Indian Journal of Nuclear Medicine

: 2011  |  Volume : 26  |  Issue : 5  |  Page : 16--19



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. Endocrinology.Indian J Nucl Med 2011;26:16-19

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. Endocrinology. Indian J Nucl Med [serial online] 2011 [cited 2023 Feb 9 ];26:16-19
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Estimation of late (24 hour) radioiodine uptake using early (2 hour) uptake measurement in patients of thyrotoxicosis

Baghel NS, Rajashekharrao B, Abhyankar A, Rajan MGR

Radiation Medicine Centre, BARC, Tata Memorial Centre Annexe, Parel, Mumbai, India

Introduction: Thyroid uptake determination is the measurement of the fraction of an administered amount of radioactive iodine that accumulates in the thyroid at selected times following ingestion. The measurement of uptake is performed using a sodium iodide [NaI (Tl)] uptake probe with suitable shielding and a flat field collimator interfaced with multichannel analyzer and a counter. The measurements are taken with 25-30 cm distance between the face of the crystal and the anterior neck. Counts without and with shield and the radioiodine capsule (25 μCi) is counted in neck phantom before oral administration. The usefulness of the radioiodine uptake measurement is to differentiate hyperthyroidism from that caused by sub acute thyroiditis or factitious hyperthyroidism. The diagnosis of thyrotoxicosis is made with measurement of serum thyroid hormones and TSH levels. Thyroid uptake is one of the measurement to diagnose hyperthyroidism in which 2 h and 24 h measurements are taken in our department. Aims and Objectives: To predict late uptake (24 h) from early uptake (2 h) measurements by regression relation. Materials and Methods: Single Photomultiplier tube uptake probe (2"x 2" NaI(Tl) crystal) with flat field collimator was used for this study. The probe is connected to multichannel analyzer (MCA), which is interfaced to desktop computer through serial port. A windows based thyroid uptake calculation software fetches collected counts from MCA and calculates %age uptake. The software requires two measurements for neck without shield and one measurement for neck with shield and standard capsule counts for 100 sec each. Data was collected for 25 patients at 2 h and 24 h retrospectively to find regression relation between 2 h and 24 h uptake values and 15 patients data was collected prospectively to find correlation between predicted and measured uptake values. Results: Graph was plotted for defining the relationship between 2 h and 24 h uptake values and the linear fitting was applied to establish regression relation between both the uptakes [24 h Uptake (Y)=12.9 x 2 h Uptake (X)+ 27.8]. This relation was used to predict 24 h uptake value in 15 patients and the graph was plotted between predicted and measured 24 h uptake values. The correlation coefficient r=0.73 which is significant ( p0 =0.05). Conclusion: Same day measurement of 131-I uptake and radioiodine therapy may be correlated with reduction in inconvenience to patient without compromise in quality.


Thyroid isotope scan: Can it predict transient or permanent hypothyroidism in babies with borderline TSH values on screening test?

Pawar Shwetal 1,2 , Biassoni Lorenzo 1 , Peters Catherine, Hindmarsh Peter, Langham Shirley

1 Departments of Radiology and Endocrinology, Great Ormond Street Hospital for Children, London, UK; 2 Department of Nuclear Medicine, Seth G S Medical College and KEM Hospital, Mumbai, India

