JOSE WILLEGAIGNON DE AMORIM DE CARVALHO

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LIM/43 - Laboratório de Medicina Nuclear, Hospital das Clínicas, Faculdade de Medicina

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Assunto: Radiology, Nuclear Medicine & Medical Imaging ×

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  • article 8 Citação(ões) na Scopus
    Comparison of different dosimetric methods for red marrow absorbed dose calculation in thyroid cancer therapy
    (2012) WILLEGAIGNON, Jose; SAPIENZA, Marcelo T.; BUCHPIGUEL, Carlos A.
    Several dosimetric methods have been proposed for estimating red marrow absorbed dose (RMAD) when radionuclide therapy is planned for differentiated thyroid cancer, although to date, there is no consensus as to whether dose calculation should be based on blood-activity concentration or not. Our purpose was to compare RMADs derived from methods that require collecting patients' blood samples versus those involving OLINDA/EXM software, thereby precluding this invasive procedure. This is a retrospective study that included 34 patients under treatment for metastatic thyroid disease. A deviation of 10 between RMADs was found, when comparing the doses from the most usual invasive dosimetric methods and those from OLINDA/EXM. No statistical difference between the methods was discovered, whereby the need for invasive procedures when calculating the dose is questioned. The use of OLINDA/EXM in clinical routine could possibly diminish data collection, thus giving rise to a simultaneous reduction in time and clinical costs, besides avoiding any kind of discomfort on the part of the patients involved.
  • conferenceObject
    Case study: Evaluating the new University of Florida hybrid pediatric phantoms and tissue weighting factors from ICRP Publication 103 for diagnostic dosimetry
    (2018) JOSEFSSON, Anders; HOBBS, Robert; RANKA, Sagar; SCHWARZ, Bryan; CARVALHO, Jose Willegaignon de Amorim de; BUCHPIGUEL, Carlos Alberto; SAPIENZA, Marcelo Tatit; BOLCH, Wesley; SGOUROS, George
  • article 5 Citação(ões) na Scopus
    Evaluation of Parotid Salivary Gland Echo Texture by Ultrasound Examinations and Correlation With Whole-Body Scintigraphy After Radioiodine Therapy in Patients With Differentiated Thyroid Carcinoma
    (2020) LIMA, Graziele Aparecida Simoes; LOPEZ, Rossana Veronica Mendoza; FREITAS, Ricardo Miguel Costa de; WILLEGAIGNON, Jose; SAPIENZA, Marcelo Tatit; CHAMMAS, Maria Christina; COURA-FILHO, George Barberio
    Objectives This study aimed to evaluate the echo texture of the parotid salivary glands before and after radioiodine therapy (RIT) using ultrasound (US) images in patients with differentiated thyroid cancer and to evaluate the correlations between post-RIT whole-body scintigraphy (WBS) images and US image patterns in salivary and cervical areas. Methods A retrospective study was performed with data on demographic and clinical information, US examinations, and WBS images collected through medical recordings. Results Comparing the US features before and after RIT, significant echo texture heterogeneity was found in 31.3% of all patients evaluated. When evaluated according to the level of iodine 131 (I-131) radioactivity (<5.6, 5.6-<9.3, and >= 9.3 GBq), echo texture heterogeneity was significantly associated with the 5.6-GBq I-131 radioactivity group (P < .001). No association was found for any level of I-131 post-RIT WBS uptake intensity and changes in US feature patterns. Conclusions Ultrasound may be a useful tool for evaluating chronic sialadenitis after RIT, and the I-131 uptake intensity using a routine post-RIT WBS is not associated with US echo texture changes.
