals. Maxigesic tablets combine acetaminophen and ibuprofen in clinically appropriate doses to simplify administration and dosage regimen. We compared this combination with each of the constituent drugs for the relief of pain after extraction of third molar teeth. METHODS: Adults (more than 16 yr) having one or more wisdom teeth removed under general or local anaesthesia were instructed to take two tablets before operation, then two tablets every 6 h for up to 48 h of: (i) a combination of acetaminophen 500 mg and ibuprofen 150 mg per tablet (Maxigesic); (ii) acetaminophen 500 mg per tablet alone; or (iii) ibuprofen 150 mg per tablet alone. The primary outcome measure was the area under the curve (AUC) of the 100 mm visual analogue scale pain measurements taken for up to 48 h after surgery, divided by time, at rest and on activity. Pharmacokinetic data were collected in a subset of patients. RESULTS: The mean (sem) time-corrected AUC on rest and activity, respectively, were: combination group 22.3 (3.2) and 28.4 (3.4); acetaminophen group 33.0 (3.1) and 40.4 (3.3); and ibuprofen group 34.8 (3.2) and 40.2 (3.4); P<0.01 for each of the four comparisons of combination vs constituent drug. There was no pharmacokinetic interaction between acetaminophen and ibuprofen administered together. CONCLUSIONS: Maxigesic tablets provide superior pain relief after oral surgery to acetaminophen or ibuprofen alone.

A follow-up study on the effects of a milk supplement on bone mineral density of postmenopausal Chinese women in Malaysia.

BACKGROUND: A previous study on a randomized controlled trial in 173 postmenopausal Chinese women in Kuala Lumpur showed that milk supplementation was effective to reduce bone loss at the total body, lumbar spine, femoral neck and total hip compared to the control group on a usual diet (Chee et al. 2003). OBJECTIVE: The objective was to determine whether the results were sustained after the conclusion of the study. DESIGN: A follow-up study, 18 months after a randomized controlled trial of milk supplementation was concluded. A total of 139 participants were followed up 21 months after the study ended. Bone mineral density (BMD) was measured at the total body, lumbar spine, femoral neck and total hip by dual energy X-ray absorptiometry, and anthropometric measurements as well as changes in dietary habits were measured. RESULTS: At the follow-up, the milk supplement group did not show significant bone loss from baseline at most sites (mean differences +/- SE) (total body 0.42 +/- 0.25%, femoral neck 0.44 +/- 0.58%, total hip -0.06 +/- 0.46%), unlike the control group (total body -1.07 +/- 0.28% p < 0.005, femoral neck -1.49 +/- 0.56% p < 0.05, total hip -0.89 +/- 0.57% p < 0.05). However, both the milk and control groups showed bone loss from baseline at the lumbar spine (milk -2.01%, control -3.29%, p superior 0.05). The calcium intake of the milk group remained significantly higher than the control group (milk 710 mg/day, control 466 mg/day, p < 0.005) despite discontinuation of the milk supplement. CONCLUSIONS: The results showed that some of the beneficial effects of a milk supplement were still evident at follow-up and it was possible to motivate subjects to adopt a positive change in dietary calcium intake after intervention.

Biodistribution study of [99mTc] TRODAT-1 alone or combined with other dopaminergic drugs in mice with macroautoradiography.

