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UNLABELLED: The Nuclear Regulatory Commission (NRC) regulations that govern release of patients administered radioactive material have been revised to include dose-based criteria in addition to the conventional activity-based criteria. A licensee may now release a patient if the total effective dose equivalent to another individual from exposure to the released patient is not likely to exceed 5 mSv (500 mrem). The result of this dose-based release limit is that now many patients given therapeutic amounts of radioactive material no longer require hospitalization. This article presents measured dose data for 26 family members exposed to 22 patients treated for non-Hodgkin's lymphoma with (131)I-anti-B1 antibody after their release according to the new NRC dose-based regulations. METHODS: The patients received administered activities ranging from 0.94 to 4.77 GBq (25--129 mCi). Family members were provided with radiation monitoring devices (film badges, thermoluminescent or optically stimulated luminescent dosimeters, or electronic digital dosimeters). Radiation safety personnel instructed the family members on the proper wearing and use of the devices. Instruction was also provided on actions recommended to maintain doses to potentially exposed individuals as low as is reasonably achievable. RESULTS: Family members wore the dosimeters for 2--17 d, with the range of measured dose values extending from 0.17 to 4.09 mSv (17--409 mrem). The average dose for infinite time based on dosimeter readings was 32% of the predicted doses projected to be received by the family members using the NRC method provided in regulatory guide 8.39. CONCLUSION: Therapy with (131)I-anti-B1 antibody can be conducted on an outpatient basis using the established recommended protocol. The patients can be released immediately with confidence that doses to other individuals will be below the 5-mSv (500 mrem) limit.

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OBJECTIVE: This retrospective study describes the phenotype associated with the single most common cause of genetic hearing loss. The frequency of childhood deafness is estimated at 1/500. Half of this hearing loss is genetic and approximately 80% of genetic hearing loss is nonsyndromic and inherited in an autosomal recessive manner. Approximately 50% of childhood nonsyndromic recessive hearing loss is caused by mutations in the connexin 26 (Cx26) gene (GJB2/DFNB1), making it the most common form of autosomal recessive nonsyndromic hearing loss with a carrier rate estimated to be as high as 2.8%. One mutation, 35delG, accounts for approximately 75% to 80% of mutations at this gene. METHODS: Hearing loss was examined in 46 individuals from 24 families who were either homozygous or compound heterozygous for Cx26 mutations. A subset of these individuals were examined for vestibular function, otoacoustic emissions, auditory brainstem response, temporal bone computed tomography, electrocardiography, urinalyses, dysmorphology, and thyroid function. RESULTS: Although all persons had hearing impairment, no consistent audiologic phenotype was observed. Hearing loss varied from mild-moderate to profound, even within the group of families homozygous for the common mutation 35delG, suggesting that other factors modify the phenotypic effects of mutations in Cx26. Furthermore, the hearing loss was observed to be progressive in a number of cases. No associations with inner ear abnormality, thyroid dysfunction, heart conduction defect, urinalyses, dysmorphic features, or retinal abnormality were noted. CONCLUSION: Newborns with confirmed hearing loss should have Cx26 testing. Cx26 testing will help define a group in which approximately 60% will have profound or severe-profound hearing loss and require aggressive language intervention (many of these patients will be candidates for cochlear implants).

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OBJECTIVE: To compare the probability of cancer in a solitary pulmonary nodule using standard criteria with Bayesian analysis and result of 2-[F-18] fluoro-2-deoxy-D-glucose-positron emission tomographic (FDG-PET) scan. SETTING: A university hospital and a teaching Veteran Affairs Medical Center. METHODS: Retrospective analysis of 52 patients who had undergone both CT scan of the chest and a FDG-PET scan for evaluation of a solitary pulmonary nodule. FDG-PET scan was classified as abnormal or normal. Utilizing Bayesian analysis, the probability of cancer using "standard criteria" available in the literature, based on patient's age, history of previous malignancy, smoking history, size and edge of nodule, and presence or absence of calcification were calculated and compared to the probability of cancer based on an abnormal or normal FDG-PET scan. Histologic study of the nodules was the gold standard. RESULTS: The likelihood ratios for malignancy in a solitary pulmonary nodule with an abnormal FDG-PET scan was 7.11 (95% confidence interval [CI], 6.36 to 7.96), suggesting a high probability for malignancy, and 0.06 (95% CI, 0.05 to 0.07) when the PET scan was normal, suggesting a high probability for benign nodule. FDG-PET scan as a single test alone was more accurate than the standard criteria and standard criteria plus PET scan in correctly classifying nodules as malignant or benign. CONCLUSION: FDG-PET scan as a single test was a better predictor of malignancy in solitary pulmonary nodules than the standard criteria using Bayesian analysis. FDG-PET scan can be a useful adjunct test in the evaluation of solitary pulmonary nodules.

