Methamphetamine (MA), a psychostimulant drug, was first produced in Germany and Japan in the late 1800s. MA use and trafficking have been a problem since the 1970s in the United States (U.S.) [National Drug Intelligence Center (NDIC). (2006). National Drug Threat Assessment 2006. Retrieved March 18, 2006 from http://www.usdoj.gov.ndic/pubs11/18862/MA.htm] and have increased in recent years [Office of Applied Studies (OAS). (September 16, 2005). The National Survey on Drug Use and Health report: Methamphetamine use, abuse, and dependence: 2002, 2003, and 2004. Rockville, MD: Substance Abuse and Mental Health Services Administration]. MA is associated with violent behavior yet the nature of this relation remains poorly understood, largely due to methodological shortcomings. The present paper critically examines the empirical literature on MA use and its relation to violence. Methodological issues and challenges are discussed and suggestions for future research are provided.

This note outlines an improved method of calculating dose per monitor unit values for small electron fields using Khan's lateral build-up ratio (LBR). This modified method obtains the LBR directly from the ratio of measured, surface normalized, electron beam percentage depth dose curves. The LBR calculated using this modified method more accurately accounts for the change in lateral scatter with decreasing field size. The LBR is used along with Khan's dose per monitor unit formula to calculate dose per monitor unit values for a set of small fields. These calculated dose per monitor unit values are compared to measured values to within 3.5% for all circular fields and electron energies examined. The modified method was further tested using a small triangular field. A maximum difference of 4.8% was found.