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Objectives: To estimate the number of patients who receive a cumulative effective dose (CED) of ≥ 100 mSv from computed tomography (CT) in a single day or episode of care.Methods: We examined 28,870 patients who underwent 49,834 CT examinations in a tertiary care centre in Italy in 2.5 years. Radiation exposures were retrieved from the hospital's automatic exposure monitoring system. Two cohorts were identified as those who received a CED of ≥ 100 mSv in a single day and within a month starting from the first examination. Organ doses were estimated for the first cohort.Results: Among the 1765 (6.1%) patients who received CED ≥ 100 mSv in the observation period, 427 received a CED of ≥ 100 mSv within a month (and 70 patients in a single day). This group represented 1.5% of all patients who underwent CT exams and 24% of those who received CED ≥ 100 mSv in the observation period. The clinical indication for referral included cancer in 132 patients (31%) and non-oncological indications in 295 patients (69%). In 68/70 patients with CED > 100 mSv in a single day, at least one organ/tissue received a dose of ≥ 100 mGy.Conclusions: The finding of a sizeable percentage of patients undergoing CT exams and receiving CED ≥ 100 mSv in a single episode of care points toward the need of imaging appropriateness criteria, to revise the routine protocols, to replace older machines, and to provide to the radiologist the patient's prior radiation history to facilitate an appropriate decision-making process.Key Points: • Patients can receive effective doses greater than 100 mSv in a single CT or in multiple CT examinations performed in a single episode of care in 1.5% of patients in a 2.5-year period. • In this study, the clinical indication for CT referral was non-oncological in 69% of patients. • The patient's prior radiation history should be provided to the referring physicians and the radiological medical practitioner to facilitate an appropriate decision-making process. [ABSTRACT FROM AUTHOR]

Introduction: The study aims were: (1) to assess the incidence in 1 year, the cumulative incidences and the period prevalence in 3/5 years of the condition of patients accruing cumulative effective dose (CED) ≥ 100 mSv in health care centres providing CT examinations in Slovakia; and (2) to quantify their variability among different centres, to test the feasibility of establishing recurrent exposure reference levels (RERL) on a nationwide level.The data were tracked during five consecutive years using the CT dose index and dose-length-product along with the patient’s ID. ED was calculated using conversion factors. Hospitals were stratified according to the number of beds in clinics (0), small (< 200), medium (201–500), or large (> 500) hospitals.The database included 1,278,928 patients who underwent 2,157,508 CT exams in 5 years. The I100;1 (%), I100;3 (%), I100;5 (%) ranged from 0% to 6.2%, from 0.3% to 23.2% and from 0.3% to 36.9%, respectively. The P100;3 (%), P100;5 (%) ranged from 0.17% to 13.3% and from 0.19% to 17.8%, respectively. No significant differences were found in epidemiological indexes among different hospital sizes. A strong positive correlation was found between the third quartile values of yearly CED and I100;1 (%) (r = 0.84; R2 = 0.70; p < 0.0001). RERL value, set as the 75th percentiles of the distributions of the 3rd quartiles of the yearly CED, amounted to 25.7 mSv.The management of patients with recurrent CT exposures is highly variable among hospitals and unrelated to the size of the institution. Incidence should be reported instead of prevalence.QuestionBeyond just reporting statistics on recurrent imaging, the question which needs to be addressed is how to use such information to optimise patient protection.FindingsIn Slovakia the 5-year incidence of patients with CED ≥ 100 mSv average 6% and range from 0.3% to 36.9% among different hospitals.Clinical relevanceThe incidence of patients with CED ≥ 100 mSv is highly variable among hospitals and unrelated to their size. The heterogeneity in the radiation exposure of recurrent patients prompts the introduction of RERL to aid in the optimisation of patient protection.Materials and methods: The study aims were: (1) to assess the incidence in 1 year, the cumulative incidences and the period prevalence in 3/5 years of the condition of patients accruing cumulative