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For prostate cancer patients who experience biochemical progression during androgen deprivation therapy (ADT), prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) has not been prospectively compared to planar bone scan plus CT. This was a single-arm, head-to-head, prospective phase II trial (NCT04928820) designed to enroll 102 men with prostate cancer who experienced biochemical progression (rising prostate-specific antigen [PSA] ≥ 1 ng/mL) during ADT. All patients received 68Ga-PSMA-11 PET/CT and 99mTc-MDP planar bone scans. Each scan was interpreted by three central independent readers. The primary endpoint was the per-patient bone metastasis detection rate of PSMA PET/CT versus planar bone scan and CT. Secondary endpoints compared the number of bone metastases detected per patient and the inter-reader agreement of each imaging modality. Twenty-two men were enrolled between July 2021 and June 2022. Due to slow accrual following approval of PSMA PET radiotracers in the U.S. and a lack of a statistical signal between the two imaging modalities on interim analysis, this trial was closed early on October 2022. Median PSA was 8.5 ng/mL (interquartile range: 1.6-77.6). There was 100% agreement between the two scans. Six patients (27%) had negative findings and 16 patients (73%) had positive findings on both scans. PSMA PET/CT and bone scan plus CT detected an equal number of bone lesions for 14 patients (64%), PSMA PET/CT detected more bone lesions for six patients (27%), and bone scan plus CT detected more bone lesions for two patients (9.1%) (p = 0.092). The inter-reader agreement rates of PSMA PET/CT and bone scan plus CT were 96% and 82%, respectively (p = 0.25). In men with biochemical progression during ADT, 68Ga-PSMA-11 PET/CT and 99mTc-MDP planar bone scan plus CT had identical bone metastasis detection rates. Bone scan plus CT can continue to serve as a cost-effective and readily accessible restaging modality in patients with biochemical progression. ClinicalTrials.gov NCT04928820. Registered 16/06/2021.

Background: Triphasic bone scintigraphy (TPBS) is often used to diagnose complex regional pain syndrome (CRPS). The primary aim of this study is to determine if the diagnosis of CRPS in patients with a positive TPBS (TPBS +ve) is accurate. A secondary aim is to determine if there was delay in treatment of patients who underwent TPBS compared to those who did not have a TPBS. Methods: Of 225 consecutive patients presenting to the first author's practice with a diagnosis of CRPS, 65 had TPBS performed before referral with 62 having TPBS +ve. The remaining 160 were clinically diagnosed and a TPBS was not done (TPBS-ND). Patients were classified into five categories – wrong diagnosis, dystonic-psychogenic hand, causalgia, flare reaction and irritative carpal tunnel syndrome (ICTS). Patients with flare reaction and ICTS were considered as having true CRPS and the rest were considered as misdiagnosis. The patients' demographics, duration of symptoms, pre- and postoperative pain, functional score and patient satisfaction were compared. Results: Of the 62 TPBS +ve, there were 38 (61%) misdiagnosis. The proportion of misdiagnoses was fewer in the TPBS-ND group (45%; p = 0.036). Thirty-two of the 62 TPBS group (52%) and 92/160 (56%) of the TPBS-ND group had surgical treatment. At a mean follow-up of 19 months, pain dropped 6.5 ± 2.5 points in the TPBS +ve group. Disabilities of the arm, shoulder and hand (DASH) score fell by 56 ± 27. The mean single assessment numeric evaluation (SANE) score was 8.6 ± 2.3. These results did not differ substantially from those of the TPBS-ND group. Conclusions: A significant number of patients in this study who had TPBS +ve were misdiagnosed in this study. Outcomes after treatment of CRPS were consistently good despite the results of the TPBS. Patients with TPBS +ve had a significant delay to diagnosis. We conclude that TPBS is not useful in the management of CRPS. Level of Evidence: Level III (Therapeutic) [ABSTRACT FROM AUTHOR]

Abstract For prostate cancer patients who experience biochemical progression during androgen deprivation therapy (ADT), prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) has not been prospectively compared to planar bone scan plus CT. This was a single-arm, head-to-head, prospective phase II trial (NCT04928820) designed to enroll 102 men with prostate cancer who experienced biochemical progression (rising prostate-specific antigen [PSA] ≥ 1 ng/mL) during ADT. All patients received 68Ga-PSMA-11 PET/CT and 99mTc-MDP planar bone scans. Each scan was interpreted by three central independent readers. The primary endpoint was the per-patient bone metastasis detection rate of PSMA PET/CT versus planar bone scan and CT. Secondary endpoints compared the number of bone metastases detected per patient and the inter-reader agreement of each imaging modality. Twenty-two men were enrolled between July 2021 and June 2022. Due to slow accrual following approval of PSMA PET radiotracers in the U.S. and a lack of a statistical signal between the two imaging modalities on interim analysis, this trial was closed early on October 2022. Median PSA was 8.5 ng/mL (interquartile range: 1.6–77.6). There was 100% agreement between the two scans. Six patients (27%) had negative findings and 16 patients (73%) had positive findings on both scans. PSMA PET/CT and bone scan plus CT detected an equal number of bone lesions for 14 patients (64%), PSMA PET/CT detected more bone lesions for six patients (27%), and bone scan plus CT detected more bone lesions for two patients (9.1%) (p = 0.092). The inter-reader agreement rates of PSMA PET/CT and bone scan plus CT were 96% and 82%, respectively (p = 0.25). In men with biochemical progression during ADT, 68Ga-PSMA-11 PET/CT and 99mTc-MDP planar bone scan plus CT had identical bone metastasis detection rates. Bone scan plus CT can continue to serve as a cost-effective and readily accessible restaging modality in patients with biochemical progression. ClinicalTrials.gov NCT04928820. Registered 16/06/2021.

