Brachytherapy sources

Protection Against Radiation From Brachytherapy Sources... 

The lineal energy spectrum of the brachytherapy source is evaluated from ... 

Protection Against Radiation from Brachytherapy Sources (1972)... 

Delayed endothelial healing. In case 1, a smooth, white lesion was detected at three and nine months. In case 2, erosion with a superficial thrombus was seen at three months. At nine months, the erosion had disappeared, although an uncovered stent was observed. In case 3, severe, circumferential erosion with superficial thrombus was detected at three months, with erosion still evident but partly improved at nine months. These results suggest that the healing process was not completed nine months after brachytherapy. Source From Ref. 73. 

SRL has developed and improved industrial, research, and medical sources since the 252 f pr0gram began. An example of the progress made can be illustrated by the history of brachytherapy sources at SRL. 

Brachytherapy Sources. The first 252cf sources for radiotherapy research were prepared at SRL about fourteen years ago (4 5). Initially, these sources resembled the classical radium needles familiar in clinical radiotherapy. Eventually, afterloading cells and applicator tubes were supplied to medical evaluators, and all medical sources were improved by the use of californium-palladium cermet wire sheathed in Pt - 10% Ir alloy (6, 7). The most recent designs for medical sources produced in quantity for therapy research are line sources and point sources containing a range of Cf from iess than 1 yg to 200 yg (Figures 9 and 10). 

Pure beta-emitters P, Sr and Y Brachytherapy sources lr wire and hairpin sources. 

Industrial gamma radiography sources High/medium dose rate brachytherapy sources 1000 > A/D > 10... 

Low dose rate brachytherapy sources (except eye plaques and permanent implants) Industrial gauges that do not incorporate high activity sources Bone densitometers Static eliminators 1> A/D >0.01... 

Radiation therapy The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body in the area near cancer cells (internal radiation therapy, implant radiation, or brachytherapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monodonal antibody, that circulates throughout the body. Also called radiotherapy, [nih]... 

Radiotherapy is a local treatment aiming to achieve local control or cure of locally confined tumours. It cannot treat metastases. Radiotherapy may be administered as external beam radiotherapy with X-rays or gamma rays, in sealed radioactive sources (e.g. prostate brachytherapy), or unsealed sources (e.g. orally administered radioiodine for thyroid cancer, intravenous strontium-89 for bone metastases). In external beam radiotherapy, the X-ray or gamma ray beams are targeted at the tumour to damage and kill the tumour cells. Inevitably, surrounding normal tissues are also affected resulting in the early and late side effects of radiotherapy. 

Brachytherapy physics is concerned with electrons, whether primary or secondary, as in the case of photon sources (Table 1). 

Table 1 Physical Characteristics of Radioactive Sources Currently Used in Brachytherapy...

The specific techniques of brachytherapy and the administration of unsealed sources of radionuclides, in nuclear medicine [10], are not dealt with in this chapter. 

Staff preparing radiopharmaceuticals to be administered for nuclear medicine diagnostic and therapeutic procedures and handling sealed sources for brachytherapy use protective blocks to shield the head and trunk. For these workers, a single personal monitor is located on the trunk. ... 

The purpose of the development work at SRL is to prepare physically small, yet intense 252 f sources for remote afterloading brachytherapy research. Remote afterloading is used by many hospitals to avoid radiation exposure to medical and hospital personnel. 

Brachytherapy is a treatment where the radiation source is in direct contact with the tumour. This method is used widely for a number of special medical cases. As cancer of the cervix is quite a common disease in many developing countries, brachiotherapy has become the method of choice for treatment because many patients can be treated relatively cheaply and effectively. One of the first big projects of this kind in a developing country was organised in Egypt with the co-operation of the World Health Organisation (WHO) and the IAEA. This method, however, is only applicable when the tumour has not spread more than a few centimetres. Fortunately, this is the case with many patients. Should the tumour be larger however, the more costly teletherapy must be applied. 

NRC. 2000b. Use of sources for brachytherapy. U.S. Nuclear Regulatory Commission. Code of Federal Regulations. 10 CFR 35.400. 

Another isotope, however, is beneficial for treating cancer, especially of the prostate. Cesium 131 has a half-life of only 10 days and emits low-energy photons that can be used to destroy cancer cells. Injection of a small source or"seed"of the radioisotope to a specific site—a process called brachytherapy—allows radiation to be aimed like bullets that can damage target receptor cells. It is especially potent against those that divide rapidly like cancer cells. 

Radium. The radium source used in brachytherapy uses mostly radium sulfate or radium chloride mixed with an inert filler and loaded into cells about 1 cm long and 1 mm in diameter. These cells are made of 0.1- to 0.2- mm-thick gold foil. Radium sources are manufactured as needles or tubes in a variety of lengths and activities. Leakage of radon gas from a radium source represents a significant hazard if the source is broken. The sources are, however, doubly encapsulated to prevent such an occurrence. Cesium-137 has replaced radium, at least in the US. 

Au seeds have long been used as radiation sources in brachytherapy , to treat carcinoma of the prostate and of the tongue . The measurable dose anisotropy... 

Low dose rate brachytherapy eye plaques and permanent implant sources X ray fluorescence (XRF) devices Electron capture devices Mossbauer spectrometry sources Positron emission tomography (PET) check sources 0.01 > A/D and A > exempt ... 

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