Tc-99m MDP Research Articles

Unusual finding on bone scintigraphy: Cerebral 99m-tc mdp involvement

99mTc-MDP (99mTc-methylene diphosphonate) uptake in the brain parenchyma was observed in the scintigraphic imaging of a 56 years old male patient with renal cell carcinoma (RCC), who was referred to our clinic for metastasis screening due to widespread bone pain. Uptake of 99mTc-MDP in the brain parenchyma in bone scintigraphy is a rare finding. This case is presented to reveal the causes of cerebral 99mTc-MDP involvement.

Biodistribution and Absorption of Radiopharmaceutical 99mTc MDP in Various Bones of Lung Cancer Patients Using SPECT/CT Modalities

Lung-to-bone cancer metastasis frequently involves bone lesions, particularly in the vertebrae. A bone scan using the radiopharmaceutical 99mTc MDP is a common diagnostic tool for detecting advanced metastases. This research aimed to determine the conversion factor of count rate to unit activity, assess the range of source activity in bones with and without lesions, and analyze the relationship between lung cancer metastasis and radiopharmaceutical activity in various bones. The study involved 28 patients. Procedures included phantom manufacturing, determining the depth of Antero Posterior (AP) and Postero Anterior (PA) position bones, converting count rates to activity units, and assessing 99mTc MDP biodistribution in bones. Results indicated that the conversion factor of count rate to activity units in AP and PA positions for lumbar vertebrae, costa vera, ilium, and sacrum were (〖13.2×10〗^(-4); 4.9〖×10〗^(-4)) mCi/cps; (4.0〖×10〗^(-4); 4.4〖×10〗^(-4)) mCi/cps; (4.0〖×10〗^(-4); 4.9〖×10〗^(-4)) mCi/cps; and (〖12.2×10〗^(-4); 〖4.5×10〗^(-4)) mCi/cps. In addition, there is a range of source activity values and percentage of activity in the bones (lumbar vertebrae; costa vera; ilium; and sacrum), namely (0.019-0.053) mCi and (0.107-0.498)%; (0.020-0.045) mCi and (0.139-0.338)%; (0.024-0.066) mCi and (0.128-0.551)%; and (0.012-0.028) mCi and (0.078-0.264)%. Furthermore, there is a range of source activity values in the lesion-indicated bone (lumbar vertebrae; costa vera; ilium; and sacrum), namely (0.038-0.053) mCi; (0.024-0.045) mCi; (0.033-0.066) mCi; and (0.017-0.028) mCi. The relationship between lung cancer metastasis to various bones studied and the range of radiopharmaceutical activity values obtained is moderately positive.

Fast SPECT/CT planar bone imaging enabled by deep learning enhancement.

The application of deep learning methods in rapid bone scintigraphy is increasingly promising for minimizing the duration of SPECT examinations. Recent works showed several deep learning models based on simulated data for the synthesis of high-count bone scintigraphy images from low-count counterparts. Few studies have been conducted and validated on real clinical pairs due to the misalignment inherent in multiple scan procedures. To generate high quality whole-body bone images from 2× and 3× fast scans using deep learning based enhancement method. Seventy-six cases who underwent whole-body bone scans were enrolled in this prospective study. All patients went through a standard scan at a speed of 20cm/min, which followed by fast scans consisting of 2× and 3× accelerations at speeds of 40 and 60cm/min. A content-attention image restoration approach based on Residual-in-Residual Dense Block (RRDB)is introduced to effectively recover high-quality images from fast scans with fine-details and less noise. Our approach is robust with misalignment introduced from patient's metabolism, and shows valid count-level consistency. Learned Perceptual Image Patch Similarity (LPIPS) and Fréchet Inception Distance (FID) are employed in evaluating the similarity to the standard bone images. To further prove our method practical in clinical settings, image quality of the anonymous images was evaluated by two experienced nuclear physicians on a 5-point Likert scale (5= excellent). The proposed method reaches the state-of-the-art performance on FID and LPIPS with 0.583 and 0.176 for 2× fast scans and 0.583 and 0.185 for 3× fast scans. Clinic evaluation further demonstrated the restored images had a significant improvement compared to fast scan in image quality, technetium 99m-methyl diphosphonate (Tc-99m MDP) distribution, artifacts, and diagnostic confidence. Our method was validated for accelerating whole-body bone scans by introducing real clinical data. Confirmed by nuclear medicine physicians, the proposed method can effectively enhance image diagnostic value, demonstrating potential for efficient high-quality fast bone imaging in practical settings.