effective dose (CED) ≥ 100 mSv in health care centres providing CT examinations in Slovakia; and (2) to quantify their variability among different centres, to test the feasibility of establishing recurrent exposure reference levels (RERL) on a nationwide level.The data were tracked during five consecutive years using the CT dose index and dose-length-product along with the patient’s ID. ED was calculated using conversion factors. Hospitals were stratified according to the number of beds in clinics (0), small (< 200), medium (201–500), or large (> 500) hospitals.The database included 1,278,928 patients who underwent 2,157,508 CT exams in 5 years. The I100;1 (%), I100;3 (%), I100;5 (%) ranged from 0% to 6.2%, from 0.3% to 23.2% and from 0.3% to 36.9%, respectively. The P100;3 (%), P100;5 (%) ranged from 0.17% to 13.3% and from 0.19% to 17.8%, respectively. No significant differences were found in epidemiological indexes among different hospital sizes. A strong positive correlation was found between the third quartile values of yearly CED and I100;1 (%) (r = 0.84; R2 = 0.70; p < 0.0001). RERL value, set as the 75th percentiles of the distributions of the 3rd quartiles of the yearly CED, amounted to 25.7 mSv.The management of patients with recurrent CT exposures is highly variable among hospitals and unrelated to the size of the institution. Incidence should be reported instead of prevalence.QuestionBeyond just reporting statistics on recurrent imaging, the question which needs to be addressed is how to use such information to optimise patient protection.FindingsIn Slovakia the 5-year incidence of patients with CED ≥ 100 mSv average 6% and range from 0.3% to 36.9% among different hospitals.Clinical relevanceThe incidence of patients with CED ≥ 100 mSv is highly variable among hospitals and unrelated to their size. The heterogeneity in the radiation exposure of recurrent patients prompts the introduction of RERL to aid in the optimisation of patient protection.Results: The study aims were: (1) to assess the incidence in 1 year, the cumulative incidences and the period prevalence in 3/5 years of the condition of patients accruing cumulative effective dose (CED) ≥ 100 mSv in health care centres providing CT examinations in Slovakia; and (2) to quantify their variability among different centres, to test the feasibility of establishing recurrent exposure reference levels (RERL) on a nationwide level.The data were tracked during five consecutive years using the CT dose index and dose-length-product along with the patient’s ID. ED was calculated using conversion factors. Hospitals were stratified according to the number of beds in clinics (0), small (< 200), medium (201–500), or large (> 500) hospitals.The database included 1,278,928 patients who underwent 2,157,508 CT exams in 5 years. The I100;1 (%), I100;3 (%), I100;5 (%) ranged from 0% to 6.2%, from 0.3% to 23.2% and from 0.3% to 36.9%, respectively. The P100;3 (%), P100;5 (%) ranged from 0.17% to 13.3% and from 0.19% to 17.8%, respectively. No significant differences were found in epidemiological indexes among different hospital sizes. A strong positive correlation was found between the third quartile values of yearly CED and I100;1 (%) (r = 0.84; R2 = 0.70; p < 0.0001). RERL value, set as the 75th percentiles of the distributions of the 3rd quartiles of the yearly CED, amounted to 25.7 mSv.The management of patients with recurrent CT exposures is highly variable among hospitals and unrelated to the size of the institution. Incidence should be reported instead of prevalence.QuestionBeyond just reporting statistics on recurrent imaging, the question which needs to be addressed is how to use such information to optimise patient protection.FindingsIn Slovakia the 5-year incidence of patients with CED ≥ 100 mSv average 6% and range from 0.3% to 36.9% among different hospitals.Clinical relevanceThe incidence of patients with CED ≥ 100 mSv is highly variable among hospitals and unrelated to their size. The heterogeneity in the radiation exposure of recurrent patients prompts the introduction of RERL to aid in the optimisation of patient protection.Conclusion: The study aims were: (1) to assess the incidence in 1 year, the cumulative incidences and the period prevalence in 3/5 years of the condition of patients accruing cumulative effective dose (CED) ≥ 100 mSv in health care centres providing CT examinations in Slovakia; and (2) to