Open AccessUsing max standardized uptake value from positron emission tomography to assess tumor responses after lung stereotactic body radiotherapy for different prescriptions
Author(s) -
Ding Meisong,
Zollinger William,
Ebeling Robert,
Heard David,
Posey Ryan
Publication year - 2018
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12453
Subject(s) - medical prescription , medicine , nuclear medicine , standardized uptake value , radiation therapy , lung cancer , positron emission tomography , radiosurgery , radiology , pharmacology
Purpose To retrospectively investigate tumor responses of lung SBRT patients for different prescriptions. To analyze the relation between optimal biologically equivalent dose ( BED ) and tumor responses. Methods and Materials Tumor responses after lung SBRT were compared by examining 48 treatments used four prescriptions. This study used simplified tumor response criteria: (a) Complete Response ( CR ) — post max SUV ( SUV post ) after SBRT in the treated tumor region was almost the same as the SUV s in the surrounding regions; (b) Partial Response ( PR ) — SUV post was smaller than previous max SUV ( SUV pre ), but was greater than the SUV s in the surrounding regions; (c) No Response ( NR ) — SUV post was the same as or greater than SUV pre . Some SUV post reported as mild or favorable responses were classified as CR / PR . BED calculated using α / β of 10 Gy were analyzed with assessments of tumor responses for SBRT prescriptions. Results For the prescriptions (9 Gy × 5, 10 Gy × 5, 11 Gy × 5, and 12 Gy × 4) historically recommended by RTOG , we observed that higher BED 10 and lower tumor volume would achieve a higher complete response rate. The highest complete response rate was observed for smallest tumor volume ( PTV ave = 6.8 cc) with higher BED 10 (105.6) of 12 Gy × 4 prescription. For 11 Gy × 5 prescription, the BED 10 (115.5) was the highest, but its complete response rate (58%) was lower than 79% of 12 Gy × 4 prescription. We observed the PTV ave of 11 Gy × 5 prescription was more than double of the PTV ave of 12 Gy × 4 prescription. For the same lung SBRT prescription ( BED 10 > 100) earlier staging tumor had more favorable local control. Conclusion We demonstrated post max SUV read from PET / CT could efficiently and accurately assess tumor response after lung SBRT . Although SBRT with prescriptions resulting in a BED 10 > 100 experienced favorable tumor responses for early staging cancer, escalation of BED 10 to higher levels would be beneficial for lung cancer patients with later staging and larger volume tumors.