Background/Objectives: Artificial intelligence (AI) is a promising tool for the enhancement of physician workflow and serves to further improve the efficiency of their diagnostic evaluations. This study aimed to assess the performance of an AI-based bone scan noise-reduction filter on noisy, low-count images in a routine clinical environment. Methods: The performance of the AI bone-scan filter (BS-AI filter) in question was retrospectively evaluated on 47 different patients' 99mTc-MDP bone scintigraphy image pairs (anterior- and posterior-view images), which were obtained in such a manner as to represent the diverse characteristics of the general patient population. The BS-AI filter was tested on artificially degraded noisy images—75, 50, and 25% of total counts—which were generated by binominal sampling. The AI-filtered and unfiltered images were concurrently appraised for image quality and contrast by three nuclear medicine physicians. It was also determined whether there was any difference between the lesions seen on the unfiltered and filtered images. For quantitative analysis, an automatic lesion detector (BS-AI annotator) was utilized as a segmentation algorithm. The total number of lesions and their locations as detected by the BS-AI annotator in the BS-AI-filtered low-count images was compared to the total-count filtered images. The total number of pixels labeled as lesions in the filtered low-count images in relation to the number of pixels in the total-count filtered images was also compared to ensure the filtering process did not change lesion sizes significantly. The comparison of pixel numbers was performed using the reduced-count filtered images that contained only those lesions that were detected in the total-count images. Results: Based on visual assessment, observers agreed that image contrast and quality were better in the BS-AI-filtered images, increasing their diagnostic confidence. Similarities in lesion numbers and sites detected by the BS-AI annotator compared to filtered total-count images were 89%, 83%, and 75% for images degraded to counts of 75%, 50%, and 25%, respectively. No significant difference was found in the number of annotated pixels between filtered images with different counts (p > 0.05). Conclusions: Our findings indicate that the BS-AI noise-reduction filter enhances image quality and contrast without loss of vital information. The implementation of this filter in routine diagnostic procedures reliably improves diagnostic confidence in low-count images and elicits a reduction in the administered dose or acquisition time by a minimum of 50% relative to the original dose or acquisition time. [ABSTRACT FROM AUTHOR]

Objective: To find out the usefulness of bone scan in all stages of breast cancer. Study Design: Prospective Observation Study. Setting: Surgical Unit I & III Ghulam Muhammad Mahar Medical College Hospital, Sukkur. Period: October 2020 till September 2022. Methods: A total of 300 patients were selected who were newly diagnosed with breast cancer (Biopsy Proven). Data was collected for all these patients which included age, risk factors for breast cancer, findings on local examination, histopathology findings, stage of the cancer and result of the bone scan. Results: In our study, 78% patients were in 4th and 5th decade of life with mean age of 53.46±7.66 years. 'Age above 40' was the commonest risk factor for breast cancer followed by positive family history for breast cancer. Tumor size ranged from 2 to 13.2 cm with mean size of 6.06±1.92 cm. In our study, most common type of carcinoma was invasive ductal carcinoma (71.3%) followed by invasive lobar carcinoma (50%). Only 32 (10.67%) out of 300 patients had positive bone scan. Majority of the bone scan positive cases belonged to the Stage IIIB, IIIC and IV. Conclusion: It is concluded in our study that routine use of bone scan in cases of stage 1 and 2 breast cancer is not recommended; only stage 3A or advances cases should undergo bone scan. [ABSTRACT FROM AUTHOR]

