Insights into the development of 99mTc-radioligands for serotonergic receptors imaging: Synthesis, labeling, In vitro, and In vivo studies.

Serotonergic (5-hydroxytryptamine; 5-HT) receptors play critical roles in neurological and psychological disorders such as schizophrenia, anxiety, depression, and Alzheimer's diseases. Therefore, it is particularly important to develop novel radioligands or modify the existing ones to identify the serotonergic receptors involved in psychiatric disorders. Among the 16 subtypes of serotonergic systems, only technetium-99m based radiopharmaceuticals have been evaluated for serotonin-1A (5-HT1A), serotonin-2A (5-HT2A), 5-HT1A/7 heterodimers and serotonin receptor neurotransmitter (SERT). This review focuses on recent efforts in the design, synthesis and evaluation of 99mTc-radioligands used for single photon emission computerized tomography (SPECT) imaging of serotonergic (5-HT) receptors. Additionally, the discussion will cover aspects such as chemical structure, in vitro/vivo stability, affinity toward serotonin receptors, blood-brain barrier permeation (BBB), and biodistribution study.

The effect of selenium supplementation on sonographic findings of salivary glands in papillary thyroid cancer (PTC) patients treated with radioactive iodine: study protocol for a double-blind, randomized, placebo-controlled clinical trial.

BACKGROUND: Thyroid cancer is a very damaging disease. The most common treatment for this disease includes thyroidectomy and then using radioactive iodine (RAI). RAI has many side effects, including a decrease in salivary secretions, followed by dry mouth and oral and dental injuries, as well as increased inflammation and oxidative stress. Selenium can be effective in these patients by improving inflammation and oxidative stress and by modulating salivary secretions. So far, only one clinical trial has investigated the effect of selenium on thyroid cancer patients treated with radioiodine therapy (RIT) conducted on 16 patients; considering the importance of this issue, to show the potential efficacy of selenium in these patients, more high-quality trials with a larger sample size are warranted. METHODS: This is a parallel double-blind randomized controlled clinical trial that includes 60 patients aged 20 to 65 years with papillary thyroid cancer (PTC) treated with RAI and will be conducted in Seyyed al-Shohada Center, an academic center for referral of patients to receive iodine, Isfahan, Iran. Thirty patients will receive 200 µg of selenium for 10 days (3 days before to 6 days after RAI treatment) and another 30 patients will receive a placebo for the same period. Sonographic findings of major salivary glands, salivary secretions, and sense of taste will be evaluated before and 6 months after 10-day supplementation. DISCUSSION: Due to its anti-inflammatory and antioxidant effects, as well as improving salivary secretions, selenium may improve the symptoms of thyroid cancer treated with radioactive iodine. In past studies, selenium consumption has not reduced the therapeutic effects of radiation therapy, and at a dose of 300 to 500 µg/day, it has not had any significant side effects in many types of cancer under radiation therapy. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20201129049534N6 . Registered on 16 September 2021.

Myocardial Perfusion Single-Photon Emission Computed Tomography (SPECT) Image Denoising: A Comparative Study.

The present study aimed to evaluate the effectiveness of different filters in improving the quality of myocardial perfusion single-photon emission computed tomography (SPECT) images. Data were collected using the Siemens Symbia T2 dual-head SPECT/Computed tomography (CT) scanner. Our dataset included more than 900 images from 30 patients. The quality of the SPECT was evaluated after applying filters such as the Butterworth, Hamming, Gaussian, Wiener, and median-modified Wiener filters with different kernel sizes, by calculating indicators such as the signal-to-noise ratio (SNR), peak signal-to-noise ratio (PSNR), and contrast-to-noise ratio (CNR). SNR and CNR were highest with the Wiener filter with a kernel size of 5 × 5. Additionally, the Gaussian filter achieved the highest PSNR. The results revealed that the Wiener filter, with a kernel size of 5 × 5, outperformed the other filters for denoising images of our dataset. The novelty of this study includes comparison of different filters to improve the quality of myocardial perfusion SPECT. As far as we know, this is the first study to compare the mentioned filters on myocardial perfusion SPECT images, using our datasets with specific noise structures and mentioning all the elements necessary for its presentation within one document.

Diagnostic Performance Evaluation of Multiparametric Magnetic Resonance Imaging in the Detection of Prostate Cancer with Supervised Machine Learning Methods.