quantify their variability among different centres, to test the feasibility of establishing recurrent exposure reference levels (RERL) on a nationwide level.The data were tracked during five consecutive years using the CT dose index and dose-length-product along with the patient’s ID. ED was calculated using conversion factors. Hospitals were stratified according to the number of beds in clinics (0), small (< 200), medium (201–500), or large (> 500) hospitals.The database included 1,278,928 patients who underwent 2,157,508 CT exams in 5 years. The I100;1 (%), I100;3 (%), I100;5 (%) ranged from 0% to 6.2%, from 0.3% to 23.2% and from 0.3% to 36.9%, respectively. The P100;3 (%), P100;5 (%) ranged from 0.17% to 13.3% and from 0.19% to 17.8%, respectively. No significant differences were found in epidemiological indexes among different hospital sizes. A strong positive correlation was found between the third quartile values of yearly CED and I100;1 (%) (r = 0.84; R2 = 0.70; p < 0.0001). RERL value, set as the 75th percentiles of the distributions of the 3rd quartiles of the yearly CED, amounted to 25.7 mSv.The management of patients with recurrent CT exposures is highly variable among hospitals and unrelated to the size of the institution. Incidence should be reported instead of prevalence.QuestionBeyond just reporting statistics on recurrent imaging, the question which needs to be addressed is how to use such information to optimise patient protection.FindingsIn Slovakia the 5-year incidence of patients with CED ≥ 100 mSv average 6% and range from 0.3% to 36.9% among different hospitals.Clinical relevanceThe incidence of patients with CED ≥ 100 mSv is highly variable among hospitals and unrelated to their size. The heterogeneity in the radiation exposure of recurrent patients prompts the introduction of RERL to aid in the optimisation of patient protection.Key Points: The study aims were: (1) to assess the incidence in 1 year, the cumulative incidences and the period prevalence in 3/5 years of the condition of patients accruing cumulative effective dose (CED) ≥ 100 mSv in health care centres providing CT examinations in Slovakia; and (2) to quantify their variability among different centres, to test the feasibility of establishing recurrent exposure reference levels (RERL) on a nationwide level.The data were tracked during five consecutive years using the CT dose index and dose-length-product along with the patient’s ID. ED was calculated using conversion factors. Hospitals were stratified according to the number of beds in clinics (0), small (< 200), medium (201–500), or large (> 500) hospitals.The database included 1,278,928 patients who underwent 2,157,508 CT exams in 5 years. The I100;1 (%), I100;3 (%), I100;5 (%) ranged from 0% to 6.2%, from 0.3% to 23.2% and from 0.3% to 36.9%, respectively. The P100;3 (%), P100;5 (%) ranged from 0.17% to 13.3% and from 0.19% to 17.8%, respectively. No significant differences were found in epidemiological indexes among different hospital sizes. A strong positive correlation was found between the third quartile values of yearly CED and I100;1 (%) (r = 0.84; R2 = 0.70; p < 0.0001). RERL value, set as the 75th percentiles of the distributions of the 3rd quartiles of the yearly CED, amounted to 25.7 mSv.The management of patients with recurrent CT exposures is highly variable among hospitals and unrelated to the size of the institution. Incidence should be reported instead of prevalence.QuestionBeyond just reporting statistics on recurrent imaging, the question which needs to be addressed is how to use such information to optimise patient protection.FindingsIn Slovakia the 5-year incidence of patients with CED ≥ 100 mSv average 6% and range from 0.3% to 36.9% among different hospitals.Clinical relevanceThe incidence of patients with CED ≥ 100 mSv is highly variable among hospitals and unrelated to their size. The heterogeneity in the radiation exposure of recurrent patients prompts the introduction of RERL to aid in the optimisation of patient protection. [ABSTRACT FROM AUTHOR]