Introduction: Neonatal biochemical screening programmes for congenital hypothyroidism (CH) allow early diagnosis and treatment of infants with CH, thereby efficiently preventing mental retardation. The purpose of the study was to assess the predictive role of Tc-99m pertechnetate thyroid scintigraphy in differentiating between transient and permanent hypothyroidism in neonates with borderline TSH results (6-19.9 mu/L) at the screening. Materials and Methods: A retrospective review of 29 neonates (19 males, 10 females) with borderline TSH results at newborn screening between January 2006 and December 2007 was performed. The thyroid scan was acquired 20-30 minutes after iv injection of 1 - 5 MBq/Kg of Tc-99m pertechnetate. Thyroid tracer uptake was graded as low (≤ salivary gland uptake), normal (>salivary and background uptake) and high (no significant salivary or background uptake seen). The patients were classified in two groups based on thyroxine requirements at 3 years of age. One group included seven children with no requirement of thyroxine replacement (transient hypothyroidism). The other group included 22 children on lifelong thyroxine replacement (permanent hypothyroidism). The pattern of thyroid uptake was evaluated in each group. Results: Within the group with transient hypothyroidism (7 patients) there was low, normal or high thyroid tracer uptake in 1 (14%), 2 (29%) and 4 (57%) children respectively. The mother of the child with low uptake had raised TSH antibodies. Within the group with permanent hypothyroidism (22 patients), there was low, normal or high thyroid uptake in 3 (14%), 12 (55%) and 7 (31%) children respectively. Only one child had an ectopically located thyroid tissue, the other children had a normally located thyroid. Conclusion: In this small group of neonates with borderline high TSH on screening the majority of babies with low or normal tracer uptake on thyroid scan had permanent hypothyroidism. Babies with high uptake had either transient or permanent hypothyroidism.


Role of 131 I SPECT/CT as a complementary tool to 131 I diagnostic and post therapy whole body scintigraphy in management modification of differentiated thyroid carcinoma

Manas Kumar Sahoo, Abhinav Singhal, Varun Singh Dhull, Bangkim Chandra Khangembam, Nishikant Damle, Chandra Sekhar Bal

Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India

Introduction: Role of Planar 131 I whole body scintigraphy ( 131 I WBS) in differentiated thyroid carcinoma (DTC) after total thyroidectomy has already been established. However, due to poor spatial resolution plannar imaging has the limitations in exactly charecterising the lesions. For this reason all guidelines recommend post therapy scan for restaging and guide in further modification of treatment protocol. However, now with advent of SPECT/CT; both functional and morphological coregistered image can correctly determine the extent of the disease and guide in management. Objective: The purpose of this study was to evaluate the role of 131 I SPECT /CT in DTC before and after radioiodine therapy using diagnostic 131 I WBS along with SPECT/CT and to determine the incremental contribution of SPECT/CT in detection of lesions and effect on management of the disease. Materials and Methods: We studied 455 consecutive DTC patients referred for 131 I therapy after thyroidectomy. A lesion was defined as an abnormal 131 I concentration / structural abnormality found on conventional imaging like CT, MRI,USG,histopathology done during staging the disease. We performed 131 I SPECT/CT In 133 patients who showed inconclusive lesions in diagnostic/ post therapy 131 I WBS. SPECT/CT was performed on 91 patients (33 males, 58 females) of DTC (85 papillary and 6 follicular) with median age 32 years (13-70) complementing to diagnostic 131 I WBS which was performed approximately after 24 hours of 55.5-74 MBq (1.5-2 mCi) 131 I administration. SPECT/CT was performed on 42 patients (15 males,27 females) of DTC (37 papillary and 5 follicular) with median age 43 years (12-70) SPECT/CT was performed 24-48 hours after therapeutic dose administration of 131 I when post therapy WBS revealed inconclusive lesions. Results: There were 223 lesions identified in 91 patients by combined structural and functional imaging. Planar imaging showed abnormal increased radioiodine uptake in 169 (76%) lesions and missed 54 (24%) lesions. Interestingly SPECT/CT showed 215(96%) lesions and missed only 8 (4%) lesions. Compared to plannar imaging SPECT/CT detected 46 (21%) additional occult lesions. SPECT/CT changed in the management by suggesting higher activity administration in 32(35.2%) patients, suggested lower activity administration in 44 (48.4%) patients and no change in activity planned in 15(16.4%) patients. There were total 117 lesions identified by combined structural and functional imaging in 42 patients who underwent SPECT/CT after 131 I therapy. planar imaging picked up 94 (80%) lesions and missed 23(20%) lesions and SPECT/CT showed total 113(96.6%) lesions and missed only 4 (3.4%) lesions. Compared to plannar imaging SPECT/CT detected 19 (16%) additional occult lesions. SPECT/CT changed in management by suggesting for further activity administration in 19 (45%) patients, suggested no more activity administration in 10 (24%) patients and no change in dose schedule in 13(31%) patients. Conclusion: 131 I SPECT/CT identified 65(19%) additional lesions. It also helped localising and characterising DTC foci, and more correctly differentiating physiological uptake from metastases. A wider use of this modality should be considered complementary to planar imaging in equivocal lesions in DTC patients.