Prostate cancer is the second leading cause of cancer-related death in men. Its early and correct diagnosis is of particular importance to controlling and preventing the disease from spreading to other tissues. Artificial intelligence and machine learning have effectively detected and graded several cancers, in particular prostate cancer. The purpose of this review is to show the diagnostic performance (accuracy and area under the curve) of supervised machine learning algorithms in detecting prostate cancer using multiparametric MRI. A comparison was made between the performances of different supervised machine-learning methods. This review study was performed on the recent literature sourced from scientific citation websites such as Google Scholar, PubMed, Scopus, and Web of Science up to the end of January 2023. The findings of this review reveal that supervised machine learning techniques have good performance with high accuracy and area under the curve for prostate cancer diagnosis and prediction using multiparametric MR imaging. Among supervised machine learning methods, deep learning, random forest, and logistic regression algorithms appear to have the best performance.

Myocardial perfusion imaging in the era of COVID-19: a systematic review.

Purpose: As COVID-19 was uncovered, it became evident that specific individuals could experience multi-organ complications for quite a while after infection. Among them, there were several cardiovascular complications. Myocardial perfusion imaging single photon emission computed tomography (MPI SPECT) can be utilized to detect and evaluate cardiac problems regardless of whether COVID caused them. By examining all publications relevant to the impacts of the pandemic on SPECT MPI imaging, we aimed to understand how the COVID pandemic affected different aspects of the MPI, how intense these effects were, and what the consequences were. Method: On the 6th of June, 2022, a four-domain search strategy was developed and implemented by searching the following databases: PubMed, SCOPUS, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials. The retrieved records have been put through two levels of screening. The search for forward and backward citations provided more results. Results: This study contained 32 papers, divided into the following three categories: 1. Case reports and series; 2. A comparison of the number of MPIs conducted before and after the pandemic; and 3. SPECT MPI findings. Conclusion: We observed through the article review that CT scans performed in combination with MPI are crucial and should be interpreted within the context of COVID, especially during outbreaks. Moreover, we discovered that in the initial months of the pandemic, the number of SPECT MPIs performed globally decreased, with the fall being more significant in some countries, primarily in low- to middle-income regions. Lastly, we found that individuals with a history of COVID-19 may be more prone to having MPIs that demonstrate abnormalities, such as ischemia.

Apigenin in cancer therapy: Prevention of genomic instability and anticancer mechanisms.

The incidence of cancer has been growing worldwide. Better survival rates following the administration of novel drugs and new combination therapies may concomitantly cause concern regarding the long-term adverse effects of cancer therapy, for example, second primary malignancies. Moreover, overcoming tumour resistance to anticancer agents has been long considered as a critical challenge in cancer research. Some low toxic adjuvants such as herb-derived molecules may be of interest for chemoprevention and overcoming the resistance of malignancies to cancer therapy. Apigenin is a plant-derived molecule with attractive properties for chemoprevention, for instance, promising anti-tumour effects, which may make it a desirable adjuvant to reduce genomic instability and the risks of second malignancies among normal tissues. Moreover, it may improve the efficiency of anticancer modalities. This paper aims to review various effects of apigenin in both normal tissues and malignancies. In addition, we explain how apigenin may have the ability to protect usual cells against the genotoxic repercussions following radiotherapy and chemotherapy. Furthermore, the inhibitory effects of apigenin on tumours will be discussed.

Comparing Different Algorithms for the Pseudo-Coloring of Myocardial Perfusion Single-Photon Emission Computed Tomography Images.

Single-photon emission computed tomography (SPECT) images can significantly help physicians in diagnosing patients with coronary artery or suspected coronary artery diseases. However, these images are grayscale with qualities that are not readily visible. The objective of this study was to evaluate the effectiveness of different pseudo-coloring algorithms of myocardial perfusion SPECT images. Data were collected using a Siemens Symbia T2 dual-head SPECT/computed tomography (CT) scanner. After pseudo-coloring, the images were assessed both qualitatively and quantitatively. The qualities of different pseudo-color images were examined by three experts, while the images were evaluated quantitatively by obtaining indices such as mean squared error (MSE), peak signal-to-noise ratio (PSNR), normalized color difference (NCD), and structure similarity index metric (SSIM). The qualitative evaluation demonstrated that the warm color map (WCM), followed by the jet color map, outperformed the remaining algorithms in terms of revealing the non-visible qualities of the images. Furthermore, the quantitative evaluation results demonstrated that the WCM had the highest PSNR and SSIM but the lowest MSE. Overall, the WCM could outperform the other color maps both qualitatively and quantitatively. The novelty of this study includes comparing different pseudo-coloring methods to improve the quality of myocardial perfusion SPECT images and utilizing our collected datasets.

