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During breathing, activation of respiratory muscles is coordinated by integrated input from the brain, brainstem, and spinal cord. When this coordination is disrupted by spinal cord injury (SCI), control of respiratory muscles innervated below the injury level is compromised leading to respiratory muscle dysfunction and pulmonary complications. These conditions are among the leading causes of death in patients with SCI. Standard pulmonary function tests that assess respiratory motor function include spirometrical and maximum airway pressure outcomes: Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), Maximal Inspiratory Pressure (PImax) and Maximal Expiratory Pressure (PEmax). These values provide indirect measurements of respiratory muscle performance(6). In clinical practice and research, a surface electromyography (sEMG) recorded from respiratory muscles can be used to assess respiratory motor function and help to diagnose neuromuscular pathology. However, variability in the sEMG amplitude inhibits efforts to develop objective and direct measures of respiratory motor function. Based on a multi-muscle sEMG approach to characterize motor control of limb muscles, known as the voluntary response index (VRI), we developed an analytical tool to characterize respiratory motor control directly from sEMG data recorded from multiple respiratory muscles during the voluntary respiratory tasks. We have termed this the Respiratory Motor Control Assessment (RMCA). This vector analysis method quantifies the amount and distribution of activity across muscles and presents it in the form of an index that relates the degree to which sEMG output within a test-subject resembles that from a group of healthy (non-injured) controls. The resulting index value has been shown to have high face validity, sensitivity and specificity. We showed previously that the RMCA outcomes significantly correlate with levels of SCI and pulmonary function measures. We are presenting here the method to quantitatively compare post-spinal cord injury respiratory multi-muscle activation patterns to those of healthy individuals.

Introduction: Radioactive contamination can occur as a result of accidental or intentional release of radioactive materials (RM) into the environment. RM may deposit on clothing, skin, or hair. Decontamination of contaminated persons should be done as soon as possible to minimize the deleterious health effects of radiation. The goal of this study was to evaluate the decontamination efficiency (for residual contaminant) of the active components of "Shudhika," an indigenously developed skin decontamination kit. The study kit is for external radioactive decontamination of intact skin., Methods: Decontamination efficiency was evaluated on the skin surface of rabbit (n = 6) and human volunteers (n = 13). 99mTc sodium pertechnetate (200-250 μCi) was used as the radio-contaminant. Skin surface area (5 × 5 cm2) of thoracic abdominal region of the rabbit and the forearm and the palm of human volunteers were used for the study. Decontamination was performed by using cotton swabs soaked with chemical decontamination agents of the kit., Results: Decontamination efficiency (% of the contaminant removed) was calculated for each component of the study. Overall effectiveness of the kit was calculated to be 85% ± 5% in animal and 92% ± 3% in human skin surfaces. Running water and liquid soap with water was able to decontaminate volunteers' hand and animal skin up to 70% ± 5%. Chemical decontamination agents were applied only for trace residues (30% ± 5%). Efficiency of all the kit components was found up to be 20% ± 3% (animal) and 28% ± 2 (human), respectively. Residual contamination after final decontamination attempt for both the models was observed to be 12% ± 3% and 5% ± 2%. After 24 and 48 hours of the decontamination procedure, skin was found to be normal (no redness, erythema and edema were observed)., Conclusion: Decontaminants of the study kit were effective in removal of localized radioactive skin contamination when water is ineffective for further decontamination. By using the chemical decontaminants of the study kit, the use of water and radioactive waste generation could be reduced. Cross-contamination could also be avoided. During radiologic emergencies where water may be radioactively contaminated, the study kit could be used.

