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Background : The pharmacokinetics of dacarbazine (DTIC), which has been shown to be an effective therapeutic agent against metastatic melanoma, has not been extensively studied. However, to improve the clinical use of the drug, more information on the kinetics is required. Methods : A pharmacokinetic study was undertaken in six patients with melanoma of an extremity who were undergoing hyperthermic isolation perfusion with DTIC in order to understand better its clinical pharmacokinetics. Plasma was sampled from the arterial and venous lines of an extracorporeal pump during the perfusion with the systemic vein and urine sampled postperfusion. Samples were analyzed for DTIC, 2-azahypoxanthine (2-AZA), and aminoimidazole carboxamide (AIC). 99m Tc (Technetium) human serum albumin (HSA) was used in the perfusion circuit to monitor the crossover of the perfusate into the systemic circulation during the procedure. The data were analyzed using a compartmental model of sampled body compartments incorporating the isolated extremity. Results : High tissue DTIC levels were maintained throughout the perfusion, whereas in the systemic circulation, plasma DTIC concentrations, when observed, were 40-100-fold less than those in the perfusate. Almost 70% of the DTIC administered was not recovered in the perfusate after the washout of the extremity. Conclusions : High levels of DTIC can be maintained in an extremity (i.e., arm or leg) during perfusion.

Granulocyte transfusions are associated with a number of side effects including febrile transfusion reactions and occasionally pulmonary infiltrates. There is evidence that the presence of preformed antibodies may be a cause of these complications. In this study, allogeneic 111Indium-labeled granulocytes were used to evaluate the pulmonary retention of radioactivity in alloimmunized and non-alloimmunized patients in an attempt to assess antibody effect on granulocyte migration. After injection of labeled allogeneic granulocytes into neutropenic patients, the ratios of lung to heart activity were calculated for the first 30 min of scanning. There was significantly greater retention of radioactivity from cells in the lungs of patients who were alloimmunized, having both lymphocytotoxic (anti-HLA) and leuko-agglutinating antibodies, compared to the activity in the lungs of non-alloimmunized patients (P less than .001) or of patients receiving autologous granulocytes (P less than .001). This study demonstrates that labeled, mismatched granulocytes may be retained in the lungs for a significantly longer time in patients with preformed antibodies. This implies that transfusion of large numbers of such mismatched granulocytes, i.e., granulocyte transfusions, may also be retained in the lungs of alloimmunized patients, which could lead to pulmonary compromise. Therefore, granulocyte transfusions from random donors should not be givenmore » to alloimmunized patients.« less

The authors have used imidazole carboxamide (DTIC) in vascular isolation and hyperthermic perfusion for melanoma. The regional and systemic toxicity and complications of this procedure were studied in 40 cases with Stage III (15) and Stage I (25) melanoma. Technetium 99m-labelled serum albumin crossover and pharmacokinetic studies were done simultaneously to see if these correlate with toxicity. Local toxicity on muscles, nerves, skin, and arteries was conspicuously absent despite using dosages of 2 g/m2 (40-45 mg/kg) for the lower extremity and 1.2 g/m2 (24-28 mg/kg) for the upper extremity. Skin and core temperature were raised to 39 degrees C to 40 degrees C. Deep vein thrombosis was noted in three patients. No death or gangrene of the extremities occurred. Local infection was noted in only one patient. Fourteen patients (35%) manifested bone marrow toxicity (leukocyte count of 4000/mm3 or platelets of 100,000/mm3) in the second or third week after perfusion. Severe hematologic toxicity was seen in two instances. Dosages of DTIC greater than 40 mg/kg were associated with toxicity in 65% of the patients. No bleeding complications occurred in seven patients with thrombocytopenia. Measurement of crossover and recovery of radionuclide were not reliable indicators of subsequent systemic toxicity. Perfusion fluid balance data also were of no predictive value. Forty-seven percent of the administered DTIC was recovered in washout fluid. Of this, less than 2% was converted to its metabolites, that is aminoimidazole carboxamide and 2-azahypoxanthine. Thirty-five of 40 patients experienced mild nausea and vomiting. Transient and mild hepatotoxicity was noted in seven patients. It appears that DTIC hyperthermic isolation perfusion is a safe procedure, however, the total dosage should be below 40 mg/kg to avoid hematologic toxicity.