Objectives: To assess the incidence (1 year) and the cumulative incidence (3 years) of the condition of patients accruing cumulative effective doses (CED) of ≥ 100 mSv and their variability among different hospitals. To establish and validate a reference level for the CED in patients with recurrent exposures (RERL) and provide a RERL value. Methods: Data of CT exposure was collected in 9 similar hospitals. The database included 294,222 patient*years who underwent 442,278 CT exams in 3 years. The incidence proportion of patients with CED ≥ 100 mSv in a given year (I100;1) and the 3-year cumulative incidence of patients with CED ≥ 100 mSv over 3 consecutive years (I100;3) were calculated and compared among different institutions. Results: I100;1 ranged from a minimum of 0.1% to a maximum of 5.1%. The percentage of recurrent patients was quite uniform among centres ranging from 23 to 38%. The I100;3 ranged from a minimum of 1.1 to 11.4%. There was a strong positive correlation between the third quartile values of yearly CED and yearly incidence (r = 0.90; R2 = 0.81; p < 0.0001). RERL value in our study was found at 34.0 mSv. Conclusion: The management of patients with recurrent exposures is highly variable among hospitals leading to a 50-fold variation in I100;1 and to a tenfold variation in I100;3. RERL could be established and used by taking as a RERL quantity the CED and as a RERL value the 75th percentile of the third quartiles of the distribution of the yearly CED obtained by surveying different hospitals. Clinical relevance statement: This is the first ever multicentre study that quantifies recurrent exposures in terms of incidence and cumulative incidence of patients with CED ≥ 100 mSv. RERL establishment and use could benefit the optimisation of radioprotection of patients with recurrent exposures. Key points: This is the first multicentre study estimating yearly incidence and 3-year cumulative incidence of patients with cumulative effective doses ≥ 100 mSv. In this study, a 50-fold inter centre variation between the maximum (5.1%) and the minimum value (0.1%) of yearly incidence of patients with cumulative effective doses ≥ 100 mSv was reported. The range of the 3-year cumulative incidence extended from 1.1 to 11.4% (a tenfold variation) The third quartile of the yearly cumulative effective doses in a centre showed a strong positive correlation with the yearly incidence of patients with cumulative effective doses ≥ 100 mSv, with a potential of being used to set reference levels for recurrent exposures. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the in vivo drainage of lymphatic spread by using the sentinel node (SN) technique and single-photon emission computed tomography (SPECT)-computed tomography (CT) image fusion, and to analyze the impact of such information on conformal pelvic irradiation. Methods and Materials: Twenty-three prostate cancer patients, candidates for radical prostatectomy already included in a trial studying the SN technique, were enrolled. CT and SPECT images were obtained after intraprostate injection of 115 MBq of 99mTc-nanocolloid, allowing identification of SN and other pelvic lymph nodes. Target and nontarget structures, including lymph nodes identified by SPECT, were drawn on SPECT-CT fusion images. A three-dimensional conformal treatment plan was performed for each patient. Results: Single-photon emission computed tomography lymph nodal uptake was detected in 20 of 23 cases (87%). The SN was inside the pelvic clinical target volume (CTV2) in 16 of 20 cases (80%) and received no less than the prescribed dose in 17 of 20 cases (85%). The most frequent locations of SN outside the CTV2 were the common iliac and presacral lymph nodes. Sixteen of the 32 other lymph nodes (50%) identified by SPECT were found outside the CTV2. Overall, the SN and other intrapelvic lymph nodes identified by SPECT were not included in the CTV2 in 5 of 20 (25%) patients. Conclusions: The study of lymphatic drainage can contribute to a better knowledge of the in vivo potential pattern of lymph node metastasis in prostate cancer and can lead to a modification of treatment volume with consequent optimization of pelvic irradiation. [Copyright &y& Elsevier]