We observed at our university-based imaging centers that when prostate-specific membrane antigen (PSMA) PET/CT became available for staging and restaging prostate cancer, the volume of bone scanning on patients with prostate cancer (BS-P) markedly decreased. We aimed to study use patterns of PSMA PET/CT and BS-P at our imaging centers during the 4-y period around U.S. Food and Drug Administration approval of PSMA PET/CT in December 2020. We tested the hypothesis that the rate of decline of BS-P accelerated after U.S. Food and Drug Administration approval, as physicians planned for use of PSMA PET/CT in their patients. Methods: Our clinical report system was searched for BS-P and PSMA PET/CT scans from January 2019 through June 2023. Numbers of scans were tabulated by quarter and year. Quantitative and statistical analyses were performed. Results: Annualized average monthly BS-P peaked at 53.7 scans/mo in 2021 and then decreased over time. There were 552 BS-Ps performed in 2019, 503 in 2020, 614 in 2021, 481 in 2022, and 152 in the first half of 2023. BS-P monthly averages declined by 22% from 2021 to 2022 and by 36% from 2022 to 2023, whereas monthly PSMA PET/CT scan averages increased by 1,416% from 2021 to 2022 and by 69% from 2022 to 2023. There was a significantly greater decline in BS-Ps from 2022 to 2023 than from 2021 to 2022 (36% vs. 22%, P < 0.0001). There were 30 PSMA PET/CT scans performed in 2021, 455 in 2022, and 384 in the first half of 2023. The greatest quarterly increase in these scans (400%) occurred at the outset of PSMA PET/CT implementation in quarter 4 of 2021. In quarter 2 of 2023, the percentage of total studies was higher for PSMA PET/CT than for BS-P (74% vs. 26%, P < 0.0001). Conclusion: At our university-based imaging centers, use of BS-P has declined in correlation with the timing of U.S. Food and Drug Administration approval and implementation of PSMA PET/CT. This study illustrates one instance of workflow changes that occur in the nuclear medicine clinic when new agents are introduced and affect clinical management options. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study. Objective: Magnetic Resonance Imaging (MRI) is often regarded as the gold standard for spinal pathology, as it provides good structural visualisation. SPECT-CT, however, provides combined structural and functional information. There is a paucity of literature comparing SPECT-CT with MRI in the spine. Our aim was to determine whether SPECT-CT provides additional information to MRI in individuals with complex spinal pathology, including deformity, which altered management. Methods: We conducted a retrospective review of all individuals seen at our tertiary spinal unit that were investigated with both MRI and SPECT-CT of the spine between 2007-2020. We reviewed imaging reports, and collated diagnoses, surgical treatment and the relative contributions of MRI and SPECT-CT to management decisions. Results: 104 individuals identified, with a mean age of 30 years (89 females and 15 males). Diagnostic categories were adolescent, adult, and congenital deformity, degenerative pathology, and miscellaneous pathology. MRI returned positive findings in 58 (55.8%), and SPECT-CT in 41 (39.4%) cases. SPECT-CT identified 10 cases of facet joint degeneration, 5 of increased uptake around metalwork suggestive of loosening, 1 pseudoarthrosis, 1 partial failure of fusion and 1 osteoid osteoma which were not reported on MRI, all in individuals who had previously undergone spinal instrumentation. Despite this, SPECT-CT only altered management for 6 individuals (5.8%). Conclusion: MRI is less useful in the setting of previous instrumentation due to metal artefact. Where MRI is inconclusive, particularly in individuals with previous spinal instrumentation, SPECT-CT may provide a diagnosis, but is not recommended as primary imaging. [ABSTRACT FROM AUTHOR]

Giant cell tumor of bone (GCTB) represents an intermediate, locally aggressive tumor, with a peak of incidence in the third decade of life with female predominance (2:1). The distal radius is the third most common localization and especially challenging in the treatment is saving the wrist joint function. In this report, we present a case of a 32-year-old patient diagnosed with a giant cell tumor of the distal radius, primarily treated with curettage of the bone. Due to aggressive tumor recurrence, considering local control of the tumor, we decided to perform a resection of the distal radius and reconstruction with an autologous proximal vascular fibular graft. We performed a SPECT/CT scan to confirm the functionality of the graft. We find this procedure a safe technique for local control of tumor recurrence and an ideal substitute for a limb salvage procedure. [ABSTRACT FROM AUTHOR]

Objective: To investigate the survival benefit of preoperative bone scan in asymptomatic patients with early-stage non-small cell lung cancer (NSCLC). Methods: This retrospective study included patients with radical resection for stage T1N0M0 NSCLC between March 2013 and December 2018. During postoperative follow-up, we monitored patient survival and the development of bone metastasis. We compared overall survival, bone metastasis-free survival, and recurrence-free survival in patients with or without preoperative bone scan. Propensity score matching and inverse probability of treatment weighting were used to minimize election bias. Results: A total of 868 patients (58.19 ± 9.69 years; 415 men) were included in the study. Of 87.7% (761 of 868) underwent preoperative bone scan. In the multivariable analyses, bone scan did not improve overall survival (hazard ratio [HR] 1.49; 95% confidence intervals [CI] 0.91–2.42; p = 0.113), bone metastasis-free survival (HR 1.18; 95% CI 0.73–1.90; p = 0.551), and recurrence-free survival (HR 0.89; 95% CI 0.58–1.39; p = 0.618). Similar results were obtained after propensity score matching (overall survival [HR 1.28; 95% CI 0.74–2.23; p = 0.379], bone metastasis-free survival [HR 1.00; 95% CI 0.58–1.72; p = 0.997], and recurrence-free survival [HR 0.76; 95% CI 0.46–1.24; p = 0.270]) and inverse probability of treatment weighting. Conclusion: There were no significant differences in overall survival, bone metastasis-free survival, and recurrence-free survival between asymptomatic patients with clinical stage IA NSCLC with or without preoperative bone scan. [ABSTRACT FROM AUTHOR]

Otosclerosis is a poorly understood clinical entity causing progressive conductive hearing loss. Here we present the first known evidence of otosclerosis demonstrating 99mTc‐MDP uptake on bone scan. This presents an opportunity to explore the role of nuclear medicine imaging in early detection, staging, and even informing treatment and prognosis of this condition. Laryngoscope, 134:4763–4765, 2024 [ABSTRACT FROM AUTHOR]

