Guidelines for paediatric bone scanning with 99mTc-labelled radiopharmaceuticals and 18F-fluoride

Whole-Body SPECT/CT: Protocol Variation and Technical Consideration-A Narrative Review

Introducing a hybrid imaging approach, such as single-photon emission computerized tomography with X-ray computed tomography (SPECT)/CT, improves diagnostic accuracy and patient management. The ongoing advancement of SPECT hardware and software has resulted in the clinical application of novel approaches. For example, whole-body SPECT/CT (WB-SPECT/CT) studies cover multiple consecutive bed positions, similar to positron emission tomography-computed tomography (PET/CT). WB-SPECT/CT proves to be a helpful tool for evaluating bone metastases (BM), reducing equivocal findings, and enhancing user confidence, displaying effective performance in contrast to planar bone scintigraphy (PBS). Consequently, it is increasingly utilized and might substitute PBS, which leads to new questions and issues concerning the acquisition protocol, patient imaging time, and workflow process. Therefore, this review highlights various aspects of WB-SPECT/CT acquisition protocols that need to be considered to help understand WB-SPECT/CT workflow processes and optimize imaging protocols.

A Case of Pediatric Leg-Length Difference After Tibial Fracture Predicted by Bone SPECT/CT

An 11-year-old boy underwent a bone single-photon emission computed tomography/computed tomography (SPECT/CT) scan 3 months after fracturing his right tibia. The standardized uptake values (SUVs) of the growth plates in his right tibia were higher compared to those in the left tibia. One year later, the right leg was 10 mm longer than the left leg with higher SUVs in the right tibial growth plates. After performing epiphysiodesis at the right proximal tibia, the leg-length difference (LLD) decreased from 17 to 12 mm with the decrease of SUVs in the growth plates of the right tibia. This case emphasizes the potential of quantitative analysis using bone SPECT/CT in predicting LLD and determining the necessity of length equalization surgery in pediatric lower limb fractures.

Using Computed Tomography skeletal surveys to evaluate for occult bony injury in suspected non-accidental injury cases - A preliminary experience

INTRODUCTION

This case series summarises our institution's preliminary experience of using computed tomography skeletal surveys (CT-SS) for the assessment of infants with suspected non-accidental injury (NAI) who were unable to undergo radiographic skeletal surveys (SS). This paper describes our experience using CT-SS in terms of radiation doses achieved, occult bony injury detection and forensic utility.

METHODS

Ten infants aged between two weeks and ten months underwent a CT-SS. The results of the CT-SS were compared with concurrent imaging results where available. Radiation doses from imaging procedures were calculated for each patient.

RESULTS

Six infants had abnormalities identified on CT-SS. Two patients had both an ante-mortem CT-SS and post-mortem imaging. All fractures identified on alternate imaging modalities were visible on at least one CT-SS reconstruction. The radiation dose associated with CT-SS imaging ranged from 0.73 to 1.46mSv.

CONCLUSION

The radiation dose received by the ten infants in this study was greater than the two skeletal survey approach but was less than the dose received during a bone scintigraphy examination, sometimes used to assess for occult bony injury in this setting. While CT-SS imaging results could not be compared with those obtained with current contemporaneous gold standard imaging techniques, CT-SS identified all fractures observed on the radiographic images where performed. CT-SS also identified additional rib fractures in two patients. Our preliminary findings indicate the need for future prospective studies to clarify the ability of CT-SS to detect metaphyseal fractures reliably.

A review of current imaging techniques used for the detection of occult bony fractures in young children suspected of sustaining non-accidental injury

Non-accidental injuries remain a leading cause of preventable morbidity and mortality in young children. The accurate identification of the full spectrum of injuries in children presenting with suspected abuse is essential to ensure the appropriate protective intervention is taken. The identification of occult bone fractures in this cohort is important as it raises the level of concern about the mechanism of injury and maintaining the child's safety. Radiographic imaging remains the modality of choice for skeletal assessment; however, current studies report concerns regarding the ability of radiographs to detect certain fractures in the acute stage. As such, alternative modalities for the detection of fractures have been proposed. This article reviews the current literature regarding fracture detectability and radiation dose burden of imaging modalities currently used for the assessment of occult bony injury in young children in whom non-accidental injury is suspected.