Modulation of the immune system by melatonin; implications for cancer therapy.

Immune system interactions within the tumour have a key role in the resistance or sensitization of cancer cells to anti-cancer agents. On the other hand, activation of the immune system in normal tissues following chemotherapy or radiotherapy is associated with acute and late effects such as inflammation and fibrosis. Some immune responses can reduce the efficiency of anti-cancer therapy and also promote normal tissue toxicity. Modulation of immune responses can boost the efficiency of anti-tumour therapy and alleviate normal tissue toxicity. Melatonin is a natural body agent that has shown promising results for modulating tumour response to therapy and also alleviating normal tissue toxicity. This review tries to focus on the immunomodulatory actions of melatonin in both tumour and normal tissues. We will explain how anti-cancer drugs may cause toxicity for normal tissues and how tumours can adapt themselves to ionizing radiation and anti-cancer drugs. Then, cellular and molecular mechanisms of immunoregulatory effects of melatonin alone or combined with other anti-cancer agents will be discussed.

Preventive Effect of L-Carnitine on Scar Formation During Acute Pyelonephritis: A Randomized Placebo-Controlled Trial.

BACKGROUND: Urinary tract infection and pyelonephritis are clinical problems that frequently occur in children. Several factors are responsible for renal tissue injury, morbidity, and renal scarring after pyelonephritis. The aim of this study was to evaluate the preventive effect of L-carnitine on renal scarring in acute pyelonephritis. METHODS: A randomized double-blind clinical trial was conducted on 65 children aged 6 months to 10 years. Patients were randomized into 2 groups to receive 7-day treatment with only antibiotics without L-carnitine (control group; n = 32) and 7-day treatment with L-carnitine (case group; n = 33) during the acute phase of infection. Technetium-99m-labeled dimercaptosuccinic acid (DMSA) scintigraphy was performed for all children during the acute phase (in 2-7 days of hospitalization) and late phase. P-value less than 0.05 was statistically significant. RESULTS: We recruited 65 participants in the study: 32 children in control group and 33 children in case group. Three children in the control group and 2 children in the case group refused to perform the second DMSA scan. Overall, data analysis at the end of the study was done on 60 patients. Age distribution of girl patients with upper urinary infection was 6.5% in girl children aged between 6 months and 12 months, 41.1% aged between 1 and 5 years, 33.3% aged between 5 and 10 years, respectively. There was no significant difference between 2 groups in age and sex. There was no significant difference between 2 groups in systolic blood pressure, diastolic blood pressure, the lab data including urine white blood cells and serum erythrocyte sedimentation rate, and antibiogram profiles. Voiding dysfunction was detected in 10% of the participants. The baseline DMSA was not significantly difference in 2 groups, but worsening of kidney lesions was significantly higher in control group after 6 months (P = 0.012). CONCLUSION: Our study showed that L-carnitine significantly decreased renal scarring because of acute pyelonephritis.

An experimental rat model of hilar splenic vessel ligation versus splenectomy for spleen trauma.

BACKGROUND: The most prevalent method of treating splenic injury is by splenectomy. This method is followed by postoperative complications. Therefore, less invasive procedures such as splenic angioembolization are introduced. This technique needs appropriate training, a high-tech setting and could be followed by complications. Thus, not all surgeons agree to do this procedure. Splenic hilar ligation of main vessels is a non-invasive procedure which has similarities to a splenectomy with unknown results. OBJECTIVES: We aim to evaluate and compare splenectomy and hilar ligation. METHODS: Thirty rats were divided into splenectomy and splenic hilar ligation groups. An identical grade 3-spleen injury was performed on all rats. After 6 weeks blood samples were obtained and hematologic and immunologic aspects were measured in their serum. Giemsa stained peripheral blood smears were obtained from the ligation group. RESULTS: Comparing the above-mentioned variables before and after the surgery in each groups showed statistical significance in all aspects except IgM, C4 and platelets levels in ligation group (P value: 0.213, 0.059 and 0.649 respectively). Analysis revealed significant deference in postoperative WBC, IgM and C4 levels between splenectomy and ligation group (P value: < 0.001, < 0.001 and 0.026 respectively). CONCLUSION: Splenic hilar ligation of main vessels is an easy way of treating splenic injury in hemodynamically stable patients with less postoperative complications. Therefore, it can be performed by all surgeons in all kind of medical centers. Spleen remains viable and continues its role although some aspects of its function become interrupted.

