Pregnancy testing before high-dose radioiodine treatment: a case report.
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This case emphasizes that negative urine pregnancy testing and a written declaration of the patient are not sufficient to safely exclude an early pregnancy. Serum pregnancy testing inherently has a diagnostic gap of about 1 wk following conception. We recommend sufficient contraception at least 1 mo before radioiodine treatment in women of childbearing age. (+info)
Sensitivity in detecting osseous lesions depends on anatomic localization: planar bone scintigraphy versus 18F PET.
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Radionuclide bone scanning (RNB) is considered to be the most practical screening technique for assessing the entire skeleton for skeletal metastases. However, RNB has been shown to be of lower sensitivity than MRI and CT in detecting osteolytic metastases. A prospective study was designed to evaluate the accuracy of planar RNB versus tomographic bone imaging with 18F-labeled NaF and PET (18F PET) in detecting osteolytic and osteoblastic metastases and its dependency on their anatomic localization. METHODS: Forty-four patients with known prostate, lung or thyroid carcinoma were examined with both planar RNB and 18F PET. A panel of reference methods including MRI of the spine, 1311 scintigraphy, conventional radiography and spiral CT was used as the gold standard. RNB and 18F PET were compared by a lesion-by-lesion analysis using a five-point score for receiver operating characteristic (ROC) curve analysis. RESULTS: 18F PET showed 96 metastases (67 of prostate carcinoma and 29 of lung or thyroid cancer), whereas RNB revealed 46 metastases (33 of prostate carcinoma and 13 of lung or thyroid cancer). All lesions found with RNB were also detected with 18F PET. Compared with 18F PET and the reference methods, RNB had a sensitivity of 82.8% in detecting malignant and benign osseous lesions in the skull, thorax and extremities and a sensitivity of 40% in the spine and pelvis. The area under the ROC curve was 0.99 for 18F PET and 0.64 for RNB. CONCLUSION: 18F PET is more sensitive than RNB in detecting osseous lesions. With RNB, sensitivity in detecting osseous metastases is highly dependent on anatomic localization of these lesions, whereas detection rates of osteoblastic and osteolytic metastases are similar. Higher detection rates and more accurate differentiation between benign and malignant lesions with 18F PET suggest the use of 18F PET when possible. (+info)
Radiation dose to the testes after 131I therapy for ablation of postsurgical thyroid remnants in patients with differentiated thyroid cancer.
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Radioiodine-131 is used in differentiated thyroid cancer (DTC) for ablation of postsurgical thyroid remnants and destruction of metastases. The question may be raised of whether 131I treatment of DTC in male patients may give an irradiation dose to the testes that could impair fertility. Few data in the literature concern the dose absorbed by the testes after 1311 therapy for DTC. Because 131I kinetics may be altered by the hypothyroid condition commonly present at the time of treatment and by the radioiodinated iodoproteins released by the damaged thyroid tissue, the dose values reported in the International Commission on Radiological Protection (ICRP) tables for euthyroid men may not be appropriate. To clarify this problem, three male subjects undergoing 131I therapy for ablation of thyroid remnants shortly after thyroidectomy for DTC were studied. METHODS: The mean administered activity was 1256 MBq, and the duration of the study was 2 wk. The gamma dose was measured by thermoluminescent dosimeters (TLDs) applied to the lower poles of the testes. Correction factors were calculated for the distance of the TLD from the center of the testes and for attenuation by the testes of the gamma rays reaching the TLD. After correction, the gamma dose to the testes ranged from 21 to 29 mGy. The gamma dose calculated by the Medical Internal Radiation Dose (MIRD) method from blood and urine samples was similar (18-20 mGy) to that measured by TLDs. The beta dose was estimated by the MIRD method from blood activity and testicular volume and ranged between 14 and 31 mGy. RESULTS: The total (beta and gamma) doses to testes were 30, 33 and 43 microGy/MBq in the three subjects. CONCLUSION: These values are close to those derived from the ICRP tables (26-37 microGy/MBq 131I) for euthyroid subjects. The present data indicate that significant irradiation is delivered to the testes after the administration of the 131I ablative dose to thyroidectomized patients. The relevance of the radiation absorbed by testes on fertility remains to be established. (+info)
Mutation analysis of protein kinase A catalytic subunit in thyroid adenomas and pituitary tumours.
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OBJECTIVE: The adenylyl cyclase system plays an important role in the control of both thyroid follicular and anterior pituitary cell function. Activating mutations affecting important pathway components such as the TSH receptor and Gsalpha occur in the majority of autonomously functioning thyroid nodules. Only a small proportion of other types of thyroid tumours, however, have been reported to harbour these mutations. Activating mutations of Gsalpha have been reported to occur in up to 40% of pituitary somatotroph adenomas. As the majority of cold thyroid nodules and pituitary tumours are unaffected by these mutations, we have investigated the possibility of activating mutations occurring in protein kinase A (PKA), which is another key component of the adenylyl cyclase pathway. DESIGN: Genomic DNA and cDNA were analysed for the presence of PKA Calpha mutations by allele-specific oligonucleotide hybridisation and single strand conformation polymorphism analysis. PATIENTS: A total of 171 tissue samples were investigated. These comprised 66 benign and 24 malignant thyroid neoplasms, 21 somatotroph adenomas, 35 non-functioning pituitary adenomas, 2 corticotroph adenomas, 1 malignant prolactinoma, and 22 normal pituitary tissue samples. RESULTS: No mutations of PKA Calpha were identified using either allele-specific oligonucleotide hybridisation or single strand conformation polymorphism analysis. CONCLUSIONS: It appears that PKA Calpha mutations at the codons investigated do not represent an oncogenetic mechanism in the development of thyroid and pituitary neoplasms. (+info)
Spuriously elevated plasma calcitonin in a patient with a thyroid nodule not associated with medullary thyroid carcinoma.