Unusual Soft Tissue Uptake of Tc-99m MDP in Radiation-induced Sarcoma: Diagnostic Conundrum

Unusual Soft Tissue Uptake of Tc-99m MDP in Radiation-induced Sarcoma: Diagnostic Conundrum

Automated Diagnosis of Bone Metastasis by Classifying Bone Scintigrams Using a Self-defined Deep Learning Model.

Patients with cancer can develop bone metastasis when a solid tumor invades the bone, which is the third most commonly affected site by metastatic cancer, after the lung and liver. The early detection of bone metastases is crucial for making appropriate treatment decisions and increasing survival rates. Deep learning, a mainstream branch of machine learning, has rapidly become an effective approach to analyzing medical images. To automatically diagnose bone metastasis with bone scintigraphy, in this work, we proposed to cast the bone metastasis diagnosis problem into automated image classification by developing a deep learning-based automated classification model. A self-defined convolutional neural network consisting of a feature extraction sub-network and feature classification sub-network was proposed to automatically detect lung cancer bone metastasis, with a feature extraction sub-network extracting hierarchal features from SPECT bone scintigrams and feature classification sub-network classifying high-level features into two categories (i.e., images with metastasis and without metastasis). Using clinical data of SPECT bone scintigrams, the proposed model was evaluated to examine its detection accuracy. The best performance was achieved if the two images (i.e., anterior and posterior scans) acquired from each patient were fused using pixel-wise addition operation on the bladder-excluded images, obtaining the best scores of 0.8038, 0.8051, 0.8039, 0.8039, 0.8036, and 0.8489 for accuracy, precision, recall, specificity, F-1 score, and AUC value, respectively. The proposed two-class classification network can predict whether an image contains lung cancer bone metastasis with the best performance as compared to existing classical deep learning models. The high accumulation of 99mTc MDP in the urinary bladder has a negative impact on automated diagnosis of bone metastasis. It is recommended to remove the urinary bladder before automated analysis.

Different Prognosis of Bone Metastasis in Breast Cancer Patients Molecular Subtypes: Luminal-A Luminal-B

The aim of study It was unclear whether breast cancer subtypes are associated of bone metastasis probability. In molecular subtypes among post-treated patients (hormone-receptor-positive breast cancer), considering statistical frequency of stages, and their prognostic significance. Methods and Materials: 101 women (I, II, III stages; hormone-receptor-positive), who underwent bone scintigraphy before and after treatment, were retrospectively studied. The study was performed with radiotracer Tc99m MDP, intravenous injection. BS data were correlated with molecular subtype (Luminal-A, Luminal-B) and stage. Results: According to the stages, molecular subtypes and bone metastasis was revealed: In the I stage - 32 (20,0%) patients: luminal A - 30 (93.7%) patients, among them with metastasis 12 (40%) cases; luminal B - 2 (6.2%) patients with metastasis 0 (0%) cases (p=0.282). II stage - 83 (51.9%) patients: luminal A = 71 (85.5%) patients, among them with metastasis - 43 (60.5%) cases; luminal B - 12 (14.4%) patients; among them with metastasis -3 (25%) cases (p=0.022) III stage =45 (28.1%) patients: Luminal A 38 (84.4%) patients, among them with metastasis - 30 (78.9%) cases; luminal B - 7 (15.5%) patients; among them with metastasis - 1 (14.2%) case (p=0.001) Conclusion: Breast cancer subtypes are associated with different metastatic patterns and confer different prognostic impacts. Among breast cancer patients molecular subtype luminal A has a high probability of spreading metastasis in bone, but there is more positive prognosis, rather than in luminal B type, that is much more rare and aggressive molecular subtype. Taking into consideration molecular subtypes and stages of breast cancer is very important, as both of them are significant prognostic factors of disease, which might be helpful in the most cases.

