The diagnostic value of dual-phase SPECT/CT scintigraphy based on transport kinetics of 99mTc-sestamibi confirmed with histopathological findings in patients with secondary hyperparathyroidism - practical consideration.

BACKGROUND: Dual phase 99mTc-sestamibi SPECT/CT preoperative parathyroid scintigraphy (PPS) is seldom discussed in terms of the transport kinetics of the tracer. OBJECTIVES: To assess the relationship between the characteristic type of tracer transport in particular PPS and histopathological findings in patients with secondary hyperparathyroidism (sHPT). MATERIAL AND METHODS: The study comprised 27 patients (13 females and 14 males) with sHPT. Based on tracer accumulation in early phase (EP) and delayed phase (DP), the following types of accumulation for PPS(+) lesions were identified: EP(-)/ DP(+) (type I), EP(+)/DP(+) (type II), EP(+)/DP(-) (type III). EP(-)/DP(-) (type IV) lesions constituted PPS(-) group invisible in SPECT/CT. Overall, 69 lesions 59 PPS(+) and 10 PPS(-) were evaluated histopathologically. RESULTS: Among SPECT/CT PPS(+), types I, II and III occurred in 9 (15%), 49 (83%), and 1 (2%) lesions, respectively. The frequency of histopathological diagnosis of normal and abnormal (APG - adenoma or hyperplasia) parathyroid gland, as well as non-parathyroid (thyroid, lymph nodes, or fat) lesions differed significantly between type I, II, and III lesions (p = 0.036). APG histopathological diagnosis was significantly more frequent in lesions with type II uptake than in lesions with type I uptake (76% vs. 33%, p = 0.0197). Type II lesions had significantly higher odds for histopathological diagnosis of APG or NPG than type IV, PPS(-) lesions [odds ratio = 13.1 (95% CI: 2.75 to 63.27)]. CONCLUSIONS: For SHP patients evaluated with SPECT/CT PPS accumulation type I is a weak premise for surgeon to find parathyroid pathology. Only persistent 99mTc-sestamibi accumulation in both phases - equivocal with accumulation type II - effectively differentiates parathyroid and non-parathyroid lesions as well as indicates with high probability the presence of adenoma or hyperplasia. Type III consistent with washout pattern is rare in sHPT.

Radiation doses of employees of a Nuclear Medicine Department after implementation of more rigorous radiation protection methods.

The appropriate radiation protection measures applied in departments of nuclear medicine should lead to a reduction in doses received by the employees. During 1991-2007, at the Department of Nuclear Medicine of Pomeranian Medical University (Szczecin, Poland), nurses received on average two-times higher (4.6 mSv) annual doses to the whole body than those received by radiopharmacy technicians. The purpose of this work was to examine whether implementation of changes in the radiation protection protocol will considerably influence the reduction in whole-body doses received by the staff that are the most exposed. A reduction in nurses' exposure by ~63 % took place in 2008-11, whereas the exposure of radiopharmacy technicians grew by no more than 22 % in comparison with that in the period 1991-2007. Proper reorganisation of the work in departments of nuclear medicine can considerably affect dose reduction and bring about equal distribution of the exposure.

Dynamic renal scintigraphy with 99mTc-DTPA for the assessment of renal function after therapy of acute lymphoblastic leukemia in children.

INTRODUCTION: Acute lymphoblastic leukemia (ALL) and its treatment may lead to impairment of kidney function. The aim of the present study was to evaluate kidney function in children after treatment of ALL. We used our 99mTc-DTPA (diethylene triamine pentaacetic acid labeled with 99mTc) dynamic scintigraphy protocol. MATERIAL AND METHODS: The study group consisted of 48 ALL patients, aged 79-275 months, in complete remission (mean duration 51 months). Treatment was according to the guidelines of the Berlin Frankfurt Münster (BFM) BFM 86 and BFM 90 protocols in 36 (75%) and 12 (25%) children, respectively. Follow-up after treatment was up to 12 months in 10 (21%) children (group I), 12-60 months in 21 (44%) children (group II), and more than 60 months in 17 (35%) children (group III). 99mTc-DTPA dynamic renal scintigraphy was done in all patients. The glomerular filtration rate (GFR) was determined according to Gates and the diuretic test was done after 18 minutes of the examination. RESULTS: The glomerular filtration rate at the end of the 5-year follow-up was less than 80 mL/min/1.73 m2 (p < 0.002) in 3 (25%) children treated with the BFM 86 protocol. In the remaining 45 (94%) patients, GFR exceeded 80 mL/ min/1.73 m2. Normal renogram curves were obtained in 40 (83%) patients. Eight (17%) children had cumulative curves with normal clearance. This finding was interpreted as non-obstructive uropathy. There was no statistical correlation between outflow disorders seen during dynamic scintigraphy, type of chemotherapy protocol, and assignment to risks group. CONCLUSIONS: 1. There was no clinically significant kidney function impairment in children after treatment of ALL. 2. Dynamic renal scintigraphy can be a valuable and non-invasive method for the assessment of kidney function in patients with a risk factor in the form of previous potentially nephrotoxic antitumor treatment.

