Prognostic value of myocardial perfusion scintigraphy for patients suspected of and diagnosed with coronary artery disease

BACKGROUND: The prognostic value of myocardial perfusionscintigraphy (MPS) continues to attract interest and provoke discussions.This study was an attempt to investigate the methods.Objective: Determination of the prognostic value of MPSfor patients suspected of and diagnosed with coronary arterydisease (CAD).MATERIAL AND METHODS: The study group included 215patients, 134 males and 81 females, aged 21–66, mean age48. Tc-99m-MIBI myocardial perfusion scintigraphy was performedand information concerning the diagnosis, aim of theexamination, past coronary episodes, clinical condition, durationand type of complaints, concomitant diseases, test results,revascularisation procedures and pharmacological treatmentwas gathered. Further history of the patients was monitoredthroughout the observation period of 52 months on average. The patients were divided into the following two groups: GroupI — suspected coronary artery disease: 124 patients aged 21–65,59 males and 65 females; Group II — diagnosed coronary arterydisease: 91 patients aged 31–66, 75 males and 16 femalesdiagnosed with CAD, including 39 s/p myocardial infarct, 31s/p infarct and revascularisation, 21 s/p revascularisation. Theprobability of CAD was calculated using the Diamond methodfor the patients suspected of CAD. The obtained results wereexamined in a statistical analysis.RESULTS: Normal MPS results were obtained for 94/124 patientssuspected of CAD, 15/91 patients diagnosed with CAD,64/81 females and 45/134 males. In Group I, apart from pathologicalMPS results, reversible ischemia was determined in asmany as 27/30 patients, and only 17/91 patients in Group II. Nopatients with normal MPS results suffered major cardiac events,only one of them underwent revascularisation. Major cardiacevents occurred in the case of patients with pathological MPSresults: Group I — 2 myocardial infarcts and 2 cardiac deaths,Group II — 3 infarcts and 10 cardiac deaths. Minor cardiacevents, apart from one case, were also only observed in thecase of patients with pathological MPS results: Group I — 10revascularisations and one case of unstable CAD, Group II— 12 revascularisations and 7 cases of unstable CAD. Patientswith normal MPS results and stenosis in coronary angioraphysuffered no cardiac events. Cardiac events occur mostly in thegroup with a medium and high risk of CAD and in the case ofpatients diagnosed with CAD.CONCLUSIONS: 1. Normal MPS results for patients suspectedof or diagnosed with CAD: s/p infarct and/or CABG prognosticatea mild course of the disease, without or with a minimalnumber of cardiac events, also in a longer observation period.2. Pathological MPS results clearly imply a greater risk of cardiacevents, and the number of events increases with the greaterprobability of CAD and with the patient’s age. 3. Normal MPS results, even with significant stenosis in coronary angiography,prognosticate a low risk of cardiac events

Optimized method for normal range estimation of standardized uptake values (SUVmax, SUVmean) in liver SPECT/CT images with somatostatin analog [99mTc]-HYNIC-TOC (Tektrotyd)

Background: 99mTc-hydrazinonicotinyl-Tyr3-octreotide ([99mTc]-HYNIC-TOC [Tektrotyd]) is a radiopharmaceutical used for the diagnosis of lesions with overexpression of somatostatin receptors. The purpose of this study was to optimize the method and estimate normal ranges for standardized uptake values of Tektrotyd in healthy livers.Material and methods: An analysis of standardized uptake value (SUVs) normal ranges was performed for images acquired in a selected “healthy group” of 42 patients evaluated for neuroendocrin tumors. The “pathological group” comprised 20 patients with liver lesions detected by scintigraphic imaging. Normal ranges for radiopharmaceutical uptake values were estimated based on the quantitative analysis of images acquired with a GE Healthcare NM/CT 850 gamma camera.Results: The method for healthy liver segmentation in single photon emission computed tomography/computed tomography (SPECT/CT) was optimized. The normal range of SUVs for the liver was: standardized uptake value body weight (SUVbw) max [5.2–14.0] g/mL and standardized uptake value lean body mass (SUVlbm) [3.5–9.5] g/mL. The relative standard error (relative SE) of activity concentration estimated in the phantom study for the largest hot spheres was: ϕ = 37 mm — 5.9%, ϕ = 28 mm— 7.1%, ϕ = 22 mm — 11.4%, and ϕ = 17 mm — 22%.Conclusions: Segmentation in the mid-coronal computed tomography (CT) image, at one-fourth of the height of the liver measured from the top, with a medium-sized volume of interest (VOI) outlined on a given transverse SPECT slice was regarded as the optimal method for estimating normal ranges for standardized uptake values. It is necessary to standardize quantification methods in the SPECT/CT studies. Our work is a step forward in obtaining standardization of SPECT/CT SUV calculationmethods. Calculations for radiopharmaceutical uptake in tumors with volumes smaller than 5 mL are biased with a significant measurement error