KÜÇÜK HÜCRELİ DIŞI AKCİĞER TÜMÖRLERİNİN DEĞERLENDİRİLMESİNDE Tc-99m MIBI SPECT’İN YERİ

Objective: In this study, it was aimed to investigate the role of Tc-99m MIBI scintigraphy in the diagnosis and evaluation of non-small cell lung cancers and also to evaluate the use of MIBI scintigraphy and MDP bone scintigraphy together in the detection of metastases. Methods: For this purpose, 30 patients with non-small cell lung cancer and 15 patients with benign lesions other than lung cancer (as a control group) were included in the study. By applying Tc-99m MIBI and Tc99m MDP scintigraphy to whole patients with benign and malign lung lesions, anterior-posterior planar and SPECT MIBI images were obtained. Bone scintigraphy was performed as whole-body images. Scintigraphic findings were compared with the histopathological diagnosis of patients. Data were analyzed statistically. Results: According to the result of the findings, the sensitivity, specificity, positive, predictive value, negative predictive value, and accuracy rate of Tc-99m MIBI scintigraphy in the detection of non-small cell lung tumors were determined as 87%, 93.5%, 96%, 77.7%, and 88.8%, respectively. Scintigraphic findings were evaluated quantitatively and visually. While there was no statistically significant difference between the early uptake rates of non-small cell lung tumors and benign lesions in the quantitative evaluation using planar MIBI images, late Tc-99m MIBI uptake rates were significantly higher in lesions with non-small cell lung tumors than that of benign lesions. However, it was detected that both the early and late uptake ratios were significantly higher in malign lesions than in benign lesions in the quantitative evaluation of SPECT images. It was observed that MIBI washout in benign lesions was higher than in malignant lesions in visual washout analysis. Additionally, multiple bone metastases were observed in 14 patients on the visual evaluation of bone scan of the patients with non-small cell lung cancer. Tc-99m MDP uptake was not observed in the malignant lung lesion region or in the soft tissue except the lesion. Conclusion: In light of the findings, it was concluded that Tc-99m MIBI scintigraphy is a noninvasive method with high sensitivity and specificity that can be used to differentiate non-small cell lung tumors from benign lesions.

Skeletal involvement in Erdheim-Chester disease: Multimodality imaging features and association with the BRAFV600E mutation

ObjectiveThe aim of this study was to characterize the distribution of skeletal involvement in Erdheim-Chester disease (ECD) by using radiography, computed tomography (CT), 18F-FDG positron emission tomography/computed tomography (PET/CT), and bone scans, as well as looking for associations with the BRAFV600E mutation. Material and methodsProspective study of 50 consecutive patients with biopsy-confirmed ECD who had radiographs, CT, 18F-FDG PET/CT, and Tc-99m MDP bone scans. At least two experienced radiologists with expertise in the relevant imaging studies analyzed the images. Summary statistics were expressed as the frequency with percentages for categorical data. Fisher's exact test, as well as odds ratios (OR) with 95 % confidence intervals (CI), were used to link imaging findings to BRAFV600E mutation. The probability for co-occurrence of bone involvement at different locations was calculated and graphed as a heat map. ResultsAll 50 cases revealed skeletal involvement at different regions of the skeleton. The BRAFV600E mutation, which was found in 24 patients, was correlated with femoral and tibial involvement on 18F-FDG PET/CT and bone scan. The appearance of changes on the femoral, tibial, fibular, and humeral involvement showed correlation with each other based on heat maps of skeletal involvement on CT. ConclusionThis study reports the distribution of skeletal involvement in a cohort of patients with ECD. CT is able to detect the majority of ECD skeletal involvement. Considering the complementary nature of information from different modalities, imaging of ECD skeletal involvement is optimized by using a multi-modality strategy.

