PMID- 9747830
OWN - NLM
STAT- MEDLINE
DCOM- 19980928
LR  - 20190708
IS  - 0360-3016 (Print)
IS  - 0360-3016 (Linking)
VI  - 42
IP  - 1
DP  - 1998 Aug 1
TI  - A brain tumor dose escalation protocol based on effective dose equivalence to 
      prior experience.
PG  - 137-41
AB  - PURPOSE: The current study describes the design of a dose escalation protocol for 
      conformal irradiation of primary brain tumors that preserves the safe experience 
      of a previous, sequential dose escalation scheme while enabling the delivery of 
      substantially higher effective doses to a central target volume. METHODS AND 
      MATERIALS: Normalized isoeffective composite dose distributions were formed for 
      20 patients treated on the original protocol (which specified three progressively 
      smaller planning target volumes [PTVs]) using the linear quadratic model (here 
      corrected to equivalent 2 Gy fractions using alpha/beta=10 Gy). These 
      distributions were investigated and a new protocol was designed to preserve a 
      similar level of efficacy and lack of toxicity for the outer volumes, but 
      allowing a higher dose to the inner PTV. Treatment plans were then investigated 
      to determine if the objectives of the new protocol were achievable. In 
      particular, plans that simultaneously achieved all biological treatment planning 
      objectives (all fields treated each day) were investigated. Finally, the success 
      of the protocol design was demonstrated by analysis of the effective dose 
      distributions of 10 patients treated using the new protocol. RESULTS: The 
      composite normalized isoeffective minimum doses to the outer PTVs (PTV3 and PTV2) 
      in the original protocol were close to 60 Gy and 75 Gy, respectively, and these 
      values are specified as the minimum doses to those volumes for the new protocol. 
      Homogeneity requirements to maintain equivalence for the outer target volume 
      domains are: not more than 25% of [PTV3 exclusive of PTV2] >75 Gy; and not more 
      than 50% of [PTV2 exclusive of PTV1] >85 Gy. Treatment plans using multiple 
      noncoplanar arrangements of beams and static intensity modulation treat all 
      volumes at each session. DVHs of the normalized isoeffective dose distributions 
      reveal the equivalence of the new protocol plans to the sequential plans in the 
      previous protocol as well as the ability to achieve a higher dose of 90 Gy to the 
      isocenter of PTV1 (+/-5% homogeneity required). CONCLUSION: The ability to 
      incorporate past experience through use of the linear quadratic model in the 
      design of a new dose escalation protocol is demonstrated.
FAU - Ten Haken, R K
AU  - Ten Haken RK
AD  - Department of Radiation Oncology, The University of Michigan, Ann Arbor 
      48109-0010, USA.
FAU - Fraass, B A
AU  - Fraass BA
FAU - Lichter, A S
AU  - Lichter AS
FAU - Marsh, L H
AU  - Marsh LH
FAU - Radany, E H
AU  - Radany EH
FAU - Sandler, H M
AU  - Sandler HM
LA  - eng
GR  - P01-CA59827/CA/NCI NIH 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
MH  - Brain Neoplasms/*radiotherapy
MH  - Dose Fractionation, Radiation
MH  - Humans
MH  - Linear Models
MH  - Models, Biological
MH  - Radiotherapy Planning, Computer-Assisted
MH  - Radiotherapy, Computer-Assisted/*methods
EDAT- 1998/09/25 00:00
MHDA- 1998/09/25 00:01
CRDT- 1998/09/25 00:00
PHST- 1998/09/25 00:00 [pubmed]
PHST- 1998/09/25 00:01 [medline]
PHST- 1998/09/25 00:00 [entrez]
AID - S0360-3016(98)00208-9 [pii]
AID - 10.1016/s0360-3016(98)00208-9 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 1998 Aug 1;42(1):137-41. doi: 
      10.1016/s0360-3016(98)00208-9.