Biomedical subjects
D A Podoloff
Publications and source records attributed to D A Podoloff.
Development of a SPECT-based three-dimensional treatment planning system for radioimmunotherapy.
UNLABELLED: Two major obstacles in the development of improved methods for more accurate dose estimates for radioimmunotherapy have been the difficulty in obtaining an accurate patient-specific three-dimensional activity map in vivo and calculating the resulting absorbed dose. We propose a method for three-dimensional internal dosimetry that integrates the three-dimensional activity map from SPECT with a dose-point kernel convolution technique to provide the three-dimensional distribution of absorbed dose. METHODS: Accurate activity quantitation was achieved with appropriate methods. The count density map from SPECT images was converted into an activity concentration map with a calibration phantom approach. This map was then convolved with an 131I dose-point kernel and three-dimensional fast Fourier transform to yield three-dimensional distribution of absorbed dose, which was then processed to provide the absorbed dose distribution in regions of interest. RESULTS: The accuracy of quantitative SPECT was validated to be within 16%. The calculated penetrating radiation absorbed dose was verified with thermoluminescent dosimeter measurements to be within 8%. With standard organs and configuration, the method calculated absorbed dose in good agreement with the MIRD formalism (less than 14%). CONCLUSION: This method overcomes the limitations of planar imaging techniques and the current routine implementation of the MIRD formalism. The results can be processed to provide the absorbed dose distribution in regions of interest and parameters for treatment optimization. Absorbed dose distribution from any plane can be graphically displayed in various ways.
The role of radionuclide scans in sarcoma.
Images were interpreted and correlated with contemporaneous CT and/or MR imaging studies. Visual qualitative analysis of all images was performed by two or more nuclear medicine physicians expert in reading these studies. Tracer uptake was graded by visual inspection according to the following scale: negative, 0; faint, 1; moderate, 2; marked, 3. The results indicated that there was a statistically significant difference (student T test) in the visual analysis scale obtained with MIBI and FDG, indicating better detection (higher sensitivity) of the sarcoma with FDG (Table 3). However, the number of cases so far studied is small. It is imperative for us to deal with cost effectiveness of our imaging procedures in an environment driven by cost containment and managed care initiatives. The question posed by the analysis of our work is this: Is the significant difference in cost between PET and SPECT justified as far as patient outcome or management is concerned? PET scans cost about $2,500 each. A SPECT scan is about $600. Will the patient benefit $1900 from the PET intervention? This is an important question for which very little objective data are available for evaluation by third-party payers, patients, or health care providers.
Detecting recurrent or residual lung cancer with FDG-PET.
UNLABELLED: We investigated the diagnostic accuracy of FDG-PET in the detection of recurrent lung cancer. METHODS: Thirty-nine lesions in 38 patients with clinically suspected recurrent or residual lung cancer were studied with PET. All PET images were visually interpreted in conjunction with thoracic CT or MRI. Semiquantitative analysis using standardized uptake values (SUVs) was also performed in 25 lesions. FDG-PET diagnoses were correlated with pathological diagnoses and clinical outcome. RESULTS: The sensitivity and specificity of FDG-PET for detecting recurrent tumors were 100% (26/26) and 61.5% (8/13), respectively. The difference in mean SUV between recurrent tumors and noncancerous lesions was statistically significant [11.2 +/- 5.7 (n = 16) vs. 3.5 +/- 1.8 (n = 9), p < 0.0001]. False-positive results showed relatively lower SUVs than true-positives and also demonstrated increased uptake in a curvilinear rather than nodular shape. CONCLUSION: FDG-PET is useful for detecting recurrent lung cancer after treatment. False-positive diagnoses might be reduced by analysis of uptake shape and serial changes in SUV, but further study is needed.
Primary breast lymphoma detected with SPECT using gallium-67-citrate.
Breast involvement by malignant lymphoma either as a primary site or as a secondary site from lymphoma elsewhere is rare. Primary breast lymphoma (PBL) accounts for only a small percentage of total malignant lymphoma involving the breast. The incidence of PBL varies from 0.004% to 0.5%. We present a case of PBL which was well demonstrated on total-body imaging as well as SPECT using 67Ga-citrate.
Phase II radioimmunotherapy trial with 131I-CC49 in colorectal cancer.