Physical quantities useful for quality control of quantitative SPECT/CT imaging

SPECT/CT imaging is transitioning from solely qualitative applications to quantitative analysis. Quantitative SPECT/CT systems require proper calibration, optimization and quality control. Various types of modern SPECT/CT scanners have different software for calibration and quality control (QC). There is still no standardization in this regard for quantitative SPECT/CT. This issue hinders the exchange of obtained results across centers and stunts the development of repeatable and reproducible measurements. The unification and standardization of calibration and quality control techniques for quantitative SPECT/CT systems is currently a pressing need for nuclear medicine departments. The present study presents three selected physical quantities characterizing the quality of quantitative SPECT/CT system and seven quantities, currently used in the literature, to assess the quality of quantitative SPECT/CT images. The measurement of these parameters requires the use of standard gamma camera software for QC, external programs for quantitative analysis of recorded data and clinical software. The authors hope this will help physicists who are willing to perform quantitative SPECT/CT in their departments

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 discussedin terms of the transport kinetics of the tracer.Objectives: To assess the relationship between the characteristic type of tracer transport in particular PPS and histopathologicalfindings in patients with secondary hyperparathyroidism (sHPT).MATERIAL AND METHODS: The study comprised 27 patients (13 females and 14 males) with sHPT. Based on tracer accumulationin 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 inSPECT/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. Thefrequency of histopathological diagnosis of normal and abnormal (APG — adenoma or hyperplasia) parathyroid gland, as wellas 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 thantype 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 findparathyroid 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 ofadenoma or hyperplasia. Type III consistent with washout pattern is rare in sHPT

Semi-quantitative method for the assessment of focal lesions in parathyroid scintigraphy with relation to histopathology: a prospective study

BBACKGROUND: The aim of this paper was to analyse our own semi-quantitative method of assessing focal lesions localised in pre-operative diagnostic scintigraphy of primary hyperparathyroidism (PHPT) using 99mTc-MIBI with washout and comparing these data with the result of the histopathological examination (HP). MATERIAL AND METHODS: A total of 40 (37 female, 3 male, average age 58.7 years) patients with a suspicion of PHPT were enrolled for prospective analysis. Dual phase planar and SPECT/CT examination with 99mTc-MIBI were performed. The tumour to background ratios in the 10th and 120th minute were calculated (TBR10 and TBR120) on the basis of the planar acquisition. PTH, ionised calcium and phosphate levels were measured. Parathyroid surgery alone or combined with subtotal/total thyreoidectomy was conducted in 23 (57.5%) and 17 (42.5%) patients, respectively. A HP was performed in all patients. RESULTS: Average concentration of PTH in the whole group was 243.95 pg/ml. There was a statistically significant correlation between medians of PTH concentration and parathyroid histopathological results (p = 0.01). A total of 45 lesions of increased uptake were found in 32 (80.0%) and 34 (85%) patients in the early phase and the delayed phase, respectively. The post-operative material contained 20 (44.5%) parathyroid adenomas, 11 (24.5%) cases of hyperplasia, 2 (4.4%) cancers, 4 (8.9%) cases of normal parathyroid tissue, 2 (4.4%) lymph nodes and 6 (13.3%) cases of thyroid gland tissue. The medians of TBR10 and TBR120 for lesions examined in the HP were respectively: 3.64 and 2.59 for adenoma; 3.08 and 2.18 for hyperplasia; 7.7 and 5.5 for parathyroid cancer, 4.89 and 3.16 for normal tissue and 5.26 and 2.95 for lymph nodes or thyroid gland tissue. A high correlation coefficient of TBR10 to TBR120 in the parathyroid adenoma and parathyroid hyperplasia groups was observed with r = 0.867 and r = 0.964, respectively. The ρr correlation coefficient of TBR10 to TBR120 for normal parathyroid was 0.4. There was a statistically significant association between the HP and TBR10 medians (p = 0.047), but not between histopathology and TBR120 medians (p = 0.840). CONCLUSIONS: The washout technique in pre-operative 99mTc-MIBI scintigraphy is effective in detecting lesions of the parathyroid (cancer, adenoma, hyperplasia, normal tissue of the parathyroid). Parathyroid cancers in semi-quantitative analysis were characterised by a slightly higher TBR. However, it is impossible to differentiate lesions based on this data. Histopathology results are significantly associated with TBR and PTH

