PMID- 19306749
OWN - NLM
STAT- MEDLINE
DCOM- 20090403
LR  - 20220408
IS  - 1879-355X (Electronic)
IS  - 0360-3016 (Linking)
VI  - 73
IP  - 5
DP  - 2009 Apr 1
TI  - Sensitivity analysis of parameters in linear-quadratic radiobiologic modeling.
PG  - 1532-7
LID - 10.1016/j.ijrobp.2008.11.039 [doi]
AB  - PURPOSE: Radiobiologic modeling is increasingly used to estimate the effects of 
      altered treatment plans, especially for dose escalation. The present article 
      shows how much the linear-quadratic (LQ) (calculated biologically equivalent dose 
      [BED] varies when individual parameters of the LQ formula are varied by +/-20% 
      and by 1%. METHODS: Equivalent total doses (EQD2 = normalized total doses (NTD) 
      in 2-Gy fractions for tumor control, acute mucosal reactions, and late 
      complications were calculated using the linear- quadratic formula with overall 
      time: BED = nd (1 + d/ [alpha/beta]) - log(e)2 (T - Tk) / alphaTp, where BED is 
      BED = total dose x relative effectiveness (RE = nd (1 + d/ [alpha/beta]). Each of 
      the five biologic parameters in turn was altered by +/-10%, and the altered EQD2s 
      tabulated; the difference was finally divided by 20. EQD2 or NTD is obtained by 
      dividing BED by the RE for 2-Gy fractions, using the appropriate alpha/beta 
      ratio. RESULTS: Variations in tumor and acute mucosal EQD ranged from 0.1% to 
      0.45% per 1% change in each parameter for conventional schedules, the largest 
      variation being caused by overall time. Variations in "late" EQD were 0.4% to 
      0.6% per 1% change in the only biologic parameter, the alpha/beta ratio. For 
      stereotactic body radiotherapy schedules, variations were larger, up to 0.6 to 
      0.9 for tumor and 1.6% to 1.9% for late, per 1% change in parameter. CONCLUSIONS: 
      Robustness occurs similar to that of equivalent uniform dose (EUD), for the same 
      reasons. Total dose, dose per fraction, and dose-rate cause their major effects, 
      as well known.
FAU - Fowler, Jack F
AU  - Fowler JF
AD  - Department of Human Oncology, School of Medicine, University of Wisconsin, 
      Madison, WI, USA. jackfowlersbox@gmail.com
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
MH  - *Algorithms
MH  - Cell Proliferation/radiation effects
MH  - Head and Neck Neoplasms/*radiotherapy
MH  - Humans
MH  - Linear Models
MH  - Male
MH  - *Models, Biological
MH  - Mouth Mucosa/radiation effects
MH  - Prostatic Neoplasms/pathology/*radiotherapy
MH  - Radiation Injuries/etiology
MH  - Radiation Tolerance
MH  - Radiobiology
MH  - Radiosurgery/adverse effects
MH  - Radiotherapy Dosage
MH  - *Relative Biological Effectiveness
MH  - Sensitivity and Specificity
MH  - Time Factors
EDAT- 2009/03/25 09:00
MHDA- 2009/04/04 09:00
CRDT- 2009/03/25 09:00
PHST- 2008/08/10 00:00 [received]
PHST- 2008/11/01 00:00 [revised]
PHST- 2008/11/22 00:00 [accepted]
PHST- 2009/03/25 09:00 [entrez]
PHST- 2009/03/25 09:00 [pubmed]
PHST- 2009/04/04 09:00 [medline]
AID - S0360-3016(08)03856-X [pii]
AID - 10.1016/j.ijrobp.2008.11.039 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2009 Apr 1;73(5):1532-7. doi: 
      10.1016/j.ijrobp.2008.11.039.