  • article 12 Citação(ões) na Scopus
    Clinical and Dosimetric Variables Related to Outcome After Treatment of Graves' Disease With 550 and 1110 MBq of I-131
    (2015) SAPIENZA, Marcelo Tatit; COURA-FILHO, George Barberio; WILLEGAIGNON, Jose; WATANABE, Tomoco; DUARTE, Paulo Schiavom; BUCHPIGUEL, Carlos Alberto
    Therapy of Graves' hyperthyroidism (HTG) with I-131 is still mostly performed on an empirical basis. The present study was carried out to evaluate clinical and dosimetric variables associated with outcome in HTG therapy, which could contribute to planning and defining the most appropriate activity to be administered. Methods Patients with HTG were randomly assigned to therapy with 555 MBq (15mci) or 1110 MBq (30 mCi) of I-131. Estimation of thyroid radiation absorbed dose was made according to MIRD methodology. Success was defined as clinical/laboratory euthyroidism or hypothyroidism one year after therapy. The association between clinical, laboratory, and dosimetric variables with 1-year outcome was measured using bivariate analysis, followed by logistic regression. Results Ninety-one patients included completed the follow-up. Therapeutic success was observed in 77 (84.6%) of them, in a greater proportion when 1110 MBq of I-131 was administered as compared with 550 MBq (94.8% vs 77.4%, P = 0.02). Besides administered activity, multivariate analysis indicated that outcome was related to patient age and gland mass. A higher therapeutic success rate was achieved with doses greater than 300 Gy as compared with doses less than 300 Gy (89% vs 60%, P = 0.01). Conclusion Administered activity, age, and gland mass were related to the outcome. Radiation absorbed dose, although not significant according to multivariate analysis, may be used as a quantitative parameter in therapy planning, with a target dose of 300 Gy. In cases where a rapid and efficient response to radioiodine treatment is required, adoption of a simplified protocol employing high activities is justified.
  • article 6 Citação(ões) na Scopus
    Estimating 131I biokinetics and radiation doses to the red marrow and whole body in thyroid cancer patients: probe detection versus image quantification
    (2016) WILLEGAIGNON, José; PELISSONI, Rogério Alexandre; LIMA, Beatriz Christine de Godoy Diniz; SAPIENZA, Marcelo Tatit; COURA-FILHO, George Barberio; QUEIROZ, Marcelo Araújo; BUCHPIGUEL, Carlos Alberto
    Abstract Objective: To compare the probe detection method with the image quantification method when estimating 131I biokinetics and radiation doses to the red marrow and whole body in the treatment of thyroid cancer patients. Materials and Methods: Fourteen patients with metastatic thyroid cancer, without metastatic bone involvement, were submitted to therapy planning in order to tailor the therapeutic amount of 131I to each individual. Whole-body scans and probe measurements were performed at 4, 24, 48, 72, and 96 h after 131I administration in order to estimate the effective half-life (Teff) and residence time of 131I in the body. Results: The mean values for Teff and residence time, respectively, were 19 ± 9 h and 28 ± 12 h for probe detection, compared with 20 ± 13 h and 29 ± 18 h for image quantification. The average dose to the red marrow and whole body, respectively, was 0.061 ± 0.041 mGy/MBq and 0.073 ± 0.040 mGy/MBq for probe detection, compared with 0.066 ± 0.055 mGy/MBq and 0.078 ± 0.056 mGy/MBq for image quantification. Statistical analysis proved that there were no significant differences between the two methods for estimating the Teff (p = 0.801), residence time (p = 0.801), dose to the red marrow (p = 0.708), and dose to the whole body (p = 0.811), even when we considered an optimized approach for calculating doses only at 4 h and 96 h after 131I administration (p > 0.914). Conclusion: There is full agreement as to the feasibility of using probe detection and image quantification when estimating 131I biokinetics and red-marrow/whole-body doses. However, because the probe detection method is inefficacious in identifying tumor sites and critical organs during radionuclide therapy and therefore liable to skew adjustment of the amount of 131I to be administered to patients under such therapy, it should be used with caution.
  • article 12 Citação(ões) na Scopus
    Graves' disease radioiodine-therapy: Choosing target absorbed doses for therapy planning
    (2014) WILLEGAIGNON, J.; SAPIENZA, M. T.; COURA-FILHO, G. B.; WATANABE, T.; TRAINO, A. C.; BUCHPIGUEL, C. A.
