A contribution of Józef Rotblat, a winner of the Nobel Peace Prize, to the development of nuclear medicine

Józef Rotblat, a nuclear physicist born and educated in Poland, is the only laureate of the Nobel Peace Prize, who made a significant contribution to the development of nuclear medicine. In 1948 he went down in the annals of nuclear medicine by obtaining, with extarnal measurements, the first "image " of a function of an internal organ - thyroid gland, by registering gamma rays with a collimated Geiger counter at many points of the patient's neck and chest. He was awarded the Nobel Prize in Rotblat in 1995 for organizing, together with the a British philosopher Bertrand Russell, the international, peaceful movement of scholars for the eradication of weapons of mass destruction (Pugwash) and multi-annual activity in this movement

Patient exposure to ionising radiation due to nuclear medicine cardiac procedures

Nuclear cardiology procedures are among the most extensivelyperformed radionuclide studies. Procedures for the assessmentof myocardial perfusion, contractile function and metabolismhave gained a prominent position in clinical practice. Healthrisk to patients from radiopharmaceuticals results only fromexposure to ionizing radiation. Nuclear medicine diagnostic procedures,including the cardiological ones, are accompanied bya very small risk of radiation induced malignant tumours. Deathrisk from stress and rest perfusion of myocardium (effective doseof about10 mSv) could be estimated as lower than 0.1 per mille

Modification of a two blood sample method used for measurement of GFR with 99mTc-DTPA

BACKGROUND Measurements of GFR may be performed with a slope/intercept method (S/I), using only two blood samples taken in strictly defined time points. The aim of the study was to modify this method in order to extend time intervals suitable for blood sampling. Modification was based on a variation of a Russel et al. model parameter, selection of time intervals suitable for blood sampling and assessment of uncertainty of calculated results. MATERIAL AND METHODS Archived values of GFR measurements of 169 patients with different renal function, from 5.5 to 179 mL/min, calculated with a multiple blood sample method were used. Concentrations of a radiopharmaceutical in consecutive minutes, from 60th to 190th after injection, were calculated theoretically, using archived parameters of biexponential functions describing a decrease in 99mTc-DTPA concentration in blood plasma with time. These values, together with injected activities, were treated as measurements and used for S/I clearance calculations. Next, values of S/I clearance were compared with the multiple blood sample method in order to calculate suitable values of exponent present in a Russel’s model, for every combination of two blood sampling time points. A model was considered accurately fitted to measured values when SEE ≤ 3.6 mL/min. Assessments of uncertainty of obtained results were based on law of error superposition, taking into account mean square prediction error and also errors introduced by pipetting, time measurement and stochastic radioactive decay. RESULTS The accepted criteria resulted in extension of time intervals suitable for blood sampling to: between 60 and 90 minutes after injection for the first sample and between 150 and 180 minutes for the second sample. Uncertainty of results was assessed as between 4 mL/min for GFR = 5–10 mL/min and 8 mL/min for GFR = 180 mL/min. CONCLUSIONS Time intervals accepted for blood sampling fully satisfy nuclear medicine staff and ensure proper determination of GFR. Uncertainty of results is entirely acceptable and for high GFR values even comparable with uncertainty of multi-sample measurements.BACKGROUND Measurements of GFR may be performed with a slope/intercept method (S/I), using only two blood samples taken in strictly defined time points. The aim of the study was to modify this method in order to extend time intervals suitable for blood sampling. Modification was based on a variation of a Russel et al. model parameter, selection of time intervals suitable for blood sampling and assessment of uncertainty of calculated results. MATERIAL AND METHODS Archived values of GFR measurements of 169 patients with different renal function, from 5.5 to 179 mL/min, calculated with a multiple blood sample method were used. Concentrations of a radiopharmaceutical in consecutive minutes, from 60th to 190th after injection, were calculated theoretically, using archived parameters of biexponential functions describing a decrease in 99mTc-DTPA concentration in blood plasma with time. These values, together with injected activities, were treated as measurements and used for S/I clearance calculations. Next, values of S/I clearance were compared with the multiple blood sample method in order to calculate suitable values of exponent present in a Russel’s model, for every combination of two blood sampling time points. A model was considered accurately fitted to measured values when SEE ≤ 3.6 mL/min. Assessments of uncertainty of obtained results were based on law of error superposition, taking into account mean square prediction error and also errors introduced by pipetting, time measurement and stochastic radioactive decay. RESULTS The accepted criteria resulted in extension of time intervals suitable for blood sampling to: between 60 and 90 minutes after injection for the first sample and between 150 and 180 minutes for the second sample. Uncertainty of results was assessed as between 4 mL/min for GFR = 5–10 mL/min and 8 mL/min for GFR = 180 mL/min. CONCLUSIONS Time intervals accepted for blood sampling fully satisfy nuclear medicine staff and ensure proper determination of GFR. Uncertainty of results is entirely acceptable and for high GFR values even comparable with uncertainty of multi-sample measurements

