| There are several ways of giving radiation dosage to | | | | Brachytherapy can be delivered with devices known |
| a cancerous tumor. The most common method is to | | | | as implants. These devices may be in the form of |
| deliver the required dosage from an external beam | | | | needles or seeds or ribbons. Brachytherapy can be |
| of radiation produced outside the body. In this case | | | | delivered with permanent or temporary implants. |
| the source of radiation beam is located 80-100 cm | | | | These implants might be temporary or permanent. |
| from the body of the person receiving radiation. | | | | Temporary implants usually have a longer half-life and |
| Sometimes placing the source of radiation within the | | | | higher energies compared to the permanent implants. |
| tumor might have advantages over delivering | | | | All temporary implants are inserted into the tumor |
| radiation from an external source. This method of | | | | during surgery. The duration of treatment for the |
| delivering required radiation from an internal source | | | | temporary implant is usually 1-3 days. |
| embedded within the tumor is called brachytherapy. | | | | Interstitial low-dose rate (LDR) brachytherapy is |
| If you are aware of the inverse square law in physics | | | | usually used for cancers involving the mouth and oral |
| you would know the dosage of radiation therapy | | | | cavity, pharynx. This mode of treatment is often |
| delivery changes by a great proportion depending | | | | used in the treatment of sarcomas. Prostate cancer |
| upon the distance of the radiation source to the | | | | treatment is the most common form of LDR |
| intended target. In brachytherapy the source of | | | | brachytherapy using seeds. Uterine cancer is the |
| radiation is within the tumor volume and the proper | | | | most common application of intracavitary LDR |
| placement of these sources of radiation within the | | | | treatment. These patients are often isolated to |
| tumor is of crucial importance. | | | | prevent radiation exposure to nursing and other |
| There are several radioactive isotopes used in the | | | | supportive staff during the care of the person. |
| brachytherapy. These include radium-226, cesium-137, | | | | The most common uses of high-dose rate (HDR) |
| cobalt-60, iridium192, iodine-125, gold-198 and | | | | brachytherapy includes treatment of esophageal |
| palladium-103. Radium has a longer half-life compared | | | | cancer, lung cancer and recently breast cancer and |
| to some of the other radioactive isotopes. In the | | | | prostate cancer. Most HDR treatments are done as |
| past radium was the primary isotope used in | | | | outpatient procedures allowing the patients to return |
| brachytherapy, but recently radium has been largely | | | | to home the same day as treatment. Patients who |
| replaced by cesium, gold and iridium, which have | | | | are receiving treatment for prostate cancer is an |
| relatively shorter half-life and lower energies and | | | | exception who may remain in the hospital for 2-3 |
| because of this the radiation from these isotopes can | | | | days during the treatment. |
| be easily shielded. | | | | |