Objective: To assess the cumulated exposure to radiation due to imaging in Hodgkin (HL) and diffuse large B‐cell (DLBCL) lymphoma patients who were not submitted to radiotherapy. Methods: The study population included 51 and 83 adult patients with HL and DLBCL, with a follow‐up duration >1 year. The cumulated exposure was expressed using patient‐specific data as cumulated effective dose (CED). Results: Fifty‐one HL patients (median age 47 years) were followed for a median of 3.5 years. The median total CED per subject was 104 mSv. CT and PET/CT examinations accounted for 75 and 25% of the total CED, respectively. 26 patients (49%) had a total CED ≥ 100 mSv and the maximum CED was 302 mSv. Eighty‐three DLBCL patients (median age 66 years) were followed for a median of 3.7 years. The median total CED per subject over the study period was 134 mSv. CT and PET/CT for 86% and 13% of the total CED, respectively. 56 patients (67%) had a total CED ≥100 mSv. The maximum CED was 557 mSv. Conclusion: Our study demonstrated the large number of imaging procedures performed for patients with lymphoma. Overall, 61% of the patients accrued a CED ≥ 100 mSv. Imaging policies were only in a partial agreement with current international guidelines. Advances in knowledge: The cumulated exposure radiation exposure may be of concern in HL patients and the contribution of CT procedures to the total CED is significant. The standardisation of clinical guidelines for managing patients with lymphoma is warranted. [ABSTRACT FROM AUTHOR]

Background: FDG-PET/CT imaging has an emerging role in staging and treatment planning of various tumor locations and a number of literature studies show that also the carcinoma of the anal canal may benefit from this diagnostic approach. We analyzed the potential impact of FDG-PET/CT in stage definition and target volume delineation of patients affected by carcinoma of the anal canal and candidates for curative radiotherapy. Methods: Twenty seven patients with biopsy proven anal carcinoma were enrolled. Pathology was squamous cell carcinoma in 20 cases, cloacogenic carcinoma in 3, adenocarcinoma in 2, and basal cell carcinoma in 2. Simulation was performed by PET/CT imaging with patient in treatment position. Gross Tumor Volume (GTV) and Clinical Target Volume (CTV) were drawn on CT and on PET/CT fused images. PET-GTV and PET-CTV were respectively compared to CT-GTV and CT-CTV by Wilcoxon rank test for paired data. Results: PET/CT fused images led to change the stage in 5/27 cases (18.5%): 3 cases from N0 to N2 and 2 from M0 to M1 leading to change the treatment intent from curative to palliative in a case. Based on PET/CT imaging, GTV and CTV contours changed in 15/27 (55.6%) and in 10/27 cases (37.0%) respectively. PET-GTV and PET-CTV resulted significantly smaller than CT-GTV (p = 1.2 ×10-4) and CT-CTV (p = 2.9 ×10-4). PET/ CT-GTV and PET/CT-CTV, that were used for clinical purposes, were significantly greater than CT-GTV (p = 6 × 10-5) and CT-CTV (p = 6 ×10-5). Conclusions: FDG-PET/CT has a potential relevant impact in staging and target volume delineation of the carcinoma of the anal canal. Clinical stage variation occurred in 18.5% of cases with change of treatment intent in 3.7%. The GTV and the CTV changed in shape and in size based on PET/CT imaging. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the potential impact of using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on staging and target volume delineation for patients affected by rectal cancer and candidates for preoperative conformal radiotherapy. Methods and Materials: Twenty-five patients diagnosed with rectal cancer T3–4 N0–1 M0–1 and candidates for preoperative radiotherapy underwent PET/CT simulation after injection of 5.18 MBq/kg of FDG. Clinical stage was reassessed on the basis of FDG-PET/CT findings. The gross tumor volume (GTV) and the clinical target volume (CTV) were delineated first on CT and then on PET/CT images. The PET/CT-GTV and PET/CT-CTV were analyzed and compared with CT-GTV and CT-CTV, respectively. Results: In 4 of 25 cases (24%), PET/CT affected tumor staging or the treatment purpose. In 3 of 25 cases (12%) staged N0 M0, PET/CT showed FDG uptake in regional lymph nodes and in a case also in the liver. In a patient with a single liver metastasis PET/CT detected multiple lesions, changing the treatment intent from curative to palliative. The PET/CT-GTV and PET/CT-CTV were significantly greater than the CT-GTV (p = 0.00013) and CT-CTV (p = 0.00002), respectively. The mean difference between PET/CT-GTV and CT-GTV was 25.4% and between PET/CT-CTV and CT-CTV was 4.1%. Conclusions: Imaging with PET/CT for preoperative radiotherapy of rectal cancer may lead to a change in staging and target volume delineation. Stage variation was observed in 12% of cases and a change of treatment intent in 4%. The GTV and CTV changed significantly, with a mean increase in size of 25% and 4%, respectively. [Copyright &y& Elsevier]