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Treatment planning based on water density image generated using dual‐energy computed tomography for pancreatic cancer with contrast‐enhancing agent: Phantom and clinical study
Author(s) -
Ohira Shingo,
Yagi Masashi,
Iramina Hiraku,
Karino Tsukasa,
Washio Hayate,
Ueda Yoshihiro,
Miyazaki Masayoshi,
Koizumi Masahiko,
Teshima Teruki
Publication year - 2018
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.13180
Subject(s) - imaging phantom , computed tomography , pancreatic cancer , medical imaging , image guided radiation therapy , contrast (vision) , hounsfield scale , radiology , radiation treatment planning , cancer , nuclear medicine , medicine , medical physics , radiation therapy , computer science , artificial intelligence
Purpose A contrast‐enhancing agent is imperative for the accurate target delineation of pancreatic tumors. This study demonstrates the potential use of treatment planning for patients with pancreatic tumors based on the water density image ( WDI ) generated by dual‐energy computed tomography ( DECT ). Methods Tissue characterization and multi‐energy phantom scanning were performed through DECT and the physical characteristics of the WDI and a virtual monochromatic image ( VMI ) were assessed. The measured and the corresponding theoretical electron density relative to water ( RED ) and mass density ( MD ) were compared. Treatment plans based on the WDI ( TP WDI ) and VMI ( TP VMI ) were compared for 22 pancreatic cancer patients who underwent contrast‐enhanced DECT scan. Results The total absolute difference in the HU value between the conventional 120 kV p images and the VMI was the smallest at the energy level of 77 keV (3.3 HU ), and the VMI at 77 keV was used for subsequent analysis. The difference between the measured and theoretical values of RED and MD for iodine using the VMI (>15%) was larger than that using WDI (<4%). In clinical cases, the maximum difference in the dosimetric parameters between TP WDI and TP WDI for the planning target volume was 3.0% when the doses were calculated using AXB , and for the duodenum, it was 1.7%. Conclusions The WDI estimated the RED and MD accurately and could form the basis for a new treatment planning approach for pancreatic cancer using contrast‐enhancing agent.