Background: Surgical and postoperative challenges impose the need for noninvasive techniques to enhance bone healing process and reduce complications during implant therapy in diabetic patients. Photobiomodulation therapy (PBMT) has shown a substantial effect in the management of postoperative pain, neurosensory recovery, and healing at surgical sites. Objectives: The present study aimed to assess the effect of PBMT on peri-implant osteoblastic activity, soft-tissue wound healing, and Post operative pain discmofort among type 2 diabetic patients. Material and Methods: Five type 2 diabetic patients with bilaterally edentulous mandibular posterior teeth necessitating 10 implants with two-segment variant type were included in the study. The study site (SS) with implants was treated with PBMT (gallium–aluminum–arsenide diode laser 810 nm), and the control site (CS) with implant (opposite side) was left untreated. The Wound Healing Index (WHI), Visual Analog Scale, and bone scintigraphy were used to assess postoperative discomfort and peri-implant osteoblastic activity, respectively. Results: The average WHI scores and Visual Analog Scale at the SS were not significantly higher than the CS score. Although lack of significant increase in osteoblastic activity was observed under bone scan, the difference in experimental values highlights a possible association of PBMT and osseointegration potential among the study group. Clinical Implications: The application of Photobiomodulation Therapy (PBMT) as an adjunct around dental implants will improve osteoblastic activity and bone healing to reduce the probability of early-onset failures in patients diagnosed with type 2 diabetes mellitus. However, to assess the impact of the PBMT on peri-implant bone with different bone densities, further well-controlled long-term trials on larger study groups are needed. Conclusion: Within the limitations of the study, irradiation using PBMT at the peri-implant tissue site has shown favorable osteoblastic activity, WHI score, and Visual Analog Score postoperatively, but the results were statistically not significant. However, further long‑term trials on diabetic individuals on a larger scale are needed for validating these study results. [ABSTRACT FROM AUTHOR]

A 65-year-old male complaining of low back pain was noted to have diffuse, homogenous bilateral lung uptake on Tc-99m methylene diphosphate (Tc99m-MDP) bone scintigraphy. The patient had no prior history of pulmonary disease with no apparent respiratory symptoms at time of imaging, but did endorse a long history of lupus nephritis and end-stage renal disease on hemodialysis. Review of prior chest CT and chest X-ray imaging over the last 5 years revealed diffuse ground-glass opacities and extensive parenchymal calcifications, consistent with metastatic pulmonary calcification. These radiological findings were further corroborated by laboratory studies, which demonstrated longstanding secondary hyperparathyroidism with a most recent work-up including an iPTH level of 1251 pg/mL. The differential diagnosis of bilateral, diffuse Tc99m-MDP uptake on bone scintigraphy includes tracer contamination, pulmonary etiologies such as pleural effusion or mesothelioma, metabolic diseases such as metastatic pulmonary calcification, and genetic diseases including pulmonary alveolar microlithiasis. In the setting of longstanding renal dysfunction and chronic hypercalcemia as in this patient, such radiological findings are a classic presentation of metastatic pulmonary calcification.

Purpose: This mini-review delves into the realm of Langerhans cell histiocytosis (LCH) in children, focusing on its skeletal involvement. By synthesizing pertinent literature, we sought to provide a comprehensive understanding of LCH's clinical and radiographic spectrum. Our study then demonstrates the diagnostic prowess of whole-body 99mTc-methyl diphosphonate (MDP) scintigraphy in LCH cases, underscoring its value in tandem with existing knowledge. Methods: Our approach involved an extensive literature review that contextualized LCH within the current medical landscape. Subsequently, we presented a case series featuring five pediatric instances of skeletal LCH, one accompanied by soft tissue infiltration. The principal aim was to illuminate the diagnostic and staging potential of whole-body 99mTc-MDP scintigraphy, augmenting existing insights. Results: Through meticulous literature synthesis, we highlighted pediatric LCH's protean clinical manifestations and radiological variability. Aligning with this spectrum, our case series underscored the role of 99mTc-MDP scintigraphy in diagnosing and staging LCH. Among the five pediatric cases, one demonstrated concurrent soft tissue involvement. This aligns with the multifaceted nature of LCH presentations. Conclusion: Pediatric LCH can present with a wide range of clinical and radiologic features. By amalgamating our cases with extant literature, we stress the necessity of a multimodal strategy. 99mTc-MDP scintigraphy emerged as an indispensable tool for accurate staging and soft tissue detection. Our findings collectively advocate for a holistic approach to managing LCH, ensuring informed therapeutic decisions for optimal patient outcomes. [ABSTRACT FROM AUTHOR]

Bone scan is a investigation which uses radionuclide phosphonate compound for whole skeletal survey. In this current study we have done the analysis of the role of bone scan in skeletal osteosarcoma at tertiary oncology care centre. This is a retrospective study conducted in a tertiary oncology centre from January 2022 to February 2023. A total of 92 patients with skeletal OGS were included in our study undergone 99 mTCcMDP whole body bone scan. 99 mTc MDP was prepared freshly every morning and dose for each patient were calculated as per EANM guidelines. Images were acquired 2–3 h of post injection. All images were acquired at GE infinia dual head machine with peak setting at 140Kev and LEAP collimator. Suspicious lesions on planer bone scan were correlated with SPECT fused with CT. All the bone scans were reviewed retrospectively by two independent nuclear medicine physicians. In this study group, 86 patients with biopsy proven skeletal OGS underwent 99 mTCcMDP bone scan of which 63 were males and 23 were females (2.7:1) with age of study group ranging from 7years to 48years. Patients referred for bone scan were retrospectively categorized in two groups, first group patients (52) were referred for initial staging of disease and second group of patients (34) were referred for follow-up or re-staging of the disease. Total 09 patients showed distant skeletal metastases on bone scan, out of which 05 were in initial staging group and 04 in follow up group. Osteosarcoma has propensity to metastasize to many sites in the body however most common site being lung followed by skeletal, nodal and rarely soft tissue metastasis. Bone scan enjoys a optimal sensitivity in case of osteosarcoma to detect skeletal metastasis but have low specificity. However being a cost effective and faster investigation makes it a wise investigation of choice in case of osteosarcoma for skeletal metastasis evaluation. [ABSTRACT FROM AUTHOR]

