PMID- 9112467
OWN - NLM
STAT- MEDLINE
DCOM- 19970508
LR  - 20220321
IS  - 0360-3016 (Print)
IS  - 0360-3016 (Linking)
VI  - 37
IP  - 3
DP  - 1997 Feb 1
TI  - Comparison of miniature multileaf collimation (MMLC) with circular collimation 
      for stereotactic treatment.
PG  - 679-88
AB  - PURPOSE: A prototype Miniature Multi-Leaf Collimator (MMLC) designed specifically 
      for radiosurgery and small field radiotherapy has been fabricated and evaluated 
      at the University of Texas M. D. Anderson Cancer Center (UTMDACC). This work 
      demonstrates the advantages of a computer-controlled MMLC vs. conventional 
      circular collimation for the treatment of an irregularly shaped target volume in 
      the brain. METHODS AND MATERIALS: Two patient treatments were selected for this 
      comparison from 38 intracranial tumors treated with radiosurgery at UTMDACC from 
      8/6/91 to 5/10/94. Target contours and critical structures defined for one of the 
      patients was used to create a simulated target volume and critical structures in 
      a spherical head phantom. Computer simulations were performed using traditional 
      single isocenter treatment with a circular collimator for a set of six arcs. The 
      same arc paths were used to compute the dose distribution for the MMLC and 
      conformed beam geometries were defined using a three-dimensional (3D) treatment 
      planning system with beam's eye view capabilities. Then, the calculated dose 
      distribution for a single isocenter, conformal treatment was delivered to the 
      spherical head phantom under static conditions by shaping the MMLC to conform the 
      target volume shape projected as a function of couch rotation and gantry angle. 
      Planar dose distributions through the target volume were measured using therapy 
      verification film located in the phantom. The measurements were used to verify 
      that the 3D treatment planning system was capable of simulating the MMLC 
      technique. For the second patient with a peanut-shaped tumor, the 3D treatment 
      planning calculations were used to compare dose distributions for the MMLC and 
      for traditional single and multiple isocenter treatments using circular 
      collimators. The resulting integral dose-volume histograms (DVHs) for the target 
      volume, normal brain, and critical structures for the three treatment techniques 
      were compared. RESULTS: (a) Analysis of the film dosimetry data exemplified the 
      degree of conformation of the high-dose region to the target shape that is 
      possible with a computer-controlled MMLC. (b) Comparison of measured and 
      calculated dose distributions indicates that the 3D treatment planning system can 
      simulate the MMLC treatment. (c) Comparison of DVHs from the single isocenter 
      MMLC and circular collimator treatments shows similar coverage of the target 
      volume with increased dose to the brain for circular collimation (4). Comparison 
      of DVHs from the single isocenter MMLC with the multiple isocenter circular 
      collimator treatment approach shows a more inhomogeneous dose distribution 
      through the target volume and increased dose to the brain for the latter. 
      CONCLUSION: Dosimetry data for single isocenter treatments using 
      computer-controlled field shaping with a MMLC demonstrate the ability to conform 
      the dose distribution to an irregularly shaped target volume. DVHs validated that 
      the single isocenter MMLC treatment is preferable to both single and multiple 
      isocenter, circular collimator treatment because it provides a more uniform dose 
      distribution to an irregularly shaped target volume and reduces the dose to 
      surrounding brain tissue for the example cases.
FAU - Shiu, A S
AU  - Shiu AS
AD  - Department of Radiation Physics, The University of Texas M.D. Anderson Cancer 
      Center, Houston 77030, USA.
FAU - Kooy, H M
AU  - Kooy HM
FAU - Ewton, J R
AU  - Ewton JR
FAU - Tung, S S
AU  - Tung SS
FAU - Wong, J
AU  - Wong J
FAU - Antes, K
AU  - Antes K
FAU - Maor, M H
AU  - Maor MH
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
MH  - Adenocarcinoma/secondary/*surgery
MH  - Brain Neoplasms/secondary/*surgery
MH  - Breast Neoplasms/pathology
MH  - Cavernous Sinus/*surgery
MH  - *Computer Simulation
MH  - Equipment Design
MH  - Female
MH  - Humans
MH  - Meningeal Neoplasms/*surgery
MH  - Meningioma/*surgery
MH  - Neoplasms, Radiation-Induced/*surgery
MH  - Neoplasms, Second Primary/*surgery
MH  - Radiosurgery/*instrumentation
MH  - Radiotherapy Dosage
MH  - Rhabdomyosarcoma, Embryonal/radiotherapy
MH  - Skull Neoplasms/radiotherapy
MH  - Therapy, Computer-Assisted/*instrumentation
EDAT- 1997/02/01 00:00
MHDA- 1997/02/01 00:01
CRDT- 1997/02/01 00:00
PHST- 1997/02/01 00:00 [pubmed]
PHST- 1997/02/01 00:01 [medline]
PHST- 1997/02/01 00:00 [entrez]
AID - S036030169600507X [pii]
AID - 10.1016/s0360-3016(96)00507-x [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 1997 Feb 1;37(3):679-88. doi: 
      10.1016/s0360-3016(96)00507-x.