A 99mTc labeled tropane derivative, [99mTc] TRODAT-1 (2beta-((N,N'-bis(2-mercaptoethyl) ethylene diamino)methyl), 3beta-(4-chlorophenyl) tropane), is a potential dopamine transporter (DAT) imaging agent for the central nervous system. To better understand the binding localization of [99mTc] TRODAT-1 both in the brain and the body, whole-body macroautoradiography (WBAR) was used in this study. The effect of DAT competing drugs, such as levadopa (L-DOPA), N-methyl-2beta-carbomethoxy-3beta-(4fluorophenyl)tropane (CFT, WIN 35,428) and methylphenidate, on the biodistribution of [99mTc] TRODAT-1 were also included in this study. Doses of 150 MBq [99mTc] TRODAT-1 were injected into normal male ICR mice through the caudal veins. For comparison, mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), L-DOPA, methylphenidate and CFT, respectively, were also investigated under the similar protocols. One and a half hours after [99mTc] TRODAT-1 injection, the mice were sacrificed. Whole-body autoradiography was performed immediately after sacrifice. Both frontal and sagittal sections showed that the liver and mucosa of stomach had the highest uptake of [99mTc] TRODAT-1. Other binding sites included the periphery of the spinal cord and the epithelium of the intestine. In the brain, autoradiographic imaging obtained from frontal sections showed symmetrical uptakes of [99mTc] TRODAT-1 in bilateral striata. Remaining binding sites include olfactory bulbs, thyroid gland, and salivary gland. The autoradiographic imaging obtained from sagittal sections showed a similar biodistribution. Mice treated with MPTP or L-DOPA showed no significant difference in the uptake of [99mTc] TRODAT-1 in bilateral striata, as compared to those of the control. In CFT or methylphenidate-treated mice, DAT binding sites were almost completely inhibited. These data showed that [99mTc] TRODAT-1 has potential clinical use for neurological investigation, such as Parkinson's and similar diseases.

The role of dopamine transporter imaging agent [99mTc]TRODAT-1 in hemi-parkinsonism rat brain.

This study aims to investigate the relationship between the determination of dopamine level by high performance liquid chromatography (HPLC) with electrochemical detection (ECD) and the detection of dopamine transporter (DAT) counts using autoradiography with DAT image agent [99mTc]TRODAT-1. For striatal lesions, pretreatment of 6-hydroxydopamine (6-OHDA) in the medial forebrain bundle shows that autoradiogaphic labeling of striatum region is reduced to near-background level. Using HPLC with ECD, unilateral 6-OHDA treatment is associated with significant (p < 0. 0002) reductions of dopamine levels. For the striatum of the 6-OHDA-lesioned side, dopamine content and DAT counts are reduced to 97% and 90%, respectively. Thus, our observation indicates a potential of using [99mTc]TRODAT-1 for the evaluation of animal DAT.

Efficacy of Re-188-labelled sulphur colloid on prolongation of survival time in melanoma-bearing animals.

UNLABELLED: In this study, the effectiveness of a 188Re labeled sulfur colloid with two particle size ranges was used to evaluate the effectiveness of this agent on melanoma tumors in mice in terms of animal lifespan. METHODS: Two separate group of animals were used for investigating biodistribution and survival time. A total of 188 B16F10-melanoma-bearing BDF(1) mice were injected intraperitoneally with 3.7 MBq (0.1mCi)/2mL of radiolabeled sulfur colloid ten days after intraperitoneal inoculation of 5x10(5) B16F10 melanoma cells/2ml. For group 1, 30 mice were sacrificed at 1, 4, 24, 48 and 72 hours for biodistribution studies. In group 2, 158 mice were divided into 9 groups (n=16 approximately 18/groups)each receiving respectively tumor alone, tumor with normal saline, cold colloid or hot colloid with 16, 23, 31, 46, 62, or 124 MBq activity. Each of these colloid groups was further divided into two groups, one receiving smaller particle sizes (<3 microm:80.4 +/-7.2%, colloid 1) and the other receiving larger particle sizes (<3 microm:12.3+/-1.0%, colloid 2). The animals were checked daily until death and their survival recorded. RESULTS: Colloid 2 showed higher accumulation in almost all tissues, the highest accumulation organ was tumor ( approximately 40%), then spleen ( approximately 20%), stomach ( approximately 15%), diaphragm ( approximately 3%), and liver ( approximately 2%). There was a significant increase in survival time with increasing amount of the larger-particle-size colloid. Administered levels of 16-31 MBq/mouse were most efficacious and with higher amounts the survival times decreased significantly below that of the controls. There was a significant difference in the dose-response curves for the two preparations. Protection factors (1/Relative-risk) of nearly 5 were achieved using the larger colloid size, and nearly 30 using the smaller colloid size. An amount of 16-31 MBq of the colloid 2 was the optimal activity in these studies. On the one hand, the survival data agreed well with the biodistribution data, where higher accumulation was found in tumor with colloid 2. CONCLUSION: Rhenium-188 offers on-site availability, medium half-life, higher beta-particle energy of 2.12 MeV for therapy and emission of 155keV gamma photon suitable for imaging. The present study demonstrated that 188Re-sulfur colloid is an effective agent in controlling tumor cells in the abdominal cavity in animals.