Preliminary assessment of interand intraobserver reproducibility, and normative values of renal mean transit time (MTT) and parenchymal transit time (PTT) for 99mTc-etylenodicysteine

BACKGROUND: The clinical significance of MTT and PTT, determined by deconvolution of renographic curves, is arguable. Their usefulness in diagnosis of obstructive uro- and nephropathy, renovascular hypertension and monitoring of transplanted kidneys is pointed out, but susceptibility of deconvolution methods to errors resulting from “statistical noise” is also stressed. So far there are no reports on normative MTT values for 99mTc-EC, although such values were already determined for 131I-OIH, 99mTc-DTPA and 99mTc-MAG3. The aim of this study is an assessment of inter- and intraobserver reproducibility of MTT and PTT for 99mTc-EC, and determination of normative values for these parameters. MATERIALS AND METHODS: 31 patients (17 women and 14 men aged 19–75, average 44 years) referred for dynamic renal scintigraphy with: unilateral flow impairment (11), unilateral nephrolithiasis (2), control after unilateral lithotripsy (4), moderate hypertension (demographically with > 99% probability of primary hypertension) (4), suspected cirrhosis of one kidney (3), future kidney donors (3), control after abdominal injuries (3), incontinence (1). 42 functionally efficient kidneys were included in the study. Criteria for recognition of a kidney as functionally efficient were: — no earlier history of renal disease, signs of renal damage in basic blood and urine tests, or abnormalities in ultrasonography; — normal result of dynamic renal scintigraphy (in terms of sequential images and renographic curve). MTT and PTT values were determined independently by two operators, using a matrix method for deconvolution of renographic curves. RESULTS: Differences between mean MTT and PTT from two studies by one operator were insignificant and those values were closely correlated (r = 0.99 and r = 0.97, respectively). Differences of values obtained by both operators were practically insignificant for MTT (r = 0.93), and significant for PTT (r = 0.81 and p < 0.001). These differences do not disqualify that processing method. The upper limits of normative values of MTT and PTT were based on the results from first study performed by more experienced operator — 200 s and 170 s, respectively. CONCLUSIONS: The procedure of processing dynamic renal scintigraphy used in this study is reproducible. Normative values of MTT and PTT for 99mTc-EC were established as 200 s and 170 s, respectively. An attempt to optimize and standardize the technique of determining parenchymal ROI in a matrix deconvolution method, followed by an evaluation of clinical usefulness of these parameters in the diagnosis of chosen renal function impairments would be a logical continuation of this initial research

