Simplified intensity-modulated arc therapy for dose escalated prostate cancer radiotherapy

Gete, E.; Chen, J.Z; Wong, Eugene

doi:10.1016/j.meddos.2003.09.003

Cited by 17 publications

(14 citation statements)

References 21 publications

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“…Our SIMAT planning results agreed with previously published data (20) . With respect to the PPO coverage, the calculated

D_{max}

and

D_{mean}

indicated that our results in the present study are higher by only 2.44% and 2.28% respectively.…”

Section: Resultssupporting

confidence: 92%

“…Also, the values of

D_{max}

in case of the RC and LF were lower only by 1.47% and 3.62% respectively. Our results indicated that the SIMAT plan could be more protective to the RC and LF than that previously published, (20) because the

D_{mean}

values were lower by 7.10% and 17.36% respectively. The large difference in the

D_{mean}

for the LF could be attributable to the definition of that structure, because the LF is delineated as both head and neck in the present study, but in the previous publication, (21) it was delineated as head only.…”

Section: Resultscontrasting

confidence: 45%

“…For SIMAT plans, the prescribed doses in phases I, II, and III were 54 Gy in 27 fractions, 12 Gy in 6 fractions, and 12 Gy in 6 fractions respectively (20) . For M‐DAT plans, the prescribed doses for the PPO and PSV were 78 Gy and 61.23 Gy in 39 fractions.…”

Section: Methodsmentioning

confidence: 99%

“…In phase III, shielded RC arcs of ranges 90 degrees – 180 degrees for left arcs and 180 degrees – 270 degrees for right arcs were used. A margin of 5 mm between field edges and the PTV was taken in all directions (20) . The SIMAT plan was produced by the sum of the three phases using the “plan sum” option of the Eclipse planning system.…”

Section: Methodsmentioning

confidence: 99%

“…The three‐phase SIMAT technique was introduced to use forward‐planning dose calculation to produce the desired concave dose distribution that conforms well to the target (prostate only or prostate plus seminal vesicles), with sparing of rectum. ( 19 , 20 ) The aim is the same as that for intensity‐modulated radiotherapy (IMRT) and intensity‐modulated arc therapy (IMAT), which are advanced techniques of 3D‐CRT and DAT respectively, in which the dose calculations are based on inverse planning.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Forward‐planning intensity‐modulated radiotherapy technique for prostate cancer

Metwaly

Awaad

El-Sayed

et al. 2007

J Applied Clin Med Phys

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In this study, we present an intensity‐modulated radiotherapy technique based on forward planning dose calculations to provide a concave dose distribution to the prostate and seminal vesicles by means of modified dynamic arc therapy (M‐DAT). Dynamic arcs (350 degrees) conforming to the beam's eye view of the prostate and seminal vesicles while shielding the rectum, combined with two lateral oblique conformal fields (15 degrees with respect to laterals) fitting the prostate only, were applied to deliver doses of 78 Gy and 61.23 Gy in 39 fractions to the prostate and seminal vesicles respectively. Dynamic wedges (45 degrees of thick end, anteriorly oriented) were used with conformal beams to adjust the dose homogeneity to the prostate, although in some cases, hard wedges (30 degrees of thick part, inferiorly oriented) were used with arcs to adjust the dose coverage to the seminal vesicles. The M‐DAT was applied to 10 patients in supine and 10 patients in prone positioning to determine the proper patient positioning for optimum protection of the rectum. The M‐DAT was compared with the simplified intensity‐modulated arc therapy (SIMAT) technique, composed of three phases of bilateral dynamic arcs. The mean rectal dose in M‐DAT for prone patients was 22.5±5.1 Gy; in M‐DAT and SIMAT for supine patients, it was 30.2±5.1 Gy and 39.4±6.0 Gy respectively. The doses to 15%, 25%, 35%, and 50% of the rectum volume in M‐DAT for prone patients were 44.5±10.2 Gy, 33.0±8.2 Gy, 25.3±6.4 Gy, and 16.3±5.6 Gy respectively. These values were lower than those in M‐DAT and in SIMAT for supine patients by 7.7%, 18.2%, 22.4%, and 28.5% and by 25.0%, 32.1%, 34.9%, and 41.9% of the prescribed dose (78 Gy) respectively. Ion chamber measurements showed good agreement of the calculated and measured isocentric dose (maximum deviation of 3.5%). Accuracy of the dose distribution calculation was evaluated by film dosimetry using a gamma index, allowing 3% dose variation and 4 mm distance to agreement as the individual acceptance criteria in prostate and seminal vesicle levels alike for all supine and prone patients. We found that fewer than 10% of the pixels in the dose distribution of the calculated area of 10×10−cm failed the acceptance criteria. These pixels were observed mainly in the low‐dose regions, particularly at the level of the seminal vesicles.In conclusion, the single‐phase M‐DAT technique with patients in the prone position was found to provide the intended coverage of the prescribed doses to the prostate and seminal vesicles with improved protection for the rectum. Accordingly, M‐DAT has replaced non‐modulated conformal radiotherapy or SIMAT as the standard treatment for prostate cancer in our department.PACS number: 87.53.Tf

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“…Our SIMAT planning results agreed with previously published data (20) . With respect to the PPO coverage, the calculated