A rare clinical presentation of lung cancer: two cases of solitary digital metastasis on Tc-99m MDP bone scan

BackgroundAcrometastases are accounted for a very small proportion of bone metastases. Lung cancer is the most common acrometastasis origin, and it often has a poor prognosis. The aim of the present cases is to describe the probability of an acrometastasis in the differential diagnosis of finger lesions and to emphasize the importance of taking local views of extremity of complaint for proper interpretation in such patients.Case presentationHere we reported two patients with metastases to the fingers with occult primary lung carcinoma and a history of prior lung malignancy, respectively. First case was a 58-year-old man with history of pain and swelling in the fourth finger of his left hand. He underwent an amputation from the metacarpophalangeal level and the pathological diagnosis was metastatic NSCLC. The second case was a 65-year-old ex-smoker man with a history of prior lung cancer (adenocarcinoma) suffered from a swollen, erythematous, painful tip of the right third finger. Phalangectomy was performed and the histological examination of the amputated part revealed the presence of a metastatic differentiated carcinoma of pulmonary origin.ConclusionsWhen assessing the masses located at fingers, possibility of a solitary metastatic lung lesion should be considered.

Tc-99m MDP Scan with Unusual and Isolated Skeletal Metastasis in Skull Bone in a Case of Testicular Seminoma.

Seminomas are common germ cell tumors (GCT) that may arise in the testes as well as in extra testicular locations such as mediastinum with/without testicular tumor. Testicular tumors are usually detected early due to their location and presentation as testicular mass. The overall prognosis of the seminomatous GCTs is good with surgery as the mainstay of treatment in localized disease. Bone metastases, especially when present in isolation are exceedingly rare in seminoma. Here, we present a rare case of skull bone metastasis in a case of testicular seminoma which was detected on technetium-99m labeled methylene diphosphonate bone scintigraphy with single-photon emission computed tomography with computed tomography.

Intense Splenic 99m Tc-MDP Uptake in Patient with Langerhans Cell Histiocytosis

Intense Splenic 99m Tc-MDP Uptake in Patient with Langerhans Cell Histiocytosis

Deep learning enhanced ultra-fast SPECT/CT bone scan in patients with suspected malignancy: quantitative assessment and clinical performance

Objectives. To evaluate the clinical performance of deep learning-enhanced ultrafast single photon emission computed tomography/computed tomography (SPECT/CT) bone scans in patients with suspected malignancy. Approach. In this prospective study, 102 patients with potential malignancy were enrolled and underwent a 20 min SPECT/CT and a 3 min SPECT scan. A deep learning model was applied to generate algorithm-enhanced images (3 min DL SPECT). The reference modality was the 20 min SPECT/CT scan. Two reviewers independently evaluated general image quality, Tc-99m MDP distribution, artifacts, and diagnostic confidence of 20 min SPECT/CT, 3 min SPECT/CT, and 3 min DL SPECT/CT images. The sensitivity, specificity, accuracy, and interobserver agreement were calculated. The lesion maximum standard uptake value (SUVmax) of the 3 min DL and 20 min SPECT/CT images was analyzed. The peak signal-to-noise ratio (PSNR) and structure similarity index measure (SSIM) were evaluated. Main results. The 3 min DL SPECT/CT images showed significantly superior general image quality, Tc-99m MDP distribution, artifacts, and diagnostic confidence than the 20 min SPECT/CT images (P < 0.0001). The diagnostic performance of the 20 min and 3 min DL SPECT/CT images was similar for reviewer 1 (paired X 2 = 0.333, P = 0.564) and reviewer 2 (paired X 2 = 0.05, P = 0.823). The diagnosis results for the 20 min (kappa = 0.822) and 3 min DL (kappa = 0.732) SPECT/CT images showed high interobserver agreement. The 3 min DL SPECT/CT images had significantly higher PSNR and SSIM than the 3 min SPECT/CT images (51.44 versus 38.44, P < 0.0001; 0.863 versus 0.752, P < 0.0001). The SUVmax of the 3 min DL and 20 min SPECT/CT images showed a strong linear relationship (r = 0.991; P < 0.0001). Significance. Ultrafast SPECT/CT with a 1/7 acquisition time can be enhanced by a deep learning method to achieve comparable image quality and diagnostic value to those of standard acquisition.