Jet nebulizers show an unreasonable variation in drug output and nebulization rates that leads to clinical and regulatory problems. Current evaluation methods appear inadequate for the purpose. Our objective was to evaluate Technetium-99m radiometry to study nebulizer parameters and the factors influencing it quantitatively. Drug output, output rate and residual mass and the effect of excipient, temperature, surface tension, air-jet speed, and equipment brand and aging were studied. Though nebulization of radiolabeled drugs followed first-order kinetics, the rates were significantly different; the heaviest drug (Tc-99m colloid) and Tc-99m salbutamol had the least nebulization. Nebulization rate for the first minute was invariably higher than the mean rate signifying the concentration effect of the solute. Drug residue was 35-75%. Drug output of different nebulizer chamber and air compressor brands was different to the extent of 270% and 180% respectively. 'Aging' of fluid chamber, cold drug fluid and obstruction in air-jet resulted in significant reduction in output, while addition of 2% saline as excipient did not change the output rate. Addition of ethyl alcohol resulted in a maximum of 260% enhancement (with Tc-99m salbutamol), while further reduction in surface tension was counterproductive irrespective of the drug used. We conclude that radiometry can provide valuable parametric information on the performance of different jet nebulizers.

Objective: The diagnostic utility of a C-methionine scan has been established in breast cancer. We were able to radiolabel methionine with Tc at our institute. Thus, we undertook clinical trials to determine the role of Tc-methionine scans in the detection of breast cancer., Methods: Scintimammography was performed in 47 female (median age 44 years, range 28-68 years) patients having palpable breast masses. All of them underwent ultrasound, mammography, fine-needle aspiration cytology, and Tc-methionine scintimammography before surgery. The final diagnosis was made after histopathological examination. Tc-methionine scintimammography was done after injecting 555 MBq of radiotracer intravenously. The results of scintimammography were compared with histopathology., Results: The histopathological findings were malignant in 33 (70%) and benign in 14 (30%) cases. Scintimammography showed true-positive findings in 29 patients out of 33 cases of breast cancer. True-negative findings were found in 13 out of 14 patients having benign breast lesions. The sensitivity, specificity, and positive predictive value were found to be 87.8, 92.8, and 96.6% respectively., Conclusion: Tc-methionine imaging can provide useful information with reasonably high sensitivity and specificity in evaluating patients having breast masses.

Objective: On the basis of our hypothesis that lipophilic cations may be more suitable for ventilation lung scintigraphy than the conventional technetium-99m diethylenetriamine penta-acetic acid (Tc-DTPA), comparative studies were carried out., Basic Methods: The nebulization potential of nine routine radiopharmaceuticals was compared on medical and scintigraphy-specific nebulizers. This was followed by ventilation scintigraphy in 14 patients with chronic obstructive airway disease (n=13) or pulmonary embolism (n=1) where either 99mTc-methoxyisobutylisonitrile (n=10) or Tc-tetrofosmin (n=4) was used. Same-patient comparison with 99mTc-DTPA ventilation scan was available in six patients using the same acquisition protocol. Comparison with 99mTc-DTPA was made with respect to the nebulization rates, radioactivity delivered per unit of radioactivity available for inhalation, and regional distribution of inhaled counts., Results: Lipophilic cation solutions had a significantly higher nebulization rate compared with 99mTc-DTPA using the medical nebulizer (235%, P<0.01) and 370% on scintigraphy-specific nebulizer (P<0.01). More than three times the counts of 99mTc-methoxyisobutylisonitrile or 99mTc-tetrofosmin was deposited in the body compared with Tc-DTPA aerosol per megabecquerel activity inhaled (1.5 vs. 0.4 kcounts/MBq) (P<0.001), preferentially in the lungs (75.2 vs. 65.2%), at the expense of oropharynx and stomach. Within the lungs, about 50% more counts were deposited in the outer one-third lung with lipophilic cations. Overall, therefore, more than 12 times the radioactivity deposition was achieved in the peripheral one-third of the lungs with the lipophilic cations., Conclusion: Ventilation lung scanning with lipophilic cations is a viable substitute of nanoparticle scintigraphy (technegas and pertechnegas, which are expensive and technically far more demanding).