Patient-specific radiation dosimetry of 99mTc-HYNIC-Tyr3-octreotide in neuroendocrine tumors.

UNLABELLED: (99m)Tc-hydrazinonicotinamide-Tyr(3)-octreotide ((99m)Tc-HYNIC-TOC) is increasingly gaining acceptance as a new radiopharmaceutical for the diagnosis of pathologic lesions overexpressing somatostatin receptors. However, little information has been published about the radiation dosimetry of this agent. The aim of this study was to assess the biodistribution and radiation dosimetry of commercially available (99m)Tc-HYNIC-TOC. A dose calculation procedure designed to be feasible to implement in a busy clinical environment was used. METHODS: Twenty-eight patients were imaged for suspected neuroendocrine tumors using a series of whole-body planar, dynamic planar, and SPECT/CT studies, after injection with (99m)Tc-HYNIC-TOC. Patient-specific dosimetry was performed using the OLINDA/EXM software with time-integrated activity coefficients estimated from a hybrid planar/SPECT technique. A phantom experiment was performed to establish adaptive thresholds for determination of source region volumes and activities. RESULTS: Pathologic uptake, diagnosed as due to neuroendocrine tumors, was observed in 12 patients. Normal organs with significant uptake included the kidneys, liver, and spleen. The mean effective dose after (99m)Tc-HYNIC-TOC injection was 4.6 ± 1.1 mSv. Average normal-organ doses were 0.030 ± 0.012, 0.021 ± 0.007, and 0.012 ± 0.005 mGy/MBq for the spleen, kidneys, and liver, respectively. The interpatient kidney dose ranged from 0.011 to 0.039 mGy/MBq, whereas the range of tumor doses varied from 0.003 to 0.053 mGy/MBq. The ratio of tumor to kidney dose ranged from 0.13 to 2.9. The optimal thresholds for recovery of true activity in the phantom study were significantly lower than those used for volume determination. CONCLUSION: The patient-specific 3-dimensional dosimetry protocol used in this study is a clinically feasible technique that has been applied to demonstrate large dose variations in tumors and normal organs between patients imaged with (99m)Tc-HYNIC-TOC.

Static renal scintigraphy with 99mTc-DMSA for the assessment of renal damage after therapy for acute lymphoblastic leukemia in children.

INTRODUCTION: Acute lymphoblastic leukemia (ALL) and its treatment may adversely affect kidney function. The aim of the present study was to determine whether 99mTc-DMSA static renal scintigraphy can be used to disclose kidney damage at the end of therapy for ALL in children. MATERIAL AND METHODS: The study group consisted of 48 ALL patients aged 6.6-22.9 years, with a mean time of continuous complete remission of 51 months. Static renal scintigraphy with 99mTc-DMSA was performed in all patients. RESULTS: Minor scars in the renal cortex were diagnosed with scintigraphy in 6 (13%) patients. A significant correlation was found between renal scarring and a history of urinary tract infection. CONCLUSIONS: No clinically significant kidney damage was found after completion of treatment of ALL. Static renal scintigraphy may be a valuable noninvasive method for visualization of renal cortex pathology.

Effectiveness of strontium-89 palliative therapy in patients with painful bone metastases.