BACKGROUND: Radiolabeled CC49, a second generation high affinity monoclonal antibody (MoAb) reactive with tumor-associated glycoprotein 72 (TAG72) has undergone previous Phase I testing in patients with colon cancer. Based on this report, the authors treated 15 refractory metastatic colon cancer patients with 131I-CC49 to determine its overall toxicity and the response to therapy of patients treated with it. METHODS: Patients received 75 mCi/m2 131I-CC49 (20 mg MoAb) intravenously for a period of 30-60 minutes. Whole body retention was derived from the measured dose-rate of I-131 monitored daily at 1 m using an ion chamber. Two whole-body and static-gamma camera images were taken of patients on days 4 and 7 after the infusion. RESULTS: Nonhematologic toxicity (Grade 1-2) consisted of nausea (two patients), arthralgias (three patients), transient fever and chills (two patients), and transient blood pressure changes (two patients). At 4-5 weeks posttreatment, reversible Grade 3-4 thrombocytopenia was observed in 7 of 15 patients, and reversible Grade 3-4 granulocytopenia was observed in 6 of 15 patients. Twelve of 13 patients tested developed human anti-mouse antibody (range, 161 to > 20,000 ng/ml) at 6-8 weeks postinfusion. Mean +/- SD whole-body half-life (whole-body retention) of 131I-CC49 was 57.3 +/- 13.4 hours. Tumors were seen in all patients. In two of three patients treated a second time, an increased whole body clearance rate correlated with elevated human anti-mouse antibody, reduced uptake in tumor, and enhanced uptake in the thyroid. Estimated tumor doses ranged from 19-667 rads. Red marrow dose estimated from whole body retention ranged from 60 to 117 rads and correlated with decreases in platelet count. No objective tumor responses (i.e., partial or complete) were observed. CONCLUSIONS: Despite minimal toxicity and favorable tumor uptake, efficacy has been limited at this dose and schedule.
Comparative tumor localization of whole immunoglobulin G anticarcinoembryonic antigen monoclonal antibodies IMMU-4 and IMMU-4 F(ab')2 in colorectal cancer patients.
BACKGROUND: Previous studies in the literature have suggested that radiolabeled F(ab')2 fragments might be superior to whole immunoglobulin G (IgG) for imaging and therapy of cancer because of their greater penetration in tumors. To test this hypothesis, the authors compared tumor and normal tissue uptake along with plasma clearance of 125I-labeled monoclonal antibody (MoAb) IMMU-4 whole IgG with its 131I-labeled F(ab')2 fragment. METHODS: Five patients with either liver metastases from colorectal cancer (n = 4) or intact primary tumors (n = 1) received a combination of 125I-IMMU-4 IgG (2 mCi/1 mg) plus 131I-IMMU-4 F(ab')2 (10 mCi/1 mg) as a single 1-hour intravenous infusion on day 1. Serial blood samples were taken for up to 72 hours postinfusion to determine plasma clearance of each MoAb. On days 3-9, patients underwent exploratory laparotomy in which biopsies of tumor as well as normal tissues (liver, normal colon, lymph node, and blood) were obtained. Tissues were weighed and counted in a gamma counter, and the percent of injected dose per kilogram (%ID/kg) of each antibody, along with the radiolocalization index (RI), was computed (RI = %ID/kg tumor.%ID/kg normal tissue). RESULTS: Tumor uptake of both antibodies (2.3 +/- 0.53 %ID/kg) was significantly higher than that of normal tissues (0.56 +/- 0.12; P < 0.001), except for blood (2.8 +/- 0.83), resulting in an RI > or = 3. There were no significant differences in uptake (%ID/g) between F(ab')2 and IgG (F[ab']2 = 2.0 +/- 0.57; IgG = 2.6 +/- 0.94). The mean +/- SD of plasma T1/2 was slightly shorter for F(ab')2 (28.8 +/- 7.2 hours) than for IgG (45.9 +/- 16.7; P = 0.08). CONCLUSION: In short, the biodistribution and pharmacokinetics of IMMU-4 F(ab')2 were comparable to those of IMMU-4-IgG.
Radioimmunoscintigraphy of pelvic lymph nodes with 111indium-labeled monoclonal antibody CYT-356.