Objectives: A study was undertaken to evaluate the diagnostic efficiency of Tc-Tetrofosmin scan and color Doppler in the characterization of benign and malignant solitary thyroid nodules., Methods: Fifty-two patients found to have a cold solitary thyroid nodule on Tc-pertechnetate scintigraphy were included in this study. All patients underwent a single-injection dual-phase (30 min and 120 min) Tc-Tetrofosmin scan. The intranodular vascularity was measured using color Doppler sonography. Fine-needle aspiration cytology was performed on all the patients. In the following days and weeks all patients underwent surgery., Results: Thirteen out of 15 patients with thyroid cancer showed delayed retention of radiotracer (on 120 min images as compared to the initial 30 min image). Thirty-six out of 37 patients harboring benign solitary nodules showed significant washout of tracer on delayed images. Sensitivity, specificity, positive predictive value and negative predictive value of delayed Tc-Tetrofosmin scintigraphy were found to be 86.6, 97.2, 92.8 and 94.7%, respectively. The Doppler study was able to demonstrate increased vascularity in the center of 8 of the 15 malignant nodules. Thirty-two patients harboring a benign solitary nodule showed normal or increased peripheral vascularity on Doppler study. Sensitivity, specificity, positive predictive value and negative predictive value of color Doppler were found to be 53.5, 86.4, 61.5 and 82%, respectively., Conclusion: Delayed Tc-Tetrofosmin scintigraphy is a highly sensitive and specific method for characterizing solitary thyroid nodules, while color Doppler has a low sensitivity but relatively high specificity in differentiating benign from malignant thyroid lesions.

Tc-99m MDP and Tc-99m ciprofloxacin scans were performed in 14 patients with suspected tubercular bone disease and in 2 cases of nontubercular bone infection. In 5 patients the findings were true negative. There were no false positives and 1 was false negative. The sensitivity, specificity, and positive predictive value were found to be 93, 71, and 87.5%, respectively, for detection of bone tubercular lesions. However, the test does not distinguish TB osteomyelitis from other types of osteomyelitis. Delayed 24 hour scans were found useful to differentiate between inflammatory and infective lesions. The aim of this study was to evaluate the usefulness of the Tc-99m ciprofloxacin scan as a means to detect tubercular bone disease.

Immunomodulatory activity of Seabuckthorn (SBT) leaf extract was evaluated in adjuvant induced arthritis (AIA) rat model. Inflammation was induced by injecting Complete Freund's Adjuvant (CFA) in the right hind paw of rats. SBT extract was administered intraperitoneally to treat the inflammation. The extent of inflammation and treatment response was evaluated by clinical analysis, scintigraphic visualization using technitium-99m-glutathione (Tc99m-GSH) and lymphocyte proliferation. Serial evaluation was carried out on days 1, 7, 14, 21 and 28 after creation of inflammation. The Tc99m-GSH uptake in the inflamed leg was compared with the normal contralateral leg of the same animal. The measurements were done by obtaining scintigraphic images using gamma camera and an online computer. Both qualitative and quantitative evaluation of radiotracer accumulation was considered to evaluate the anti-inflammatory response. The lymphocyte proliferation study revealed cellular immunosuppression during the early phase of the disease. Administration of SBT extract on the same day or 5 days prior to inflammatory insult into the joint, significantly reduced the inflammation as compared to the untreated animals in a dose dependent manner. These observations suggest that the SBT leaf extract has a significant anti-inflammatory activity and has the potential for the treatment of arthritis.

Technetium-99m methoxy isobutylisonitrate (MIBI) has been found to be taken up by various tumors, including thyroid cancer. We prospectively evaluated 77 patients with cold thyroid solitary nodules on Tc-99m pertechnetate scintigraphy to evaluate the diagnostic value of Tc-99m MIBI scintigraphy. The aim of this study was to find out if thyroid nodules can be characterized on the basis of retention of MIBI and whether preoperative evaluation of malignancy is possible using this method. Single injection, dual-phase (30 and 120 minutes) thyroid scintigraphy using Tc-99m MIBI was performed in all these patients. In the following days and weeks, all patients underwent surgery. Using the 120/30-minute thyroid lesion to background radiouptake ratio (RUR), malignant and benign thyroid nodules could be separated with a sensitivity, specificity, and positive predictive value of 84.4%, 95.45%, and 93.33%, respectively. The mean RUR for malignant thyroid lesions was found to be 1.57+/-0.32, whereas for benign lesions, the ratio was significantly lower, 0.32+/-0.19. In conclusion, fine needle aspiration cytology along with the 120/30 minutes Tc-99m MIBI scintigraphy ratio appears to be useful in the preoperative assessment of solitary thyroid nodules.