Evaluation of early-stage Parkinson's disease with 99mTc-TRODAT-1 imaging.

UNLABELLED: Parkinson's disease is a progressive neurodegenerative disorder characterized by a selective loss of dopamine in the striatum. Problems remain in the accurate diagnosis of Parkinson's disease. A 99mTc-labeled tropane derivative that binds to dopamine transporter with high selectivity is [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)] (TRODAT-1). The purpose of this study was to investigate the potential usefulness of 99mTc-TRODAT-1 imaging in the evaluation of patients with early-stage Parkinson's disease. METHODS: Thirty-four patients with early-stage idiopathic Parkinson's disease were recruited. For all patients, the Parkinson's disease was stage 2 or less as assessed by the Hoehn and Yahr scale. Seventeen age-matched healthy volunteers (8 men, 9 women) served as controls. 99mTc-TRODAT-1 was prepared from a lyophilized kit. Brain SPECT imaging was performed between 165 and 195 min after injection, using a double-head camera equipped with fanbeam collimators. Specific uptake in the striatum and its subregions, including the putamen and caudate nucleus, was calculated and compared with that of the other sides and of healthy volunteers. RESULTS: A continuous reduction in specific striatal uptake of 99mTc-TRODAT-1 with increasing disease severity was found in Parkinson's disease patients (control vs. stage I vs. stage II, 1.98 vs. 1.62 vs. 1.22, respectively, P < 0.01). The changes were magnified by measurement of specific putaminal uptake (control vs. stage I vs. stage II, 1.81 vs. 1.27 vs. 0.94, respectively, P < 0.01). The mean values of specific putaminal uptake contralateral to the more affected limbs were significantly decreased compared with the ipsilateral sides in both stage I and stage II groups (1.02 vs. 1.49 for stage I and 0.73 vs. 1.14 for stage II, P < 0.01). Moreover, a significant loss of putaminal uptake ipsilateral to the symptoms was found in the stage I group compared with the healthy volunteers (1.49 vs. 1.81, P < 0.01). The difference became greater when the posterior putaminal uptakes were compared. No remarkable adverse reactions were found in either healthy volunteers or Parkinson's disease patients during or after imaging. CONCLUSION: For clinical practice, 99mTc-TRODAT-1 may serve as a useful imaging agent for the early detection of Parkinson's disease.

Histologic study of effects of radiation synovectomy with Rhenium-188 microsphere.

Rhenium-188 microsphere is a relatively new radiation synovectomy agent developed for the treatment of rheumatoid arthritis. It has been shown that the levels of unwanted extra-articular radiation are negligible with this agent. A histologic study was conducted to assess the effect of radiation synovectomy on synovium and articular cartilage after intra-articular injection of various doses of Re-188 microspheres into the knee joints of rabbits. Intra-articular injection of Re-188 microspheres into rabbit knee joints resulted in mild reactive inflammation and thrombotic occlusion of vessels which subsided rapidly. Sclerosis of subsynovium could be seen 12 weeks after injection. No evidence of damage to articular cartilage was noted. There was no significant difference in the articular pattern after injection of 0.3 or 0.6 mCi Re-188 microspheres. This study suggests that a treatment dose of Re-188 microspheres causes transient inflammation of synovium without any detectable damage to the articular cartilage of knee joint.