INTRODUCTION: Bone metastases are observed in 30-70% of patients with cancer. Painful bone metastases require regular control and treatment. Systemic palliative radiotherapy using beta-emitting radionuclides is an alternative method to analgesics and external beam radiotherapy. The aim of the study was to establish the efficacy and risk of side effects of radionuclide therapy in patients with bone metastases. MATERIAL AND METHODS: Strontium-89 (Sr-89) therapy was performed in 49 patients, 14 women and 35 men, aged 42-82 (mean 62) years with bone metastases confirmed by MDP-Tc99m whole body scan. The primary tumour was prostate cancer in 28 patients, breast cancer in 14, bladder cancer in 2, lung cancer in 2, gastric cancer in 2, and renal cancer in 1 patient. Intravenous injection of 150 MBq of Sr-89 was given and patients were observed for at least 3 months. Blood count, intensity of pain, drugs intake, life activity, and duration of effect were assigned 0-3 points. The overall response index was very good when the points totalled 10-12, good - 7-9, satisfactory - 4-6, poor - 2-3 and no response 0-1 points. Haemotoxicity was evaluated according to the Common Toxicity Criteria of the World Health Organisation (WHO). RESULTS: We found a very good response in 10 (20%) patients, good in 20 (41%), satisfactory in 8 (16%), poor in 2 (4%), and no response in 9 (19%) patients. Transient haemotoxicity of the Sr-89 therapy was observed in 39 (80%) patients. The mean decrease in platelets and leukocytes was 33-35%, but the haemoglobin concentration was reduced by only 15% in comparison to baseline values. The majority of patients did not require any treatment for haematologic side effects. Hospitalization was necessary in only 2 patients with grade 4 CTC WHO. CONCLUSION: Palliative radionuclide treatment of painful bone metastases with Strontium-89 in various primary tumours is in most cases an effective therapy with limited haemotoxicity.

Thyroid fine-needle aspiration biopsy: which lesions should be biopsied before 131I therapy?

INTRODUCTION: Suspicion of a neoplasm is one of the contraindications to radioiodine therapy in benign thyroid disease. The aim of this study was to present an optimal qualification scheme for fine-needle aspiration biopsy (FNAB) to rule out neoplastic lesions prior to radioiodine therapy. MATERIAL AND METHODS: 4207 patients with hyperthyroidism were referred for 131I therapy in 2000-2006. Prior to 131I therapy, all patients underwent thyroid function assessment, radioiodine uptake, scintigraphy, and ultrasound. Fine-needle aspiration biopsy with cytology was done in 578 (13.7%) patients. Therapeutic radioiodine was administered to 3564 (84.7%) patients. RESULTS: Malignancy was confirmed or suspected in 12 female patients (0.28% of all patients and 2.07% of patients who underwent FNAB). Prior to the study, cytology was done in only one patient. The diameter of the lesions was 6-28 mm. Cytology confirmed papillary carcinoma in 4 patients, follicular tumour in 6, and Hürthle's cell tumour in 1. There were indications for histopathology in one patient due to the presence of atypical cells. The primary diagnosis was toxic nodular goitre in 8 patients and Graves' disease in 4 patients. One of the patients with follicular tumour was referred for radioiodine therapy due to intolerance to thyrostatic drugs, elderly age, and comorbidities. CONCLUSIONS: 1. Thyroid scintigraphy prior to therapy is important for the choice of the site of FNAB. 2. Thyroid lesions in patients with nodular Graves' disease must be carefully investigated to exclude malignancy. 3. Preselection of patients for treatment of benign thyroid disease should be followed by cytology of the lesions at the Department of Nuclear Medicine.

Response of malignant breast tumours to neoadjuvant chemotherapy evaluated with Tc-99m MIBI.

INTRODUCTION: The aim of this study was to assess the efficacy of Tc-99m sestamibi scintimammography in the prediction and evaluation of tumour response to neoadjuvant chemotherapy in patients with locally advanced breast cancer. MATERIALS AND METHODS: The subjects consisted of 14 female patients with unilateral locally advanced breast cancer eligible for anthracycline-based neoadjuvant chemotherapy followed by surgery. The patients underwent mastectomies with pathologic evaluation of the residual tumour size. The early and delayed static imaging were undertaken in all subjects at 10 and 120 minutes after intravenous injection with 720-1080 MBq of Tc-99m MIBI. Patients lay prone on the scintimammographic pad (provided by the IAEA). The acquisition included three positions: both lateral prone and anterior supine. Early, delayed tumour to background ratios (TBR) and washout rate (WOR) were calculated. Three sets of scintimammography images were obtained: baseline study (BL), the first follow-up study (FF) after two cycles of chemotherapy and the second follow-up (SF) scan on completion of chemotherapy and prior to surgery. Clinical response was evaluated following WHO criteria and classified as complete response (CR), partial response (PR), stable disease (StD) and progressive disease (PD). All patients underwent BS, seven of them FF and eight completed the study with SF. RESULTS: The only statistically significant differences in Student's t-test for matched pairs were found between mean values of TBR10 and TBR120 in BL and FF study however in the SF study it was not significant. Other differences between the mean values of TBR10, TBR120 and WOR in BL/FF, BL/SF and FF/SF studies were not statistically significant. CONCLUSION: The results obtained are encouraging, but further investigations are needed.