No large prospective study is available on use of a radionuclide method to assess frostbite and its response to conservative treatment. Recently, a large retrospective study using two-phase bone scintigraphy suggested that non-uptake (or low uptake) in frostbite lesions in the blood pool or bone phase had a strong correlation with the subsequent need for amputation. In the present study, we performed early blood pool scintigraphy with technetium-99m pertechnetate in 20 patients (10-180 days after frostbite injury; 71 clinical lesions) referred for a topical treatment protocol for mild to moderately severe frostbite, and in 22 asymptomatic controls. The aims of the study were to define the "normal" microcirculation of the hands and feet, to characterise the appearances of frostbite lesions on scintigraphy and correlate these with the clinical presentation, and to evaluate the usefulness of scintigraphy for assessing the treatment response. Six patients were "fresh", 12 had been undergoing conservative treatment (topical homeopathic) for several weeks and two had permanent fibrotic hand phalanges. Nine patients on treatment underwent serial scintigraphy a total of 22 times. Eleven patients were imaged only once, including the two with permanent fixed defects. Three distinct physiological microcirculation patterns were evident in control hands or feet: right- or left-handedness (seven subjects), subclinical inflammatory foci correlating with callosity or pressure points (36 lesions) and distinctly increased pooling of radiotracer at the thenar or hypothenar region (eight subjects). In frostbite patients, 128 lesions (48 inflammatory, 80 ischaemic) were seen on the scan. This number included all 71 lesions identified clinically, the rest being subclinical. Subclinical frostbite lesion as an entity has not been described previously. Microvasculature of normal muscle groups (in the hands, elbow or feet) was shown on scintigraphy to improve after topical treatment. The treatment resulted in improved or normalised perfusion scan in 25 of 45 ischaemic segments with matching clinical improvement, and reduction or normalisation of uptake in inflammatory lesions (n=30). The data confirm the vasodilator and anti-inflammatory action of the topical preparation, and the sensitivity of the radionuclide method in monitoring treatment response. In contrast to the previous findings that non-uptake on a scan performed 2 or more weeks after exposure correlates with the need for amputation, none of the 80 ischaemic lesions in our series required amputation while 60% showed improvement or normalisation in microvascular blood flow even though they were 10-180 days old. Our findings suggest that moderate to severe frostbite lesion can be classified as having infarcted, ischaemic or hibernating (viable) tissue, similar to the classification employed when using myocardial scintigraphy. Absence of uptake even after the initial 10 days does not necessarily indicate infarction and the need for amputation as many such lesions retain potential for vasodilation and recovery.

Tc-99m Infecton imaging was used to examine patients thought to have pelvic inflammatory disease (PID) based on clinical and sonographic findings. Twenty-one patients with PID had Tc-99m Infecton scans. Eleven patients underwent a second radionuclide scan after 1 month of antibiotic treatment. The diagnosis of PID was confirmed by laparoscopy in one patient who was later found to have a tubercular infection. In the remaining patients, the diagnosis was based on uterine tenderness, fever and lower abdominal pain that responded to antibiotics, and ultrasound findings. These patients had infection of the uterus, fallopian tubes, the cul-de-sac, or all of these. The Tc-99m Infecton scan appears to be useful in the diagnosis of possible PID and is recommended after a complete course of antibiotics for monitoring treatment response.

