Appraisal of radiation dose with 64-slice computed tomography perfusion in lung cancer patients with special reference to SSDE: An initial experience in a tertiary care hospital.

Abstract

Context:Computed tomography perfusion (CTP) is an important functional tool for lung cancer. It is expected to deliver high radiation dose, making its accurate estimation important. Size-specific dose estimate (SSDE) is a new dose metric, which includes the scanner output as well as the patient size.Aims:To determine radiation dose [CT dose index (CTDIvol), dose length product (DLP), effective dose (ED), and SSDE] for CTP in lung cancer and the correlation of CTDIvol, DLP, and SSDE with effective diameter and SSDE with weight, body mass index (BMI), and the scan length.Settings and Design:Cross-sectional study in the Department of Radio-diagnosis from October 2015 to March 2016.Patients and Methods:Due ethical approval and informed consent was taken. Thirty consecutive adult patients of lung cancer undergoing CTP study were included; various radiation dose parameters were determined and presented as mean ± SD.Statistical Analysis Used:Paired Student's t-test and Pearson correlation using Statistical Package for the Social Sciences, Version 16.Results:Mean radiation dose was CTDIvol = 270.138 ± 1.627 mGy, DLP = 681 ± 53.496 mGy.cm, ED = 12.501 ± 0.923 mSv, SSDE = 388.90 ± 81.27 mGy. The CTDIvol and DLP had significant positive correlation (r = 0.556, P = 0.000 and r = 0.522, P = 0.003, respectively) with effective diameter. SSDE had strong negative correlation (r = −0.997, P = 0.000) with effective diameter, significant negative correlation with the BMI (r = −0.889; P = 0.000) and weight (r = −0.910, P = 0.000) of patients. Scan length was not significantly correlated in SSDE (r = −0.012, P = 0.951).Conclusions:Smaller sized patients had greater SSDE.