Assessment the diagnostic accuracy of sentinel lymph nodes lymphoscintigraphy using technetium-99m phytate in breast cancer

Technetium-99m phytate [[99m]Tc-ph] is a readily available radiopharmaceutical and has been suggested as a suitable agent for sentinel lymph node [SLN] detection. In this study, the diagnostic accuracy and false-negative rate of radionuclide SLN mapping using [99m]Tc-ph were investigated. Forty three women [mean age 52.3 years, range 31-74 years], who all had been diagnosed with breast cancer were enrolled in the study. All patients had no palpable axillary lymph nodes and had not undergone exploratory tumor resection or any drug treatment, previously. [99m]Tc-ph was injected peri-tumorally at four sites. Following SLN scintigraphic imaging, the patients were operated. Intraoperatively SLN were detected by a scintillation probe and a blue dye technique. Modified radical mastectomies with radical axillary dissection were performed with excision of the lymph nodes, to evaluate the accuracy of the SLN technique. Intraoperative scinti-mapping identified SLN in 40 of the 43 patients [detection rate: 93%]. Scintigraphically, none of the patients had internal mammary drainage or contralateral axillary involvement. The blue dye detection rate in 23 patients under study was 87% and all lymph nodes detected by the blue dye technique were also detected as "hot" spots in the lymphoscintigraphy. Using pathology as the gold standard, the sensitivity and negative predictive value of scintigraphic lymphatic mapping in detection of SLN by [99m]Tc-ph were 90% and 90.9%, respectively. The same values for blue dye lymphatic mapping were 84.6% and 77.7%, respectively. [99m]Tc-ph used for SLN mapping is readily available, has low cost and gives better results than the blue dye technique. Long-term follow-up is required to assess accurately the incidence of failure in patients with negative SLN and the overall diagnostic accuracy and efficacy of the SLN mapping using [99m]Tc-ph as the radioactive tracer

Catheter related artifacts on bone scans: report of two cases

Bone scanning using the 99mTc-phosphate analogs is an established diagnostic modality and a commonly requested radioisotope examination for a variety of pathologies involving the skeleton, such as osteomyelitis, bony metastases, and occult fractures. The bone scan is one of the most commonly requested procedure in most nuclear medicine department. The images show areas of increased and decreased activity usually related to the bone turnover. The bone scan is interpreted by evaluating the pattern of radioactive localization in the skeleton and identifying areas of increased uptake [hot spots] or, less frequently, decreased or absent activity [1]. Unfortunately, the findings are most often very nonspecific and do not tell us the exact underlying cause of the abnormal activity. A variety of factors may change the normal distribution of bone-seeking radiopharmaceuticals. Although most of the times these areas of abnormal radiotracer activities are due to true pathologic bone states, however, it is not infrequent that they are caused by technical errors such as urinary contamination, nonuniformity of gamma camera, and attenuation of activity by foreign bodies. These artifactual causes warrant careful attention to prevent unnecessary interventions. In certain conditions, nonosseous structures other than the urinary tract are seen on the bone scan. For example, there may be localized muscle uptake, such as myositis ossificans, or localization in a pleural effusion. Such serendipitous findings may constitute welcome diagnostic information [1]. On the other hand, soft-tissue uptake may at times hamper interpretation of the study by bringing in artifacts that degrade the quality of the images. Therefore, recognition of patterns of nonbony uptake is important for correct identification of artifacts and accurate interpretation of the scan [1]. This paper presents two cases of artifactual causes of odd radiotracer activity in bone scans. In both cases the artifact is at least somewhat related to an indwelling catheter

[Agreement of two methods of planar and SPECT scintigraphy with 99mTc- RBC in detection of liver Hemangioma]

Hemangiomas are the most frequent benign tumors of the liver and detecting them from metastasis or other malignant hepatic tumors is of outmost importance. 99mTc- RBC scan is highly specific and is the method of choice for this differentiation. This scintigraphy is performed in Planar and SPECT modes. These two procedures are in agreement most of the times, however since SPECT is more expensive and time consuming we planned a study to evaluate the agreement of these two methods. Sixty two patients [age range 20-80 yr, mean age 42 yr], 41 female [67%] and 20 male [33%], who were under evaluation for liver mass detected on abdominal ultrasound or CT scan, underwent 99mTc- RBC scan with both Planar and SPECT methods. The data was processed by computer and SPSS software [11.5]. Planar scan was positive in 42% and negative in 59% of cases, while for SPECT study these values were 68.9% and 31.1%, respectively. The Kappa value for planar and SPECT scan results was 48%, and there were 17 lesions [27%] which were detected only by SPECT. SPECT scan defined 35% of the posteriorly located hemangiomas, and 58.3% of hemangiomas smaller than 3 cm, which were not detected by planar scans. Also 75% of patients with multiple hepatic lesions showed more lesions by SPECT as compared to planar scan. Since there is a weak agreement between SPECT and Planar scan, SPECT is considered the more reliable method in diagnosis of liver hemangioma and this is especially true when the hemangioma is of small size, has a posterior location or in cases of multiple lesions

[Myocardial 99m Tc-MDP uptake on the bone scintigraphy in the hemodialysis-associated amyloidosis:a case report]