Prognostic impact of serial radioiodine and 18 F-FDG PET scans in patients of advanced differentiated thyroid carcinoma

Mandakini Phukan, Gaurav Malhotra, Ramesh Asopa, MGR Rajan

Radiation Medicine Centre, Bhabha Atomic Research Centre, TMC Annexe, Jerbai Wadia Road, Parel, Mumbai, India

Introduction and Aim: Distant metastatic involvement in differentiated thyroid cancers is rare but, nevertheless, distant metastases are the main cause of thyroid cancer related deaths. Conventionally (F-18)FDG PET-scans are indicated in thyroid cancer patients who have high serum thyroglobulin but no abnormality on radioiodine scans. The data on (F-18)FDG PET imaging vis-à-vis radioiodine scan as prognostic tools in patients of advanced thyroid cancer is lacking. One of the aims of the present study was to compare the biologic behavior of radioiodine-avid and -non-avid as well as (F-18)FDG-avid and non-avid metastatic lesions in serial scans. Another aim was also to ascertain whether inclusion of routine (F-18)FDG PET imaging in the diagnostic algorithm of such patients would be of additional benefit in the disease management. Materials and Methods: This was a retrospective analysis of all patients of advanced thyroid cancer who underwent serial radioiodine and (F-18)FDG PET scans between January 2005 and January 2011. Only those patients with at least one study of each type (radioiodine and PET scan) and documented radioiodine avid lesion(s) were include in the study group. The study group comprised 34 patients (16 females and 18 males; (age range: 11-72 yrs) who underwent 40 whole body (F-18)FDG PET scans and 71 whole body radioiodine scans as per the institution protocol. A lesion based comparison was done between the two modalities. Value of serial FDG-PET scans and change in management as a result of PET scan findings was also assessed. Appropriate statistical tools were applied wherever it was required. Results: Thirty three of 40 (82.4%) PET-scans showed metabolically active disease. Concordant findings with radioiodine scans were seen in 29 of 40 PET scans (72.5%). A total of 259 lesions were diagnosed in 34 patients by both the scans. 186 of 259 lesions (71.8%) were revealed on radioiodine scans while 163 of 259 lesions (62.9%) were documented on (F-18)FDG PET imaging. Eighty one of 259 lesions (31.2%) were concordant on PET and radioiodine scans while 71 of 259 lesions (28.5%) were diagnosed on PET scan but were radioiodine negative. Inclusion of (F-18)FDG PET scans resulted in a change in management in 18 of 34 patients (52.9%). Conclusion: The study demonstrates the utility of (F-18)FDG PET scan in diagnostic armamentarium of carcinoma thyroid patients who have distant metastases at presentation. PET-scans can reveal (F-18)FDG avid lesions that also show radioiodine uptake and therefore need aggressive management. This is because it is possible that the said lesions may precede development of non-radioiodine concentrating FDG avid lesions as there is gradual de-differentiation of tumor clones. On the other hand, a normal (F-18)FDG PET scan in radioiodine avid extensive disease is likely to be a better prognostic indicator than lesions showing both radioiodine and FDG avidity. Further studies are required to validate this point.


I-131 MIBG imaging in Pheochromocytoma - a case report

Mathur M, Prasad DC 1 , Asha P, S Kumar

Department of Nuclear Medicine, Jawaharlal Nehru Cancer Hospital and Research Centre, Idgah Hills Bhopal, 1 BSR Cancer Hospital, Bhilai, Madhya Pradesh, India