Vertical Appearance of Urinary Bladder on Bone Scintigraphy Might Not Always Suggest Adjacent Pathology.

Previous publications suggested that vertical appearance of the urinary bladder on 99m Tc-MDP whole-body bone scintigraphy was likely due to an adjacent abnormality. Here we report bone scan findings of a vertical appearance of the urinary bladder in a 66-year-old man with lung cancer without corresponding pathology nearby.

Safety and Efficacy of 68 Ga- or 177 Lu-Labeled DOTA-IBA as a Novel Theranostic Radiopharmaceutical for Bone Metastases : A Phase 0/I Study.

We designed and synthesized a novel theranostic bisphosphonate radiopharmaceutical ( 68 Ga- or 177 Lu-labeled DOTA-ibandronic acid [ 68 Ga/ 177 Lu-DOTA-IBA]) for bone metastasis. In this study, the dosimetry, safety, and efficacy of 68 Ga/ 177 Lu-DOTA-IBA as a theranostic radiopharmaceutical for bone metastases were evaluated in patients with malignancy based on 68 Ga- and 177 Lu-DOTA-IBA images, blood samples, and dosimetric analysis. Eighteen patients with bone metastasis and progression under conventional therapies were included in this study. Baseline 99m Tc-MDP SPECT and 68 Ga-DOTA-IBA PET/CT were performed for comparative purposes within 3 days. After receiving 891.5 ± 301.3 MBq 177 Lu-DOTA-IBA, serial 177 Lu-DOTA-IBA SPECT bone scan was performed over 14 days. Dosimetric evaluation was performed for main organs and tumor lesions. Safety was assessed by blood biomarkers. Karnofsky Performance Status, pain score, and follow-up 68 Ga-DOTA-IBA PET/CT were performed for response evaluation. Baseline 68 Ga-DOTA-IBA PET demonstrated a higher efficacy for detecting bone metastases compared with 99m Tc-MDP SPECT. The time-activity curves showed fast uptake and high retention of 177 Lu-DOTA-IBA in bone metastases (24 hours: 9.43 ± 2.75 %IA; 14 days: 5.45 ± 2.52 %IA). Liver, kidneys, and red marrow time-activity curves revealed a low uptake and fast clearance. The radiation-absorbed dose in bone metastasis lesions (6.40 ± 2.13 Gy/GBq) was significantly higher than that in red marrow (0.47 ± 0.19 Gy/GBq), kidneys (0.56 ± 0.19 Gy/GBq), or liver (0.28 ± 0.07 Gy/GBq), with all P 's < 0.001. Compared with baseline level, only one patient developed new grade 1 leukopenia (toxicity rate, 6%). The 177 Lu-DOTA-IBA therapy had no statistically significant effect on bone marrow hematopoietic function, liver function, and kidney function at any follow-up visit. Bone pain palliation was achieved in 82% (14/17) of patients. The 8-week follow-up 68 Ga-DOTA-IBA PET/CT demonstrated partial response in 3 patients, disease progression in 1 patient, and stable disease in 14 patients. 68 Ga/ 177 Lu-DOTA-IBA provides a set of potential theranostic radiopharmaceuticals and may have a good prospect for the management of bone metastasis.