How may Doppler indices help in the differentiation of obstructive from nonobstructive hydronephrosis?

BACKGROUND: We assess the potency of different Doppler indices in the differentiation of obstructive and nonobstructive hydronephrosis. MATERIALS AND METHODS: In this study, infants and children who were referred for the evaluation of unilateral hydronephrosis were enrolled. Ultrasonography for the assessment of the degree of hydronephrosis and a voiding cystourethrogram for the exclusion of vesicoureteral reflux was performed. Then, Doppler ultrasonography was done for both kidneys of each patient using four classic Doppler indices as well as the difference (delta) of each index between to kidneys. Diuretic renography with 99 mTc-ethylene dicysteine (99 mTc-EC) was performed for each patient. RESULTS: Thirty-nine patients met the inclusion criteria. After diuretic renography, 29 (74.35%) patients had shown a nonobstructive pattern, and ten (25.65%) patients had a partial (intermediate) or complete obstruction. Using receiver operating characteristic (ROC) curve, none of the classic indices of Doppler duplex (i.e., resistive index [RI], resistance index, end diastolic velocity, and peak systolic velocity) had the ability to make a difference between obstructive and nonobstructive hydronephrosis. However, by calculating the difference (delta) of these indices between two kidneys of each patient, delta RI could differentiate the nonobstructive condition, significantly (P = 0.006). A cutoff value of 0.055 has 60% sensitivity and 82.8% specificity. The area under the ROC curve for delta RI is 0.795 (standard error: 0.086, 95% confidence interval [CI]: 0.626, 0.964). Furthermore, RI ratio between two kidneys of each patient could differentiate the nonobstructive condition, significantly (P = 0.012). A cutoff point of 1.075 has 70% sensitivity and 82.8% specificity. The area under the ROC curve for RI ratio was 0.769 (standard error: 0.104, 95% CI: 0.565, 0.973). CONCLUSION: This study shows that RI ratio and delta RI with a high specificity could differentiate nonobstructive hydronephrosis and therefore it is a promising way to use especially in the follow-up of children with hydronephrosis.

Comparison of Accuracy in Calculation of Absorbed Dose to Patients Following Bone Scan with (99m)Tc-Marked Diphosphonates by Two Different Background Correction Methods.

To improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with (99m)Tc-marked diphosphonates ((99m)Tc-MDP) by two different methods of background correction in conjugate view method. This study involved 22 patients referring to the Nuclear Medicine Center of Shahid Chamran Hospital, Isfahan, Iran. After the injection of (99m)Tc-MDP, whole-body images from patients were acquired at 10, 60, 90, and 180 min. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Finally, the absorbed dose was calculated using the Medical Internal Radiation Dosimetry (MIRD) technique. The results of this study showed that the absorbed dose per unit of injected activity (rad/mCi) ± standard deviation for pelvis bone, bladder, and kidneys by Buijs method was 0.19 ± 0.05, 0.08 ± 0.01, and 0.03 ± 0.01 and by conventional method was 0.13 ± 0.04, 0.08 ± 0.01, and 0.024 ± 0.01, respectively. This showed that Buijs background correction method had a high accuracy compared to conventional method for the estimated absorbed dose of bone and kidneys whereas, for the bladder, its accuracy was low.

Comparison of the Absorbed Dose for (99m)Tc-Diethylenetriaminepentaacetic Acid and (99m)Tc-Ethylenedicysteine Radiopharmaceuticals using Medical Internal Radiation Dosimetry.

The aim of this study was the investigation of absorbed dose to the kidneys, spleen, and liver during technetium-99 m ethylene dicysteine and technetium-99 m diethylenetriaminepentaacetic acid ((99m)Tc-EC and (99m)Tc-DTPA) kidney scan. Patients who had been prepared for the kidney scan, were divided into two groups (Groups 1 and 2). The first group (Group 1) and the second group (Group 2) received intravenous injection of (99m)Tc-EC and (99m)Tc-DTP, respectively. A certain amount of radiopharmaceuticals was injected into each patient and was immediately imaged with dual-head gamma camera to calculate the activity through the conjugated view method. Then, the doses of kidney, liver, and spleen were measured using medical internal radiation dosimetry method. Finally, absorbed dose of these organs was compared. Based on these different results (P < 0.05), organs absorbed dose was significantly less with radiopharmaceutical (99m)Tc-EC as compared with (99m)Tc-DTPA.