    Purpose: The precise determination of organ mass (m(th)) and total number of disintegrations within the thyroid gland ((A) over tilde) are essential for thyroid absorbed-dose calculations for radioiodine therapy. Nevertheless, these parameters may vary according to the method employed for their estimation, thus introducing uncertainty in the estimated thyroid absorbed dose and in any dose-response relationship derived using such estimates. In consideration of these points, thyroid absorbed doses for Graves' disease (GD) treatment planning were calculated using different approaches to estimating the m(th) and the (A) over tilde. Methods: Fifty patients were included in the study. Thyroid I-131 uptake measurements were performed at 2, 6, 24, 48, 96, and 220 h postadministration of a tracer activity in order to estimate the effective half-time (T-eff) of I-131 in the thyroid; the thyroid cumulated activity was then estimated using the Teff thus determined or, alternatively, calculated by numeric integration of the measured time-activity data. Thyroid mass was estimated by ultrasonography (USG) and scintigraphy (SCTG). Absorbed doses were calculated with the OLINDA/EXM software. The relationships between thyroid absorbed dose and therapy response were evaluated at 3 months and 1 year after therapy. Results: The average ratio (+/- 1 standard deviation) between m(th) estimated by SCTG and USG was 1.74 (+/- 0.64) and that between (A) over tilde obtained by Teff and the integration of measured activity in the gland was 1.71 (+/- 0.14). These differences affect the calculated absorbed dose. Overall, therapeutic success, corresponding to induction of durable hypothyroidism or euthyroidism, was achieved in 72% of all patients at 3 months and in 90% at 1 year. A therapeutic success rate of at least 95% was found in the group of patients receiving doses of 200 Gy (p = 0.0483) and 330 Gy (p = 0.0131) when m(th) was measured by either USG or SCTG and (A) over tilde was determined by the integration of measured I-131 activity in the thyroid gland and based on T-eff, respectively. No statistically significant relationship was found between therapeutic response and patients' age, administered I-131 activity (MBq), 24-h thyroid I-131 uptake (%) or T-eff (p >= 0.064); nonetheless, a good relationship was found between the therapeutic response and mth (p >= 0.035). Conclusions: According to the results of this study, the most effective thyroid absorbed dose to be targeted in GD therapy should not be based on a fixed dose but rather should be individualized based on the patient's m(th) and (A) over tilde. To achieve a therapeutic success (i.e., durable euthyroidism or hypothyroidism) rate of at least 95%, a thyroid absorbed dose of 200 or 330 Gy is required depending on the methodology used for estimating m(th) and (A) over tilde. (C) 2014 American Association of Physicists in Medicine.
  • article 8 Citação(ões) na Scopus
    Iodine/FDG ""Flip-Flop"" Phenomenon Inside a Large Metastatic Thyroid Cancer Lesion Better Characterized on SPECT/CT and PET/CT Studies
    (2018) DUARTE, Paulo Schiavom; MARIN, Jose Flavio Gomes; CARVALHO, Jose Willegaignon de Amorim de; SAPIENZA, Marcelo Tatit; BUCHPIGUEL, Carlos Alberto
    Iodine/FDG flip-flop phenomenon inside large metastatic thyroid cancer lesions has been rarely described. We present a case of this phenomenon better characterized using SPECT/CT and PET/CT studies.
  • article 0 Citação(ões) na Scopus
    Outpatient Radioiodine Therapy for Thyroid Cancer A Safe Nuclear Medicine Procedure
    (2011) WILLEGAIGNON, Jose; SAPIENZA, Marcelo; ONO, Carla; WATANABE, Tomoco; GUIMARAES, Maria Ines; GUTTERRES, Ricardo; MARECHAL, Maria Helena; BUCHPIGUEL, Carlos
    Purposes: To evaluate the dosimetric effect of outpatient radioiodine therapy for thyroid cancer in members of a patient's family and their living environment, when using iodine-131 doses reaching 7.4 GBq. The following parameters were thus defined: (a) whole-body radiation doses to caregivers, (b) the production of contaminated solid waste, and (c) radiation potential and surface contamination within patients' living quarters. Methods: In total, 100 patients were treated on an outpatient basis, taking into consideration their acceptable living conditions, interests, and willingness to comply with medical and radiation safety guidelines. Both the caregivers and the radiation dose potentiality inside patients' residences were monitored by using thermoluminescent dosimeters. Surface contamination and contaminated solid wastes were identified and measured with a Geiger-Muller detector. Results: A total of 90 monitored individuals received a mean dose of 0.27 (+/- 0.28) mSv, and the maximum dose registered was 1.6 mSv. The mean value for the potential dose within all living quarters was 0.31(+/- 0.34) mSv, and the mean value per monitored surface was 5.58 Bq/cm(2) for all the 1659 points measured. The overall production of contaminated solid wastes was at a low level, being about 3 times less than the exemption level indicated by the International Atomic Energy Agency. Conclusions: This study indicates that the treatment of thyroid cancer by applying radioiodine activities up to 7.4 GBq, on an outpatient basis, is a safe procedure, especially when supervised by qualified professionals. This alternative therapy should be a topic for careful discussion considering the high potential for reducing costs in healthcare and improving patient acceptance.