BackgroundTo prospectively demonstrate the feasibility of performing dual-phase SPECT/CT for the assessment of the small joints of the hands of rheumatoid arthritis (RA) patients, and to evaluate the reliability of the quantitative and qualitative measures derived from the resulting images.MethodsA SPECT/CT imaging protocol was developed in this pilot study to scan both hands simultaneously in participants with RA, in two phases of 99mTc-MDP radiotracer uptake, namely the soft-tissue blood pool phase (within 15 minutes after radiotracer injection) and osseous phase (after 3 hours). Joints were evaluated qualitatively (normal vs. abnormal uptake) and quantitatively [by measuring a newly developed metric, maximum corrected count ratio (MCCR)]. Qualitative and quantitative evaluations were repeated to assess reliability.ResultsFour participants completed seven studies (all four were imaged at baseline, and three of them at follow-up after 1-month of arthritis therapy). A total of 280 joints (20 per hand) were evaluated. The MCCR from soft-tissue phase scans was significantly higher for clinically abnormal joints compared to clinically normal ones; P

Abstract Bone regeneration is crucial for repairing bone tissue following various injuries. Research techniques that enable the study of metabolic changes in bone tissue under different conditions are important for understanding bone repair and remodeling. This study used bone scintigraphy to evaluate osteogenesis secondary to osteotomy in a preclinical model of New Zealand rabbits. For this purpose, we conducted a longitudinal, prospective, case-control study in which scintigraphic variables were measured in both the right forearm (case-operated) and the left forearm (control - non-operated). The study sample consisted of 10 rabbits subjected to osteotomy, followed by a 12-week postoperative evaluation period, divided into six imaging stages at 1, 2, 3, 4, 8, and 12 weeks. We observed that the operated forearm showed significantly higher external radiation than the control side, using the pinhole collimator, denoting an increase in the biodistribution and tropism of the radiopharmaceutical to the operated forearm. Among the three evaluated time points, osteoblastic activity was highest in the second week and presented a significant decline in the 8th and 12th weeks, denoting regeneration and resolution of the surgical injury; the control forearm was also influenced by the inactivity imposed by the operated forearm. This fact was notably evidenced by the reduction in the metabolic activity of osteoblasts in the left forearm. Our study suggested that bone scintigraphy was sensitive enough to semi-quantitatively differentiate the metabolic activity of osteoblasts in the operated forearm in the three temporal landmarks evaluated in the study.

Accurate detection and reliable assessment of therapeutic responses in bone metastases are imperative for guiding treatment decisions, preserving quality of life, and ultimately enhancing overall survival. Nuclear imaging has historically played a pivotal role in this realm, offering a diverse range of radiotracers and imaging modalities. While the conventional bone scan using 99mTc marked bisphosphonates has remained widely utilized, its diagnostic performance is hindered by certain limitations. Positron emission tomography, particularly when coupled with computed tomography, provides improved spatial resolution and diagnostic performance with various pathology-specific radiotracers. This review aims to evaluate the performance of different nuclear imaging modalities in clinical practice for detecting and monitoring the therapeutic responses in bone metastases of diverse origins, addressing their limitations and implications for image interpretation.

Myxofibrosarcoma is a type of soft tissue sarcoma, predominantly characterized by a high propensity for local recurrence, albeit demonstrating a relatively diminished risk for distant metastasis. Its prevalence is notably higher in elderly patients. Here, we present a case of a 73-year-old woman diagnosed with Myxofibrosarcoma. She was subjected to a whole-body bone scan using 99mTc-methylene diphosphonate (MDP) to survey potential bony metastasis. It revealed marked MDP accumulation with peripheral soft tissue uptake in the right lateral chest region of this patient. This imaging phenotype could potentially be attributed to the augmented vascularity within the tumor, a finding that was prominently displayed in this particular case. [ABSTRACT FROM AUTHOR]

Although parathyroid bone disease is rarely seen nowadays, skeletal manifestation can be the first sign of hyperparathyroidism (HPT) in some clinical practice. Nevertheless, the diagnosis of HPT is often overlooked. We describe three cases of multiple brown tumors (BT) in which bone pain and destruction were the first symptoms that masqueraded as a malignancy. However, according to the results of bone scan and targeted single-photon emission computed tomography/computed tomography (SPECT/CT), we considered BTs as the diagnosis in all of three cases. The final diagnoses were confirmed by laboratory tests and post-parathyroidectomy pathology. Parathyroid hormone (PTH) is significantly elevated in primary hyperparathyroidism (PHPT) as we know. However, such elevation is virtually never seen in malignancies. Diffuse or multiple foci of tracer uptakes in the bone scan were always seen in bone metastasis, multiple myeloma, and other bone neoplasm. When patients visited nuclear medicine for first consultation without biochemical results, radiological evidence from planar bone scan and targeted SPECT/CT can help in distinguishing the skeletal diseases. Lytic bone lesions with sclerosis, intra-focal or ectopic ossification and calcification, fluid–fluid level, and distribution of the lesions may be helpful in the differential diagnosis in these reported cases. In conclusion, when patients present with multiple foci of uptake on bone scan, targeted SPECT/CT is acquired for suspicious lesions, which can increase the diagnostic sensitivity and reduce unnecessary interventions and treatment. Moreover, BTs should be always kept in differential diagnosis of multiple lesions without a conclusive primary tumor. [ABSTRACT FROM AUTHOR]

