Category: P

Permission given by the federal government to equipment manufacturers to sell their devices to the medical profession.  

A comparatively slow gyration of the axis of a spinning body (so as to trace out a cone) caused by the application of a torque. The magnetic moment of a nucleus with spin will experience such a torque when inclined at an angle to the magnetic field, resulting in precession at the larmor frequency.  

A family of particles that can be created in nuclear reactions; pions are unstable but can survive long enough to be formed into beams and used in certain types of medical therapy. For example, they can be used to treat brain tumors. Pions of suitable energy can penetrate the skull, spare overlying normal tissue, and…

A device used in many radiation detection applications that converts low levels of light into electrical pulses. A bank of such tubes is used in gamma cameras to view the crystal.  

A clinical trial to assess the risk that might come from administering a new treatment modality. A phase-two study evaluates the clinical effectiveness of the new modality, while a phase-three study compares its effectiveness with the best existing treatments.  

The rate of blood flow through capillaries per unit mass of tissue, described in ml/min per 100 g.  

A method of arranging radioactive sources for interstitial or intercavitary applicators developed in the 1 930’s at the Christie Hospital and Holt Radium Institute in Manchester, England. The system utilizes sources of specific relative loadings arranged according to defined rules which lead to a homogeneous dose in the implanted region.  

The condition in which the maximum decrease in treated tumor volume is at least 50% but less than 100%. In cancer care, a reduction in the size of readily identifiable tumors by 50% or more.  

Discomfort or burning during urination. The problem usually results from an infection in the urinary tract, although it may also be caused by inflammation of the prostate gland (prostatitis) or a calculus or stone in the urinary tract. In women, it can be caused by a problem of the reproductive system such as cancer of…

Aches or pains that begin in the testicles, the glands contained within the scrotum, which is the skin-covered pouch between the legs in a man. Sometimes, the discomfort radiates into the lower abdomen. Usually such aches and pains are not cause for alarm. However, severe pain from one side that comes on suddenly, particularly if…