Introduction: A 35 years old female patient presented with findings of hypertension, loss of weight, anxiety and irregular menses. On ultrasonography small right kidney with multiple calculi and mild hydronephrosis, a heterogenous moderately vascular mass in left para aortic region adherent to aorta were noted. CT scan revealed a well defined enhancing mass lesion in left para aortic region likely to be adherent to aorta and abutting the left kidney and renal vessels. I-131 MIBG scan was advised. Materials and Methods: Following IV injection of 500 micro curie of I-131 MIBG, whole body planar images were obtained at 48 hours. Whole body I-131 MIBG scan showed abnormal deposit of radiopharmaceutical in left adrenal area suggestive of neuroendocrine tumour (pheochromocytoma/ paraganglianoma). Results and Discussion: Pheochromacytoma arises from neural crest cells in the adrenal medulla, sympathetic ganglia, aortic and carotid chemoreceptors. Extramedullary tumours can also be present. Patient typically presents with hypertension, headache, tremors, palpitations, weight loss and hyperglycemia. There may be elevated urine vanilmandelic acid and metanephrine. Structurally MIBG resembles norepinephrine and guanethidine (neuro secretory granule in adnergic tissue of neural crest origin.) MIBG localizes to granules in the adrenergic tissue of neural crest origin. Certain sympathetic or sympathimimetic drugs needs to be withheld prior to the test which include alpha and beta blockers,guanethedine, antipsychotics and nasal decongestants which tends to block the MIBG uptake. Thyroid uptake should be blocked prior to study. I-131 MIBG shows normal uptake in the salivary glands, liver, bowls and heart.I-131 MIBG imaging has a sensitivity of 80% to 90% and a specificity of 95% to 99%.


Role of Tc99m DMSA (V) scintigraphy in post operative patients with medullary thyroid carcinoma

Madan Parmar, Pinaki Dutta 1 , Ashwani Sood, Anish Bhattacharya, Baljinder Singh, BR Mittal

Department of Nuclear Medicine and 1 Endocrinology, PGIMER, Chandigarh, India

Introduction: Calcitonin is considered to be highly sensitive and specific for detection of recurrence or metastatic disease in cases of postoperative medullary thyroid cancer. However the identification of location of such sites is necessary, once it become evident with calcitonin levels to contemplate any further management. The conventional imaging modalities are not very successful. Tc99m DMSA (V) has been successfully used to image patients with medullary thyroid carcinoma (MTC) both pre- and postoperatively. We retrospectively analysed the role of Tc99m DMSA (V) scintigraphy in post-operative follow-up of patients with medullary thyroid carcinoma. Matierials and Methods: A retrospective analysis 25 patients' data who had undergone Tc99m DMSA (V) scintigraphy was done. Out of 25 patients, 2 had MEN IIA syndrome, 3 had MTC with phaeochromocytoma and 20 were MTC alone. 21 of the 25 patients had undergone total or near total thyroidectomy along with lymph nodes dissection with histopathological confirmation. Four patients did not undergo surgery because of other co-morbid conditions. Serum calcitonin levels were measured in post-operative period in all patients, while baseline calcitonin levels were taken into account in 4 patients not undergone surgery. Tc99m DMSA (V) scans were performed in all MTC patients. Two patients had undergone scan twice during follow-up in post-operative period. Standard whole body images in anterior and posterior views were acquired at 30 mins and 2 hrs after i.v inj of 10 mCi of Tc99m DMSA (V) in all patients. Results: Of the 25 patients, 10 were male and 15 female with age ranging from 14 to 72 years (mean 41.0 years). Twelve of the 21 post operative cases showed abnormally elevated serum calcitonin levels and 9 post-operative patients had normal/mildly raised calcitonin level. One of the 4 patients with no surgery showed elevated baseline calcitonin level. Tc99m DMSA (V) scintigraphy showed foci of abnormal radiotracer uptake in 13 patients - 4 in the thyroid bed and cervical node, 1 in thyroid bed with distant metastasis, 4 in cervical lymph nodes only and 4 in distant metastasis only. Two patients undergoing DMSA (V) twice revealed resolution of disease along with drop in calcitonin levels followimg treatment. One patient with phaeochromocytoma also showed uptake in adrenal gland suggesting recurrence. Two patients underwent FDG PET-CT wholebody imaging. One of them revealed recurrence in cervical and mediastinal nodes, and lung nodule with elevated calcitonin level, however DMSA (V) scan was normal post-operatively. In second patient, pre-operative CECT done, revealed cystic lesions in pancreas which were non-avid on FDG PET-CT, also confirmed by FNAC. Post-operative calcitonin level and DMSA (V) scan were also normal in this patient. The average serum calcitonin levels in three patients with local recurrence and distal metastasis on scintigraphy was 41,500 pg/ml. In the remaining six patients with local recurrence in thyroid bed or cervical lymphnodes the average serum calcitonin levels were 1,371 pg/ml. Two MEN IIA patients showed presence of parathyroid adenoma on Tc99m sestamibi imaging. Tc99m MDP bone scans done in both patient revealed increased tracer uptake in femur in one patient, also evident on DMSA (V) scintigraphy, suggestive of metastasis and in second patient, MDP scan showed lumbar vertebral uptake. Conclusion: Tc-99m DMSA(V) scan appears to be a reliable, cost effective, non-invasive localization technique during post -operative follow up of MTC patients having elevated levels of serum calcitonin.