The application of SPECT/CT scintigraphy with MIBI-Tc99m in the diagnosis of thyroid nodules - a preliminary report

Wstęp: Niediagnostyczne badania cytologiczne (FNAB, fine needle aspiration biopsy) guzków tarczycy lub inne przyczyny utrudniające podjęcie decyzji o leczeniu operacyjnym tarczycy, takie jak wiek pacjenta lub zawansowanie choroby towarzyszące, stanowią poważną przyczynę w ostatecznym wyborze posterowania, szczególnie jeżeli nie ma jednoznacznych danych wskazujących na obecność zmiany nowotworowej. Dodatkowym sposobem wyjaśnienia charakteru zmiany jest badanie radioizotopowe z MIBI-Tc99m. Gromadzenie MIBI jest interpretowane jako sygnał zwiększający ryzyko złośliwości, zwłaszcza gdy utrzymuje się przez dłuższy czas. W pracy postanowiono ocenić przydatność badania scyntygraficznego SPECT/CT z MIBI-Tc99m metodą wymywania w relacji do wyników badania histopatologicznego. Materiał i metody: W 2009 roku wykonano u 12 chorych w wieku 54-75 (śr. 63,5) lat badania scyntygraficzne tarczycy planarne oraz SPECT/CT z MIBI-Tc99m, poprzedzone o badanie wymywania. Wyliczono wskaźniki wymywania i wskaźniki guz/tło w obrazach wczesnych i późnych. Chorzy ze wzmożonym wychwytem znacznika byli operowani i badani histopatologicznie. Wyniki: Wzmożone gromadzenie MIBI-Tc99m obserwowano u 8 pacjentów (10 zmian), a brak gromadzenia (prawidłowy wynik) u 4 (5 zmian). Na 15 badań w 13 przypadkach zaobserwowano wymywanie się radiofarmaceutyku ze zmiany, które sugeruje łagodny charakter zmiany. Operowano trzech chorych ze zmianami gromadzącymi MIBI-Tc99m w badaniu scyntygraficznym, niemniej wynik badania histopatologicznego był we wszystkich przypadkach prawidłowy. Zaobserwowano, że interpretacja obrazów tarczycy SPECT/CT z MIBI-Tc99m uzyskiwanych metodą wymywania jest łatwiejsza i czytelniejsza niż w badaniu planarnym. U 3 z pozostałych 5 chorych dane kliniczne nie zwiększają obecnie podejrzenia raka, u 2 nie kontynuowano obserwacji. Wnioski: Ocena scyntygraficzna tarczycy wykonywana z zastosowaniem SPECT/CT z MIBI-Tc99m metodą wymywania może być pomocna w diagnostyce różnicowej guzków tarczycy. (Endokrynol Pol 2010; 61 (5): 422-426)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-Tc99m 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-Tc99m 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-Tc99m may be used to exclude malignancy in lesions indeterminate by FNAB we propose to use SPECT-CT derived images and standardized evaluation criteria. (Pol J Endocrinol 2010; 61 (5): 422-426

