CET Cancer Center, High Dose Rate (hdr) Brachytherapy Specialist with 25 years of experience
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As of January 4, 2010 Dr. Demanes and the program have relocated to UCLA.



Commonly Used Terms in HDR Brachytherapy

There are many terms or acronyms associated with Raditation Therapy that you may not have heard before. Below is a list of words you may hear during your treatment.


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Adjuvant Treatment

A treatment that is given in addition to the primary treatment to enhance its effectiveness and reduce the chance of tumor recurrence. For example, androgen deprivation therapy in addition to radiation treatment for prostate cancer.

Androgen Suppression

The use of medications such as Lupron and Casodex to block the growth stimulating effect of the male hormone on prostate cancer.


A device used to hold a radioactive source in place during brachytherapy.

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Balloon Catheter

A brachytherapy device with a balloon that surrounds the hollow channel into which the radiation source is inserted. It is commonly used in breast brachytherapy.


An additional dose of radiation that is given after an initial course of radiation to enhance tumor control.


The prefix "brachy" is the Greek word for "short" distance. Brachytherapy is a form of internal radiation treatment where radioactive sources are placed on or into cancer tissues.

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A group of diseases in which abnormal cells divide uncontrollably, forming a tumor or mass.


A tube inserted into the body that can be used to deliver radiation during brachytherapy.

CT (CAT Scan)

A computer assisted tomography scan is an X-ray procedure that uses a computer to produce detailed pictures of the body.

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It is the distribution of radiation that encompasses the tumor. It is the treatment planning process of calculating and describing how the radiation is delivered into the tissue.

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Endo-Rectal Coil MRI (ERC-MRI)

A magnetic resonance imaging scan is a procedure that uses a magnetic field to create detailed pictures of the body. In this case, a special device is inserted into the rectum to get a detailed image of the prostate and the surrounding structures.

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Specialized hard plastic hollow catheters which can be implanted directly into the tumor site.

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Gleason Score

A standard system of grading prostate tumor tissue seen under the microscope. The pathologist reports it as a number between 2 and 10. The lower the number, the lower the statistical risk. The higher the number, the higher the statistical risk.

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HDR stands for high dose rate. It is a form of brachytherapy that involves the rapid (minutes) and accurate delivery of radiation directly into the target tissue. It is distinguished from LDR or low dose rate brachytherapy where the sources are left in place for a longer period (either days or permanently like "seeds") of time.

HDR Remote Afterloading Machine

A computerized medical device that drives a small radioactive source through catheters to predetermined dwell positions for a specific time in a patient’s body during brachytherapy.

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Another term for brachytherapy, internal radiation therapy involves placing radioactive sources inside the patient close to or in the tumor.

Interstitial Brachytherapy

A form of brachytherapy where the applicators or radioactive sources are placed directly into the tumor.

Intracavitary Brachytherapy

A type of brachytherapy where the radioactive sources are placed into existing body cavities. Common sites for intracavitary brachytherapy are the upper airways and bronchus, esophagous, and gynecological sites.

Isodose Cloud

A term that describes a 3D contour around the tumor that is all the same dose level. It is like a cloud of radiation representing a uniform dose distribution.

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Treatment of cancer using one modality (i.e HDR radiation alone for prostate cancer.

MRI Scan

A magnetic resonance imaging (MRI) scan is a procedure that uses a magnetic field to create detailed pictures of the body.

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PET Scan

A positron emission tomography scan uses a small dose of a chemical called a radionuclide combined with a sugar, which is injected into the patient. The radionuclide emits positrons. The PET scanner detects the positron emissions given off by the radionuclide.

Prostate Specific Antigen

Prostate specific antigen is an enzyme that is produced only by prostate cells and can be measured with a simple blood test. An elevated level raises the suspicion of prostate cancer.

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Radiation Oncologist

A doctor who specializes in treating cancer and other diseases with radiation therapy.

Radiation Oncology

The medical specialty that deals with treating cancer and other diseases with radiation.

Radiation Therapy

The careful use of various forms of radiation to treat cancer and other diseases.

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The process of planning radiation therapy to allow the radiation to be delivered to the intended location.

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Treatment Plan

A radiation oncologist’s prescription describing how a patient should be treated with radiation therapy. The radiation oncology team uses sophisticated treatment planning software to maximize radiation to the tumor while sparing healthy tissue.

Transurethral Resection of the Prostate (TURP)

A urologic procedure done for men with benign prostatic hyperplasia. This procedure is done to remove a portion of the prostate gland tissue so as to decrease urinary symptoms.


An abnormal lump or mass of tissue.