  • article 9 Citação(ões) na Scopus
    Pediatric 131I-MIBG Therapy for Neuroblastoma: Whole-Body 131I-MIBG Clearance, Radiation Doses to Patients, Family Caregivers, Medical Staff, and Radiation Safety Measures
    (2018) WILLEGAIGNON, Jose; CREMA, Karin Paola; OLIVEIRA, Nathalie Canhameiro; PELISSONI, Rogerio Alexandre; COURA-FILHO, George Barberio; SAPIENZA, Marcelo Tatit; BUCHPIGUEL, Carlos Alberto
    Purpose I-131-metaiodobenzylguanidine (I-131-MIBG) has been used in the diagnosis and therapy of neuroblastoma in adult and pediatric patients for many years. In this study, we evaluated whole-body I-131-MIBG clearance and radiation doses received by patients, family caregivers, and medical staff to establish appropriate radiation safety measures to be used in therapy applications. Methods Research was focused on 23 children and adolescents with metastatic neuroblastoma, with ages ranging from 1.8 to 13 years, being treated with I-131-MIBG. Based on measured external dose rates from patients, dosimetric data to patients, family members, and others were calculated. Results The mean SD I-131-MIBG activity administered was 8.55 +/- 1.69 GBq. Percent whole-body retention rates of I-131-MIBG at 24, 48, and 72 hours after administration were 48% +/- 7%, 23% +/- 7%, and 12% +/- 6%, with a whole-body I-131-MIBG effective half-life of 23 +/- 5 hours for all patients. The mean doses for patients were 0.234 +/- 0.096 mGyMBq(-1) to red-marrow and 0.251 +/- 0.101 mGyMBq(-1) to whole body. The maximum potential radiation doses transmitted by patients to others at 1.0 m was estimated to be 11.9 +/- 3.4 mSv, with 97% of this dose occurring over 120 hours after therapy administration. Measured mean dose received by the 22 family caregivers was 1.88 +/- 1.85 mSv, and that received by the 19 pediatric physicians was 43 +/- 51 Sv. Conclusion In this study, we evaluated the whole-body clearance of I-131-MIBG in 23 pediatric patients, and the radiation doses received by family caregivers and medical staff during these therapy procedures, thus facilitating the establishment of radiation safety measures to be applied in pediatric therapy.
  • article 0 Citação(ões) na Scopus
    Influence on voxel-based dosimetry: noise effect on absorbed dose dosimetry at single time-point versus sequential single-photon emission computed tomography
    (2023) FONDA, Uysha de S.; LEITAO, Andre L. A.; PAIVA, Marcia M. D. P.; WILLEGAIGNON, Jose; JOSEFSSON, Anders; BUCHPIGUEL, Carlos A.; SAPIENZA, Marcelo T.
    ObjectiveThe purpose of this study was to evaluate how statistical fluctuation in single-photon emission computed tomography (SPECT) images propagate to absorbed dose maps. MethodsSPECT/computed tomography (CT) images of iodine-131 filled phantoms, using different acquisition and processing protocols, were evaluated using STRATOS software to assess the absorbed dose distribution at the voxel level. Absorbed dose values and coefficient of variation (COV) were analyzed for dosimetry based on single time-point SPECT images and time-integrated activities of SPECT sequences with low and high counts. ResultsConsidering dosimetry based on a single time-point, the mean absorbed dose was not significantly affected by total counts or reconstruction parameters, but the uniformity of the absorbed dose maps had an almost linear correlation with SPECT noise. When high- and low-count SPECT sequences were used to generate an absorbed dose map, the absorbed dose COV for each of the temporal sequences was slightly lower than the absorbed dose COV based on the single SPECT image with the highest count included in the sequence. ConclusionThe impact of changes in SPECT counts and reconstruction parameters is almost linear when dosimetry is based on isolated SPECT images, but less pronounced when dosimetry is based on sequential SPECTs.