Evaluation of the role of vertebral augmentation in chronic vertebral compression fractures: A retrospective study

ObjectivesVertebral augmentation is recommended for acute or subacute vertebral compression fractures (VCFs); few studies claim its usefulness in chronic VCFs also. Use of radionuclide imaging may improvise identification of chronic VCFs that may benefit from vertebral augmentation; hence we have evaluated efficacy of vertebral augmentation procedures in chronic VCFs with incomplete fracture healing suggested either by MRI or Tc99m- MDP bone scan. Materials and MethodsPatients with chronic osteoporotic VCFs (>12 weeks) during the period of June 2013 to June 2019 were included in this retrospective study; patients with evidence of incomplete fracture healing either by MRI or bone scan imaging with Tc 99m-MDP underwent vertebroplasty or kyphoplasty. Primary outcome measure was patient’s pain score measured by numerical rating scale (NRS); secondary outcome measures were patient’s disability assessed by Roland Morris Disability questionnaire (RDQ); quality of life assessed by Quality of life questionnaire of European Foundation of Osteoporosis (QUALLEFO) and analgesic usage. P ​< ​0.050 was considered as significant. Results34 patients were enrolled for the study with median fracture age of 36 months. The median NRS pain scores, RDQ scores, QUALEFFO scores and analgesic usage were significantly reduced at all-time points as compared to the baseline value over the follow up period of 1 year after vertebral augmentation procedure (P ​< ​0.050). Cement leakage was seen in 5 patients (15%). ConclusionVertebral augmentation procedures provided significant improvements in pain scores, disability and quality of life in patients of chronic osteoporotic VCFs with median fracture age of 36 months.

Analysis of Tc99m MDP Radiopharmaceuticals in the Spinal Areas of Breast Cancer Patients

The aim of this study was to obtain doses in the spine of breast cancer patients. This dose is very important in pharmacy to determine the distribution of drugs in the body's organs, especially the spine. The data of this study came from the results of bone scintigraphy examinations which had known the value of the injection dose and the percentage of absorption in the spine. This research was conducted by simulating the biological half-life values for 3 hours, 4 hours, 5 hours, 6 hours, and 7 hours to find the total half-life which will produce a total decay constant that will be used in calculating spinal dose. The results obtained were the lowest mean dose in the spinal 0.680 ± 0.160 mCi when the decay constant had the highest value (biological half-life 3 hours) and the largest mean dose in the spinal 1.011 ± 0.238 mCi when the decay constant had the lowest value (biological half-life 7 hours). In the spine, the thoracic region is the area with the highest dose because it is located closest to the breast organs (breast cancer) so it will experience the highest damage/metastasis. Then the Tc99m MDP radiopharmaceutical absorbed into the thoracic region will be higher. By simulating the biological half-life, it is hoped that we can find the exact biological half-life for the absorbed dose

Osteopoikilosis mimicking osteoblastic bone mets: A Case report

Background: Osteopoikilosis is a benign, uncommon disorder that is inherited by the autosomal dominant gene. Multiple benign enostoses are present in this specific kind of sclerosing skeletal dysplasia, which can be mistaken for osteoblastic skeletal metastases. Case Presentation: We present here a case of 50-year-old male patient with pain in lower back for 3 months. His pelvic X-ray showed few sclerotic rounded lesions in ilium, acetabulum and proximal femur. His MRI pelvis showed T1WI and T2WI hypo intense focal lesions in ilium and acetabulum. His 99mTc MDP bone scan was done showing no focal abnormal uptake in lesion reported on pelvic X-ray and MRI. These features are suggestive of Osteopoikilosis, ruling out osteoblastic skeletal metastasis. Conclusion: Osteopoikilosis is usually an incidental finding on radiograph. Both x-ray and MRI findings can mimic skeletal metastasis, but a normal bone scan can rule out metastasis and is useful if metastatic disease is thought to be a possibility.

99m-Tc MDP Bone Scan Image Enhancement using Pipeline Application of Dynamic Stochastic Resonance Algorithm and Block-Matching 3D Filter.