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Leukocytes labeled with 99mTc-HMPAO and 111In have been used extensively in imaging inflammatory disorders, including inflammatory bowel disease (IBD), which has the appearance of tubular bowel activity. Peritonitis is inflammation of the serosal surfaces lining the peritoneal cavity which envelopes the bowel, giving a pattern of diffuse abdominal uptake on imaging. We present a case of an elderly man with surgically and pathologically confirmed peritonitis whose preoperative leukocyte scan mimicked the findings of IBD. Our findings suggest that diffuse peritonitis can mimic IBD on an 111In-leukocyte scan.

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We compared the abilities of positron emission tomography and computed tomography to detect N2 or N3 lymph node metastases (N2 or N3) in patients with lung cancer. Positron emission tomography detects increased rates of glucose uptake, characteristic of malignant cells. Patients with peripheral tumors smaller than 2 cm and a normal mediastinum were ineligible. All patients underwent computed tomography, positron emission tomography, and surgical staging. The American Thoracic Society lymph node map was used. Computed and positron emission tomographic scans were read by separate radiologists blinded to surgical staging results. Lymph nodes were "positive" by computed tomography if larger than 1.0 cm in short-axis diameter. Standardized uptake values were recorded from areas on positron emission tomography corresponding to those from which biopsy specimens were taken; if greater than 4.2, they were called "positive." Seventy-five lymph node stations (2.8 per patient) were analyzed in 27 patients. Computed tomography incorrectly staged the mediastinum as positive for metastases in three patients and as negative for metastases in three patients. Sensitivity and specificity of computed tomographic scans were 67% and 83%, respectively. Positron emission tomography correctly staged the mediastinum in all 27 patients. When analyzed by individual node station, there were four false positive and four false negative results by computed tomography (sensitivity = 60%, specificity = 93%, positive predictive value = 60%). Positron emission tomography mislabeled one node station as positive (100% sensitive, 98% specific, positive predictive value 91%). The differences were significant when the data were analyzed both for individual lymph node stations (p = 0.039) and for patients (p = 0.031) (McNemar test). Positron emission tomography and computed tomography are more accurate than computed tomography alone in detecting mediastinal lymph node metastases from non-small-cell lung cancer.

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BACKGROUND AND OBJECTIVE: Positron emission tomography (PET) utilizing 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) has been demonstrated to be highly accurate in differentiating benign from malignant pulmonary nodules. Transthoracic fine-needle aspiration biopsy (TTNA) is generally the initial procedure of choice in the evaluation of peripheral lesions suspected to be malignant. Our objective was to determine whether PET-FDG imaging, a noninvasive test, was equally efficacious as TTNA in the evaluation of lung lesions suspected to be malignant. PATIENT SELECTION: Thirty-three patients with 35 lung lesions who had undergone both PET-FDG imaging and TTNA were retrospectively selected from an ongoing prospective study of PET-FDG imaging in the evaluation of solitary pulmonary nodules. MEASUREMENTS: Diagnostic efficacy was determined by calculating sensitivity, specificity, positive and negative predictive value, and overall predictive accuracy for both PET-FDG imaging and TTNA in differentiating benign from malignant lesions. Complication rate also was documented for the two tests. RESULTS: The PET imaging correctly identified all 26 malignant lesions, including 21 lesions diagnosed by TTNA and 7 of the 9 benign lung lesions. The TTNA was positive for malignancy in 21 lung lesions and missed the diagnosis of malignancy in 5 lesions. Diagnostic sensitivity, specificity, positive and negative predictive value, and overall predictive accuracy was 100, 78, 93, 100, and 94% for PET imaging and 81, 100, 100, 64, and 86 for TTNA, respectively. Pneumothorax was documented in 16 patients (46%), and 9 patients (26%) required a chest tube. There were no complications with PET imaging. CONCLUSION: We conclude that PET imaging of the lung is as efficacious as TTNA, with less risk, and offers an alternate noninvasive option in the evaluation and management of lung lesions suspected to be malignant.

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Preliminary data indicate that positron emission tomography (PET) following injection of fluorodeoxyglucose F18 (FDG) is sensitive and specific for detecting malignant cells in chest tumors and mediastinal lymph nodes. We report a case of non-small cell lung cancer metastatic to clinically normal scalene lymph nodes that was correctly staged by FDG-PET.

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