TY - JOUR
T1 - Magnetic resonance-only simulation and dose calculation in external beam radiation therapy
T2 - a feasibility study for pelvic cancers
AU - Kemppainen, Reko
AU - Suilamo, Sami
AU - Tuokkola, Terhi
AU - Lindholm, Paula
AU - Deppe, Martin H.
AU - Keyriläinen, Jani
PY - 2017/5/4
Y1 - 2017/5/4
N2 - Background: The clinical feasibility of using pseudo-computed tomography (pCT) images derived from magnetic resonance (MR) images for external bean radiation therapy (EBRT) planning for prostate cancer patients has been well demonstrated. This paper investigates the feasibility of applying an MR-derived, pCT planning approach to additional types of cancer in the pelvis. Material and methods: Fifteen patients (five prostate cancer patients, five rectal cancer patients, and five gynecological cancer patients) receiving EBRT at Turku University Hospital (Turku, Finland) were included in the study. Images from an MRCAT (Magnetic Resonance for Calculating ATtenuation, Philips, Vantaa, Finland) pCT method were generated as a part of a clinical MR-simulation procedure. Dose calculation accuracy was assessed by comparing the pCT-based calculation with a CT-based calculation. In addition, the degree of geometric accuracy was studied. Results: The median relative difference of PTV mean dose between CT and pCT images was within 0.8% for all tumor types. When assessing the tumor site-specific accuracy, the median [range] relative dose differences to the PTV mean were 0.7 [−0.11;1.05]% for the prostate cases, 0.3 [−0.25;0.57]% for the rectal cases, and 0.09 [−0.69;0.25]% for the gynecological cancer cases. System-induced geometric distortion was measured to be less than 1 mm for all PTV volumes and the effect on the PTV median dose was less than 0.1%. Conclusions: According to the comparison, using pCT for clinical EBRT planning and dose calculation in the three investigated types of pelvic cancers is feasible. Further studies are required to demonstrate the applicability to a larger cohort of patients.
AB - Background: The clinical feasibility of using pseudo-computed tomography (pCT) images derived from magnetic resonance (MR) images for external bean radiation therapy (EBRT) planning for prostate cancer patients has been well demonstrated. This paper investigates the feasibility of applying an MR-derived, pCT planning approach to additional types of cancer in the pelvis. Material and methods: Fifteen patients (five prostate cancer patients, five rectal cancer patients, and five gynecological cancer patients) receiving EBRT at Turku University Hospital (Turku, Finland) were included in the study. Images from an MRCAT (Magnetic Resonance for Calculating ATtenuation, Philips, Vantaa, Finland) pCT method were generated as a part of a clinical MR-simulation procedure. Dose calculation accuracy was assessed by comparing the pCT-based calculation with a CT-based calculation. In addition, the degree of geometric accuracy was studied. Results: The median relative difference of PTV mean dose between CT and pCT images was within 0.8% for all tumor types. When assessing the tumor site-specific accuracy, the median [range] relative dose differences to the PTV mean were 0.7 [−0.11;1.05]% for the prostate cases, 0.3 [−0.25;0.57]% for the rectal cases, and 0.09 [−0.69;0.25]% for the gynecological cancer cases. System-induced geometric distortion was measured to be less than 1 mm for all PTV volumes and the effect on the PTV median dose was less than 0.1%. Conclusions: According to the comparison, using pCT for clinical EBRT planning and dose calculation in the three investigated types of pelvic cancers is feasible. Further studies are required to demonstrate the applicability to a larger cohort of patients.
UR - http://www.scopus.com/inward/record.url?scp=85014718031&partnerID=8YFLogxK
U2 - 10.1080/0284186X.2017.1293290
DO - 10.1080/0284186X.2017.1293290
M3 - Article
AN - SCOPUS:85014718031
SN - 0284-186X
VL - 56
SP - 792
EP - 798
JO - Acta Oncologica
JF - Acta Oncologica
IS - 6
ER -