The radionuclide, gallium-67, accumulates in a wide variety of neoplastic and inflammatory lesions. Diffuse bilateral lung localization of67Ga occurred in two cases of interstitial pneumonitis associated with bleomycin therapy. Clinical symptoms and laboratory evaluation of pulmonary status correlated with scintigraphic studies in these two patients, while discrepancies between scinti-graphic and roentgenographic findings were observed.Cancer 36:1966–1972,1975.

We evaluated the significance of bile seen in the stomach at the time of endoscopy. Twenty-three percent of 110 consecutive patients undergoing elective panendoscopy were found to have bile in their stomachs. Gastric biopsies were obtained from these patients. To assess the significance of bile reflux, the patients underwent a quantitative gastric bile analysis on two separate days. On day 1, gastric juice was aspirated by nasogastric suction, and bile acid concentrations were measured. On day 2, bile reflux into the stomach was quantitated by scintiscan measurement of gastric nucleotide after intravenous administration of 99mTc-DISIDA. Approximately half the patients with bile reflux showed histologic evidence of mucosal injury. However, fewer than half with histologic injury had significant bile reflux when measured by quantitative methods. There was no correlation among the gastric bile acid concentration, degree of histologic injury, or severity of endoscopic changes. We conclude that finding bile reflux at endoscopy is probably of no clinical significance.

Scintigraphic imaging procedures are now available that routinely permit visualization and quantitation of cardiac function. Image formation, while the most powerful form of data acquisition, carries with it a penalty of reduced detection sensitivity. As a consequence, there is a lower limit to the duration of physiologic phenomena that can be studied with present imaging methods.A number of medically interesting situations can be identified, however, in which the knowledge of regional function provided by imaging studies is not of primary importance. Instead, changes in global left ventricular function subsequent to various interventions might be of interest. In such cases, the temporal constraints of imaging procedures can, in large measure, be overcome by using non-imaging detectors or “probes”. Probes can be constructed with detection efficiencies for left ventricular radioactivity that are at least on order of magnitude greater than for imaging devices. Such devices would be expected to yield measurements whose statistical precision was similar to that for imaging studies but requiring less than one-tenth the data acquisition time.To realize these advantages in practice requires consideration of the entire acquisition-processing system as well as the detector design. The micro-processor based system described in this report was designed for maximum flexibility and utility. While the principle function of the system is to acquire, create, analyze and display (in real-time) left ventricular time activity (or volume) curves, provision is also made to acquire additional physiologic signals (e. g., ECG, flowmeter, etc.) and to calculate and display relationships between these various data. The system was designed for interactive use so that the system user can alter the course of a series of measurements based on previous results. These general capabilities are illustrated with several examples. In the first, LV function was measured continuously in a subject from (supine) rest through exercise and recovery. The second example illustrates the use of the system in acquiring (LV) pressure-volume loops. Several technical problems, such as correction for LV background radiation, appear at present to limit the probes applicability. Even now, however, probe systems are demonstrably useful in the study of global left ventricular function when this function is changing rapidly with time in response to various interventions.

The records of 122 patients with non-Hodgkin's lymphoma were reviewed, and the findings of the gallium scan analyzed. The scans of 93 patients were reread without knowledge of the previous readings. Two nuclear medicine physicians agreed with the original readings in 70 per cent of the cases and with each other in 89 per cent of the cases. When the data are analyzed case by case, 52 per cent true positive, 13 per cent false positive and 34 per cent false negative scans were found with only 17 per cent of the scans locating disease not found by routine physical examination and roentgenograms. Looking at individual sites of disease, the gallium scan yields an over-all detection of diseased sites of 18.5 per cent, with 72 per cent of all sites being correctly classified as positive or negative. The diffuse histiocytic, mixed and undifferentiated histologies were detected more accurately than all others, with mediastinal and extranodal sites being identified more frequently than any nodal site. The gallium scan revealed a site of disease which advanced the clinical stage in only one of 122 patients (upstaged). Only one of 122 patients was upstaged as a result of gallium scanning. These data suggest that gallium scanning may not be cost effective in the routine staging of patients with non-Hodgkin's lymphoma.

Twenty-seven patients with Ewing's sarcoma were evaluated by whole-body radionuclide studies, using 67Ga citrate and 18F or 99mTc polyphosphate. Correlative diagnostic radiography was performed on all patients. Gallium scanning, bone scanning, and roentgen rays were of equal usefulness in diagnosing the primary lesion. Skeletal metastases were evaluated most effectively with bone scanning, 12 of 13 cases being thus detected, whereas 8 of 13 were detected on gallium images and 4 of 13 on radiographs. Lung metastases were found in 7 of 8 cases with radiography but in only 1 of 8 gallium scans.

