PMID- 10661360
OWN - NLM
STAT- MEDLINE
DCOM- 20000210
LR  - 20220408
IS  - 0360-3016 (Print)
IS  - 0360-3016 (Linking)
VI  - 46
IP  - 2
DP  - 2000 Jan 15
TI  - A simple method of obtaining equivalent doses for use in HDR brachytherapy.
PG  - 507-13
AB  - PURPOSE: To develop a simple program that can be easily used by clinicians to 
      calculate the tumor and late tissue equivalent doses (as if given in 2 Gy/day 
      fractions) for different high-dose-rate (HDR) brachytherapy regimens. The program 
      should take into account the normal tissue sparing effect of brachytherapy. 
      METHODS AND MATERIALS: Using Microsoft Excel, a program was developed 
      incorporating the linear-quadratic (LQ) formula to calculate the biologically 
      equivalent dose (BED). To express the BED in terms more familiar to all 
      clinicians, it was reconverted to equivalent doses as if given as fractionated 
      irradiation at 2 Gy/fraction. Since doses given to normal tissues in HDR 
      brachytherapy treatments are different from those given to tumor, a normal tissue 
      dose modifying factor (DMF) was applied in this spreadsheet (depending on the 
      anticipated dose to normal tissue) to obtain more realistic equivalent normal 
      tissue effects. RESULTS: The spreadsheet program created requires the clinician 
      to enter only the external beam total dose and dose/fraction, HDR dose, and the 
      number of HDR fractions. It automatically calculates the equivalent doses for 
      tumor and normal tissue effects, respectively. Generally, the DMF applied is < 1 
      since the doses to normal tissues are less than the doses to the tumor. However, 
      in certain circumstances, a DMF of > 1 may need to be applied if the dose to 
      critical normal tissues is higher than the dose to tumor. Additionally, the 
      alpha/beta ratios for tumor and normal tissues can be changed from their default 
      values of 10 Gy and 3 Gy, respectively. This program has been used to determine 
      HDR doses needed for treatment of cancers of the cervix, prostate, and other 
      organs. It can also been used to predict the late normal tissue effects, alerting 
      the clinician to the possibility of undue morbidity of a new HDR regimen. 
      CONCLUSION: A simple Excel spreadsheet program has been developed to assist 
      clinicians to easily calculate equivalent doses to be used in HDR brachytherapy 
      regimens. The novelty of this program is that the equivalent doses are expressed 
      as if given at 2 Gy per fraction rather than as BED values and a more realistic 
      equivalent normal tissue effect is obtained by applying a DMF. Its ease of use 
      should promote the use of LQ radiobiological modeling to determine doses to be 
      used for HDR brachytherapy. The program is to be used judiciously as a guide only 
      and should be correlated with clinical outcome.
FAU - Nag, S
AU  - Nag S
AD  - Division of Radiation Oncology, Arthur G. James Cancer Hospital and Research 
      Institute, Ohio State University, Columbus 43210, USA. nag.1@osu.edu
FAU - Gupta, N
AU  - Gupta N
LA  - eng
GR  - 5P30CS16058/PHS HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
CIN - Int J Radiat Oncol Biol Phys. 2000 Oct 1;48(3):907-8. PMID: 11183737
MH  - *Algorithms
MH  - *Brachytherapy
MH  - Dose Fractionation, Radiation
MH  - Esophageal Neoplasms/radiotherapy
MH  - Female
MH  - Humans
MH  - Male
MH  - Prostatic Neoplasms/radiotherapy
MH  - Radiation Oncology/*methods
MH  - *Radiotherapy Dosage
MH  - *Software
MH  - Uterine Cervical Neoplasms/radiotherapy
EDAT- 2000/02/08 00:00
MHDA- 2000/02/08 00:01
CRDT- 2000/02/08 00:00
PHST- 2000/02/08 00:00 [pubmed]
PHST- 2000/02/08 00:01 [medline]
PHST- 2000/02/08 00:00 [entrez]
AID - S0360-3016(99)00330-2 [pii]
AID - 10.1016/s0360-3016(99)00330-2 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2000 Jan 15;46(2):507-13. doi: 
      10.1016/s0360-3016(99)00330-2.