Evaggelos Pantelis1, Christos Antypas2, Maria Cristina Frassanito3, Liana Sideri4, Katerina Salvara4, Leonidas Lekas4, Olga Athanasiou4, Maria Piperis4, Nikolaos Salvaras4, Pantaleo Romanelli5. 1. 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. 2. 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. 3. Mater Dei Hospital, C.B.H. Città di Bari Hospital s.p.a., Via Hahnemann 10, 70126 Bari, Italy. 4. CyberKnife and TomoTherapy Department, Iatropolis Clinic, 54-56 Ethnikis-Antistaseos, 15231, Athens, Greece. 5. CyberKnife Center, Via Saint Bon 20, 20147, Milano, Italy.
Abstract
PURPOSE: Pregnancy during radiosurgery is extremely rare in clinical practice. We report fetal dose results during CyberKnife radiosurgery for a brain tumor in pregnancy. METHODS AND MATERIALS: 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.
PURPOSE: Pregnancy during radiosurgery is extremely rare in clinical practice. We report fetal dose results during CyberKnife radiosurgery for a brain tumor in pregnancy. METHODS AND MATERIALS: 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.