The radionuclide gallium-67 has been shown to accumulate in a variety of inflammatory and neoplastic lesions, thereby permitting Identification of these abnormalities by radioisotope imaging. We have found that 67Ga also accumulates selectively in recently infarcted myocardium. Acute myocardial infarction was induced in dogs by ligation of the left anterior descending coronary artery, then 67Ga (3 to 4 mc) was injected intravenously. Hearts were removed 24 hours later, and isotope localization was evaluated by an Anger camera and by autoradiography. In five of eight dogs, 67Ga was found to accumulate preferentially in regions of visible infarction. Tissue creatine phosphokinase (CPK), measured in four of the five dogs, was greatly reduced and white blood cell infiltration was intense in the infarcted region. The infarcts of three dogs without preferential 67Ga uptake showed lesser degrees of CPK reduction and white blood cell infiltration. Localization of 67Ga in regions of acute myocardial infarction was also demonstrable by scanning intact, closed chest dogs. Hearts of two animals with transient (20 minutes) ischemia showed neither 67Ga accumulation nor decreased CPK. Thus, 67Ga localization discriminates infarcted from normal or only transiently ischemic myocardium. Unlike potassium and its analogs, 67Ga scanning does not depend on resolution of “cold” areas nor is it likely to introduce ambiguities due to flow limitation of isotope delivery. For these reasons 67Ga may prove particularly useful in the imaging of acute myocardial infarction in man.

An ECG-gated, scintigraphic imaging procedure is described in which a complete, average cardiac cycle is visualized with high temporal resolution. The ability of this method to detect wall motion abnormalities and quantitate left ventricular function is illustrated in a patient with severe coronary artery disease. These results are compared to (contrast) angiographic findings in the same patient.

Seventeen patients were studied after separate oral and intravenous administra- tion of 50 1iCi Zn-69m to determine if Zn-69m is suitable for studying zinc metabolism in humans and to determine if the route of administration affects kinetics. Patients stayed on a metabolic ward for each study. Activity was measured in the total body, urine, feces, blood, plasma, red blood cells, and by detectors over liver and thigh. Five day urine to fecal ratios were 0.44 (intravenous), 0.018 (oral). Most activity went rapidly to liver, then followed two component exponential loss patterns in both cases. Thigh area doubling time was 5.7 days whether the zinc was given orally or intravenously. Plasma activity decreased to less than 2% of that injected by 24 hr after intravenous administration and decreased from a maximum of 1.2% of that ingested, 3 hr after oral adminis- tration to 0.7% by 24 hr. Red blood cell activity increased through the 5-day study period to maximum values of 6.4% of that injected after intravenous administration and 2.4% of that ingested after oral administration. Similar metabolic patterns were observed regardless of whether Zn-69m was administered intravenously or orally, suggesting that these patterns were not affected by the mode of administration for the cases studied. Am. J. Cim. Nuir. 32: 559-569, 1979.

Vasogenic cerebral edema was induced cryogenically in rhesus monkeys. Serial scans in both axial and coronal planes were used to study the onset, peak, and regression of edema. Progression of edema, predominantly involving the white matter, was analyzed from the postmortem distribution of a blood/brain barrier indicator (Evans blue) injected at surgery. Specific gravity was measured in fresh, unfixed specimens from both the edematous and normal hemispheres and correlated with corresponding CT attenuation values obtained before death. The drop in specific gravity closely corresponded to the decrease in CT attenuation.

The potentially fatal interstitial pneumonia of Pneumocystis carinii is a frequent opportunistic invader of patients treated for malignancy with immunosuppressive and cytotoxic agents. Generalized Ga-67 pulmonary localization which is markedly disproportionate to the clinical and radiographic findings has led to earlier diagnoses by open lung biopsy in this setting. The potential usefulness of gallium scintigraphy in patients with suspected P. Carinii pneumonia is presented.

A Monte-Carlo technique was utilized to calculate the solid angle subtended by a solid, right, circular cylinder as seen from a point in space for two height-to-radius ratios of the cylinder, two-to-one and one-to-one. The calculation was made for source-point distances out to twelve cylinder radii from the cylinder center and for angular displacements of the source point up to ninety degrees from the cylinder axis.