Occupational exposure at the Department of Nuclear Medicine as a work environment: A 19-year follow-up.

BACKGROUND: This study assessed the radiation safety at Nuclear Medicine Department being a work environment. Ionizing radiation exposure of the employees in the last 19 years and the effects of legislative changes in radiological protection were analyzed. MATERIAL/METHODS: All employees of the investigated department were regularly and individually monitored using chest badges equipped with Kodak film type 2. Overall, 629 annual doses of the employees of nuclear medicine department, registered in the period 1991-2009, were analyzed statistically. RESULTS: Technicians were found to be the largest exposed professional group, whereas nurses received the highest annual doses. Physicians received an average annual dose at the border detection methods. Ancillary and administration staff occasionally received doses above the method detection limit (MDL). The average annual dose for all dosimetry records was 0.7 mSv, and that for dosimetry records equal and higher than MDL was 2.2 mSv. CONCLUSIONS: There was no case of an exceeded dose limit for a worker. Furthermore, improvement of radiological protection had a significant impact on the reduction of doses for the most exposed employees.

The application of SPECT/CT scintigraphy with MIBI-Tc99(m) in the diagnosis of thyroid nodules - a preliminary report.

INTRODUCTION: Thyroid cancer diagnosis is based mainly on fine needle aspiration biopsy (FNAB) performed under ultrasonography guidance. Questions arise in cases of an inconclusive FNAB result - when there is no clear evidential data to support the existence of a malignant lesion or when there are any other reasons which make the decision process difficult, such as the patient's age or coexisting diseases. To clarify this issue the patient should be encouraged to undergo surgery treatment or to be followed up. Thyroid scintigraphy with an oncophilic tracer such as MIBI-Tc99(m) may be helpful. MATERIAL AND METHODS: The study comprised a group of 12 patients, aged 54-75 (av. 63.5) years, who, in 2009, underwent planar and SPECT/CT thyroid scintigraphy with MIBI-Tc99(m) using washout method. The tumour/background ratio in early and delayed images was calculated and the wash-out ratio was estimated. Patients with increased focal lesion uptake were operated on and the lesions were histopathologically verified. RESULTS: Abnormal scintigraphy results were obtained in 8 patients (10 lesions) and normal results in 4 patients (5 lesions). Out of 15 studies, in 13 cases the washout from the lesion was observed within 2 hours. It was noticed that the images obtained with SPECT/CT washout method were clearer and easier to read in comparison to planar studies. Three patients with an abnormal results underwent surgery and had benign histopathology results after the operation, in 3 patients the observation is being confirmed without any increase in malignancy suspicions, and 2 were lost for observation. CONCLUSIONS: Our preliminary results do support the use of MIBI-Tc99m in the evaluation of indeterminate thyroid nodules. To validate the hypothesis that MIBI-Tc99(m) may be used to exclude malignancy in lesions indeterminate by FNAB we propose to use SPECT-CT derived images and standardized evaluation criteria.

The occurrence of malignant thyroid lesions in patients after radioiodine treatment due to benign thyroid diseases.

INTRODUCTION: Radioiodine treatment (RT) of benign thyroid diseases is a well-known, safe, and effective treatment. In a group of patients after RT, who remained in long-term follow-up, sporadic cases of malignant thyroid lesions occurred. The aim of the study was to estimate how often it happened despite the exclusion of malignancy before RT. MATERIAL AND METHOD: A group of 4314 patients (7438 person-years) underwent RT and subsequently were followed-up for 1-8 years (mean 20.69 months). Apart from thyroid function estimation, if needed, fine needle aspiration biopsy (FNAB) of the thyroid or neck focal lesions was performed based on ultrasonographic or clinical examination. Patients with pathological FNAB were analyzed and histopathologically verified. RESULTS: In 12 out of 4314 cases (0.27%) suspicious FNAB results were found. Suspicious thyroid lesion results were found in 9 patients (8 F, 1 M), aged 46-73 (average 56 years) followed up for 3-57 months after RT: papillary cancer in two patients, Hürthle cell tumour in one patient, and suspicious cells in two patients (with benign lesions on postoperative histopathology). Two patients refused surgery (a suspicion of papillary cancer in one case and suspicious cells in FNAB in the second case). A follicular tumour in FNAB was suspected in two cases (no data about the first, and the second with lung cancer was not operable). In the remaining 3 cases FNAB revealed lymph node metastases due to other cancers. CONCLUSIONS: Malignant thyroid lesions in patients after RT due to benign thyroid diseases are seldom detected. However, periodical clinical and ultrasonographic evaluation is recommended.

