scholarly journals Dose-Response Relationship in Differentiated Thyroid Cancer Patients Undergoing Radioiodine Treatment Assessed by Means of 124I PET/CT

2016 ◽  
Vol 57 (7) ◽  
pp. 1027-1032 ◽  
Author(s):  
R. Wierts ◽  
B. Brans ◽  
B. Havekes ◽  
G. J. Kemerink ◽  
S. G. Halders ◽  
...  
2015 ◽  
Vol 54 (03) ◽  
pp. 137-143 ◽  
Author(s):  
A.-S. Moldovan ◽  
M. Ruhlmann ◽  
R. Görges ◽  
A. Bockisch ◽  
S. Rosenbaum-Krumme ◽  
...  

SummaryAim: A theoretical dosimetry-based model was applied to estimate the lowest effective radioiodine activity for thyroid remnant ablation of low-risk differentiated thyroid cancer patients. Patients, methods: The model is based on the distribution of the absorbed (radiation) dose per administered radioiodine activity and the absorbed dose threshold of 300 Gy for thyroid remnants, the level believed to destroy most thyroid remnants. For this purpose, 124I PET/CT images of 49 thyroid-ectomised patients were retrospectively analysed to measure the distribution of the (average) absorbed doses to thyroid remnant per administered 131I activity. The fraction of thyroid remnants that received at least 300 Gy was determined for standard activities between 0.37 and 5.55 GBq. The lower activity was considered to be equally effective to that obtained with higher activity if the (absolute) fraction difference was below 5%. Results: A total of 62 thyroid remnants were included. The medians and ranges (in parentheses) for the absorbed dose per unit 131I activity were 359 Gy/GBq (34 to 1825 Gy/ GBq). The fractions of thyroid remnants receiving more than 300 Gy at different therapy activities (within parentheses) were 60% (1.11 GBq), 76% (1.85 GBq), 79% (2.22 GBq), and 81–82% for activities between 2.59 and 3.70 GBq. The therapy activity of 1.11 GBq is considerably less effective than that of 1.85 or 2.22 GBq; therapy activities were equally effective in the range between 2.22 to 3.70 GBq. Conclusion: On the basis of the model and the patients' data included, the lowest effective therapy activity appears to be approximately 2.2 GBq to ablate thyroid remnants. The results of this study may help to guide the design of prospective clinical studies.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Michael Sørensen ◽  
Mette Marie Fode ◽  
Jørgen Baltzer Petersen ◽  
Marianne Ingerslev Holt ◽  
Morten Høyer

Abstract Purpose Stereotactic body radiotherapy (SBRT) is increasingly used for treatment of liver tumors but the effect on metabolic liver function in surrounding tissue is largely unknown. Using 2-deoxy-2-[18F]fluoro-d-galactose ([18F]FDGal) positron emission tomography (PET)/computed tomography (CT), we aimed to determine a dose–response relationship between radiation dose and metabolic liver function as well as recovery. Procedures. One male subject with intrahepatic cholangiocarcinoma and five subjects (1 female, 4 male) with liver metastases from colorectal cancer (mCRC) underwent [18F]FDGal PET/CT before SBRT and after 1 and 3 months. The dose response was calculated using the data after 1 month and the relative recovery was evaluated after 3 months. All patients had normal liver function at time of inclusion. Results A linear dose–response relationship for the individual liver voxel dose was seen until approximately 30 Gy. By fitting a polynomial curve to data, a mean TD50 of 18 Gy was determined with a 95% CI from 12 to 26 Gy. After 3 months, a substantial recovery was observed except in tissue receiving more than 25 Gy. Conclusions [18F]FDGal PET/CT makes it possible to determine a dose–response relationship between radiation dose and metabolic liver function, here with a TD50 of 18 Gy (95% CI 12–26 Gy). Moreover, the method makes it possible to estimate metabolic recovery in liver tissue.


2014 ◽  
Vol 28 (10) ◽  
pp. 970-979 ◽  
Author(s):  
Sertac Asa ◽  
Sabire Yılmaz Aksoy ◽  
Betül Vatankulu ◽  
Anar Aliyev ◽  
Lebriz Uslu ◽  
...  

Author(s):  
V.F. Stepanenko ◽  
◽  
A.D. Kaprin ◽  
S.A. Ivanov ◽  
P.V. Shegay ◽  
...  

Individual retrospective dosimetry was developed at A. Tsyb Medical Radiological Research Centre (A. Tsyb MRRC) after the Chernobyl accident for assessment and analysis of radiation effects on people lived in radioactively contaminated settlements in the Kaluga and Bryansk regions. The method was also used in radiation epidemiology case-control studies within frames of international pilot projects. The ob-tained data demonstrated reliable dose-response relationship for thyroid cancer in patients with diag-nosed thyroid cancer, who were children and adolescents at the time of the accident and resided in radi-oactively contaminated areas in the Bryansk region. The dose-response relationship for diagnosed inva-sive breast cancer was found in women, resided in radioactively contaminated settlements since the acci-dent till the first diagnosis of cancer that was established within the period from October 2008 to February 2013. Their age at diagnosis was under 55 years. At the same time, no dose-response relationship for leu-kaemia was found in children under 5 years old at the time of the accident. The individual retrospective dosimetry method has been updated and used in pilot studies for verifying conservative estimates of radi-ation doses to the population exposed to radiation as a result of nuclear tests at the Semipalatinsk nuclear test site, as well as for verifying estimates of external radiation doses to people affected by the accident at the Fukushima Daiichi NPP. The method was also used for estimating individual doses from residual radi-oactivity for the survivors of the Hiroshima and Nagasaki atomic bombings. The long-term collaboration continues under bilateral International Collaboration Agreements between the National Medical Research Radiological Centre and leading research centres in the Republic of Kazakhstan and Japan. Since 2016 researchers and physicians of A. Tsyb MRRC have modi-fied method of stimulated luminescence of natural and synthetic materials and developed innovative technology in vivo dosimetry that has been put into clinical practice for estimating spatial radiation doses distribution in internal organs at risk during the brachytherapy of prostate cancer, gynecologic and recur-rent pelvic tumors, as well as for estimating local radiation dose to the skin of the breast gland with the tumor. The 35-year experience in the development and application of methods for individual retrospective dosimetry after the Chernobyl accident formed the basis for identifying future-pointing trends for the de-velopment of novel applications of stimulated luminescence techniques. Radiation-induced stimulated luminescence dosimetry can be applicable in uncontrolled radiation events; retrospective dosimetry method applicable for neutron beam radiation therapy is under development. The method of in vivo do-simetry is useful in radiation oncology. Now assembled thermoluminiscent micro-sized dosimeters are used for arterial radioembolization. At present, feasibility of using items of clothing and special inserts (buttons, fastenings, etc.), parts of wearable electronic devices as natural dosimeters, as well as the feasi-bility of using luminescent microdosimeters, made of different materials, after exposure to high LET radiation ranged from a fraction of mGy to the dose greater than 60 Gy have been examined. Development of flexible planar microdosimeter assemblies in order to obtain more detailed information about possible discrepancy in distribution of planned and actual radia-tion doses to patients during radiotherapy is considered.


2015 ◽  
Vol 40 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Leonardo Pace ◽  
Michele Klain ◽  
Barbara Salvatore ◽  
Emanuele Nicolai ◽  
Emilia Zampella ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document