Biomaterial Database

Radiation protection considerations for endocavitary X ray units. 1985

J A Purdy, and S C Prasad, and B J Walz, and G W Cotter

Application of a contact X ray therapy unit for endocavitary irradiation of selected rectal carcinomas is gaining acceptance as a treatment of choice. The patient is placed on a proctoscopic table in the surgical suite and the anus is anesthetized and dilated to allow insertion of a 3 cm diameter proctoscope designed to admit the X ray tube. The measured half-value layer for 50 kVp X rays filtered by 1.0 mm of aluminum was determined to be 0.65 mm of aluminium. The dose rate at the end of the 4.0 cm source-skin-distance (SSD) cone was measured to be on the order of 1000 rad/minute. Radiation surveys performed for several treatment geometries indicate that exposure rate levels in the environs immediately around the patient can be quite high. Radiation measurements were made for the following locations: where the radiotherapist stands holding the X ray tube; at the side of the patient where the technologist or any supporting personnel might stand; and at the patient's posterior surface in the direction where the anesthesiologist might stand. Radiation levels ranged from 0.001 to 1.0 roentgen (R) per hour and depend primarily on the depth and angle of the X ray tube inserted into the rectum.

UI	MeSH Term	Description	Entries
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D011351	Proctoscopy	Endoscopic examination, therapy or surgery of the RECTUM; ANAL CANAL; and ANUS.	Anoscopic Examination,Anoscopy,Proctoscopic Surgical Procedures,Rectoscopy,Surgical Procedures, Proctoscopic,Proctoscopic Surgery,Surgery, Proctoscopic,Anoscopic Examinations,Anoscopies,Examination, Anoscopic,Examinations, Anoscopic,Procedure, Proctoscopic Surgical,Procedures, Proctoscopic Surgical,Proctoscopic Surgeries,Proctoscopic Surgical Procedure,Proctoscopies,Rectoscopies,Surgeries, Proctoscopic,Surgical Procedure, Proctoscopic
D011835	Radiation Protection	Methods and practices adopted to protect against RADIATION.	Protection, Radiation
D011879	Radiotherapy Dosage	The total amount of radiation absorbed by tissues as a result of radiotherapy.	Dosage, Radiotherapy,Dosages, Radiotherapy,Radiotherapy Dosages
D012004	Rectal Neoplasms	Tumors or cancer of the RECTUM.	Cancer of Rectum,Rectal Cancer,Rectal Tumors,Cancer of the Rectum,Neoplasms, Rectal,Rectum Cancer,Rectum Neoplasms,Cancer, Rectal,Cancer, Rectum,Neoplasm, Rectal,Neoplasm, Rectum,Rectal Cancers,Rectal Neoplasm,Rectal Tumor,Rectum Cancers,Rectum Neoplasm,Tumor, Rectal
D001918	Brachytherapy	A collective term for interstitial, intracavity, and surface radiotherapy. It uses small sealed or partly-sealed sources that may be placed on or near the body surface or within a natural body cavity or implanted directly into the tissues.	Curietherapy,Implant Radiotherapy,Plaque Therapy, Radioisotope,Radioisotope Brachytherapy,Radiotherapy, Interstitial,Radiotherapy, Intracavity,Radiotherapy, Surface,Brachytherapy, Radioisotope,Interstitial Radiotherapy,Intracavity Radiotherapy,Radioisotope Plaque Therapy,Radiotherapy, Implant,Surface Radiotherapy,Therapy, Radioisotope Plaque
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012542	Scattering, Radiation	The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Radiation Scattering,Radiation Scatterings,Scatterings, Radiation