In an attempt to define the possible role of radioimmunoscintigraphy to assess noninvasively the pelvic lymph nodes, we studied 19 patients with prostate cancer. All 19 men underwent conventional radiographic imaging of the pelvis with computerized tomography or magnetic resonance imaging before bilateral pelvic lymph node dissection. In addition, radioimmunological scanning with 111indium-labeled monoclonal antibody CYT-356 was performed. Pathologically 8 of the 19 patients had histological confirmation of metastatic nodal disease ranging from 1 to 15 mm. The monoclonal scan was positive at a site corresponding to the histologically confirmed nodal foci in 4 of the 8 patients. Since each hemipelvis could be independently assessed for pathological disease and imaging status, we report site-specific analysis of the monoclonal antibody scan in 38 hemipelves. The overall accuracy was 76% with a sensitivity and specificity of 44% and 86%, respectively. The negative predictive value was 83% and the positive predictive value was 50%. The administration of a single dose of CYT-356 antibody is safe, feasible and capable of detecting soft tissue nodal disease. A negative scan enables the physician to predict noninvasively a low probability of nodal disease for individuals at high risk. The detection threshold of this antibody scan appears to be disease foci 5 mm. or greater.
The gallium scan predicts relapse in patients with Hodgkin's disease treated with combined modality therapy.
The gallium scan (GS) is an important indicator of disease activity in untreated Hodgkin's disease, especially in the upper torso, and may be an important predictor of results for patients who have completed chemotherapy and radiotherapy (XRT). To better define the importance of the GS in predicting treatment results in a group of patients treated with uniform therapy, we performed GS prior to treatment in 46 patients with pathologically or clinically staged I-III Hodgkin's disease who received three cycles of NOVP (Novantrone, vincristine, vinblastine, prednisone) followed by XRT. Staging methods included computerized tomography (CT) of the chest, abdomen, and pelvis, lymphangiogram, and the GS, using 8 to 10 millicuries with single photon emission computed tomography (SPECT) of the upper and lower torso. Only 3 patients had negative GS before chemotherapy. After three cycles of NOVP and prior to XRT, the other 43 had repeat GS performed. Complete remission (CR) was judged by disappearance of disease after all therapy without considering GS results. The CR for those with initial positive GS was 93%. The three-year freedom from progression result for stage I-II was 94%, and the three-year overall survival was 96%; corresponding results for stage III were 86% and 100%, respectively. None of the prognostic factors for analysis, including bulky adenopathy, hilar involvement, or B symptoms, was an important predictor of results. However, only 1 of the 33 with a negative GS after these NOVP has had progressive disease compared to 3 of the 10 with a GS that remained positive.(ABSTRACT TRUNCATED AT 250 WORDS)
Phase I trial of murine monoclonal antibody 14G2a administered by prolonged intravenous infusion in patients with neuroectodermal tumors.
PURPOSE: The purpose of this phase I trial was to determine the toxicity and maximum-tolerated dose (MTD) of murine monoclonal antibody (Mab) 14G2a (anti-GD2) in cancer patients. PATIENTS AND METHODS: Following tracer doses of iodine-131-labeled 14G2a to determine tumor uptake, 18 patients with refractory melanoma, neuroblastoma, or osteosarcoma received unlabeled 14G2a at total concentrations of 50, 100, and 200 mg/m2 administered as daily 24-hour infusions for 5 days. RESULTS: The overall sensitivity of external immunoscintigraphy was 64 of 74 known metastases (86%). Toxicity from prolonged infusion of 14G2a consisted of severe generalized pain, hyponatremia, fever, rash, paresthesias, weakness, and chronic refractory postural hypotension (two patients). Toxicity was less severe in pediatric patients. The MTD of Mab was 100 mg/m2. Sixteen of 18 patients developed human antimouse antibodies (HAMA) to 14G2a. Terminal-phase half-life (T1/2) of unlabeled Mab was 6.6 +/- 1.8 hours for patients receiving 50 mg/m2 and 39.5 +/- 13.3 hours at the 100-mg/m2 level. Tumor biopsies from six melanoma patients were positive for GD2 antigen, but only two of six had trace amounts of 14G2a present. Three mixed responses (two melanoma, one osteosarcoma) and two partial responses (PRs; neuroblastoma) were observed. CONCLUSION: Mab 14G2a has modest antitumor activity at the expense of significant toxicity. Dose-limiting neurologic sequelae may significantly limit phase II studies other than in pediatric patients with neuroblastoma.
Technetium 99m-labeled IMMU-4, a monoclonal antibody against carcinoembryonic antigen, for imaging of occult recurrent colorectal cancer in patients with rising serum carcinoembryonic antigen levels.
