Whether it is safe to sleep next to someone after radiation treatment is a common concern for patients and their families. The answer depends entirely on the specific type of radiation therapy received. Safety precautions range from none at all to temporary, well-defined restrictions designed to protect close contacts, especially children and pregnant individuals. Understanding the difference between external and internal treatments is the first step in assessing any potential risk.
External Beam Radiation Therapy and Residual Risk
External Beam Radiation Therapy (EBRT) is the most common form of treatment, directing high-energy rays at the tumor from outside the body. This process does not place radioactive material inside the patient. The radiation affects cells only while the machine is turned on during the daily session. The moment the machine is switched off, the radiation stops, and the patient is no longer radioactive. Consequently, patients undergoing EBRT pose no radiation risk to others. It is completely safe to hug, kiss, or sleep next to someone immediately after treatment, and no special precautions are necessary.
Internal Radiation Therapy and Temporary Precautions
Internal radiation therapy, including brachytherapy and systemic radiation, places a radioactive source either directly inside the body or circulates it throughout the body. These treatments temporarily make the patient a source of radiation, requiring precautions to protect others. Brachytherapy involves placing sealed radioactive sources, such as seeds or capsules, directly into or near the tumor. In temporary brachytherapy, the source is removed quickly, eliminating the radiation risk. Permanent brachytherapy, often used for prostate cancer, leaves tiny seeds in place that emit low levels of radiation which decay over weeks or months. Systemic radiation therapy uses unsealed radioactive substances, like radioiodine, which travel throughout the body. Since the substance is unsealed, it can leave the body through saliva, sweat, blood, and urine, making these bodily fluids temporarily radioactive.
Practical Safety Measures During Close Proximity
For patients receiving internal radiation, safety measures minimize exposure based on the principles of time, distance, and shielding. Medical teams recommend restricted contact, which is most important for pregnant women and small children who are more sensitive to radiation. Common recommendations include maintaining a distance of at least six feet from others, especially for prolonged periods, and avoiding shared sleeping arrangements.
For systemic therapy where bodily fluids are radioactive, specific hygiene guidelines must be followed:
- Flush the toilet twice after each use and wash hands thoroughly.
- Use separate towels and utensils.
- Wash laundry separately from the rest of the household.
In cases of permanent seed implants, patients may be asked to use a condom during sexual activity for a period, as a seed could rarely be dislodged.
Duration of Restrictions and Clearance Protocols
The length of time a patient must follow safety precautions is determined by the specific radioactive material used and its rate of decay. For systemic therapy, the duration is governed by the radioactive half-life—the time it takes for half of the radioactive atoms to decay. For example, radioactive iodine used for thyroid cancer has a physical half-life of about eight days. Clearance is achieved either by a fixed time protocol or by direct measurement. The oncology or nuclear medicine team uses a specialized device to confirm that radiation levels have dropped below a safe threshold before lifting all restrictions. Patients with permanent brachytherapy seeds may have restrictions for up to two months, depending on the isotope. These restrictions are typically limited to avoiding prolonged, very close contact with children. Patients must follow the exact, personalized instructions provided by their care team.