Radiation Dose to Pediatric Patients From Radiopharmaceuticals

Enhanced Diagnostic Accuracy of Pulmonary Embolism: Integrating Low-Dose CT with V/Q SPECT

OBJECTIVE

This study aimed to retrospectively assess the benefits of combining low-dose computed tomography (LDCT) with ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) for the diagnosis of pulmonary embolism (PE).

METHODS

A retrospective analysis was performed on 92 patients with suspected PE who underwent V/Q SPECT with ldCT (V/Q SPECT CT) between January 2020 and December 2022 at King Khalid Hospital Najran. Data were collected using the hospital's picture archiving and communication system. Scans were categorized on the basis of perfusion defects, matched or mismatched ventilation, and CT findings. The specificity of V/Q SPECT CT was compared with that of Q SPECT CT.

RESULTS

This study included 92 patients (54 females and 38 males; median age, 53 years). The results demonstrated that V/Q SPECT CT had higher specificity (93%) than V/Q SPECT alone (88%). If CT had been used as a ventilation substitute, 21% of patients would have been reported to be positive for PE (8% false-positive), yielding a specificity of 60% for Q SPECT CT. These findings align with the existing literature, although discrepancies in specificity values were noted due to the different study designs and sample sizes.

CONCLUSION

This study highlights the enhanced specificity of V/Q SPECT CT compared to V/Q SPECT and Q SPECT CT alone. Including low-dose CT improves diagnostic accuracy by reducing false positives and providing detailed anatomical information. V/Q SPECT CT offers superior specificity in diagnosing PE compared with V/Q SPECT alone, supporting its use in clinical practice.

Nuclear medicine and pediatric nephro-urology: a long-lasting successful partnership

Congenital anomalies of the kidney and urinary tract, as well as urinary infections, are very frequent in children. After the clinical and laboratory evaluation, the first imaging procedure to be done is a renal and bladder ultrasound, but afterwards, a main contribution comes from nuclear medicine. Through minimally invasive and sedation-free procedures, nuclear medicine allows the evaluation of the functional anatomy of the urinary tract, and the quantification of renal function and drainage. If pediatric dosage cards provided by scientific societies are used, radiation exposure can also be low. In the pediatric conditions previously mentioned, nuclear medicine is used both for initial diagnosis and follow-up, mostly in cases of suspicion of ureteropelvic or ureterovesical junction syndromes, as well as vesicoureteral reflux or renal scars of febrile infectious episodes. Pediatric nephro-urology constitutes a significant workload of pediatric nuclear medicine departments. The following paragraphs are a revision of the renal radiopharmaceuticals, as well as the nuclear nephro-urology procedures - dynamic and static renal scintigraphy, and direct and indirect radionuclide cystography. A summary of the techniques, main indications, interpretation criteria and pitfalls will be provided. Some future directions for the field are also pointed out, among which the most relevant is the need for nuclear medicine professionals to use standardized protocols and integrate multidisciplinary teams with other pediatric and adult health professionals that manage these life-long pediatric pathologies, which are recognized as an important cause of adult chronic kidney disease.