Application of stress-only myocardial perfusion imaging

BACKGROUND: Single-photon emission computed tomography myocardial perfusion study is usually a sequence of stress and rest part. In case of a normal stress study rest part can be given up. The objective of this study was to examine factors affecting concordance of results of stress-only (SO) and stress-rest (SR) studies. MATERIAL AND METHODS: SO and SR studies without and with attenuation correction (AC) of 212 selected patients (without cardiomyopathy, history of myocardial infarction or coronary artery bypass grafting) were analyzed visually. Influence of percutaneous coronary intervention (PCI) in the past, type of stress (physical/pharmacological) and application of AC (in form of combined method of non-corrected and corrected images — CM), patient body mass index (BMI) and gender on concordance rates of SO and SR studies were examined. RESULTS: Neither a history of PCI, nor a type of stress affected concordance rate. AC (in form of CM) improved concordance rate significantly, from 60% to 68% (p = 0.018). Patient BMI affected concordance rates — 72% in non-obese and 59% in obese patients (p = 0.05). In the whole group, risk of overlooking patients with abnormal perfusion in SO study was small (< 2%), but it grew significantly with patient BMI. Rest study was necessary in about 20% of non-obese and in about 50% of obese patients. CONCLUSION: MPS can be limited to stress part in appropriately selected, especially non-obese, patients provided that AC is applied, due to a low risk of overlooking patients with abnormal perfusion. In case of obese patients, careful analysis of exercise images for their normality is particularly important

Usefulness of clearance parametric images in detection of regional renal parenchyma dysfunction

BACKGROUND: The aim of the study was to examine whether parametric clearance images (PAR) enhance diagnostic potential of a dynamic renal scintigraphy with detection of local dysfunction of kidneys, on a model of kidneys after treatment with extracorporeal shock wave lithotripsy (ESWL), MATERIAL AND METHODS: Kidneys after ESWL were accepted as a proper model for the implementation of this objective because of the previously proven damaging effect of a shock wave on renal parenchyma and known region of ESWL application. Forty patients (23 males and 17 females) at the age of 37 to 70 years (mean value 54) with untreated earlier single, one-sided nephrolithiasis, currently treated with ESWL, underwent a study. A dynamic renal 99mTc-EC scintigraphy was performed three times: before ESWL, a week and a month after this therapeutic intervention. PAR images generated with use of an in-house developed software were compared with summation (SUM) of images obtained from radiopharmaceutical uptake phase and quantitative global function parameters (GFP) of each kidney, like split function, MTT — mean transit time and PTT — parenchymal transit time. RESULTS: PAR and SUM images of all 40 kidneys before ESWL were normal. PAR images revealed local or diffused defects a week and a month after therapeutic intervention in statistically significantly larger numbers of kidneys than SUM images (19 vs. 6, p = 0.002 and 16 vs. 5, p = 0.003, respectively). A week after ESWL, when defects in PAR images were observed in about a half of all renal segments (29/57 — 51%) all GFP values were significantly worse than in kidneys without defects. A month after ESWL defects in PAR images could be observed in ab. 1/3 (17/48 — 35%) of segments and were less extensive, whereas GFP values did not differ significantly from values in kidneys without clearance function impairment in the PAR images. CONCLUSIONS: PAR images enhance diagnostic potential of a dynamic renal scintigraphy with detection of local function defects. These images allow to detect more local renal function defects than SUM images

Lung perfusion scintigraphy in the assessment of pulmonary circulation after completion of surgical treatment of a hypoplastic left heart syndrome (HLHS)