99Tcm-citrate has been shown to incorporate irreversibly in the skeleton with a biodistribution different to that on a conventional bone scan. The aims of this study were to confirm the bone-imaging properties of 99Tcm-citrate, to identify the variabilities influencing its skeletal uptake, to compare its uptake in bone with that of 99Tcm-MDP and to assess its possible role in bone scintigraphy. Appropriate animal and human studies (n = 45) were conducted. The 3 h lesion-to-bone ratio of 99Tcm-citrate was compared with that of 99Tcm-MDP in more than 150 lesions, including osteoblastic sites (Group A), lesions undergoing treatment or healing (Group B), and degenerative or old healed lesions (Group C). The uptake ratio was classified as concordant (< 20% variation), mildly discordant (20-50% variation) or significantly discordant (> 50% variation). Animal experiments showed most bone uptake of 99Tcm-citrate when prepared at a pH of 6.0-6.5. The two radiopharmaceuticals appeared to compete for bone uptake, suggesting related but different sites of bone accumulation. The 99Tcm-citrate/99Tcm-MDP uptake ratio in Group A was concordant (mean +/- S.D. = 0.92 +/- 0.15), while Group C lesions had a significantly lower 99Tcm-citrate/99Tcm-MDP uptake ratio (0.34 +/- 0.24, P < 0.01). A comparison of Group B lesions showed wide variation in intensity and area of involvement in many lesions (uptake ratio < 0.5 or > 1.5 in 13 of 30 sites). We conclude that 99Tcm-citrate has a different site of bone localization than phosphonates, possibly in the organic matrix. Although its skeletal uptake is lower than that of 99Tcm-MDP, it may have better specificity in differentiating osteoblastic from degenerated or healed bony lesions, and therefore be useful in predicting healing of bone secondaries, fractures or osteomyelitic lesions.

One hundred and forty eight subjects with euthyroid solitary thyroid nodules (STN) were taken up for radionuclide perfusion study. They were found to have a cold STN on 99mTc thyroid static scan. All had fine needle aspiration cytology (FNAC), and except for subjects with chronic lymphocytic thyroiditis, were subjected to surgery for tissue diagnosis by histopathology. The diagnostic findings in these patients of solitary thyroid nodules were correlated with the histopathology. Radionuclide perfusion study is considered useful to differentiate benign from malignant cold thyroid solitary nodules with high degree of sensitivity (95%) and specificity (87.9%).

The authors present a prospective analysis of Tc-99m MDP and Tc-99m citrate scintigraphy in 108 patients with known malignant or degenerative benign bone disease. Of 108 patients, 59 (group A) had malignant bone disease. The other 49 patients (group B) had degenerative benign bone disease for which the results of Tc-99m MDP scans were positive. In both groups the Tc-99m citrate scan was performed 1 week after the Tc-99m MDP scan. The Tc-99m citrate/Tc-99m MDP lesion-to-background radioisotope uptake ratio (RUR) was calculated for each lesion 3 hours after radionuclide administration. The mean RUR for the malignant lesions was 1.0 +/- 0.484; for the benign lesions, the RUR was 0.29 +/- 0.250. Static imaging was also done for 10 lesions each from the malignant and benign groups at 1, 3, and 24 hours to study the kinetics of Tc-99m citrate. Time-activity curves for malignant lesions showed that the RUR remained high for 24 hours, whereas benign lesions showed a drastic decrease at 3 and 24 hours compared with the 1-hour images. The ratio of Tc-99m citrate to Tc-99m MDP is a promising parameter to differentiate malignant from benign degenerative lesions seen as areas of increased activity on Tc-99m MDP bone scans. The sensitivity and specificity of this technique were 97.8% and 95%, respectively.

A 24-year-old man with congenital bladder diverticula leading to bilateral hydronephrosis diagnosed on radionuclide scintigraphy is described. Diagnostic findings of sonogram and CT scan are also mentioned.

A pelvic hypervascular blush often creates a diagnostic dilemma during radionuclide abdominal imaging studies in females. This blush is shown to be due to uterine vascularity that is more prominent in the secretory and menstrual phases of the menstrual cycle. Significant uterine vascularity in the earlier phases is inappropriate and may be pathologic. Three such cases are presented in which increased uterine vascularity on radionuclide imaging during the proliferative phase either lead to a diagnosis or supported a clinical finding.

