Characterization of the scan length of 8 commonly performed adult computed tomography examinations : An overview in clinical practice of private and public French centres.

Congress:

EuroSafe 2023

Poster Number:

ESI-17061

Type:

EuroSafe Imaging

Keywords:

Radiation physics, Radioprotection / Radiation dose, Thorax, CT, Physics, Radiation safety, Dosimetric comparison

Authors:

I. Rousselle, L. A. GONZALEZ MENDEZ, L. palduplin, B. Royer, A. Noel, J. Farah

DOI:

DOI-Link:

https://dx.doi.org/

Purpose or learning objective

Justifying the CT scan length can sometimes be complicated, depending largely on the clinical indication for the examination as well as on the experience and awareness of the operating radiographers and the prescribing radiologist. Additionally, this information is not commonly reported in the literature while fewer papers have discussed how this parameter can be optimized [1-9]. In fact, the «Guide to Radiological Procedures» (GRP) [10], introduced by the French Society of Radiology in 2006, provides information for professionals on the correct way to perform a...

Methods or background

Guidance Length and Reference Length Dose Length Product (DLP, mGy.cm) (with Volume Computed Tomography Dose Index CTDIvol in mGy) is one of the dosimetric parameters reported at the console for each examination. In the GRP, DLP is considered as the product of the imaged scan length and the CTDIvol. In our precedent research works [11-14], overranging length (Lov) was defined and computed as the difference between total exposed scan length (Lexp = DLP/CTDIvol) and total imaged scan length (Lim = [(|first slice position — last...

Results or findings

In this study, the patient typical height is 1.68 m (1.70 m in the GPR). Table 1 shows a summary of scan length values from the literature which were used as comparative reference values. [Table 1] Table 2 and Fig 3 show that the interquartile explored lengths (25th-75th percentiles) for the head CT examination (16.5 cm) are within the min-max range proposed by the GRP. This result is consistent with the literature [7] (16.45 cm). The proposed value is 6.5 cm less than that reported...

Conclusion

The exploration limits proposed, for the Head and Abdomen-pelvis examinations, by the GRP are consistent with our results. By contrast, for the cervical and lumbar spine, results showed differences between our values and those from the GRP. This can be explained by the fact that medical indications were not specified in the DACS. The LR and GL values proposed in this study could be used similarly as Diagnostic Reference Levels and Diagnostic Guide Values in terms of CTDIvol and DLP. For a group of patients,...

References

[1] O. Yar, M. R. Onur, İ. S. İdilman, E. Akpınar, et D. Akata, « Excessive z-axis scan coverage in body CT: frequency and causes », Eur Radiol, vol. 31, no 6, p. 4358-4366, juin 2021, DOI : 10.1007/s00330-020-07510-4. [2] F. K. Eddy, S. O. Ngano, F. A. Jervé, et A. Serge, « Optimization of the scan length of head traumas on the pediatric and adult CT scan and proposition of a new acquisition limit », Sci Rep, vol. 11, no 1, p. 10958, déc....

Personal information and conflict of interest

I. Rousselle: Nothing to disclose L. A. GONZALEZ MENDEZ: Nothing to disclose l. palduplin: Nothing to disclose B. Royer: Nothing to disclose A. Noel: Nothing to disclose J. Farah: Nothing to disclose

Fig 1: Distribution of CT scanners per manufacturer in the studied sample.

Fig 2: Distribution of CT examinations in the studied sample.

Table 1: Summary of literature reported scan length values per clinical examination.

Table 2: Imaged scan length results in the head region.

Fig 3: Imaged scan lengths in the head region.

Table 3: Imaged scan length results in the trunck region.

Fig 4: Imaged scan lengths in the trunck region.

Table 4: Guide Length (GL) and Reference Length (RL) values per CT examination proposed...