Contributions of nuclear medicine in paediatric non-tumour musculoskeletal pathology

Non-tumour musculoskeletal pathology in children represents a high percentage of the nuclear medicine studies requested by paediatricians. As these are immature bones and joints, in constant growth and remodelling, they present their own physiological and anatomical peculiarities that require a specific management for the paediatric age group. Using different clinical scenarios frequently observed in medical appointments (limping, back pain or fever, among others), we have summarised the possible findings or artefacts that can be obtained in the different Nuclear Medicine explorations, including bone scintigraphy and hybrid images such as PET/CT. To obtain high quality images requires careful attention to technique and positioning in children. Bone scintigraphy is a common paediatric nuclear medicine procedure and plays an important role in the diagnosis of musculoskeletal pathologies and can be complemented by techniques such as SPECT to improve localisation and diagnostic accuracy. In addition, ¹⁸F-FDG PET/CT is increasingly applied in the evaluation of children. This article reviews the usual indications of, mainly, bone scintigraphy and ¹⁸F-FDG PET/CT in paediatric non-tumour musculoskeletal diseases, how to interpret them properly, being essential to know the normal physiological distribution of each radiopharmaceutical, as well as the common variants of paediatric growth that can simulate disease, implying possible misinterpretations between normal and pathological structures.

[Evaluation of Post-reconstruction Filtering in Resolution Recovery Reconstruction for Bone SPECT Imaging]

PURPOSE

The aim of this study was to clarify the optimal post-reconstruction filtering type in the three- dimensional ordered subset expectation maximization (3D-OSEM) method for bone single photon emission computed tomography (SPECT) from image quality and quantitative values.

METHOD

We scanned a National Electrical Manufactures Association's body phantom for bone SPECT filled with radioactive solution of ^99mTc whose radioactivity concentration was accurately measured. The SPECT images were created using the 3D-OSEM method. Post-reconstruction filtering was performed using a Butterworth filter (BW), a Gaussian filter (GA), and a Hanning filter (HA) with various parameters. The image quality was evaluated by the normalized mean-squared error (NMSE) value and % of contrast-to-noise ratio (QNR₁₇). The image quality was evaluated by the error values between the measured radioactivity concentration and the true radioactivity concentration in the BG region and insert sphere.

RESULTS

The minimum NMSE values were 0.034 (BW), 0.036 (GA), and 0.035 (HA), and there was no difference depending on the filter type. The values of QNR₁₇ were 2.5 (BW), 2.6 (GA), and 2.6 (HA), and there was no difference depending on the filter type. The BG region was greatly affected by parameter changes in GA but less by those in BW and HA. The error values of the 37 mm insert sphere were 18.0% (BW), 28.2% (GA), and 26.2% (HA), and BW showed the lowest value.

CONCLUSION

Our results suggest that the post-reconstruction filtering type used in the 3D-OSEM method was BW from the image quality and quantitative values.

Prediction of painful temporomandibular joint osteoarthritis in juvenile patients using bone scintigraphy

The study aims to evaluate whether bone scintigraphy is effective in diagnosing temporomandibular joint (TMJ) osteoarthritis (OA) in juvenile patients. A retrospective study was conducted with 356 consecutive patients with TMJ-OA who were clinically assessed according to the Research Diagnostic Criteria for Temporomandibular Disorders. Patients were assigned to three groups based on their ages: Group 1: aged 12-16 years; Group 2: aged 17-19 years; and Group 3: aged 20 years. Additionally, we performed qualitative and quantitative analyses of bone scintigraphy images for the TMJ uptake ratio of the involved joint. The diagnostic rate of TMJ-OA (n = 356, 100%), and the overall presence of subjective pain (n = 282, 77.3%) was closest to the results of bone scintigraphy (n = 333, 91.2%). In addition, reported TMJ pain was significantly associated only with the results of bone scintigraphy and not with the results of panoramic radiography or cone beam computed tomography (CBCT) in all age groups. With CBCT as the reference standard, the optimal cutoff values of the uptake ratio for the diagnosis of TMJ-OA were 2.171 and 2.017 in Groups 1 and 2, respectively (P value < 0.05). Our results suggest that bone scintigraphy can be considered a useful modality for diagnosing TMJ-OA in juvenile patients.

Does quantification have a role to play in the future of bone SPECT?

Routinely, there is a visual basis to nuclear medicine reporting: a reporter subjectively places a patient's condition into one of multiple discrete classes based on what they see. The addition of a quantitative result, such as a standardised uptake value (SUV), would provide a numerical insight into the nature of uptake, delivering greater objectivity, and perhaps improved patient management.For bone scintigraphy in particular quantification could increase the accuracy of diagnosis by helping to differentiate normal from abnormal uptake. Access to quantitative data might also enhance our ability to characterise lesions, stratify and monitor patients' conditions, and perform reliable dosimetry for radionuclide therapies. But is there enough evidence to suggest that we, as a community, should be making more effort to implement quantitative bone SPECT in routine clinical practice?We carried out multiple queries through the PubMed search engine to facilitate a cross-sectional review of the current status of bone SPECT quantification. Highly cited papers were assessed in more focus to scrutinise their conclusions.An increasing number of authors are reporting findings in terms of metrics such as SUVmax. Although interest in the field in general remains high, the rate of clinical implementation of quantitative bone SPECT remains slow and there is a significant amount of validation required before we get carried away.

