Ultra-low dose protocol on photon-counting computed tomography as an alternative to radiographic shunt series in the diagnosis of mechanical ventriculoperitoneal shunt complications – an ex vivo phantom study for children and adults
摘要
The standard modality for the diagnosis of ventriculoperitoneal (VP) shunt failure is the radiographic shunt series (RSS). However, ultra-low dose computed tomography (ULD-CT) may replace RSS. The aim of this study was to compare the radiation doses of RSS and ULD-CT in the diagnosis of mechanical shunt failure in human phantoms including pediatric phantoms and to further reduce the total CT dose by reducing the topogram radiation.
MethodsMechanical VP shunt complications were placed on human phantoms representing ages of 1, 5, 10 and 30 years. RSS and ULD-CT were performed on each phantom with different radiation doses of the topogram with varying tube currents (10, 20, 30, 40 and 50 mAs). Effective doses of RSS and ULD-CT were estimated by using conversion factors.
ResultsULD-CT demonstrated lower effective doses than RSS in phantoms representing ages 5, 10 and 30 years, while successfully depicting all mechanical shunt complications. However, higher effective doses were assessed for ULD-CT scans of the 1-year phantom than RSS. The effective doses for RSS and ULD-CT (utilizing 10 mAs topograms), respectively, were estimated as follows: 1-year: 0.056 vs. 0.133 mSv; 5-year: 0.186 vs. 0.123 mSv; 10-year: 0.240 vs. 0.107 mSv; 30-year: 0.641 vs. 0.076 mSv.
ConclusionThis study demonstrated ULD-CT as an alternative to RSS for the detection of mechanical VP shunt complications, reducing radiation doses in phantoms equivalent to 5 years of age and older while demonstrating the complications equally to RSS. This may be of clinical interest, especially in children due to the reduction of radiation risks.