Dual malignancies in the setting of thyroid carcinoma: Synchronous or metachronus nature, other variables associated with dual malignancies including impact of radioiodine treatment on occurrence of second malignancy

Sunny Gandhi, A Abhyankar, Sandip Basu, R Asopa

Radiation Medicine Center, B. A. R. C., Tata Memorial Centre Annexe, Parel, Mumbai, India

Introduction: Prevalence of multiple primary malignancies vary between 0.73% to 10%. SEER cancer registry and a multinational record linkage study clearly suggested increased risk of second primary tumour after occurrence of first primary tumour. Thyroid cancer accounts for only 1-2% of all new cancer case. However, it is one of the most common endocrine malignancies. The overall survival rate is high. The standard treatment for differentiated thyroid carcinoma is total thyroidectomy followed by ablation therapy using high dose of RAI. Study of dual malignancies can provide insight into the aetiological factors of these malignancies. One of the most important etiological factors can be malignancy arising from carcinogenicity of therapeutic agents applied to 1 st primary cancer. Study of dual malignancy can not only provide information of etiological factors but it can also help in establishing safety of cancer treatment and can help in following up patient who are given potentially carcinogenic treatment. Aims and Objective: To study the synchronous or metachronous nature, impact of radioiodine treatment on the occurrence of second malignancy and other variables associated with two malignancies. Materials and Methods: A total of 8,641cases were screened who had referred for 131 I treatment post surgery having a histopathologically proven differentiated CA Thyroid from January 1963 to March 2011 (38 yrs duration) were included in this study. The other inclusion criteria was a histopathologically proven second primary synchronous (within 6 months of detection of 1 st tumor) or metachronous (after 6 months from the diagnosis of 1 st tumor) malignant tumor in a different organ in the same individual. The data was collected and analyzed. Results: Out of a total of 42 patients, 22 patients were male while 18 patients were females. Most common 2 nd malignancy noted in male was HandN tumors while in females CA Breast was the most common 2 nd malignancy. Out of total 42 patients with dual malignancies, 18 patients were of synchronous nature while 22 patients of metachronus nature. In the metachronous group, 20 patients had CA thyroid as a metachronous to other malignancies and only 4 patients had other metachronous 2 nd malignancy to CA thyroid. Among synchronous malignancies, 33% patients had H and N tumours, 22% patients had CA Breast, and 22% had GI malignancy. The other group of metachronous malignancy in which CA thyroid occurred as metachronous to other malignancy, 35% patients were of H and N tumours, 29% patients had lymphoma, 18% of GI malignancies, 12% of CA breast. In this group of patients with carcinoma thyroid as metachronus to other malignancy, 11 patients had history of EBRT, while in 9 patients EBRT history was not known or negative. The malignancies noted in the 4 patients who had other metachronous 2 nd malignancy subsequent to carcinoma thyroid included breast carcinoma, renal cell carcinoma and colorectal carcinoma. Conclusion: In this series, there appeared an increased risk of thyroid malignancy after EBRT delivered for other primary head-neck tumors No significant risk of second primary malignancy post radioactive iodine treatment for differentiated thyroid carcinoma in our study.