INTRODUCTION: Hypoplastic left heart syndrome (HLHS) is an inborn complex heart malformation. A multi-stage treatment is initiated in a neonatal period with a Norwood surgery. The next step is Glenn surgery — a bidirectional superior cavo-pulmonary anastomosis. At the last stage anastomosis of inferior vena cava (IVC) with the right pulmonary artery (RPA) is formed as a result of a Fontan surgery. The aim of this study was to assess lung perfusion in patients with HLHS after completion of a surgical therapy, using a scintigraphic method. MATERIAL AND METHODS: In 92 patients with HLHS a planar lung scintigraphy in anterior and posterior projections after administration of 99mTc-macroaggregates in activity 18-111MBq was carried out twice (in several day intervals). At first, a radiopharmaceutical was administered to the right extremity in order to assess the lung distribution of blood flowing through the anastomosis of superior vena cava (SVC) with RPA. In the next study, after administration of the tracer to the right lower extremity, the distribution of blood flowing through the anastomosis of IVC with RPA was assessed. The relative percentage of each lung in the total lung perfusion was calculated on a Xeleris workstation using the “Lung perfusion analysis” program. Lung perfusion was considered close to symmetrical when the proportion was in the range of 40–60%. RESULTS: In spite of the fact that mean relative values of distribution of blood flowing through the anastomosis of SVC with RPA to the left lung (LL) and right lung (RL) in the entire study group did not differ significantly: LLmean = 47%; RLmean = 53%, p = 0.14, relative values of perfusion of both lungs were differentiated — in 26% of patients LL was better perfused, in 38% RL was better perfused and in 36% a perfusion of both lungs was similar. The analysis of blood distribution by anastomosis of IVC with RPA showed that the mean relative perfusion of RL was significantly higher than that of LL (70% vs. 30%, p < 0.0000001). No signs of pulmonary emboli were detected. In 13% of studied patients, uptake of the radiopharmaceutical in kidneys was shown indicating the presence of shunt “from right to left”. CONCLUSIONS: After completion of surgical treatment of patients with HLHS, differentiated blood supply of the lungs was observed through SVC with RPA anastomosis and a tendency to higher blood supply of RL than LL by anastomosis of IVC with RPA. No signs of pulmonary embolism were detected. The study revealed a “right to left” shunt in some patients

Should non-movement specialists refer patients for SPECT-DaTSCAN?

Background. SPECT with radioligand DaTSCAN (SPECT-DaTSCAN) is a sensitive tool used for assessing the functional integrity of the presynaptic part of the nigrostriatal dopaminergic system. The procedure is useful whenever there is a need to distinguish between neurodegenerative parkinsonism and other parkinsonian syndromes in subjects with equivocal signs and symptoms. It can be assumed that the neurologist’s decision to perform SPECT-DaTSCAN depends on his or her experience and skill in the diagnosis of parkinsonian and tremor syndromes. Aims. To assess the accuracy of referrals to SPECT-DATSCAN made by non-movement disorders specialists. Material and methods. Sixty seven patients referred for SPECT-DaTSCAN by a general neurologist were studied. In all subjects, a movement disorder specialist performed the neurological examination, collected medical history, and analysed previous treatments and the results of diagnostic tests. Results. Evaluation carried out by a movement disorder specialist did not confirm an indication for SPECT-DaTSCAN in 31 patients (46.3%). General neurologists needed support for clinical diagnosis with SPECT-DaTSCAN most frequently in subjects with parkinsonism even though they were presenting a full-blown disease manifestation and even though the patients met the diagnostic criteria for Parkinson’s disease or one of the atypical parkinsonian syndromes. Conclusions. Our presented results probably reflect the limited experience of general neurologists in the evaluation of parkinsonian syndromes and tremor. The use of SPECT-DaTSCAN by non-movement disorders specialists is associated with a significant risk of overuse of this tool. To minimise this risk, the skills of general neurologists in diagnosing parkinsonian and tremor syndromes should be improved. Moreover, patients should be provided with access to movement disorders specialists

The effect of image translation table on diagnostic efficacy of myocardial perfusion SPECT studies

