Biomedical subjects
Publications and source records attributed to D Front.
The authors describe a patient with myelofibrosis who showed intense Ga-67 uptake in spite of being severely leukopenic and receiving large amounts of antibiotics. They conclude that false-negative results associated with leukopenia or intensive antibiotic treatment may not always be correct.
Two hundred and twenty five liver hemangiomas in 166 patients were studied with Tc-99m labeled RBC and are the basis for this atlas. All hemangiomas showed various presentations of the perfusion blood pool mismatch, which is the basis for diagnosis. The size of the hemangiomas was the factor that determined the mixing of the Tc-99m RBC with the blood and, hence, the sequence of visualization of the lesion. Hemangiomas may appear as multiple lesions on liver scan and imitate metastases. Ninety-five hemangiomas appeared in 36 patients as multiple focal abnormalities. Hemangiomas are extremely variable in size. They may be huge (31 hemangiomas) and sometimes occupy most of the abdomen. Or they can be very small and are then detected only by SPECT (two cases). Thrombosed large hemangiomas appear as focal defects on Tc-99m RBC.
The negative predictive value (PV-) and positive predictive value (PV+) of gallium-67 scintigraphy and computed tomography (CT) were compared after treatment in 43 patients with Hodgkin disease and in 56 patients with non-Hodgkin lymphoma. The usefulness of these studies in predicting survival was also evaluated. In patients with Hodgkin disease, the PV- of Ga-67 scintigraphy was 0.84 and of CT was 0.88. The PV+ was 0.80 for Ga-67 studies and only 0.29 for CT. In patients with non-Hodgkin lymphoma, the PV- of Ga-67 scintigraphy was 0.84 and of CT was 0.80. The PV+ was 0.73 and 0.35, respectively. For both groups, the differences in disease-free survival between patients with negative and positive Ga-67 studies were significant (P less than .05 in Hodgkin disease and P less than .001 in non-Hodgkin lymphoma), but the differences were not significant for CT. These data show that, after treatment of patients with lymphoma, Ga-67 scintigraphy is a good predictor of clinical outcome and can be used beneficially in patient treatment.
Quantitative bone scintigraphy (QBS), which measures 99mTc-MDP uptake expressed as percent of injected dose per cc, indicates bone metabolism. It is measured in the bones of patients before and after radiation treatment and then compared to normal controls. QBS was performed in a group of 22 normal individuals and was measured twice, 2-10 mo (mean 4.9) apart. There was no significant difference between the two measurements. QBS was performed also in 28 patients before, immediately after and at certain time intervals after radiation therapy for cancer. Both the irradiated and the nonirradiated bones showed significant decreases in bone metabolism at 2-18 mo (mean 8.8) after irradiation. In addition, increases and decreases of 99mTc-MDP uptake were similar in the irradiated and in the nonirradiated bones, and there were significant correlations of the QBS values in the different bones of each individual patient. The etiology of the changes in bone metabolism in the nonirradiated bones is not yet fully understood, but it appears to be the result of a systemic effect of radiation.
Three patients with osteosarcoma of the femur developed abnormal radiopharmaceutical uptake in the bones of the contralateral leg. This uptake was not due to metastases. The histology in one patient, the form of the lesion and the disappearance of the abnormal uptake without treatment in the other two, indicated that the uptake was probably due to stress fractures. Changes in weight bearing and walking in the normal leg as a result of the osteosarcoma in the other leg could have been the cause of the stress fractures. It should be recognized that new abnormal uptake on bone scintigraphy in patients with osteosarcoma of the leg may not necessarily indicate metastasis. It may be caused by a stress fracture and disappears after rest.
Concentrations of bleomycin labeled with cobalt 57 (Co-bleo) over time were measured in vivo in 17 patients with 32 sites of lymphoma and 18 patients with lung tumors after administration of the same dose of bleomycin. There were marked variations in individual tumor drug concentrations even among tumors with the same histologic type, indicating that the tumor concentration of this drug in individuals cannot be predicted from the administered dose. Also, tumor concentration could not be predicted from the area under the concentration over time curve (AUC) of Co-bleo in the blood; there was no correlation (r = 0.53) between the AUC and the concentration in the tumor at any point in time between 30 minutes and 8 hours after injection. There was no significant difference in the percent of the injected dose per milliliter (%ID/ml) which was delivered to the tumor when low and high amounts of bleomycin were administered to the same patient. Also, a good correlation (r = 0.88) between the %ID/ml over time was found when injection of low and high doses of bleomycin were compared. The results indicate that using quantitative single photon emission computed tomography (SPECT) and a labeled tracer dose it is possible to predict what fraction of the dose of a chemotherapeutic drug will concentrate in an individual patient's tumor in vivo. They also show that, for bleomycin, escalation of dose will result in a proportional increase of tumor concentration. This increase depends on individual properties of tumors which can be measured quantitatively in vivo by SPECT and are expressed as percent of %ID/ml of tumor tissue.