Individualization of Radionuclide Therapies: Challenges and Prospects

The article presents the problems of clinical implementation of personalized radioisotope therapy. The use of radioactive drugs in the treatment of malignant and benign diseases is rapidly expanding. Currently, in the majority of nuclear medicine departments worldwide, patients receive standard activities of therapeutic radiopharmaceuticals. Intensively conducted clinical trials constantly provide more evidence of a close relationship between the dose of radiopharmaceutical absorbed in pathological tissues and the therapeutic effect of radioisotope therapy. Due to the lack of individual internal dosimetry (based on the quantitative analysis of a series of diagnostic images) before or during the treatment, only a small fraction of patients receives optimal radioactivity. The vast majority of patients receive too-low doses of ionizing radiation to the target tissues. This conservative approach provides “radiation safety” to healthy tissues, but also delivers lower radiopharmaceutical activity to the neoplastic tissue, resulting in a low level of response and a higher relapse rate. The article presents information on the currently used radionuclides in individual radioisotope therapies and on radionuclides newly introduced to the therapeutic market. It discusses the causes of difficulties with the implementation of individualized radioisotope therapies as well as possible changes in the current clinical situation

Patient-specific dosimetry of 99mTc-HYNIC-Tyr3-Octreotide in children

Background: Technetium-99m-hydrazinonicotinamide-Tyr3-octreotide (99mTc-HYNIC-TOC) is recognized as a promising radiopharmaceutical for diagnosing neuroendocrine tumors (NETs). However, 99mTc-HYNIC-TOC dosimetry has been investigated only for adults. As pediatric radionuclide therapies become increasingly common, similar dosimetric studies for children are urgently needed. The aim of this study is to report personalized image-based biodistributions and dosimetry evaluations for children studies performed using 99mTc-HYNIC-TOC and to compare them with those from adult subjects. Eleven children/teenage patients with suspected or diagnosed NETs were enrolled. Patient imaging included a series of 2–3 whole-body planar scans and SPECT/CT performed over 2–24 h after the 99mTc-HYNIC-TOC injections. The time-integrated activity coefficients (TIACs) were obtained from the hybrid planar/SPECT technique. Patient-specific doses were calculated using both the voxel-level and the organ-level approaches. Estimated children doses were compared with adults’ dosimetry. Results: Pathologic uptake was observed in five patients. TIACs for normal organs with significant uptakes, i.e., kidneys, spleen, and liver, were similar to adults’ TIACs. Using the voxel-level approach, the average organ doses for children were 0.024 ± 0.009, 0.032 ± 0.017, and 0.017 ± 0.007 mGy/MBq for the kidneys, spleen, and liver, respectively, which were 30% larger than adults’ doses. Similar values were obtained from the organ-level dosimetry when using OLINDA with adapted organ masses. Tumor doses were 0.010–0.024 mGy/MBq. However, cross-organ contributions were much larger in children than in adults, comprising about 15–40% of the total organ/tumor doses. No statistical differences were found between mean doses and dose distributions in patients with and without pathologic uptakes. Conclusion: Although the children TIACs were similar to those in adults, their doses were about 30% higher. No significant correlation was found between the children’s doses and their ages. However, substantial inter-patient variability in radiotracer uptake, indicating disparity in expression of somatostatin receptor between different patients, emphasizes the importance and necessity of patient-specific dosimetry for clinical studies.Medicine, Faculty ofNon UBCRadiology, Department ofReviewedFacult

The practical considerations of dose constraints in diagnostic medical departments using ionizing radiation

The term “dose constraint” has been used in radiological protection since 1990. Its practical application has varied from country to country to the present day. The authors of this paper believe that it is an underestimated tool for the purpose of radiological protection. This study aims to estimate local dose constraints for workers in conventional nuclear medicine and radiology departments, on the basis of doses received in the last 3 to 4 years by different groups of workers. The levels of exposure to employees of the nuclear medicine department correspond well to levels in other countries, but for employees belonging to the radiology department, the levels are significantly lower. Unification of the practical application of dose constraints and legislation concerning their specific values would increase the relevance and effectiveness of these operational units. This is a playing field for radiation safety officers for the determination and widespread publication of local dose constraints in their particular medical departments