Radiation dose to the fetus during CyberKnife radiosurgery for a brain tumor in pregnancy.
OBJECTIVE
Pregnancy during radiosurgery is extremely rare in clinical practice. We report fetal dose results during CyberKnife radiosurgery for a brain tumor in pregnancy.


METHODS
A 26 year old pregnant woman with a rapidly growing deep-seated grade-III glioma was treated during the third trimester of gestation using CyberKnife. Ultrasound imaging was used to determine the position of the embryo prior to treatment. A dose of 1400 cGy was prescribed aiming to control tumor growth until delivery of the child. Prior to radiosurgery, the treatment was simulated on an anthropomorphic phantom. Radiation dose to the embryo was measured using a Farmer chamber and EBT3 films.


RESULTS
Fetal doses of 4.4 cGy and 4.1 cGy were measured for the embryo's head and legs, lying at 56 cm and 72 cm from the isocenter, respectively, using the Farmer chamber situated at 8.5 cm depth beneath the phantom surface. Dose results of 4.4 cGy, 3.5 cGy and 2.0 cGy were measured with the films situated at depths of 6.5 cm, 9.5 cm and 14.5 cm, respectively. An average dose of 4.2 cGy to the fetus was derived from the above values. A corresponding dose of 3.2 cGy was also calculated based on results obtained using EBT3 films situated upon the patient skin.


CONCLUSIONS
The measured fetal doses are below the threshold of 10 cGy for congenital malformations, mental and growth retardation effects. The radiogenic cancer risk to the live-born embryo was estimated less than 0.3% over the normal incidence. The treatment was administered successfully, allowing the patient to deliver a healthy child.
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece; Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 11527 Athens, Greece. Electronic address: vpantelis@phys.uoa.gr.
Evaggelos
E
Pantelis
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece; First Department of Radiology, Aretaieion Hospital, Medical School, University of Athens, Athens, Greece.
Christos
C
Antypas
Mater Dei Hospital, C.B.H. Città di Bari Hospital s.p.a., Via Hahnemann 10, 70126 Bari, Italy.
Maria Cristina
MC
Frassanito
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece.
Liana
L
Sideri
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece.
Katerina
K
Salvara
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece.
Leonidas
L
Lekas
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece.
Olga
O
Athanasiou
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece.
Maria
M
Piperis
CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece.
Nikolaos
N
Salvaras
CyberKnife Center, Via Saint Bon 20, 20147, Milano, Italy.
Pantaleo
P
Romanelli
D000328:Adult; D000886:Anthropometry; D001932:Brain Neoplasms / Q000601:surgery*; D002138:Calibration; D005260:Female; D005333:Fetus / Q000528:radiation effects*; D005910:Glioma / Q000601:surgery*; D006801:Humans; D018811:Maternal Exposure; D019047:Phantoms, Imaging; D011247:Pregnancy; D011252:Pregnancy Complications, Neoplastic / Q000601:surgery*; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D015203:Reproducibility of Results; D016896:Treatment Outcome
CyberKnife; Fetal dose; Glioma; Pregnancy