Extracorporeal shock-wave lithotripsy has altered the therapeutic approach to urinary stone disease. Recently, a method was developed in which shock-wave generation is obtained piezoelectrically. To evaluate the effect of extracorporeal piezoelectric lithotripsy (EPL) on renal function, 20 patients were studied prior to and after EPL of renal calculi. Renal cortical function was evaluated by using a previously described and validated quantitative single photon emission computerized tomography (SPECT) method to measure individual absolute uptake of technetium-99m dimercaptosuccinic acid (Tc-99m-DMSA). Twenty kidneys were treated, and the 19 contralateral kidneys were without stone disease (1 patient had a single kidney). The absolute kidney uptake of Tc-DMSA in the normal kidneys was 21.4% +/- 6.2% before and 22.2% +/- 6.4% after EPL. For the treated kidneys the absolute update was 16.8% +/- 5.3% and 16.8% +/- 4.7% before and after, respectively. There was no statistical significant difference between pre- and post-treatment values. The absolute kidney uptake was significantly lower (p less than 0.01) in the treated than in the normal kidneys. This study indicates that the EPL procedure did not cause any damage to cortical function detectable by the DMSA uptake.
The ability to evaluate kidney function in each kidney separately by quantitative SPECT was tested in 20 patients with a single kidney and varying degrees of renal disease. Technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) uptake was compared with renal function measured by creatinine clearance and serum creatinine. There was a good correlation for both serum creatinine (r = 0.89, y = 24.6 *X -1.15, error = 5.6, p less than 0.001) and creatinine clearance (r = 0.76, y = 0.6 *X 0.84, error = 8.0, p less than 0.001). The results indicate that SPECT quantitation of 99mTc-DMSA uptake can be used as an indicator of the function of each kidney individually.
Tumor concentrations of the chemotherapeutic drug, bleomycin, labeled with cobalt-57 (Co-bleo) were compared in mouse tumor models and in human lung tumors using quantitative single-photon emission computed tomography. Drug concentrations in histologically similar human tumors showed marked variability for the same injected dose (ID). Small cell carcinomas showed concentrations between 1.09 and 8.85 %ID/cc x 10(-3) while non-small cell lung tumors showed a concentration variation between 0.36 and 6.75 %ID/cc x 10(-3). In contrast to the situation in human tumors, uptake in mouse tumors showed only slight variability in animals with the same tumor model. EMT-6 tumors in mice showed at 6 hr significantly higher uptake of Co-bleo (p less than 0.001) and significantly higher tumor-to-lung ratio (p less than 0.001) when compared to murine fibrosarcomas. The EMT-6 tumors in contrast to the fibrosarcomas responded to bleomycin treatment in a dose dependent manner. The results indicate that while in mice the tumor dose closely follows the administered dose, in humans, the tumor dose and the tumor-to-lung ratio in the individual patient cannot be predicted from the administered dose.
One hundred ninety patients with breast cancer were prospectively evaluated for bone pain and had technetium Tc 99m-methylene diphosphonate bone scintigraphy for bone metastases. Of the 66 patients showing evidence for bone metastases, 21 (32%) did not have bone pain. There were 155 sites of skeletal metastases, but pain was found only in 50 sites. The age of the patient or involvement of weight-bearing bones did not seem to affect the association between bone metastases and pain. We discuss the need for periodic bone scintigraphy, even when the clinical state does not seem to warrant it.
Scintigraphy with 99mTc-labeled red blood cells was performed in five patients for demonstration of normal anatomy and in 18 patients for evaluation of suspected or apparent space-occupying abdominal lesions. In 14 cases of abdominal lesions, the study demonstrated the extent, vascularity, and relation of the lesion to neighboring organs. We found the method was primarily useful for evaluating cases of retroperitoneal tumor and vascular malformation.
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Patterns of pertechnetate uptake were correlated with ultrastructural properties of the endothelial wall in 14 human brain tumours. In tumours with reduced uptake of the radionuclide, intercellular tight junctions were observed whereas absence of intercellular tight junctions was characteristic of all tumours with an increased uptake of pertechnetate. In some tumours with increased uptake, fenestrated endothelial wall was seen while in others non-fenestrated wall was evident. We concluded that intercellular junctions and not fenestrations affect the permeability of brain tumours to pertechnetate.
Differences in the rate of uptake of 99Tcm-diphosphonate were found in 20 human bone tumours investigated. As some tumours have a slow rate of uptake it is suggested that the time used for routine scintigraphy at 3 hours is not always optimal and a further study should be performed in some cases. Various degrees of tumour vascularity and vessel permeability were found. The rate of diphosphonate uptake correlates with the vascularity, while it does not correlate with permeability which is generally increased as compared to normal bone.
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Bones of the face and skull may be involved directly by adjacent primary tumors of the head and neck. Radiography, at present the standard method for detection of bone involvement in such tumors, is not sufficiently sensitive. Of 22 patients who showed bone involvement in scintigraphy, radiography in 15 was initially normal, in 6 the extent of the lesion was not completely shown and only in 3 was it as informative as scintigraphy. Bone scintigraphy should become a standard method for evaluation of the context of bone invasion by tumors of the head and neck.
Delayed 24-hour scintigraphy was performed in 23 patients. It was found to be useful in enhancing abnormal uptake, enabling better anatomic localization and verifying doubtful uptakes in the 4-hour study. The underlying causes of these observations are probably a better lesion-to-blood ratio and a slow uptake in certain lesions.
A doughnut phenomenon was observed in bone scintigraphy in three cases of metastatic thyroid carcinoma to the skull. Additional dynamic and static studies were performed to evaluate the relative roles of vascularity, vessel permeability and new bone formation in producing this phenomenon. This was accomplished through the use of 99mTc-diphosphonate, 99mTc-labeled red blood cells and 99mTc-pertechnetate. The important factor was found to be a new bone formation. Late uptake of diphosphonate was shown only in the periphery of the lesion, where formation of new bone takes place. This occurred even in the presence of increased vascularity and vessel permeability in the lesion as a whole.