Objective: We aimed to develop deep learning classifiers for assessing therapeutic response on bone scans of patients with prostate cancer. Methods: A set of 3791 consecutive bone scans coupled with their last previous scan (1528 patients) was evaluated. Bone scans were labeled as "progression" or "nonprogression" on the basis of clinical reports and image review. A 2D-convolutional neural network architecture was trained with three different preprocessing methods: 1) no preprocessing (Raw), 2) spatial normalization (SN), and 3) spatial and count normalization (SCN). Data were allocated into training, validation, and test sets in the ratio of 72:8:20, with the 20% independent test set rotating all scans over a five-fold testing procedure. A Grad-CAM algorithm was employed to generate class activation maps to visualize the lesions contributing to the decision. Diagnostic performance was compared using area under the receiver operating characteristics curves (AUCs). Results: The data consisted of 791 scans labeled as "progression" and 3000 scans labeled as "nonprogression." The AUCs of the classifiers were 0.632–0.710 on the Raw dataset, were significantly higher with the use of SN at 0.784–0.854 (p < 0.001 for Raw versus SN), and higher still with SCN at 0.954–0.979 (p < 0.001 for SN versus SCN). Class activation maps of the SCN model visualized lesions contributing to the model's decision of progression. Conclusion: With preprocessing of spatial and count normalization, our deep learning model achieved excellent performance in classifying the therapeutic response of bone scans in patients with prostate cancer. [ABSTRACT FROM AUTHOR]

Background: The location and proximity to the spinal cord in spinal osteoid osteoma can increase the likelihood of an incomplete resection. Intraoperative bone scintigraphy (IOBS) can be used to verify location and complete surgical resection. Objective: To review our experience using IOBS for resection of intraspinal osteoid osteoma. Methods: IRB approved, retrospective review of IOBS-guided resection over 10 years. Patients underwent injection of 200 uCi/kg (1–20 mCi) 99mTc-MDP 3–4 h prior surgery. Portable single-headed gamma camera equipped with a pinhole collimator (3- or 4-mm aperture) was used. Images were obtained pre-operatively, at the start of the procedure, and intraoperatively. Operative notes were reviewed. Evaluation of recurrence and clinical follow-up was performed. Results: Twenty IOBS-guided resections were performed in 18 patients (median age 13.5 years, 6–22 years, 12 males). Size ranged 5–16 mm, with 38.9% (7/18) cervical, 22.2% (4/18) thoracic, 22.2% (4/18) lumbar, and 16.7% (3/18) sacral. In all cases, IOBS was able to localize the lesion. After suspected total excision, IOBS altered the surgical plan in 75% of cases (15/20), showing residual activity prompting further resection. Median length of follow-up was 6 months (range 1–156 months) with 90% (18/20) showing complete resection without recurrence. Two patients had osteoid osteoma recurrence at 7 and 10 months following the original resection, requiring re-intervention. Conclusions: IOBS is a useful tool for real-time localization and assessment of spinal osteoid osteoma resection. In all cases, IOBS was able to localize the lesion and changed surgical planning in 75% of cases. Ninety percent of patients achieved complete resection and remain recurrence free. [ABSTRACT FROM AUTHOR]

In this presented case, a 77-year-old woman with an implanted prosthesis and ongoing knee pain underwent a bone scan using 99mTc-hydroxydiphosphonate (HDP) in suspicion for bone infection. An incidental finding from this scan revealed diffuse cardiac uptake, necessitating further diagnostic procedures to exclude the possibility of cardiac amyloidosis. In the subsequent 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scan and SPECT images, no perceptible cardiac uptake was observed at all. Upon retrospective review of the patient's medical records, she received 1000 mg of ferric carboxymaltose for iron-deficient anemia the day before the 99mTc-HDP bone scan. Therefore, it was assumed that the diffuse and temporary cardiac activity was due to the transient iron overload. We present and share these bone scan images in order to avoid possible future misinterpretation of cardiac amyloidosis. [ABSTRACT FROM AUTHOR]

A 13-year-old male patient presented with right leg pain and walking difficulty. Contrast-enhanced magnetic resonance imaging showed a softtissue lesion between muscle groups in the anterior half of the right thigh. The excisional biopsy result ended in an inflammatory myofibroblastic tumor (IMT). The 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan showed hypermetabolism in the multifocal soft tissue lesion and also confirmed that no other distant foci were present. A three-phase Tc-99m-methylene diphosphonate study of the region showed heterogeneously increased vascularity within the region. We described an unusual case of IMT in a pediatric patient and the importance of PET/CT scanning to delineate the lesion. [ABSTRACT FROM AUTHOR]