Tc-99m HIG has recently come into prominence as an inflammation seeking radiotracer. The authors describe a novel use of the agent for imaging protein-losing enteropathy. The agent may have certain advantages over Tc-99m HSA, which is currently being used for imaging protein loss.

The authors present four cases of internal biliary fistulae (IBF) identified on hepatobiliary scintigraphy. All of the cases share common history of external biliary leak closure. Scintigraphy in all four cases showed a similar pattern of direct visualization of transverse colon without any significant small bowel activity. This suggests an increased frequency of IBF formation in cases with external fistulous tract closure. Retrospectively, it appears that spontaneous closure of external leak may be pathological consequence of formation of IBF involving hepatic flexure.

Seventy-seven adult patients with suspected skeletal metastases were divided into two groups. In group A (n = 30), following intravenous administration of 20 mCi (740 MBq) of technetium-99m methylene diphosphonate (99mTc-MDP), 3- and 24-h scintigraphy of bone lesions was performed. The 24/3 h lesion to bone background radiouptake ratio (RUR) was calculated for each lesion. In group B (n = 47), the same procedure was followed with dexamethasone intervention (10 mg in 24 h) following the 3-h acquisition. In group A, after determination of the critical point, malignant and degenerative bone lesions could be separated with a sensitivity, specificity and accuracy of 0.76, 0.72 and 0.73, respectively. The mean RUR of the malignant lesions was 1.20 +/- 0.23, and that of the benign lesions, 0.95 +/- 0.15. In group B cases, significantly increased sensitivity, specificity and accuracy of 0.87, 0.94 and 0.92, respectively, were found (P < 0.001). The mean RUR of the malignant lesions was 1.48 +/- 0.34, and that of degenerative lesions, 0.88 +/- 0.19. Dexamethasone interventional bone scintigraphy seems to be a new cost-effective method for differentiating malignant from degenerative bone lesions using the RUR.

Thirty cases of recurrent pulmonary infection and ten control cases underwent radionuclide gastroesophagography endoscopy, histopathology and barium esophagography to evaluate the clinical efficacy of scintigraphic technique in, detection of gastroesophageal reflux. After ingesting 500 micro curie of Tc-Sulphur colloid mixed in milk, patients esophageal activity was monitored using the gamma camera for forty-five minutes continuously. By using histopathology as standard of comparison, the sensitivity and specificity of radionuclide esophagography was 78.54 and 81.25%, respectively. Because of its physiologic nature, low radiation exposure and convenience, radionuclide esophagography is recommended as a suitable screening test for detecting gastroesophageal reflux where available.

Rest and exercise radionuclide angiocardiographic measurement of left ventricular functions were obtained in 12 normal subjects (group I) and 42 patients with well documented coronary artery disease (group II). Additionally thirty-five patients had an exercise tread mill test. Resting left ventricular ejection fraction less than 50% provided the greatest diagnostic information. Exercise was induced by supine bicycle exercise ergometer. In group II 32 patients of coronary artery disease with normal global ventricular function at rest, new regions of dysfunction developed during exercise and global ejection fraction fell by 8 to 15 percent while in group I there was an increase in LVEF and no areas of any ventricular wall motion abnormalities were detected. Exercise radionuclide angiocardiography is a useful non invasive technique which permits accurate assessment of the presence and functional severity of coronary artery disease.

The rare presentation of hyperthyroidism caused by an intrathoracic goiter with a normal-sized cervical thyroid gland is described. The toxic intrathoracic goiter demonstrated avid uptake of [131I] and [99mTc]pertechnetate, with comparatively faint isotopic accumulation seen in the cervical thyroid. A chest roentgenogram and radioisotope scan should be mandatory in cases of hyperthyroidism having no cervical thyroid enlargement to explore the possibility of a toxic intrathoracic goiter.