(99m)Tc-Phytate Lymphoscintigraphy for Detection of Sentinel Node: Preliminary Results of the First Year's Clinical Experience in Isfahan, Iran.

Sentinel lymph node is the first regional lymph node that drains the lymph from the primary tumor. It is potentially the first node to receive the seeding of lymph-borne metastatic cells. This study aimed to discuss lymphoscintigraphy procedural guidelines for detection of sentinel node using (99m)Tc-Phytate in Isfahan, Iran. Moreover, the preliminary results of the first year's clinical experience of lymphoscintigraphy in Isfahan, Iran are also presented. A total of 36 consecutive sentinel node procedures were performed following our protocol in March 2013 to March 2014. For all 36 patients, after intradermal injection of 0.5-1 mCi of (99m)Tc-Phytate, 5, 30 and 120 min with hands up lymphoscintigraphy was performed. All procedures were performed in a 1-day setting with (99m)Tc-Phytate injection in intradermal volume of about 0.1 cc. At 5, 30 and 120 min after injection, anterior and lateral images (4 min), were acquired using gamma-camera (energy 140 keV, window 15-20% and LEHR collimator). For all patients, at least one axillary sentinel lymph node was detected. For three patients, 2 SNs were seen. The images 5 min after injection showed at least one axillary sentinel node in 18 of 36 patients. However for the remaining patients, more delayed images (after 30 and 120 min) were needed. Although, no changes were seen in 120 min images compared to 30 min images. Considering the used protocol, from the evaluated data it can be concluded that lymphoscintigraphy after 30 min periareolar injection of about 0.5-1 mCi (99m)Tc-Phytate in an intradermal volume of about 0.1 cc yields an axillary sentinel node in all the patients. Imaging 120 min after injection is of no additional value and can be omitted.

Do ejection fraction and other gated stress rest myocardial perfusion parameters differ by age and gender?

BACKGROUND: We have studied the end-diastolic volume (EDV), the end-systolic volume (ESV), and the ejection fraction (EF) for patients who had normal results on treadmill exercise tests and perfusion scans. We also studied normal wall motion as diagnosed by gated myocardial perfusion imaging with the quantitative gated single photon emission tomography (QGSPECT) software set to launch a range of normal values. In addition, we evaluated differences based on age and gender. MATERIALS AND METHODS: All subjects with normal results on Bruce exercise and myocardial perfusion imaging QGSPECT using the 2-days stress-rest technetium-99m (99mTc) sestamibi protocol were enrolled in the study. The quantitated functional data of EDV, ESV, and EF using the QGSPECT software were assessed in the rest and stress studies. The association of quantitated functional data with age and sex at both stress and rest was studied in 78 subjects with no symptoms from the cardiovascular system and normal QGSPECT imaging, 29 males (mean age: 58.41 ± 9.0 years) and 49 females (mean age: 58.18 ± 9.0 years). Also studied were differences between males and females. RESULTS: Our results showed that in women compared with men only stress EF showed a significantly higher value (P = 0.02), whereas all other parameters including REF, SESV, SEDV, RESV, and REDV did not demonstrate a significant difference between men and women (P value > 0.05). CONCLUSION: The study showed that EF as determined by the QGSPECT technique should be considered as gender-matched normative parameter.

Estimation of Organ Activity using Four Different Methods of Background Correction in Conjugate View Method.

To make an accurate estimation of the uptake of radioactivity in an organ using the conjugate view method, corrections of physical factors, such as background activity, scatter, and attenuation are needed. The aim of this study was to evaluate the accuracy of four different methods for background correction in activity quantification of the heart in myocardial perfusion scans. The organ activity was calculated using the conjugate view method. A number of 22 healthy volunteers were injected with 17-19 mCi of (99m)Tc-methoxy-isobutyl-isonitrile (MIBI) at rest or during exercise. Images were obtained by a dual-headed gamma camera. Four methods for background correction were applied: (1) Conventional correction (referred to as the Gates' method), (2) Buijs method, (3) BgdA subtraction, (4) BgdB subtraction. To evaluate the accuracy of these methods, the results of the calculations using the above-mentioned methods were compared with the reference results. The calculated uptake in the heart using conventional method, Buijs method, BgdA subtraction, and BgdB subtraction methods was 1.4 ± 0.7% (P < 0.05), 2.6 ± 0.6% (P < 0.05), 1.3 ± 0.5% (P < 0.05), and 0.8 ± 0.3% (P < 0.05) of injected dose (I.D) at rest and 1.8 ± 0.6% (P > 0.05), 3.1 ± 0.8% (P > 0.05), 1.9 ± 0.8% (P < 0.05), and 1.2 ± 0.5% (P < 0.05) of I.D, during exercise. The mean estimated myocardial uptake of (99m)Tc-MIBI was dependent on the correction method used. Comparison among the four different methods of background activity correction applied in this study showed that the Buijs method was the most suitable method for background correction in myocardial perfusion scan.