Nineteen patients with known or suspected neoplasms of the skull and/or brain were studied with 99mTc pertechnetate, 99mTc polyphosphate, and 67Ga citrate. Lesions of the calvaria were detected most accurately with 99mTc polyphosphate. In some cranial lesions, 67Ga citrate localized within the core, 99mTc polyphosphate outlined the periphery, and 99mTc pertechnetate demonstrated the entire affected area. In postcraniotomy patients, the combination of 67Ga citrate and 99mTc polyphosphate provided a basis for distinguishing the surgical scar from a recurrent intracranial tumor. Purely intracerebral lesions were generally poorly localized with 99mTc polyphosphate.

Patients with Sjögren's syndrome accumulated abnormal amounts of 99mtechnetium pertechnetate in the region of the nose during isotopic salivary flow studies. It was concurrently and independently observed that many patients with Sjögren's syndrome had hyposmia and pathological changes in the nasal mucous membranes. Fourteen patients with Sjögren's syndrome were studied for the relationship of the above observations and the nasal accumulation of radionuclide was compared with a control group of 16 subjects. Eleven of 14 patients with Sjögren's syndrome (78%) had nasal accumulation of the radionuclide; 14 had hyposmia and 13 of 14 had chronic inflammation of the nasal mucous membrane. One of 16 controls (6%) localized radionuclide in the nasal region. Results suggest that hyposmia, inflammatory changes in the nasal mucous membrane, and nasal accumulation of 99mtechnetium pertechnetate are interrelated aspects of Sjögren's syndrome.

This study analyzes the value of the liver scan as a preoperative screening procedure for occult liver metastases in patients with melanoma, sarcoma, head and neck carcinoma, and pelvic carcinoma. The records of 566 consecutive patients admitted to the Surgery Branch of the National Cancer Institute between 1969 and 1974 were reviewed and 323 patients were found acceptable for inclusion in the study. In these patients, although the liver scan had an overall accuracy of 95%, the scan identified only 50% of the patients with occult metastases to the liver and did not siginificantly add to the yield of the other screening procedures. It was useful as an adjuvant to an abnormal routine workup to confirm and localize metastases to the liver. Scans with only non specific abnormalities were of little help. Liver metastases were not identified in any patients with sarcoma, head and neck cancer, or clinically localized carcinoma of the cervix. Therefore, the liver scan was determimed to be an unnecessary part of their screening workup. Patients with recurrent or advanced carcinoma of the cervix and advanced melanoma were found to have an increased incidence of liver metastases. There was a 10% incidence of occult metastases to liver in patients with melanoma and the incidence increased with advancing clinical stage of disease. Even in this high-risk group of patients the screening liver scan did not significantly add information to that gained by history, physical examination, and blood work.

Abnormalities of right and left ventricular ejection fraction and segmental wall motion may be detected by radionuclide angiography (RNA) following blunt chest trauma. Of 111 patients with blunt chest trauma who were admitted to a large regional shock trauma center and underwent combined first-pass and equilibrium gated RNA, abnormalities were present in 40 (36%). These abnormalities were confined to the right ventricle in 33 patients. There was a positive association between RNA abnormalities and the presence of right bundle branch block (10 of 40, p less than 0.05) and a negative association between RNA abnormalities and the finding of rib fractures (6 of 40, p less than 0.05). The in-hospital death rate of these patients was low (3 of 40 patients with an abnormal RNA and 2 of 71 patients with a normal RNA). Follow-up RNA was performed at 10 +/- 4 days in 26 of the 40 patients with initially abnormal scans, and 22 (85%) of the 26 had reverted to normal. Thus although RNA abnormalities appear common following blunt chest trauma, among patients who survive for more than 24 hours and who undergo subsequent RNA, the complication rate is low despite an abnormal scan. We conclude that routine RNA adds little to clinical management following acute blunt chest trauma.