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An increase in plasma calcitonin concentration is widely regarded as a specific and sensitive indication of underlying medullary thyroid carcinoma (MTC). We present a case in which the association of increased plasma calcitonin concentration and a thyroid nodule was not due to MTC. Subsequent measurement of plasma calcitonin by a variety of methods highlighted the variability that exists in calcitonin measurement and the potential for clinically misleading results. The rationale for investigation and treatment of MTC, including a recommendation to screen all patients with thyroid nodules using plasma calcitonin measurement, is based on the use of specific two-site calcitonin assays which are not universally used in the UK or USA. (+info)
Comparison of telomerase and CD44 expression as diagnostic tumor markers in lesions of the thyroid.
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The analysis of the tissue expression patterns of both the telomerase enzyme and the adhesion molecule CD44 has highlighted these molecules as potential tumor markers. In this study, the expression of these markers was analyzed in frozen tissue samples of the same human thyroid lesions, and the data were compared to evaluate their application to tumor diagnosis. The study analyzed 12 malignant specimens, including 5 papillary, 3 follicular, 2 anaplastic, 1 medullary, and 1 low-grade Hurthle cell carcinoma and 17 specimens from benign lesions, including cases of adenoma, hyperplasia, and Graves' disease. Telomerase expression was analyzed by assay of enzyme activity using the telomeric repeat amplification protocol and by reverse transcription-PCR detection of human telomerase reverse transcriptase (hTERT) mRNA. Nine of 12 (75%) malignant samples and the two Graves' disease samples were evaluated as positive for telomerase activity by the telomeric repeat amplification protocol assay. The presence of hTERT mRNA was detected in 8 (67%) of 12 malignant tissues and in 5 (29%) of 17 benign thyroid tissue samples. The expression of CD44 transcripts containing variant exons 7, 8, and 11 was evaluated by reverse transcription-PCR/Southern blot analysis. Of the 12 malignant samples, 9 (75%) included transcripts containing exon 7, 10 (83%) included transcripts containing exon 11, and 11 (92%) included transcripts containing exon 8. However, these CD44 exons were also present in transcripts in a high proportion of benign samples. Five (28%), 10 (59%), and 6 (35%) benign samples contained CD44 transcripts, including variant exons 7, 8, and 11, respectively. The measurement of telomerase activity proved to be the most specific for the detection of thyroid carcinoma in frozen tissue samples as a single analyte, but diagnostic accuracy was increased by the combination of telomerase and CD44 analyses. (+info)
Environmental radioactivity, population exposure and related health risks in the east Baltic region.
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The paper considers radioactive contamination of the east Baltic region, population exposures, and the risk of damage to human health. Principal sources include global fallout, the Chernobyl accident, and marine transport of radionuclides. A mean annual exposure of 2-3 mSv comes from environmental radioactivity. Main contributors are primarily radon and its decay products. The Chernobyl accident brought an additional dose of about 0.5 mSv in southern Finland and 1.4 mSv in the most contaminated districts of the Leningrad region, Russia. Both external and internal exposure via contaminated food contributed. Currently, significant long-term radiological consequences of the Chernobyl accident include persistent radioactive contamination of natural terrestrial (forest) and freshwater (oligotrophic lakes) ecosystems and food products. Radiation health risks are lung cancer among the general population from indoor exposure to radon, acute radiation syndrome from occupational exposure, thyroid cancer among children in heavily contaminated non-Baltic areas, and mutations among offspring of exposed parents. (+info)
Galectin-3 and CD44v6 isoforms in the preoperative evaluation of thyroid nodules.
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PURPOSE: Thyroid cancer is the most frequently occurring endocrine malignancy; however, preoperative diagnosis of some lesions, in particular those with follicular histology, is difficult, and a consistent number of not otherwise-specified "follicular nodules" are surgically resected more for diagnosis than therapeutic purposes. In this study, we investigated whether the lectin-related molecules CD44v6 and galectin-3, the expression of which is altered during deregulated cell growth and malignant transformation, could be potential markers for improving the diagnostic accuracy of conventional cytology. MATERIALS AND METHODS: A comparative immuno-chemical and molecular analysis was performed on 157 thyroid specimens representative of normal, benign, and malignant tissues, and on 36 cytologic samples obtained preoperatively by fine-needle aspiration biopsy from nonselected patients with palpable thyroid nodules. RESULTS: Normal thyrocytes did not express galectin-3 nor CD44v6. Although the expression of CD44v6 isnegligible in thyroiditis, these molecules are variably detected in benign and malignant proliferative lesions. Interestingly, galectin-3 is never expressed in benign lesions, but it is invariably detected in cancers. A comparative evaluation of CD44v6 and galectin-3 expression in thyroid malignancies demonstrated that these molecules are coexpressed at the messenger RNA and protein level in almost all lesions. CONCLUSION: Our findings suggest that CD44v6 and galectin-3 could be potential markers to preoperatively identify malignant transformed thyrocytes. Immunodetection of these molecules on cytologic specimens obtained by fine-needle aspiration biopsy is an accurate and improved method for selecting, on a molecular basis, those nodular lesions of the thyroid gland that need to be surgically resected. (+info)