Target delineation and dose prescription of adaptive replanning intensity‐modulated radiotherapy for nasopharyngeal carcinoma

Late-course accelerated hyperfractionated intensity-modulated radiotherapy for nasopharyngeal adenoid cystic carcinoma: A case report

“…Radiotherapy was performed in an adaptive manner which we have previously reported in NPC. 3 In the 22th fraction (46.6 Gy), nasopharynx MRI reviewed a suspected progressed tumor. Under this circumstance, no optimal management was reported before.…”

“…Under the dose tolerance limit requirements of the RTOG 0225 protocol, the dose constraints for OARs were calculated via multiplying the dose tolerance limit (D tolerance limit ) by the percentage of dose of each plan in total dose. 3 In the 22th fraction, nasopharynx MRI was performed and indicated that the right-lateral wall of nasopharynx and the posterior wall of the right roof were significantly thickened with a bigger range compared with the previous one. Right medial pterygoid swelled and significantly enhanced.…”

“…Size and position of tumor and normal organs would change during 1-course radiotherapy, and adaptive replanning IMRT was practiced for NPC in our group since 2013, 3 with a plan-I made for the first 25 fractions followed by a plan-II for the remaining 7 fractions. In this case, plan-I was made with a dose prescription of PGTV-I 53 Gy, PCTV1-I 48 Gy, and PCTV2-I 46 Gy in 25 F over 5 weeks.…”

“…The plan-II was performed after plan-I finished. 3 LCAF-IMRT with an interval of at least 6 hours between fractions was adopted in plan-II with a dose of 19.2 Gy and 16 Gy in 16 fractions over 8 days (twice a day) for PGTV-II and PCTV1-II, respectively. The plans were evaluated via dose-volume histograms and dose coverage.…”

Distribution of regional lymph lode metastasis in unilateral nasopharyngeal carcinoma and the suggestions for selective prophylactic irradiation with intensity‐modulated radiotherapy

“…contralateral lymph node, intensity-modulated radiotherapy, regional lymph node metastasis, selective prophylactic irradiation, unilateral nasopharyngeal carcinoma (high-risk clinical target volume of LNs, CTV1) was defined as GTV + 5-10 mm. The low-risk CTV (CTV2) was defined as having a 5-10 mm margin surrounding CTV1, including the bilateral prophylactically irradiated LN drainage areas which was based on our previous studies 7,12 (Figure 1 shows the CTV2 area of N0 patients). Planning target volume (PTV) was created by expanding 3 mm from all target volumes from the head-to-foot, front-to-back, and left-to-right directions around the target volumes mentioned above to compensate for geometric uncertainties and patient movements, such as PGTVnd (Planning target volume of metastatic LN), PCTV1(Planning highrisk clinical target volume of LNs), and PCTV2 (Planning low-risk clinical target volume).…”