111In-labeled granulocytes were used to study the effects of histocompatibility factors on the migration of transfused granulocytes to infected sites. Fourteen alloimmunized and 20 nonalloimmunized patients received approximately 10(8) 111In-labeled granulocytes from ABO-compatible, non-HLA-matched donors, and scans were performed over known infected sites. All 14 alloimmunized patients had lymphocytotoxic antibody (LCTAb) and required HLA-matched platelet transfusions. Of the nonalloimmunized patients, 20/20 had positive scans at sites of infection. None of the 20 had LCTAb, 0/17 had a positive lymphocytotoxic crossmatch (LCTXM) with the donor, and 3/18 had a positive leukoagglutinin crossmatch (LAXM). Thus, histocompatibility testing was not found to be important in nonalloimmunized patients. In contrast, only 3/14 alloimmunized patients had positive scans at sites of infection (p = 0.00001 compared to nonalloimmunized patients). One of 3 had a positive LCTXM and 2/3 had a positive LAXM. Of the alloimmunized patients, 10/11 with negative scans had a positive LCTXM and 8/11 had a positive LAXM. Labeled granulocytes failed to reach sites of infection in 11/14 (78%) alloimmunized patients, demonstrating that histocompatibility factors can be of major importance in affecting the outcome of granulocyte transfusions. Granulocytes from random donors are unlikely to be effective in alloimmunized patients. The lack of an adequate crossmatching technique is a major problem limiting the ability to provide granulocyte transfusions for alloimmunized patients.

Six days after tumor transplantation three daily intraperitoneal doses of 0.9% NaCl, bleomycin (BLM), or a new 111In-bleomycin complex (BLMC, 15 microCi/g body weight) were administered to glioma-bearing mice. After therapy, tumors in mice treated with /sup 111/In-BLMC were smaller than those treated with BLM. Sixteen days after the first injection tumor size for /sup 111/In-BLMC-treated mice was 560 (240-1,030) mm3, 1980 (1400-3290) mm3 for BLM (P less than 0.025), and 4830 (2580-9180) mm3 for NaCl (0.1 less than P less than 0.2). Thirteen days after tumor transplantation glioma-bearing mice received single intratumor injection of 0.9% NaCl, BLM, or /sup 111/In-BLMC (1.5 mCi, carried by 0.5 mg BLM/g tumor weight). The average tumor size for /sup 111/In-BLMC was smaller than that for BLM by a factor of 2.5-3.7. Host weights for these two groups were similar, and morphologic abnormalities were not found in kidney or liver.

Radioisotopic studies were performed on baboon kidneys during isolated bloodless perfusion. The perfusion was equilibrated with either 100% oxygen or 100% helium gas. The clearance of 133 Xe was found to be a very sensitive method in assessing renal circulation. Oxygen had a vasoconstrictive effect on the cortical vessels resulting in a decreased renal cortical perfusion flow. The distribution of labeled carbon microspheres did not reflect a difference in cortical flow during oxygen and helium exposure. Particles of the size employed did not remain fixed in the vascular tree. In some instances free or unbound isotope was detected. 203 Hg chlormerodrin was poorly concentrated both during oxygen and helium exposure, presumably as a result of the absence of plasma proteins in the perfusate. Helium-exposed kidneys showed a more normal distribution and excretion of 131 I hippuran than oxygen-exposed kidneys.

The liver-spleen scans were reviewed from 108 patients with Hodgkin's disease, including 71 not previously treated. The results were correlated with clinical and pathologic findings in 122 liver biopsies and 50 spleens. Splenomegaly on scan was associated with advancing stage and tumor involvement of the spleen and liver. All 13 spleens measuring over 15 cm on scan and all 7 with filling defects were positive for tumor. In combination with the physical examination and lymphangiogram, the scan enabled accurate prediction of splenic tumor in 43% of the cases. Mean size of the right and left hepatic lobes was greatest in patients with tumor in the liver, but this finding was attributable to the advanced stage of these cases. Filling defects were not a reliable sign of liver involvement. The combination of the lymphangiogram, physical examination, and liver scan proved useful in selecting groups with very high and very low probability of liver involvement.

65 Zn chloride and 69m Zn chloride and citrate have been studied in a total of 34 dogs, 2 rhesus monkeys, and 10 men. Timed concentrations were measured in the blood of all and in the bile, urine, and fresh tissues of 32 dogs and 2 monkeys. In addition, the influence of castration, timing, testosterone proprionate treatment, pilocarpine administration, and other combinations of these factors were studied. We have shown that significant prostatic concentrations of radioactive zinc were obtainable in the dog, in the monkey, and in man. In vitro scans of the dog prostate were obtained using 65 Zn chloride. Both in vivo and in vitro, clinical human prostatic scans were performed using 69m Zn chloride.

