Technology & treatment

Iodine-125 seed implantation

Principle & mechanism

I-125 seed implantation is brachytherapy: sealed radioactive sources are placed within or near target tissue. Radiation comes from implanted sources, not external beams.

What informs suitability

Suitability depends on organ, tumour type, access, spread, and dose planning. Prior treatment and radiation-protection needs require review.

Typical pathway

Imaging and dose planning precede guided seed placement. The team then checks dose distribution and provides follow-up and safety instructions.

Risks & evidence limits

Bleeding, infection, source migration, or nearby-tissue injury can occur. Family precautions depend on source and site, not instructions copied from another procedure.

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Original BKC explainers

24 seconds · silent text video

Radiation, ablation, surgery: what differs?

Read the video transcript

Radiation targets a planned area. CyberKnife uses X-rays. It is not surgery with a blade.
Ablation acts on a local target. RFA uses heat from radiofrequency energy. Risks and target location need assessment.
Surgery describes a procedure. Procedure, access approach, and recovery are three different questions.
Start with the care goal. Discuss options and combinations with a doctor, based on diagnosis and patient condition.

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Reading sources

Prepared by BKC editorial, 22 October 2026. General education, not a diagnosis or personal treatment selection. A topic listing does not establish availability at a particular hospital.

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Specialties & teams

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Different names. Understand how they work.

Compare principles, assessment, and evidence limits. A reading tool, not a way to select your treatment.

Concept diagram: Iodine-125 seed implantation — Iodine-125 seed implantation

Concept diagram: CyberKnife / SRS / SBRT — CyberKnife / SRS / SBRT

Read principles, assessment, and risks

Concept comparison, without rankings or recommendations.
Aspect	Iodine-125 seed implantation	CyberKnife / SRS / SBRT
How it works	I-125 seed implantation is brachytherapy: sealed radioactive sources are placed within or near target tissue. Radiation comes from implanted sources, not external beams.	CyberKnife is an image-guided robotic stereotactic radiotherapy system. SRS and SBRT describe focused radiation approaches; radiosurgery does not mean cutting surgery.
What is assessed	Suitability depends on organ, tumour type, access, spread, and dose planning. Prior treatment and radiation-protection needs require review.	Size, location, target motion, nearby sensitive organs, and previous radiation affect planning. Large doses per fraction do not suit every tumour.
Risks & limits	Bleeding, infection, source migration, or nearby-tissue injury can occur. Family precautions depend on source and site, not instructions copied from another procedure.	Radiation can affect healthy tissue. Side effects depend on site and dose; follow-up images and size changes require clinical interpretation.

Iodine-125 seed implantation CyberKnife / SRS / SBRT

Schematics are conceptual. Technologies with different purposes are not necessarily alternatives. Open each topic for its sources and context.

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Doctors assess options from the case, beyond a technology name alone.

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