靜脈久置性注射腔對放射劑量分布的影響

化學治療是治療惡性腫瘤的一種相當重要的方法，臨床上，病人在經過多次靜脉注射抗癌藥物以後，常會遭遇到因爲靜脉萎縮沒有淺層靜脉可供給藥的困擾；近年來，因爲靜脉久置性注射腔在臨床上的廣泛使用，解决了這方面的難題。由於注射腔常常植於前胸壁皮下，以便其導管插入鎖骨下靜脉中；假如這個病人同時在此部位接受放射治療，那麽注射腔底下組織的放射劑量，將會不均勻及降低。本實驗用不同種類及不同能量的放射線束，包括 6MV及10MV X光，與9•12•15•及18MeV電子束，測量金屬與矽膠兩種不同材質注射腔底下不同深度的劑量分布，來瞭解注射腔所造成的影響。實驗的結果顯示注射腔會改變劑量分布的均勻，幷且使深度劑量降低；例如以9MeV電子束爲例，於金屬注射腔存在下，注射腔下方2.5cm處的中心軸劑量會降低至37%。由本研究的發現，建議1.將注射腔裝置於可能的放射照野之外。2.設計放射治療技術時，將照野避開注射腔。3.選用矽膠製的注射腔。4 避免使用電子束。

關鍵字

注射腔；放射效應；光子；電子；化學治療

並列摘要

Chemotherapy is a very important method in cancer treatment. Clinically, the patient would suffer from lack of adequate venous access for administration of chemotherapeutic agents after multiple courses of chemotherapy. The problem is resolved by the extensive use of venous injection ports. Injection ports are usually implanted in the anterior chest wall, with their catheter inserted into the subclavian vein. If the patient must receive radiotherapy over these areas, the radiation dose under injection ports would be lower. This paper trys to find out the influence of metallic or silicon injection ports on the dose distribution of K-rays and electron beams. Two different kinds of radiation beams, with different energy levels, were used in these experiments. They were 6MV and 10 MV K-rays, and 9, 12, 15 and 18MeV eletron beams. In order to understand the influence of injection ports, all dose measurements were made at different depths under the ports. The data revealed that the presence of injection ports alters the dose uniformity and decreased the depth dose. For example, the dose underlying metal injection portals at 2.5cm depth reduced to 37% when 9MeV electrons are used. This paper recommends that 1.The injection port should be implanted outside the potential irradiation field. 2. Avoid irradiation of the injection port whenever possible. 3. Use silicon-made injections port. 4. Avoid selecting electron beams for treatment.

並列關鍵字

Injection ports ； Radiation effect ； Photons ； Electrons ； Chemotherapy

國際替代計量

靜脈久置性注射腔對放射劑量分布的影響

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