Brachytherapy

Terminology description

Type of clinical procedure where encapsulated radioactive sources are used for the treatment of tumor cells is referred as Brachytherapy. A source of Brachytherapy is radioactive elements. They irradiate the radioactive sources volume without any interruption. As time of exposure increases, dosage rate decreases. Therapeutic range of radioactive source is measured in terms of mm to cm size. Most of the brachytherapist opt for Cesium (Ce) as radioactive source, especially to treat gynecological problems. Ce has more long half-life period.  It is a bit different in providing tumor dose localization when compared to normal radiation technology.

Methods of Brachytherapy

Two different methods of Brachytherapy are

• Intercavitary approach
• Interstitial approach

Intercavitary approach: In this approach, radioactive elements are located inside the body cavities and are in close proximity to the dose of tumor volume. This intercavitary implant is not permanent.

Interstitial approach: In this approach, the radioactive elements are directly transferred in to tumor volume. Interstitial implant can be either permanent or temporary.

Applications of Brachytherapy

With the advent of anatomic sites, Brachytherapy find its own applications in

• Prostrate seed implant to treat localized prostate cancer
• Mammo site irradiation of breast
• Irradiation of intravascular to prevent coronary restenosis

Instances of Brachytherapy procedure

Prostate seed implant therapy

Radioactive elements: Palladium – 103 seeds and I seeds are used in this implant procedure

Benefits: Use of transrectal ultrasonography gives precise and accurate results and discussions

Requirement: Extensive planning for treatment according to each source to obtain the combined effect

Steps of prostate seed implant: Preplanning for tumor volume and intraoperative planning

Preplanning benefits: Pre evaluation of treatment to be administered, ideal distribution of dose, optimal time requirement for planning

Intravascular Brachytherapy

Radioactive elements: ¹⁹²Ir, ³²P, ⁹⁰Sr and ¹²⁵I

Operating treatment: 3 to 25 minutes

Benefit: Used to treat restenosis

Mammo site Brachytherapy

Radioactive source: Iridium

Operating time: 15 min each for 5 days

Benefit: Breast cancer

Questions:

• Explain the future prospect of BRACHYTHERAPY
• State the postulates of BRACHYTHERAPY