AbstractID: 7643 Title: When Is a Combination of IMRT/Conformal Radiation Therapy Is
Superior to Either IMRT or Conformal Therapy Alone?
Three-dimensional treatment planning has raised the art of radiation therapy. Plans
are more easily modified to increase dose to target tissues while sparing critical
dose-limiting structures and has facilitated patient dosimetry by calculating dose to
these structures. Two types of 3D plans used today are conformal therapy and
intensity-modulated radiation therapy (IMRT), each has its own strengths and
weaknesses. This study compares conformal treatment, IMRT, and a combination
of the two and considers when one treatment is preferred over the others.
Seven representative cases were selected for this review. For each case, the patient
received a CT scan, which was used to plan a treatment with either ADAC for
conformal therapy, PEACOCK for IMRT, or conformal therapy followed by a
boost to the target using IMRT. In order to compare the three sets of plans for
each case, specific parameters representing dose distributions to target and nontarget tissues had to be calculated for each type of treatment, analyzed and then
summed for the case of combination therapy. The three parameters selected were:
the target vs. non-target dose ratio, the DVH, and dose to critical structures. For
each case, the three plans were analyzed and ranked according to target vs. nontarget dose ratio, the DVH, dose to critical structures and treatment time. The
combination therapy ranked better than either the conformal or conventional
therapy alone in cases of head/neck and abdominal radiation treatment, indicating
that a combination therapy may be superior to either conformal therapy or IMRT
plans alone.
AbstractID: 7643 Title: When Is a Combination of IMRT/Conformal Radiation Therapy Is
Superior to Either IMRT or Conformal Therapy Alone?