Contribution of ultrasound examination in the detection of neck recurrence in low-risk differentiated thyroid carcinoma patients at first follow-up visits.

BACKGROUND: In the most patients with differentiated thyroid carcinoma (DTC), recurrent disease occurs in the neck region, but the usefulness of neck ultrasound (US) in its diagnosis is not clear. The aim of this study was to evaluate the significance of US in the detection of neck recurrence in low-risk DTC patients at first follow-up visits. MATERIAL AND METHODS: A total of 32 patients, who had a history of DTC and radioiodine therapy after thyroidectomy with low doses of iodine 131 (3.7 GBq), were enrolled in this study. About 6 months after first ablation, the patients underwent clinical examination, iodine 131 scanning, measurement of thyroglobulin (Tg) after T4 withdrawal, thyroid-stimulating hormone measurement, TgAb measurement, and neck sonography with US. RESULTS: Recurrence of thyroid cancer was suspected in the neck region in 17 patients (53.1%) of the study cohort. There were six groups based on the results of posttreatment serum Tg levels, 131I whole body scan (131I WBS), and US in the detection of DTC neck recurrences. Fifteen patients had negative results of three modalities (group 1); seven patients had US evidence of neck lesions but negative 131I WBS and serum Tg results(group 2); three patients had positive results of 131I WBS but negative US and serum Tg results (group 3); four patients had positive results of serum Tg results but negative US and 131I WBS results (group 4); two patients lacked 131I WBS evidence of neck lesions, but US and serum Tg suggested the diagnosis of neck recurrence (group 5), and one subject had evidence of neck recurrence in three modalities (group 6). CONCLUSION: These findings may imply that neck sonography together with determination of serum Tg levels and 131I WBS after thyroid-stimulating hormone therapy should be considered the diagnostic modality of choice for postoperative surveillance, even in low-risk DTC patients.

Estimation of Organ Absorbed Doses in Patients from (99m)Tc-diphosphonate Using the Data of MIRDose Software.

The purpose of this study was to compare estimation of radiation absorbed doses to patients following bone scans with technetium-99m-labeled methylene diphosphonate (MDP) with the estimates given in MIRDose software. In this study, each patient was injected 25 mCi of (99m)Tc-MDP. Whole-body images from thirty patients were acquired by gamma camera at 10, 60, 90, 180 minutes after (99m)Tc-MDP injection. To determine the amount of activity in each organ, conjugate view method was applied on images. MIRD equation was then used to estimate absorbed doses in different organs of patients. At the end, absorbed dose values obtained in this study were compared with the data of MIRDose software. The absorbed doses per unit of injected activity (mGy/MBq × 10(-4)) for liver, kidneys, bladder wall and spleen were 3.86 ± 1.1, 38.73 ± 4.7, 4.16 ± 1.8 and 3.91 ± 1.3, respectively. The results of this study may be useful to estimate the amount of activity that can be administered to the patient and also showed that methods used in the study for absorbed dose calculation is in good agreement with the data of MIRDose software and it is possible to use by a clinician.

Comparison of SPECT bone scintigraphy with MRI for diagnosis of meniscal tears.

BACKGROUND: Scintigraphy has been considered as competitive to MRI, but limited data are available on the accuracy of single photon emission tomography (SPECT) compared with MRI for the assessment of meniscal tears. Our objective was to assess the value of SPECT in comparison to MRI. METHODS: Between January 2003 and March 2004, sixteen patients were studied with both modalities and the accuracy rates of SPECT scan results, and MRI findings in the diagnosis of meniscal tears were compared. Arthroscopy was the gold standard. RESULTS: The respective sensitivity rate, specificity rate, and positive and negative predictive accuracies of MRI were 89%, 94%, 93%, and 79% and for SPECT those were 78%, 94%, 94%, and 88%. There was good agreement on the presence or absence of tears between two modalities (κ statistic = 0.699). CONCLUSION: SPECT and MRI are both valuable imaging techniques. SPECT is a useful alternative when MRI is unavailable or unsuitable and it is beneficial when more possible accuracy is desired (such as when MRI results are either inconclusive or conflict with other clinical data).