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  1. QDefinition:
    Brachytherapy is a technique in which radioactive sources are placed within or close to the target volume.
    1. These sources can be placed directly into the tumor and surrounding tissues (interstitial Brachytherapy),
    2. within body cavities (intracavitary Brachytherapy), or
    3. onto epithelial surfaces (surfacemoldBrachytherapy).
  2. Brachytherapy implants can be temporary or permanent.
    1. Temporary implants usually are long-lived isotopes, such as
      1. Radium 226
      2. Cesium 137
      3. Iridium 192
    2. Permanent implants are short-lived isotopes, such as
      1. Cesium 133             
      2. Gold 198
      3. Iodine 125
      4. Palladium 103
      5. Yttrium
  3. The advantages of brachytherapy over external beam irradiation are twofold.
    1. First, the radiation is mainly confined to the implant volume, so a greater dose can be delivered to the tumor with a lesser dose to adjacent normal tissues. This produces greater local tumor control and fewer complications.
    2. Second, most brachytherapy is delivered continuously at a low dose rate. This is theoretically more effective than intermittent high-dose-rate administration of external beam radiation in the management of hypoxic or slowly proliferating cancers. High-dose-rate temporary brachytherapy has become more popular because it allows shorter treatment times.
  4. Selection criteria:
    1. Brachytherapy implants are effective only if the entire tumor volume is involved. The tumor must be accessible and relatively well demarcated.
    2. Large or poorly defined cancers usually are not irradiated with brachytherapeutic techniques because it is difficult to reach peripheral extensions of the cancer with the implant. Brachytherapy also is not used as the only treatment modality if there is high risk of regional lymph node metastasis.
    3. If the implant is used as the sole treatment, the sources usually are left in place for 5 to 7 days to deliver a dose of 70 to 80 Gy to the target volume. An alternative is to use implants to supplement the dose delivered with external beam irradiation. In this case a dose of 40 to 50 Gy is delivered with external beam irradiation followed by a 2- to 3-day implant to deliver an additional 30 to 40 Gy to bring the total dose to 70 to 80 Gy.
  5. Doses of RT
    Doses are given in fractionation and fractionation schedules are followed:
    Fractionation Radiotherapy refers to the division of the total dose into a number of separate fractions, conventionally given on a daily basis, usually 5 days a week (Monday to Friday).
    1. Conventional fractionation
    2. Hyperfractionation RTQ
    3. Accelerated RTQ
    4. CHART regimen: for lung cancer & head-neck malignanciesQ
    5. ​Hypofractionation RT​


  1. Instead of giving once a day radiation therapy, multiple doses of radiation (b.i.d or t.i.d) can be given to exploit the radiobiological advantages.
  2. Firstly, by giving multiple fractions per day (hyperfractionation), higher radiation dose can be delivered to the tumor. Secondly, hyperfractionation result in 15% higher local control and survival rates than conventional radiotherapy with very minimal late complications. This approach has been explored in tumors where conventionally fractionated RT has often failed cure tumors e. g. cerebral gliomas & advanced head & neck cancer.
  3. The most encouraging results of Hyperfractionation radiotherapy have been found in localized head & neck cancers & small cell carcinoma of lung.

Hypofractionation RT: when radiotherapy is used for palliation of advanced cancers, the duration is very short (5 to 10 days only) and dose per fraction is more concentrated. It is more logical in treating tumors with higher capacity for repair e.g. melanomas, soft tissue sarcomas & in palliative RT (bone metastases & non-small cell lung cancers).Q

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