Radiotherapy treatment plans with RapidArc for prostate cancer involving seminal vesicles and lymph nodes.

Dosimetric results and treatment delivery efficiency of RapidArc plans to those of conventional intensity-modulated radiotherapy (IMRT) plans were compared using the Eclipse treatment planning system for high-risk prostate cancer. This study included 10 patients. The primary planning target volume (PTV(P)) contained prostate, seminal vesicles, and pelvic lymph nodes with a margin. The boost PTV (PTV(B)) contained prostate and seminal vesicles with a margin. The total prescription dose was 75.6 Gy (46.8 Gy to PTV(P) and an additional 28.8 Gy to PTV(B); 1.8 Gy/fraction). Three plans were generated for each PTV: Multiple-field IMRT, one-arc RapidArc (1ARC), and two-arc RapidArc (2ARC). In the primary IMRT with PTV(P), average mean doses to bladder, rectum and small bowel were lower by 5.9%, 7.7% and 4.3%, respectively, than in the primary 1ARC and by 3.6%, 4.8% and 3.1%, respectively, than in the primary 2ARC. In the boost IMRT with PTV(B), average mean doses to bladder and rectum were lower by 2.6% and 4.8% than with the boost 1ARC and were higher by 0.6% and 0.2% than with the boost 2ARC. Integral doses were 7% to 9% higher with RapidArc than with IMRT for both primary and boost plans. Treatment delivery time was reduced by 2-7 minutes using RapidArc. For PTVs including prostate, seminal vesicles, and lymph nodes, IMRT performed better in dose sparing for bladder, rectum, and small bowel than did RapidArc. For PTVs including prostate and seminal vesicles, RapidArc with two arcs provided plans comparable to those for IMRT. The treatment delivery is more efficient with RapidArc.

Yoo S ，Wu QJ ，Lee WR ，Yin FF ... -  《-》

Dosimetric advantages and superior treatment delivery efficiency of RapidArc over conventional intensity-modulated radiotherapy in high-risk prostate cancer involving seminal vesicles and pelvic nodes.

To compare the dosimetry and treatment delivery efficiency of RapidArc with conventional intensity-modulated radiotherapy (IMRT) in the treatment of high-risk prostate cancer. Fifteen patients with high-risk localised prostate cancer were studied. Sequential treatment was used. The initial planning target volume (PTV-L) included the prostate, seminal vesicles and pelvic lymphatics, whereas the prostate boost PTV (PTV-P) included the prostate and seminal vesicles only. The total prescription dose was 76 Gy (44 Gy to PTV-L, 32 Gy to PTV-P; 2 Gy/fraction). Two separate planning techniques were generated for each patient: seven static-field IMRT versus two-arc RapidArc. Dose-volume parameters for the organs at risk, conformity index and homogeneity index for the PTVs, the calculated monitor units and treatment delivery time for both techniques were compared. RapidArc gave more conformal plans than IMRT for both PTVs. RapidArc gave a higher homogeneity index to the PTV-P and a similar homogeneity index to the PTV-L. The two techniques gave similar dosimetric results for the rectum, bladder and femoral heads. The mean dose (Dmean) and the maximum dose (Dmax) of the bowel space were reduced by 3.06 and 2.83%, respectively, with RapidArc. The V20 Gy, V30 Gy and V40 Gy for healthy tissues were reduced by 7.77, 14.25 and 17.55%, respectively, with RapidArc. The calculated treatment delivery time and monitor units were reduced by 74.09%/60.93% and 68.32%/48.06% for the PTV-L/PTV-P, respectively, with RapidArc. RapidArc is better than conventional IMRT in terms of dosimetry and delivery efficiency for high-risk prostate cancer.

Poon DM ，Kam M ，Leung CM ，Chau R ，Wong S ，Lee WY ，Wong KC ，Yu B ，Chan A ... -  《-》

Dosimetric study of pelvic proton radiotherapy for high-risk prostate cancer.

Chera BS ，Vargas C ，Morris CG ，Louis D ，Flampouri S ，Yeung D ，Duvvuri S ，Li Z ，Mendenhall NP ... -  《-》

Assessing the role of volumetric modulated arc therapy (VMAT) relative to IMRT and helical tomotherapy in the management of localized, locally advanced, and post-operative prostate cancer.

To quantify differences in treatment delivery efficiency and dosimetry between step-and-shoot intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT) for prostate treatment. Twenty-five prostate cancer patients were selected retrospectively for this planning study. Treatment plans were generated for: prostate alone (n = 5), prostate + seminal vesicles (n = 5), prostate + seminal vesicles + pelvic lymph nodes (n = 5), prostate bed (n = 5), and prostate bed + pelvic lymph nodes (n = 5). Target coverage, dose homogeneity, integral dose, monitor units (MU), and sparing of organs at risk (OAR) were compared across techniques. Time required to deliver each plan was measured. The dosimetric quality of IMRT, VMAT, and HT plans were comparable for target coverage (planning target volume V95%, clinical target volume V100% all >98.7%) and sparing of organs at risk (OAR) for all treatment groups. Although HT resulted in a slightly higher integral dose and mean doses to the OAR, it yielded a lower maximum dose to all OAR examined. VMAT resulted in reductions in treatment times over IMRT (mean = 75%) and HT (mean = 70%). VMAT required 15-38% fewer monitor units than IMRT over all treatment volumes, with the reduction per fraction ranging from 100-423 MU from the smallest to largest volumes. VMAT improves efficiency of delivery for equivalent dosimetric quality as IMRT and HT across various prostate cancer treatment volumes in the intact and postoperative settings.

Davidson MT ，Blake SJ ，Batchelar DL ，Cheung P ，Mah K ... -  《-》

A treatment planning study comparing volumetric arc modulation with RapidArc and fixed field IMRT for cervix uteri radiotherapy.

Cozzi L ，Dinshaw KA ，Shrivastava SK ，Mahantshetty U ，Engineer R ，Deshpande DD ，Jamema SV ，Vanetti E ，Clivio A ，Nicolini G ，Fogliata A ... -  《RADIOTHERAPY AND ONCOLOGY》