TURKISH JOURNAL OF ONCOLOGY 2019 , Vol 34 , Num 1
Dose Rate Definition in Brachytherapy
Güler YAVAŞ
1Department of Radiation Oncology, Selçuk University, Konya-Turkey DOI : 10.5505/tjo.2019.1924 Brachytherapy (BRT) is defined as treatment from a short distance. The word is derived from the word "brachy" that means "short" in Greek. Treatment in BRT is performed by placing the radioactive source in or near the tumor tissue. According to the report 38 of the International Commission on Radiation Units and Measurements (ICRU 38), BRT is divided into three types according to the activity of the radioactive source. Low-dose rate (LDR) implants deliver dose at the rate of 0.4?2 Gy/h, requiring treatment times of 24?144 h. LDR BRT has extensive experience with well-known efficacy and side effects. Medium-dose rate (MDR) BRT, defined as the 2?12 Gy/h range, is rarely used. High-dose rate (HDR) BRT uses dose rates in excess of 0.2 Gy/min (12 Gy/h). Although not defined in ICRU 38, there is also a very-low dose (ultra LDR: ultra-low dose rate (ULDR)) BRT of 0.01?0.3 Gy/h. Pulse dose rate (PDR) BRT is a new BRT concept that is also not defined in ICRU 38. PDR BRT combines physical advantages of HDR BRT technology with the radiobiological advantages of LDR BRT. Each dose rate in the clinic has its advantages and disadvantages. It is difficult to compare the efficacy of dose rates in the clinic because of the lack of prospective randomized studies comparing the defined dose rates with each other. In this review, we aimed to explain the advantages, disadvantages, and common clinical sites of use of different dose rates. Keywords : Brachytherapy; high-dose rate; low-dose rate; medium-dose rate; pulse dose rate; ultra-low dose rate