Ultima Vez Modificado: 29 de octubre del 2008
Dear OncoLink "Ask The Experts,"
If someone is receiving internal radiation therapy (brachytherapy) for cervical cancer treatment, is she emitting rays that would affect other people? Is it safe for the patient to be close to a baby?
Neha Vapiwala , MD, Senior Editor of OncoLink and Chief Resident in the Department of Radiation Oncology at the Hospital of the University of Pennsylvania, responds:
The answer to this question depends upon the type of brachytherapy for cervical cancer that a person is receiving. Brachytherapy can be done as an outpatient procedure, such as with high-dose rate (HDR) therapy, or as an inpatient, which is typically low-dose rate (LDR) therapy. Both HDR and LDR can be used in the management of gynecologic malignancies.
HDR therapy means that a high dose of radiation is given over a relatively brief period of time, as compared with LDR, (low dose rate), in which the radiation is usually delivered over a day or two.
HDR is given by inserting a probe, also called an applicator, into the vagina. This probe is connected to a machine that safely houses a radiation source. The machine automatically feeds the radiation source into the probe, where it remains for a predetermined time, known as the dwell time (typically 10-20 minutes). Once the time is up, the machine retracts the radiation source and the vaginal applicator is removed. As soon as the applicator is removed, the patient does not give off any radiation or emit any radioactivity. She is sent home and does not pose a risk to anyone around her. This procedure is typically repeated several times over a period of weeks.
When LDR brachytherapy is given, it is done so over several days, with the patient staying in the hospital for that period of time. An applicator is inserted into the vaginal or uterine cavity. The radiation source is inserted into the applicator and remains there for several days. During this time, the patient stays in a special lead-lined room. In the hospital room, large lead-lined portable shields are used to protect those who will enter the room to care for the patient (i.e. they will stand behind the shield whenever possible). In order to protect anyone who enters the room from radiation exposure, one should follow the principles of time and distance. In other words, stay for as short a time as possible when in closer proximity to the patient, and/or stay longer but remain as far away as possible from the patient. Visitors are encouraged to not visit in person, but call on the phone. Contact with infants and pregnant women is strongly discouraged.
When the treatment is complete, the radiation sources and applicator are removed, and the patient is discharged home. As with HDR, a patient is not sent home with radiation sources in her body, so she is not emitting any radiation at that point, and it is safe for people, including infants and pregnant women, to be around them.