ObjectiveTo compare the dosimetric differences among the double-arc volumetric-modulated arc therapy (VMAT), 7 field intensity-modulated radiotherapy (IMRT) and 3-dimensional conformal radiotherapy (3D-CRT) techniques in treatment planning for cervical cancer as adjuvant radiotherapy. MethodFifteen patients who underwent adjuvant chemotherapy for cervical cancer between March 1st and September 30th, 2013 were chosen to be our study subjects through random sampling. Under Pinnacle 9.2 planning system, the same CT image was designed through three different techniques:VMAT, IMRT and 3D-CRT. We then compared target zone fitness index, evenness index, D98%, D2%, D50% among those different techniques. Monitor unit (MU) and treatment time were also analyzed. ResultsThree techniques showed similar target dose coverage. The IMRT and VMAT plans achieved better target dose conformity, which reduced the V20 of the pelvic, the V50 of the rectum and bladder, as well as the V40/50 of the small intestine (P<0.05). The VMAT technique showed few dosimetric advantages over the IMRT technique. VMAT technique had the advantages of less MU (P>0.05) and shorter overall treatment time (P<0.01) compared with IMRT technique. ConclusionsThe IMRT and VMAT plans achieve similar dose distribution to the target, and are superior to the 3D-CRT plans, in adjuvant radiotherapy for cervical cancer. VMAT technique has the advantages of less MU and shorter overall treatment time.
Nasopharyngeal carcinoma (NPC) is rather common in Southeast Asia and Southern China. The standard treatment for NPC is intensity-modulated radiotherapy (IMRT). A large number of the NPC survivors benefit from the IMRT, while some suffer from the late toxicities which can be life-threatening or significantly erode the patients’ quality of life and functional status, especially in the locally advanced NPC. Nowadays the late radiotherapy-related toxicities have been the most important concern for the radiotherapists and patients, who look forward to the better long-term tumor local control and overall survival. Therefore, we carried out a review about the late radiotherapy-related toxicities of the vital organs at risk after IMRT for NPC patients.