BACKGROUND: The aim of this study was to determine which of the most popular colour scales used in the Xeleris processing system (GE) should preferably be used during a clinical interpretation of myocardial perfusion images, and to find out whether a colour scale saturation level affects the diagnostic efficacy of the study. MATERIAL AND METHODS: From among 100 patients in whom a myocardial perfusion scintigraphy had been performed, a subgroup of people referred for coronary angiography, with neither prior history nor ECG signs of a myocardial infarction has been selected retrospectively. This group consisted of 41 patients (14 females) in the age group 46 to 76 years. All patients underwent two-day myocardial perfusion SPECT imaging using 99mTc-MIBI as a radiopharmaceutical. Reconstructed slices were interpreted in 3 colour scales: white-red-yellow-green-blue-black with computer-assigned thresholds (French 100%), the same French scale but without a white colour (image maximum set manually to a border value between red and white &#8212; French w.w.), and a white-yellow-violet- pink-blue-black scale (GEcolor), by consensus of two experienced nuclear medicine specialists. A semiquantitative method for evaluation of perfusion images was applied, based on myocardium segmentation. Perfusion in each segment was scored using a five-point system. Study interpretation (normal/ abnormal perfusion) was based on summed stress scores (SSS), being equal/above or below a given threshold value. The choice of optimal SSS threshold value was based on sensitivity and specificity of the study in detection of perfusion defects resulting from critical stenoses of main coronary arteries RESULTS: SSS values differed among colour scales (p < 0.00001). The lowest values were obtained for a French 100% scale (mean value = 5.0, SD = 8.0), the highest for French w.w. (mean values = 8.1, SD = 8.7), and for GE colour scale &#8212; mean value &#8212; 5.6, SD &#8212; 7.9. A French 100% scale gave high sensitivity (88%), as well as specificity (83%), but only when a low SSS threshold value of 2, hardly acceptable for study interpreters, was used. When higher threshold values were applied, they compromised the sensitivity of the study. A French w.w. scale with SSS threshold values lower than 3 provided a slightly higher sensitivity (94%), but with a significant reduction in specificity (to values below 50%). Only a threshold value of 4 provided acceptable, but still low specificity (63%) with preserved high sensitivity (88%). At the same time, the scale GE colour provided indices of diagnostic efficacy with the SSS threshold value of 3 as high as a scale French 100% with threshold value of 2. CONCLUSIONS: A French scale (Xeleris, GE) is not the scale of choice for the interpretation of myocardial perfusion SPECT images. It seems that a GE colour scale is better suited for this purpose. SSS threshold values accepted as diagnostic criteria for the detection of myocardial perfusion abnormalities should be suited separately for every translation table. The choice of optimal value should be verified by results of coronary angiography. Nuclear Med Rev 2010; 13, 2: 64&#8211;6

Perfusion lung scintigraphy for the prediction of postoperative residual pulmonary function in patients with lung cancer

BACKGROUND: Accurate prediction of postoperative pulmonary function in patients with non-small cell lung cancer is crucial for proper qualification for surgery, the only effective therapeutic method. The aim of the study was to select the most accurate method for acquisition and processing of lung perfusion scintigraphy (LPS) combined with spirometry for prediction of postoperative pulmonary function in patients qualified for surgery. MATERIAL AND METHODS: LPS was performed in 70 patients (40 males, 30 females), with preoperative spirometry (mean FEV1preop = 2.26 ± 0.72 L), after administration of 185 MBq of 99mTc-microalbumin/macroaggregate, using planar (appa) and SPECT/CT methods. Predicted postoperative lung function (FEV1pred) was calculated as a part of active lung parenchyma to remain after surgery. A non-imaging segment counting method was also applied. FEV1pred(appa, SPECT, SPECT/CT, segm.) were further compared with actual FEV1postop values obtained from postoperative spirometry. RESULTS: In the whole studied group (47 lobectomies, 23 pneumonectomies) mean value of FEV1postop was equal to 1.76 (± 0.56) L. FEV1pred(appa, SPECT, SPECT/CT, segm.) were equal to 1.75 (± 0.58) L, 1.71 (± 0.57) L, 1.72 (± 0.57) L and 1.57 (± 0.58) L, respectively. A segment counting method systematically lowered predicted FEV1 values (p &lt; 10–5). Moreover, in 31 patients with FEV1preop &lt; 2 L error of predicted values was assessed with Bland-Altman method. Mean absolute differences FEV1postop – FEV1pred amounted to: appa — (0.04 ± 0.13) L, SPECT — (0.07 ± 0.14) L, SPECT/CT — (0.06 ± 0.14) L and segm. — (0.21 ± 0.19) L, respectively. Lower limit of 95% confidence interval calculated for planar — optimal method, was equal to –220 mL (also determined separately in subgroups after lobectomy and pneumonectomy). CONCLUSIONS: This study shows that planar LPS may be applied for prediction of postoperative pulmonary function in patients qualified for pneumonectomy and lobectomy. If actual FEV1postop value is to be ≥ 800 mL, predicted value should exceed 1000 mL