Differential diagnosis of Parkinson's disease and vascular parkinsonism by (99m)Tc-TRODAT-1.

UNLABELLED: The aim of this study was to use brain SPECT to differentiate vascular parkinsonism (VP) from Parkinson's disease. METHODS: Fourteen VP patients (age range, 59-87 y; mean age, 70 +/- 7.5 y), 30 Parkinson's disease patients (age range, 54-84 y; mean age, 65 +/- 8.8 y), and 26 healthy (control) individuals (age range, 50-85 y; mean age, 60 +/- 9 y) were examined. A 925-MBq (25 mCi) dose of (99m)Tc-TRODAT-1 was injected intravenously, and brain SPECT images were acquired 4 h after injection. The ratio of specific to nonspecific striatal (99m)Tc-TRODAT-1 binding was measured and compared. RESULTS: After a region-of-interest analysis of the images from VP patients, Parkinson's disease patients, and healthy volunteers was performed to obtain ratios of putamen to occipital and striatal to occipital binding as a measurement of specific binding to the dopamine transporters in these regions of the brain, where dopamine neurons are concentrated, the specific binding in the 14 VP patients was slightly lower than but not statistically different from that of the healthy individuals in both putamen and caudate areas. A significant decrease in uptake of (99m)Tc-TRODAT-1 in the striatum (P<0.01) was found in Parkinson's disease patients. Reduction of the uptake was more pronounced in the contralateral putamen of Parkinson's disease patients than that of VP patients (P<0.001). A significant bilateral striatal asymmetry was also observed in Parkinson's disease patients but not in VP patients (P< 0.01). CONCLUSION: Our findings clearly show that, for VP patients, (99m)Tc-TRODAT-1 SPECT is a reliable method to differentiate VP from Parkinson's disease. Further studies, including those to differentiate Parkinson's disease from arteriosclerotic parkinsonism and patients with both VP and Parkinson's disease, are needed to help rule out the possibility of Parkinson's disease as early as possible.

The optimal imaging time for [99Tcm]TRODAT-1/SPET in normal subjects and patients with Parkinson's disease.

Imaging of dopamine transporters (DATs) in the brain using [99Tcm]TRODAT-1 showed excellent pharmacokinetics for estimation of transporter concentrations. It has been reported that there may be differences in the binding kinetics of DAT radiotracers to DATs between normal subjects and patients with Parkinson's disease (PD). The aim of this study was to determine an optimal time point for (99Tcm]TRODAT-1 brain single photon emission tomography (SPET) acquisition that provides stable target to non-target ratios reflecting the DAT concentration in the brain. Serial [99Tcm]TRODAT-1 brain SPET images 2, 3 and 4 h after intravenous injection of [99Tcm]TRODAT-1 (925 MBq) were performed in five healthy subjects and nine PD patients. Regions of interests were drawn, and caudate/occipital (C/O) and putamen/occipital (P/O) specific to non-specific [99Tcm]TRODAT-1 binding ratios were calculated. The C/O and P/O ratios in healthy subjects showed consistent increases with time, but in PD patients, the C/O and P/O ratios of [99Tcm]TRODAT-1 reached a stable level at 3 h post-injection. There was a statistically significant difference (P < 0.001) between PD and normal subjects at 4 h post-injection for both the C/O and the P/O ratios. In conclusion, we recommend the acquisition of [99Tcm]TRODAT-1 SPET images at 4 h post-injection, as at this time point the C/O and P/O ratios can be used to discriminate between PD patients and healthy subjects.

The case for daily dialysis: its impact on costs and quality of life.