Summary: Background: Nuclear scintigraphy is commonly used as a diagnostic tool in equine medicine, particularly in the orthopaedic field. However, the scintigraphy protocol varies in the literature. Objectives: To gather data on scanning protocols and radiation safety measures commonly employed in equine practice. Study design: Prospective, descriptive, and questionnaire‐based study. Methods: An electronic survey was distributed by Medical Imaging Electronic to clinics using an equine scanner scintigraphy unit (n = 150). The survey was designed to document staff experience therewith, operating procedures, and radiation safety practices. Results: The response rate was 30% (45/150). Scintigraphy was used as a diagnostic tool in 6.8%–22.2% of the horses that presented for lameness examination. The most commonly used bone tracer was hydroxyethylene diphosphonate (51.1%; 23/45). The vascular and pool phases were rarely (<10% of horses) performed. The whole‐body scintigraphy was performed in 61–90% of the horses in 53.3% (24/45) of the participating clinics. The acquisition time of 90 s per image was commonly used (46.7%, 21/45). Fifty‐five percent of the operators underestimated or did not know the personnel's radiation exposure during the acquisition of bone scintigraphy and 34% of the personnel did not wear radiation protective clothes. Non‐musculoskeletal scintigraphy was never or rarely used in 88.9% of the clinics. Main limitations: The relatively low response rate may indicate that the reported findings are not fully representative of all equine practices. Conclusions: This survey provides preliminary data, which may be used to establish a guideline for equine nuclear scintigraphy in the future. [ABSTRACT FROM AUTHOR]

This study measured 99mTc-MDP bone scintigraphy radiation risks, as low-dose radiation exposure is a growing concern. Dosimeter measurements were taken at four positions (left lateral, right lateral, anterior, and posterior) around the patients at 30, 60, 100, and 200 cm at 0, 1.5, and 3 h. The highest dose rates were recorded from 51% of the patients, who emitted ≥ 25 µSv/h up to 49.00 µSv/h at the posterior location at a distance of 30 cm. Additionally, at the anterior location at a distance of 30 cm, 42% of patients emitted ≥ 25 µSv/h up to 38.00 µSv/h. Furthermore, at 1.5 h after the tracer injection, 7% of the dose rates exceeded 25 µSv/h. There was a significant reduction in mean dose rates for all positions as distance and time increased (p-value < 0.05). As a result, radiation levels decreased with increased distance and time as a result of radiation decay, biological clearance, and distance from the source. In addition, increasing the distance from the patient for all positions reduced the radiation dose, as was substantiated via exponential regression analysis. Additionally, after completing the bone scintigraphy, the patients' dose rates on discharge were within the current guidelines, and the mean radiation doses from 99mTc-MDP were below occupational limits. Thus, medical staff received less radiation than the recommended 25 μSv/h. On discharge and release to public areas, the patients' mean dose rates were as follows: 1.13 µSv/h for the left lateral position, 1.04 µSv/h for the right lateral, 1.39 µSv/h for the anterior, and 1.46 µSv/h for the posterior. This confirms that if an individual was continuously present in an unrestricted area, the dose from external sources would not exceed 20 µSv/h. Furthermore, the patients' radiation doses were below the public exposure limit on discharge. [ABSTRACT FROM AUTHOR]

A bone scan (BS) plays a pivotal role in many oncological and non-oncological conditions. The planar BS is characterized by high sensitivity but low specificity. With respect to planar imaging, the implementation of single-photon emission computed tomography (SPECT) has allowed increased image contrast and more accurate tracer localization. Recent technological innovations in the field of BS are treated, with a particular focus on multi-field-of-view devices allowing to cover the entire scan length with a 3D acquisition (WB-SPECT/CT). In addition, the applications of cadmium zinc telluride/CzT detectors capable of converting gamma photons directly into electrical impulses (i.e. 'digital SPECT') are discussed. Initial clinical experiences indicate that WB-SPECT/CT is characterized by higher sensitivity, diagnostic accuracy, and increased confidence in image interpretation with respect to the 'old-fashioned' BS (planar images with or without a single field-of-view SPECT). Furthermore, CzT-based detectors, thanks to their superior sensitivity, might be helpful to implement fast acquisition protocols. Further studies are needed to better define the clinical impact of bone CzT WB-SPECT/CT on patients' management and outcome, as well as its cost–benefit ratio. [ABSTRACT FROM AUTHOR]

Abstract Background Metastases to the bones are a frequent location of metastasis in advanced breast cancer and are responsible for substantial morbidity and healthcare expenses. Imaging has been crucial in directing patient therapy for decades, contributing to the staging and response evaluation of the skeleton. This research aimed to assess the diagnostic value of whole-body magnetic resonance imaging with diffusion-weighted imaging added to radionuclide bone scans for early diagnosis of bone metastases in breast cancer patients. Results The study was a prospective observational cohort study performed on 20 patients with breast cancer and suspected bone metastases. The patients were evaluated first by obtaining a detailed personal history. Laboratory tests, including CBC, liver, and kidney function tests were assessed. All patients were examined by diffusion-weighted whole-body MRI (DWIBS; diffusion-weighted imaging with background body signal suppression) images and bone scintigraphy after intravenous injection of 20 mci of technetium-99m (99mTc) methylene diphosphonate using a dual head gamma camera. The total number of lesions detected by bone scan was 74, and 75 lesions were seen by DWIBS. Twenty-four lesions were missed by bone scan and detected by DWIBS. Fourteen lesions were detected by bone scan and found free by DWIBS examination in the spine and pelvic bones. Conclusions Whole body DWIBS seems to be a promising method of imaging in detecting bone metastases from breast cancer that could be used complementary to the traditional bone scan for more accurate diagnosis and staging of the tumor, helping to determine the most appropriate protocol of management.