PURPOSE: We tested whether nuclear imaging with technetium 99m-labeled murine monoclonal antibody (MoAb) against carcinoembryonic antigen (CEA) IMMU-4 will detect recurrent colorectal disease in patients with a rising serum CEA level but negative abdominal and pelvic computed tomographic (CT) scan, chest radiograph, and colonoscopy, or barium enema. PATIENTS AND METHODS: Sixteen patients with completely resected, CEA-producing colorectal cancer were given 1 mg of 99mTc-labeled IMMU-4 intravenously with no toxic side effects. Planar and single-photon emission CT (SPECT) scans were acquired at 6 hours. Fifteen patients underwent an exploratory laparotomy at 24 hours. Results of the scintigraphy were correlated with surgical findings. RESULTS: Twelve of 15 patients (80%) had true-positive (TP) scans when correlated with surgery. Two of 15 (13%) had true-negative (TN) scans inasmuch as exploratory laparotomy failed to detect recurrent disease. A false-positive (FP) scan was obtained in one of 15 (7%). There were no false-negative (FN) scans. Sensitivity, specificity, accuracy, and the positive predictive value (PPV) were 100%, 67%, 93%, and 92%, respectively. Twenty-six histologically confirmed areas of malignancy were found and correlated with areas of increased activity seen on IMMU-4 scintigraphy. Twenty-one were TP; five were not detected by scintigraphy and were thus considered to be FN. There were five FP lesions and 25 TN regions. Sensitivity, specificity, accuracy, and the PPV in these 26 cancer tissues were 81%, 83%, 82%, and 81%, respectively. The median radioactivity ratio of tumorous tissue to normal tissue was 3.33, with a range of 0.89 to 17.16. CONCLUSIONS: These results suggest that 99mTc IMMU-4 scintigraphy is an important addition to the armamentarium available for diagnostic imaging and may help detect occult metastatic cancer missed by abdominal and pelvic CT in patients with rising CEA levels.
Monoclonal antibody imaging in patients with colorectal cancer and increasing levels of serum carcinoembryonic antigen. Experience with ZCE-025 and IMMU-4 monoclonal antibodies and proposed directions for clinical trials.
In an effort to identify the site of recurrent colorectal cancer in patients with occult metastasis and increasing serum CEA levels, we conducted two trials using monoclonal antibodies (MoAb) against CEA. The first utilized Indium-111-labeled ZCE-025; an immunoglobulin G1 (IgG1) anticarcinoembryonic antigen (anti-CEA) antibody (Hybritech, San Diego, CA). The second study used Tc-99m-labeled Fab' fragment of IMMU-4 (Immunomedics, Morris Plains, NJ). Eighteen patients were imaged with the ZCE-025 and 14 with the Tc-99m Fab' IMMU-4. True-positive scans, defined as at least one correct correlation of the MoAb scan and surgical/histologic findings, were observed in 12 of 15 patients undergoing exploration or biopsy using the ZCE-025 and 11 of 14 using the IMMU-4. There were no true-negative scans with the ZCE-025 and only 2 of 14 with the IMMU-4. There were 3 false-positive scans with the ZCE-025 and 1 of 14 with IMMU-4. There were no false-negative scans with either ZCE-025 or IMMU-4. Four (31%) of 13 patients undergoing exploration and imaged with ZCE-025 and 5 (36%) of 14 imaged with IMMU-4 had complete tumor resection. Treatment decisions were affected in 3 (16%) of 18 ZCE-025-imaged patients and 3 (21%) of 14 IMMU-4 ones. Two (14%) of 14 patients imaged with IMMU-4 had negative MoAb scans and negative laparotomies. Despite these findings, it is not known whether such early detection and resection will translate into improved survival rates. The authors suggest two randomized studies, one designed to ascertain the role of MoAb added to blind exploratory laparotomy. In that study, patients with increasing CEA levels and a negative workup will be randomized to an exploratory laparotomy preceded by MoAb anti-CEA scans or a straight exploratory laparotomy without the assistance of a MoAb anti-CEA scan. Endpoints will be differences in complete resectability and survival. A second study will examine the merits of blind exploratory laparotomies. In that study, patients with increasing CEA levels and a negative workup would be randomized to MoAb imaging, exploratory laparotomy, and radioimmunoguided surgery, and the other cohort of patients would continue to have conventional radiologic workup. Exploration in this latter group would be performed only when indicated by radiologic or endoscopic studies. The endpoint of the study would compare survival in the two cohorts of patients. These two studies may ultimately settle the debate regarding the correct approach to patients with occult metastatic colorectal cancer and a increasing levels of serum CEA.
Clinical correlation of oral-dental findings with radiographs and with total body bone scans.