In this pilot study, we have proposed and evaluated pipelined application of the dynamic stochastic resonance (DSR) algorithm and block-matching 3D (BM3D) filter for the enhancement of nuclear medicine images. The enhanced images out of the pipeline were compared with the corresponding enhanced images obtained using individual applications of DSR and BM3D algorithm. Twenty 99m-Tc MDP bone scan images acquired on SymbiaT6 SPECT/CT gamma camera system fitted with low-energy high-resolution collimators were exported in DICOM format to a personal computer and converted into PNG format. These PNG images were processed using the proposed algorithm in MATLAB. Two nuclear medicine physicians visually compared each input and its corresponding three enhanced images to select the best-enhanced image. The image quality metrics (Brightness, Global Contrast Factor (GCF), Contrast per pixel (CPP), and Blur) were used to assess the image quality objectively. The Wilcoxon signed test was applied to find a statistically significant difference in Brightness, GCF, CPP, and Blur of enhanced and its input images at a level of significance. Images enhanced using the pipelined application of SR and BM3D were selected as the best images by both nuclear medicine physicians. Based on Brightness, Global Contrast Factor (GCF), CPP, and Blur, the image quality of our proposed pipeline was significantly better than enhanced images obtained using individual applications of DSR and BM3D algorithm. The proposed method was found to be very successful in enhancing details in the low count region of input images. The enhanced images were bright, smooth, and had better target-to-background ratio compared to input images. The pipelined application of DSR and BM3D algorithm produced enhancement in nuclear medicine images having following characteristics: bright, smooth, better target-to-background ratio, and improved visibility of details in the low count regions of the input image, as compared to individual enhancements by application of DSR or BM3D algorithm.

Role of multimodality imaging for primary bone tumors among children: a case report

ABSTRACT Background: Bone lesions in children are very common and can be benign or malignant. Benign bone lesions, fortunately, are more common as compared to rare malignant neoplasms of bone. Osteosarcoma and Ewing sarcoma are the most common malignant bone tumors in younger age group. Multimodality imaging plays a major role in bridging the gap between clinical diagnosis and final diagnosis Case Presentation: We present here a case of 8-year-old male patient complained of progressive soft tissue swelling and pain in left thigh from 25-30 days. His X-ray of left femur showed a mixed density, predominantly sclerotic lesion involving mid-diaphysis. His contrast enhanced MRI of left thigh showed large, ill-defined, abnormal signal intensity medullary lesion seen in left femur involving mid to lower diaphyseal shaft, extending to metaphyseal region. His 99mTc MDP bone scintigraphy was done showing abnormal radiotracer uptake in lower half of left femur and adjoining soft tissue. Conclusion: Single modality imaging may not be enough in predicting the true extent of bone pathologies. Multimodality imaging plays a major role in characterizing the lesions to differentiate benign from malignant and bridging the gap between clinical diagnosis and final diagnosis. Keywords: Osteosarcoma, Ewing sarcoma, 99mTc MDP bone scintigraphy, case report

Assessment of Radiation Exposure Dose for Nuclear Medicine Workers from 18F-FDG, 99mTc MDP, and 99mTc.

Nuclear medicine or diagnostic radiology personnel are always exposed to low-level radiation from radionuclides used in medical diagnostics, which lead to potential biological hazards or effects. External exposure for workers in two nuclear medicine centers was measured by recruiting 120 patients. Three nuclear medicine examinations were performed using F18-FDG PET/CT,99mTc- MDP bones scan, and 99mTc thyroid scan by a digital radiation dosimeter. The average received accumulative radiation dose for workers was found to be 0.838±0.17, 0.527±0.11, and 0.270±0.05 µSv for F18-FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. The annual effective dose for workers was estimated to be 2.09±0.42, 1.34±0.27, and 0.68±0.14 mSv, respectively. Moreover, the average patient-to-staff dose coefficients were found to be 0.024±0.005, 0.003±0.001, and 0.007±0.002 µSv m2/MBq h for F18- FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. It is clear from the results that the radiation doses received by workers during the nuclear medicine imaging examinations were less than the doses recommended by the International Commission on Radiological Protection (ICRP) for such examinations.