Research suggests daily hemodialysis may improve clinical outcomes. To date, a comprehensive review of its implications on quality of life has not been performed, and little is known about its economic impact. We conducted an economic evaluation comparing short daily or nocturnal hemodialysis with thrice-weekly conventional in-center dialysis. Data on the quality of life and clinical effects of daily dialysis were obtained from more than 60 reports from 13 daily dialysis programs around the world (n = 197). Cost data were derived principally from the US Renal Data System, Centers for Disease Control, and Medicare Payment Advisory Commission. Resource use during daily hemodialysis was modeled after two ongoing programs in the United States. Results suggest that patients feel better and direct treatment costs could be reduced with daily dialysis. Costs are sensitive to assumptions about the effect of daily dialysis on hospital days. Reductions of at least 8% in hospital days are required for these modalities to be cost saving compared with documented reductions of 30% to 100%. Larger well-controlled studies of daily versus conventional dialysis would be helpful to determine whether daily dialysis fulfills these promises. Medicare policy, which limits payment for most patients to three dialysis treatments weekly, poses a disincentive to more widespread adoption among dialysis centers. Given this constraint to broader acceptance, we address several policy options to gain a better understanding of the potential risks and benefits of daily dialysis.

Sedation and analgesia in adult patients: evaluation of a staged-dose system based on body weight for use in abdominal interventional radiology.

PURPOSE: To evaluate the safety and effectiveness of a systematic protocol for sedation and analgesia in interventional radiology. MATERIALS AND METHODS: Ninety-one adult patients underwent 113 abdominal interventional procedures. Fentanyl citrate and midazolam hydrochloride were administered in one to five steps (A, B, C, D, E) until the patient was drowsy and tranquil at the effective loading dose (ELD). Doses per step were as follows: A, fentanyl 1 microg per kilogram of body weight; B, midazolam 0.010-0.035 mg/kg; C, repeat dose in A; D, repeat half the dose in B; and E, midazolam 1-2-mg boluses (maximum, 0.15 mg/kg). RESULTS: The ELD was reached in no procedure after step A, in 70 after B, in 23 after C, and in 18 after D. Step E was needed in two procedures. The mean maximum pain score (scale of 0 to 10) was 3.4; pain scores in 85 (75%) procedures were 4 or less (discomforting). Severe pain occurred in seven (6%) procedures. Hypoxia (oxygen saturation < 90%) occurred in 11 (22%) procedures performed in patients breathing room air and four (6%) performed in those breathing supplemental oxygen (P: =.04). All patients responded to supplemental oxygen. CONCLUSION: This stepwise "ABCDE protocol" allows safe and effective sedation of patients. It is easy to use and may be useful in training radiology residents, staff, and nurses in the techniques of sedation and analgesia. Supplemental oxygen should be used routinely.

Decreased dopamine transporter binding in Machado-Joseph disease.

UNLABELLED: The aim of this study was to use 99mTc-TRODAT-1 brain SPECT for investigation of the binding of dopamine transporter (DAT) in the nigrostriatal dopaminergic pathway of symptomatic Machado-Joseph disease (MJD) and to compare the results with the abnormal cytidylate, adenylate, and guanylate (CAG) expansion in the MJD1 gene and other clinical factors. METHODS: Ten symptomatic MJD patients (8 women, 2 men; age range, 20-71 y; mean age +/- SD, 36.4 +/- 10.6 y; mean duration of illness, 9.8 +/- 5.4 y) and 21 healthy volunteers (age range, 24-71 y; mean age, 47.6 +/- 20.1 y) were examined. Brain SPECT images were acquired 4 h after injection. The ratio of specific to nonspecific nigrostriatal 99mTc-TRODAT-1 binding was measured and compared with the clinical symptoms, duration of illness, and size of abnormal expanded CAG repeats. RESULTS: All nigrostriatal 99mTc-TRODAT-1 ratios were significantly lower in MJD patients than in healthy volunteers (P < 0.05). Discriminant function analysis of all MJD patients showed that the decreased binding of 99mTc-TRODAT-1 in the putamen was not significantly different from that in the caudate nucleus. Eight of 10 MJD patients had significantly decreased 99mTc-TRODAT-1 uptake. Of these 8, 2 had extrapyramidal signs and 6 had no obvious extrapyramidal signs. The other 2 patients, who had normal 99mTc-TRODAT-1 uptake, had no obvious extrapyramidal signs. CONCLUSION: Our findings indicate that 99mTc-TRODAT-1 brain SPECT is an appropriate method for evaluating damage to the nigrostriatal DAT in symptomatic MJD patients with and without extrapyramidal signs. The decreased binding of 99mTc-TRODAT-1 in the nigrostriatal dopaminergic pathway in symptomatic MJD patients correlates with the phenotype of extrapyramidal signs but not with the abnormal CAG repeat length, age at disease onset, or disease duration.