A patient with impaired renal function due to granulomatous sarcoid replacement of the renal parenchyma is described through two separate courses of therapy with corticosteroids. Serial measurements of renal function, periodic renal scintiscans and intravenous pyelograms, and serial histologic studies of the kidney by percutaneous renal biopsy are presented. The variety of modes by which sarcoidosis may affect the kidneys is reviewed. Hypercalcemia or hypercalciuria is responsible for most instances of renal disease from sarcoidosis. In the present case, kidney damage resulted from extensive replacement of renal parenchyma by sarcoid lesions in the absence of hypercalcemia or hypercalciuria. The value of renal biopsy is seriously limited by reason of the focal nature of the disease and the chance of sampling error. Renal scintiscan provided not only presumptive evidence for diagnosis but also a method to assess the extent of the disease and the effect of therapy. Serial determination of renal function demonstrated improvement following each course of therapy. However, a gradual decrease in creatinine clearance was observed during the prolonged second course of steroid therapy without increase in sarcoid "lesions" by scintiscan. It is considered likely that fibrosis associated with regression or healing of active granulomas may have been responsible. It is concluded that alternate periods of exacerbation followed by regression with steroid therapy should be avoided because of the potential of progressive fibrosis and destruction of renal parenchyma.

Several cases are presented to illustrate how the radioisotope renogram has become an important adjunct in the postoperative evaluation of cancer patients requiring ileal conduit urinary diversion. The use of the renogram in the immediate postoperative period is best exemplified by its ability to aid in differentiating between the causes of oliguria. The sensitivity of the renogram in detecting urinary tract obstruction makes it particularly valuable in the long term management of these patients, whose urinary tract is in constant jeopardy, since it is safer and more convenient than commonly employed radiographic procedures.

The liver scan is a significant aid to clinical diagnosis. The value of liver scanning is greatly enhanced when abnormal findings are rechecked with additional scanning at intervals determined by the individual situation. Sequential liver scans have been particularly useful in evaluating the response to therapy of neoplastic disease metastatic to the liver and of liver abscess.

The principal imaging devices used in clinical and research medicine are mentioned with a more detailed discussion of the instruments used in clinical practice and the modified devices presently in operation at Donner Laboratories. Radionuclide imaging techniques have become remarkably sophisticated since the first mechanical scanner was introduced 20 years ago. Today, high-resolution scintigrams can be produced in minutes, and sequential images, each requiring only a few seconds, provide data on blood flow distribution and organ function. Tomographic imaging has further extended the capability and reliability of organ imaging.

Three patients with truncated left hepatic lobe on scintiscan of the liver have been presented to illustrate this diagnostic finding. This scintiscan finding should evoke more definitive study.

Radiosotopic imaging of the mediastinal blood pools is a well established technique. Although the method provides data relating to the size and location of these pools, additional valuable diagnostic information can be easily obtained through transmission scintigraphy performed prior to blood pool imaging. From an appropriate external radionuclide source, the radiation passes through the radiolucent chest structures to a gamma camera forming an outline image of the more radiodense structures. Subsequent to the transmission study, an emission study of mediastinal blood pools is obtained. The transmission and emission images are similar in size and directly comparable for evaluation of mediastinal structures. The routine use of radionuclide transmission scintigraphy is recommended as an adjunct to emission scintigraphy in the evaluation of mediastinal tumors, myocardial hypertrophy, and pericardial effusions.

Hepatic hydrothorax is a complication in approximately 5% of patients with cirrhosis. Ascites is almost always present and helps to suggest the correct diagnosis. However, when ascites is absent, radionuclide imaging has proven to be helpful in establishing that the pleural effusion originated from ascitic fluid. When pleural fluid is rapidly removed, such as by thoracostomy tube drainage, the radioisotope may accumulate outside the thorax and produce a negative scan of the chest. When the radionuclide scan is nondiagnostic and the pleural space is being rapidly drained, the pleural fluid collecting system should always be imaged before rejecting a diagnosis of hepatic hydrothorax.

Atresia and hypoplasia of the bile ducts are the most common congenital biliary anomalies of clinical importance. Surgical correction can help about 10% of these infants. However, surgery should be performed within the first month of life to avoid irreversible liver parenchymal changes. It is difficult to separate the surgical condition, biliary atresia, from conditions in which the trauma of laparotomy should be avoided, such as neonatal hepatitis and other clinically indistinguishable causes of obstructive jaundice. Radionuclide imaging with the 99mTc-labeled N-substituted iminodiacetic acids (HIDA, PIDIDA, DISIDA, etc) have been helpful in the differential diagnosis of biliary atresia.

Following intravenous injection of zinc 69m chloride, much of the zinc 69m was prompty removed by and concentrated in the liver. Techinically good liver scans were obtained using this radioactive agent. The half life and photon energy of zinc 691 make it a desirable isotope for clinical work.