Optimization of low-dose CT protocol in pediatric nuclear medicine imaging.

UNLABELLED: This study was performed to find the optimal low-dose CT protocol for children being imaged on SPECT/CT scanners not equipped with automatic dose control. For SPECT/CT systems with manually adjustable x-ray tube voltage (kV) and anode current (mA), an optimized protocol makes it possible to minimize the dose to patients. METHODS: Using the 4-slice low-dose CT component of a commercially available SPECT/CT scanner, we compared the signals reaching the CT detector after radiation passes through objects of different sizes. First, the exit dose rates were measured for combinations of available voltages and currents. Next, imaging parameters were selected on the basis of acceptable levels of exit dose rates, cylindric phantoms of different diameters approximating children of different sizes were scanned using these parameters, and the quality of the CT images was evaluated. Finally, weighted CT dose indexes for abdomen and head CT dose phantoms simulating, respectively, adult and pediatric patients were measured using exactly the same techniques to estimate and compare doses to these 2 groups of patients. RESULTS: For children with torsos smaller than 150 mm, imaging can be performed using the lowest available voltage and current (120 kV and 1 mA, respectively). For children with torsos less than 250 mm, 140 kV and 1.5 mA can be used. For patients with torsos greater than 250 and less than 300 mm, 140 kV and 2 mA can be used. Regarding the signal-to-noise ratio, all these parameters give an excellent signal and fully acceptable noise levels. CONCLUSION: For the SPECT/CT system studied, even the lowest available voltage and current used for scanning pediatric patients did not cause signal-to-noise degradation, and the use of these settings substantially lowered the dose to the patients.

[Occurrence of malignant lesions in patients referred to 131I therapy due to benign thyroid diseases]. / Analiza wystepowania zmian nowotworowych w tarczycyu pacjentów kierowanych do leczenia 131I w przebiegulagodnych chorób tego gruczolu.

INTRODUCTION: (131)I therapy should be performed after exclusion of any morphological pathology that needs surgery--usually malignancy or its suspicion. The aim of the study was to evaluate the range of this problem in patients considered for radioiodine therapy due to benign thyroid diseases. MATERIAL AND METHODS: In 2000-2005 year 3663 patients with hyperthyreosis were referred to (131)I therapy. All patients were subjected to routine procedure which comprised of thyroid function assessment, radioiodine uptake, thyroid scan, ultrasound examination. In 505 (13.8%) patients according to indications fine needle biopsy (FNAB) with cytological examination was performed. (131)I therapy dose was given to 3083 (84.2%) patients. RESULTS: Eight patients (1.6%) were positive or with suspicion of malignancy on FNAB. All but one had no cytological examination before referral. The diameter of the lesions ranged from 6 to 28 mm. Cytological diagnosis was: in 3 patients--ca papillare, in 3--follicular tumour, in 1--Hürthle'a cell tumour, and in one patient histopathological examination was required without definitive cytological diagnosis. In six patients primary diagnosis was toxic nodular goiter, in three patients Graves' disease. CONCLUSION: 1. Obtained data underline the need for bigger malignancy alert of nuclear medicine physicians during qualification of patients for (131)I treatment despite of patients preselection by referring doctors. 2. Performing FNAB is a very important part of qualification to radioiodine treatment. 3. Thyroid scan is supportive in choosing a proper place for FNAB.

Ectopic thyroid tissue as a tumour of the heart--case report and review of the literature.

Here we report a case of a 48-year-old woman with ectopic thyroid tissue in the right ventricle. The tumour involved 1/3 of the ventricle and adhered to the myocardium. The lesion was removed completely and a bioprosthesis was placed due to tricuspid insufficiency, and then a pacemaker was implanted. The diagnosis was made upon examination of the postoperative tissue. The paper discusses embryological implications of the development of thyroid tissue in the heart. This case is first in the Polish literature.