Background: Bone scans are often used to identify bone metastases, but their low specificity may necessitate further studies. Deep learning models may improve diagnostic accuracy but require both medical and programming expertise. Therefore, we investigated the feasibility of constructing a deep learning model employing ChatGPT for the diagnosis of bone metastasis in bone scans and to evaluate its diagnostic performance. Method: We examined 4626 consecutive cancer patients (age, 65.1 ± 11.3 years; 2334 female) who had bone scans for metastasis assessment. A nuclear medicine physician developed a deep learning model using ChatGPT 3.5 (OpenAI). We employed ResNet50 as the backbone network and compared the diagnostic performance of four strategies (original training set, original training set with 1:10 class weight, 10-fold data augmentation for positive images only, and 10-fold data augmentation for all images) to address the class imbalance. We used a class activation map algorithm for visualization. Results: Among the four strategies, the deep learning model with 10-fold data augmentation for positive cases only, using a batch size of 16 and an epoch size of 150, achieved the area under curve of 0.8156, the sensitivity of 56.0 %, and specificity of 88.7 %. The class activation map indicated that the model focused on disseminated bone metastases within the spine but might confuse them with benign spinal lesions or intense urinary activity. Conclusions: Our study illustrates that a clinical physician with rudimentary programming skills can develop a deep learning model for medical image analysis, such as diagnosing bone metastasis in bone scans using ChatGPT. Model visualization may offer guidance in enhancing deep learning model development, including preprocessing, and potentially support clinical decision-making processes.

Bone is the most common site of metastasis in prostate cancer (PCa) patients and is correlated with poor prognosis and increasing economic burden. Few studies have analyzed the prognostic prediction for metastatic PCa patients with the assistance of neural networks. Four convolutional neural network (CNN) models are developed and evaluated to predict the overall survival (OS) of PCa patients with bone metastasis. All the CNN models are first trained with 64 samples and evaluated with 10 samples; two models use only bone scan images and two models use both bone scan images and clinical parameters (CPs). The predictions of the best models are compared with those by two urology surgeons on 20 test samples. Our best models can predict OS of PCa patients with bone metastasis with AUC=0.8022 by using only bone scan images and AUC=0.8132 by using both bone scan images and CPs on 20 test samples. The best Youden indexes of the two models are 0.6263 and 0.7142, respectively, which are 0.3077 and 0.3131 higher than that of the urologists' average Youden index, which indicate that CNN models exhibit significant advantages. CNN models are suitable to predict OS in PCa patients with bone metastasis using bone scan images and CPs. Our models show better performance in terms of accuracy and stability than urology surgeons. [ABSTRACT FROM AUTHOR]

Background: The myocardial uptake of bone-seeking tracers suspicious for transthyretin cardiac amyloidosis (ATTR-CA) can be incidentally detected in patients undergoing bone scintigraphy for noncardiac reasons. We conducted a systematic review and meta-analysis to assess the prevalence of these scintigraphic findings. Methods: A comprehensive literature search was performed using two bibliographic databases (PubMed/MEDLINE and Cochrane Library), searching for articles related to the review question. Eligible articles were selected, and relevant data were extracted by two authors. The pooled prevalence of incidental findings suspicious for ATTR-CA among patients undergoing bone scintigraphy was calculated on a per-patient-based analysis using a random-effects model. The pooled measure was provided with 95% confidence interval (95% CI) values. Results: Among 219 records, 11 articles were selected for the systematic review and 10 for the meta-analysis. The pooled prevalence of incidental findings suspicious for ATTR-CA was 1.1% (95% CI: 0.7–1.4%) with heterogeneity due to the characteristics of the included studies, patients, and index tests. These findings are more prevalent in older men. Conclusions: The prevalence of incidental findings of ATTR-CA among patients undergoing bone scintigraphy is low but not negligible. Nuclear medicine physicians should suggest, in the scintigraphic report, further clinical investigations when these findings are detected. Prospective studies are warranted. [ABSTRACT FROM AUTHOR]

Aim: This study investigates the effect of microbiological characteristics of causative organisms on the scintigraphic patterns of labelledwhite blood cell (WBC) scans in cases of proven osteomyelitis. Methods: Retrospective analysis of 25 patients referred with suspected osteomyelitis and had both bone and labelled WBC scans performed and complete records of the microbiological culture of the causative organism. The bone and labelled WBC scans were retrieved and reviewed by two nuclear medicine physicians. Any definite focal accumulation of labelled WBCs within the bone was considered positive for osteomyelitis. Diagnosis of osteomyelitis in the discharge summary was considered the reference standard and was based on a combination of the clinical scenario, imaging, and laboratory findings including microbiology. A correlation of the pattern of labelled WBC and the type of microorganisms was done. Results: A total of 16 patients were included in this study, seven females and nine males. Of these, seven patients had Gram-positive whereas nine patients had Gram-negative organisms. The majority (85.7%) of Gram-positive organisms showed increased accumulation of labelled WBCs, whereas only one-third (33.3%) of patients with Gram-negative organisms had such findings. Conclusion: The pattern observed in this study shows that the falsenegative results of labelledWBC scans were mainly noted in patients with Gram-negative as opposed to Gram-positive infections. This confirms the experimental animal study findings that the secretion of anti-chemotactic factors by Gram-negative organisms, seems to be inhibiting the migration of labelled WBCs to the site of infection. The inhabitation is decreasing the accumulation of labelled WBCs and consequently resulting in a falsenegative finding. The study adds to evidence that microbiological characteristics of the causative organisms are another explanation for the falsenegative WBC in proven osteomyelitis. [ABSTRACT FROM AUTHOR]