Evaluation of three rhenium-188 candidates for intravascular radiation therapy with liquid-filled balloons to prevent restenosis.

BACKGROUND: Intravascular brachytherapy is an effective method for inhibiting coronary restenosis after percutaneous transluminal coronary angioplasty. A new concept for preventing restenosis is the use of a liquid-filled balloon containing a beta-ray-emitting radioisotope. Generator-produced rhenium-188 (Re-188) is a good candidate for intravascular brachytherapy. However, in the unlikely event of balloon rupture, release of Re-188 perrhenate may cause a high radiation dose to the thyroid and stomach. In this study, we compared the biodistributions of three Re-188 preparations (Re-188 perrhenate, Re-188 pentetic acid [DTPA], and Re-188 MAG3) to assess the radiation dose to organs in a rat model that mimicked balloon rupture. METHODS AND RESULTS: After injection of Re-188 preparations intravenously, rats were killed at 10 minutes, 30 minutes, 60 minutes, 2 hours, and 6 hours (n = 5/group). Tissue concentrations were calculated and expressed as percent injected dose per gram or per milliliter. In addition, urine excretion and thyroid gland uptake were evaluated in rats (n = 5/group) with a gamma camera after administration of 37 MBq (1 mCi) of each agent. Our data showed all 3 agents were excreted primarily via urine. In the Re-188 MAG3 group, 82% was excreted within 1 hour, but in the Re-188 perrhenate group, only 28% was excreted. The biodistribution data for these agents revealed that radioactivity levels in the stomach and the thyroid gland were high in the perrhenate group but low in the Re-188 DTPA and Re-188 MAG3 groups. The concentration levels in other tissues including lung, liver, testis, muscle, and blood were low throughout this study for all 3 agents. The thyroid radiation values were 0.163, 0.0167, and 0.00728 mGy/MBq for Re-188 perrhenate, Re-188 DTPA, and Re-188 MAG3, respectively. The stomach radiation values were 0.127 mGy/MBq for Re-188 perrhenate, 0.013 mGy/MBq for Re-188 DTPA, and 0.0104 mGy/MBq for Re-188 MAG3. CONCLUSIONS: In the event of balloon rupture, the release of Re-188 MAG3 or Re-188 DTPA results in lower radiation doses than release of Re-188 perrhenate, especially to the thyroid gland and the stomach.

Pentavalent Tc-99m dimercaptosuccinic acid imaging of hepatocellular carcinoma.

Tc-99m (V)-dimercaptosuccinic acid (DMSA) has been used to image various kinds of tumors. However, from a review of the literature, it has never been applied to hepatocellular carcinoma (HCC). Low uptake of Tc-99m (V)-DMSA has been demonstrated in normal liver tissue, thus, Tc-99m (V)-DMSA may be useful for the detection of HCC. Nine male patients with focal nodular HCC were studied with sequential X-ray CT, Tc-99m (V)-DMSA and Tc-99m phytate liver scan. Our data showed that eight patients had increased uptake of Tc-99m (V) DMSA in HCC. Four cases demonstrated higher Tc-99m (V) DMSA uptake in HCC than in adjacent liver, and four cases demonstrated HCC uptake equal to liver uptake. One case showed no uptake of Tc-99m (V) DMSA in HCC. The detection sensitivity of Tc-99m (V)-DMSA was 88.9%. From our early results, Tc-99m (V)-DMSA is a readily available tumor imaging agent that appears to accumulate in HCC.