Bone scans are frequently used to detect osteoblastic areas in bone, including bony metastases in patients with existing tumors. Various dental conditions have been found to cause areas in the jaws to have increased uptake of radiopharmaceuticals. We studied 30 patients with an existing cancer or previous history of cancer with the use of total body bone scans, panoramic radiographs, and dental examinations, and we found no correlation between the intensity of radionuclide uptake in the jaws on the bone scans and the number of teeth in each jaw, the age of the patient, the degree of periodontal disease, or the number of dental pathoses per jaw. The frequency and intensity of positive scan results were related to the presence or absence of intrabony lesions in the jaws. Dental disease therefore does not appear to mask metastatic disease in the jaws; however, when metastasis is suspected, a dental examination with radiographs is recommended.
Imaging of colorectal carcinoma with technetium-99m radiolabeled Fab' fragments.
In this phase III study, patients who had previously undergone surgery for colorectal cancer were studied using a technetium-99m (99mTc)-labeled anti CEA antibody (IMMU-4 [Immunomedics, Morris Plains, NJ] 1mg of protein) to evaluate recurrence. Total-body, planar, and single photon emission computed tomography (SPECT) images were performed within 6 hours of injection. Objectives were to evaluate the efficacy of the 99mTc-labeled anti-CEA antibody, to assess sensitivity and specificity of the agent in known lesions, and to detect occult disease. The impact of antibody study on subsequent surgery was also evaluated. The Fab' fragment has a molecular weight of 54,000 and is supplied as a lyophilized kit that can be instantaneously labeled with 20 to 30 mCi of [99mTc]pertechnetate. In 9 patients with known disease, planar spot imaging identified lesions in 7 (78% sensitivity), SPECT imaging detected lesions in 8 (88% sensitivity), and 1 patient did not have SPECT. In the group of 10 patients with occult (or equivocal) disease, planar imaging sensitivity was 50%, and SPECT sensitivity was 100%. Analysis by site showed 14 of 24 lesions detected by planar imaging (58% sensitivity), and SPECT detected 24 of 24 lesions (100% sensitivity). Tumors as small as .5 cm were visualized in the 19 patients studied. The surgeon judged the antibody study to be impact neutral in 73% of the cases and helpful in 27% of the cases when antibody study altered the presurgical plan.
Nuclear hepatobiliary imaging.
Recent improvements in hepatobiliary radiopharmaceuticals and the high prevalence of biliary tract disease have resulted in a larger role for hepatobiliary imaging in clinical applications. The use of hepatobiliary imaging in assessing hepatic blood flow, hepatocyte function, biliary drainage, and complications in patients with jaundice or abdominal pain or surgery, as well as its primary use in diagnosing acute cholecystitis, is discussed.
Evaluation of sensitivity and specificity of upper extremity radionuclide venography in cancer patients with indwelling central venous catheters.
Two hundred twenty upper extremity radionuclide venograms were performed using upper extremity injection of 5 mCi of Tc-99m DTPA in each arm of patients with indwelling central lines. Evidence of obstruction was found in 123 patients, collateral flow without anatomic obstruction in six patients, and a slow-flow pattern in 12 patients. Twenty-six of these also underwent upper extremity contrast venography within 48 hours of the scan. Contrast venograms and radionuclide venograms agreed in 19 patients (16 correctly identified as obstructed, three correctly identified as unobstructed). Six patients showed the slow-flow pattern without collaterals or obstruction. Subsequently, six follow-up contrast studies showed no evidence of obstruction or collaterals. The authors conclude that obstruction with collateral flow on radionuclide venograms correctly predicts obstruction. However, the slow-flow pattern does not and should not be used as the sole criterion to diagnose partial obstruction.
Differentiation of residual or recurrent tumors from post-treatment changes with F-18 FDG PET.
Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) was used to differentiate recurrent or residual malignant disease from the effects of cancer treatment. Transaxial images were obtained after injection of 5-10 mCi (185-370 MBq) of F-18 FDG in 68 patients (including 33 with brain tumors) whose posttreatment computed tomographic (CT) or magnetic resonance (MR) imaging findings had been suggestive of malignant disease. PET findings were correlated with surgical results in 18 patients and with the outcomes of CT, MR imaging, clinical, and laboratory 9-month follow-up studies in 50 patients. There was good agreement between F-18 FDG uptake and presence or absence of malignant disease except in four cases of brain tumors in which histologic findings could not be correlated with biologic behavior. The putative sensitivity and specificity in the 33 cases of brain tumors were 80% and 94%, respectively. The authors conclude that PET with F-18 FDG is useful in detection of previously treated metabolically active tumors but is limited in diagnosis of recurrent microscopic or metabolically inactive tumors.