Amyloidosis is characterized by an abnormal extracellular deposition of amyloid in different organs, where it usually causes some type of dysfunction. Its cause is unknown. Five different types of amyloidosis have been described according to the underlying disease; immunoglobulin amyloidosis, familial amyloidosis, senile systemic amyloidosis, secondary amyloidosis and hemodialysis-associated amyloidosis. We report a case of hemodialysis-associated amyloidosis in a 56-year-old man that radionuclide imaging demonstrated intense uptake of Tc-99m MDP within the myocardium. The diagnosis of amyloidosis was established by analysis of aspirated abdominal fat, although other non- invasive modalities didn't reveal any positive findings. The first clue to the possible presence of amyloidosis in this case was provided by the radionuclide bone scan performed, which revealed intense tracer uptake in the heart suggesting amyloid deposit. We conclude that in cases of extraosseous accumulation of Tc-99 MDP especially as a diffuse pattern of myocardial uptake, a diagnosis of amyloidosis should be considered, in an appropriate clinical setting

[Radioiodine treatment effect on lacrimal glands function in patients with thyroid cancer]

There is a limited number of case reports published in the past decade confirming the radio-iodine presence in the tear. These observations as well as reported cases of salivary and lacrimal gland dysfunction after radioiodine therapy stimulated investigators to clarify whether lacrimal gland function can be affected post-radioiodine therapy. Hence we planned a historical cohort study to evaluate this effect. We studied 100 eyes of 50 patients who were referred to the nuclear medicine department of Dr. Shariati hospital from 01.1383 to 02.1384 and had received high doses [accumulative dose: 100-450mCi] of I-131 treatment of differentiated thyroid carcinoma with their latest admission at least 3 months previously. Dry eye symptoms [obtained via a standard questionnaire] and Schirmer I test results [mm/5min] of this group were compared with those of an unexposed group [100 eyes of 50 individuals] matched by sex and age. Cases with another known cause[s] of dry eye were not included in either group. 51% of the exposed eyes and 50% of the unexposed ones revealed at least one of the dry eye symptoms in the questionnaire. Data analysis showed no significant difference between the number of symptoms of two groups, but 2 symptoms [burning, unrelated to light and erythema] were significantly higher in the exposed eyes. From 9 exposed eyes complaining of erythema, Schirmer test result was abnormal only in 2 [one patient]. Also among the 10 eyes with burning symptom [unrelated to light] one patient [2 eyes] revealed abnormal Schirmer test result. The study also demonstrated a significantly lower wetting amount of the Schirmer paper in exposed group compared to others. In the patients undergone radio-iodine therapy, results were 0-4 mm in 21%, 5-9 mm in 20% and 10 mm or more in 59%. These results were seen in the unexposed group in 6%, 17% and 77%, respectively. File review of the 21 exposed eyes with 0-4 mm Schirmer test results revealed presence of the migraine history in five [4 woman] surprisingly and 131I-avid skull metastasis in another patient [2 eyes]. Long-term reduction in the tear secretion from major and/or minor lacrimal glands is seen after high-dose radio-iodine therapy, which seems to be severe in the majority of patients; however these patients complain of dry eye symptoms no more than unexposed population. Conditions such as migraine may be unknown causes of impaired tear secretion and need further investigation

[Evaluation of diagnostic role of 99mTc-terofosmin scintigraphy in cold thyroid nodules]

Various radiopharmaceuticals, including 67Ga, 201Tl, and 99mTc-sestamibi have been used to differentiate benign from malignant thyroid nodules. 99mTc-Tetrofosmin, a lipophilic cationic radiotracer, and 99mTc-sestamibi have also been reported to accumulate in thyroid tumors. In this study, we evaluated the role of 99mTc-Tetrofosmin in the differentiation of malignant from benign thyroid nodules. We prospectively studied 108 patients with solitary cold thyroid nodule on 99mTc-pertechnetate scintigraphy [33 malignant and 75 benign] to investigate the diagnostic value of 99mTc-Tetrofosmin scintigraphy. 99mTc-Tetrofosmin scintigraphy was performed 15, 60, and 120 minutes following IV injection of 20 mCi [740 MBq] of radiotracer in the anterior planar mode with a gamma camera equipped with LEAP collimator. The scans were visually analyzed by two experienced nuclear physician. The nodules with late tracer retention [activity more than adjacent thyroid tissue] were classified as positive and nodules without late retention were interpreted as negative for malignancy. Fine needle aspiration [FNA] was performed in all patients in 3-7 days interval. 52 patients were subsequently operated on while 56 patients refused surgery. These 56 patients, however, had at least two negative FNA results. 45 out of 108 nodules show high 99mTc-Tetrofosmin uptake on delayed images; 27 of them were malignant. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated to be 81.8%, 76.0%, 54.0%, and 90.4% respectively. Accuracy of the test was also determined to be 77.7%. We concluded that 99mTc-Tetrofosmin scintigraphy is a relatively sensitive, but not enough specific, method in diagnosing malignant thyroid nodules. This agent could be of value in the presence of FNA limitations

Quantitative evaluation of normal uptake of mandibular condyle in bone scan with Tc99m-MDP

Unilateral condylar hyperplasia is the main cause of mandibular asymmetry. Radionuclide bone scanning is a useful procedure for functional evaluation of temporomandibular joint. In this study, 39 patients with normal bone scan and no facial asymmetry were studied. All patients were below 22 years of age. Normal condylar uptake was determined in this group of patients. Right and left condylar uptakes were not completely identical and some difference [Below 10%] between right and left condylar uptake was seen. No significant difference in condylar uptake in male and female patients were observed [P=0.26, alph=0.05]