Guidelines on nuclear medicine imaging in neuroblastoma

Nuclear medicine has a central role in the diagnosis, staging, response assessment and long-term follow-up of neuroblastoma, the most common solid extracranial tumour in children. These EANM guidelines include updated information on ¹²³I-mIBG, the most common study in nuclear medicine for the evaluation of neuroblastoma, and on PET/CT imaging with ¹⁸F-FDG, ¹⁸F-DOPA and ⁶⁸Ga-DOTA peptides. These PET/CT studies are increasingly employed in clinical practice. Indications, advantages and limitations are presented along with recommendations on study protocols, interpretation of findings and reporting results.

Pediatric Nuclear Medicine and its Development as a Specialty

Pediatric Nuclear Medicine (PNM) offers to the pediatrician noninvasive procedures, with high clinical impact and low dosimetry. New techniques have been adapted to children, diminishing doses, always looking for less dosimetry, higher sensitivity and higher resolution images. PNM is and will remain a minority subspecialty, but highly complex for general NM physicians due to the different diagnostics in children and due to the higher technical complexity of the examinations. General NM physicians have to be trained and regularly receive CME in this field.

The EANM practice guidelines for bone scintigraphy

PURPOSE

The radionuclide bone scan is the cornerstone of skeletal nuclear medicine imaging. Bone scintigraphy is a highly sensitive diagnostic nuclear medicine imaging technique that uses a radiotracer to evaluate the distribution of active bone formation in the skeleton related to malignant and benign disease, as well as physiological processes.

METHODS

The European Association of Nuclear Medicine (EANM) has written and approved these guidelines to promote the use of nuclear medicine procedures of high quality.

CONCLUSION

The present guidelines offer assistance to nuclear medicine practitioners in optimizing the diagnostic procedure and interpreting bone scintigraphy. These guidelines describe the protocols that are currently accepted and used routinely, but do not include all existing procedures. They should therefore not be taken as exclusive of other nuclear medicine modalities that can be used to obtain comparable results. It is important to remember that the resources and facilities available for patient care may vary.

Preliminary Comparison of PET/CT Studies Performed After Intravenous and Oral Administration of 18F-Fluoride

A 78-year-old man with prostate cancer was referred for 18F-NaF PET/CT for assessing bone metastases. An 18F-NaF PET/CT study was performed after the intravenous administration of the radiopharmaceutical. Five days later, a second study was done after oral administration of the radiopharmaceutical as part of a research protocol.

Sodium 18F-fluoride PET/CT of bone, joint, and other disorders

The use of (18)F-sodium fluoride ((18)F-NaF) with PET/CT is increasing. This resurgence of an old tracer has been fueled by several factors including superior diagnostic performance over standard (99m)Tc-based bone scintigraphy, growth in the availability of PET/CT imaging systems, increase in the number of regional commercial distribution centers for PET radiotracers, the recent concerns about potential recurring shortages with (99m)Tc-based radiotracers, and the recent decision by the Centers for Medicare and Medicaid Services to reimburse for (18)F-NaF PET/CT for evaluation of patients with known or suspected bone metastases through the National Oncologic PET Registry. The major goal of this article is to review the current evidence on the diagnostic utility of (18)F-NaF in the imaging assessment of the bone and joint in a variety of clinical conditions.

PET/CT study performed after an oral administration of 18F-fluoride

A 52-year-old woman with right breast cancer was referred for 18F-fluoride whole-body PET/CT for the assessment of bone metastases. The peripheral i.v. access was not obtained after multiple attempts. The radiopharmaceutical was administered by oral route.

Evaluation of motion correction processing in equine bone scintigraphy by Scheffé's method of paired comparisons

Equine bone scintigraphy is usually performed with horses in standing position under sedation. However, swaying motion often leads to poor-quality images. To examine the usefulness of motion correction (MC) processing, equine bone scintigrams were evaluated using Scheffé's method of paired comparisons. A significant difference in evaluation scores was detected by analysis of variance (F test, P<0.01). According to all observers, Yardstick analysis scores were higher for images use of MC processing than for those no use of MC processing, for all parts. Overall scores of 5 observers were as follows: without MC 100% acquisition time (AT, lowest), use of MC with 25% AT, MC 50% AT, MC 75% AT and MC 100% AT (highest). Thus, MC processing shortens AT in equine bone scintigraphy, and it contributes to a reduction in the external radiation exposure of nurses/technicians.