The role of radiologic technologists during the COVID-19 pandemic.

During the pandemic, stress of coronavirus disease 2019 (COVID-19) on a radiology department has caused major change in the workflow and protocol, which can inflame unnecessary anxiety among the staff. We have adapted and responded quickly however, to the volatile clinical situations owing to a close consultant in infection control. Our repeatedly revised procedures since the 2014 Ebola outbreak possess the expertise and were very useful. In-house training sessions have been held and updated accordingly. In-house networking service has now become more common in our department instead of the emergency contact network relaying the message to the person on the phone tree. Up until January 2022, we examined 10,861 chest X-rays with no in-hospital infection. We sincerely hope our chest X-ray strategies comply with infection prevention and control standards and minimize use of personal protective equipment will be embraced as a positive initiative by frontline radiologic technologists and relieve their anxiety.

Enhancing the use of computed tomography and cardiac catheterization angiography in Zambia: A project report on a global extension of medical technology in Japan.

Cardiovascular disease (CVD) is one of the leading causes of death in adults in Zambia among the non-communicable diseases. The Government of the Republic of Zambia through the Ministry of Health procured Japanese radiological systems, computed tomography, and angiography for the University Teaching Hospitals (UTHs) - Adult in 2015. However, the operation of these diagnostic systems has not been optimal due to lack of a proper maintenance service plan, lack of competent health professionals, and erratic supply of medical consumables. In this study, we report our experiences of providing intensive training to multidisciplinary healthcare teams of the radiology department at UTHs - Adult from 2017 to 2019 to strengthen the quality management system of the radiological equipment so as to provide effective healthcare services. However, the COVID-19 pandemic has had enormous negative impact on essential healthcare. Long-term support through continuous hands-on training must be provided to establish sustainable healthcare services.

A breathing movement sensor for chest radiography during inspiration in children aged less than 3 years: a prospective randomized controlled study.

Chest radiographs should be obtained at the peak of inspiration so that radiological findings can be precisely interpreted. However, this is not easily achieved, particularly in young children who do not follow the instruction to hold their breath. We developed a sensor that detects the breathing movements and conducted a randomized controlled study to determine whether the sensor would increase the proportion of chest radiographs obtained in the inspiration phase. We recruited 124 infants and children aged less than 3 years, who visited the pediatric department of a general hospital in Tokyo, Japan, and allocated them into one of two groups: with-sensor and without-sensor groups. Overall, 81% of all images were obtained during inspiration. The proportion of chest radiographs taken during inspiration was not statistically different between the two groups (81% vs. 82%). In the with-sensor group, radiologic technologists were able to obtain chest radiographs of the same quality while not observing the chest movement, but the sensor. The use of the sensor did not increase the proportion of chest radiographs taken in the inspiration phase in this study. However, this null result may indicate the possibility of utilizing the sensor for automatizing chest radiography in the future.

Radiation absorbed dose estimates for 18F-BPA PET.

Background Boron neutron capture therapy (BNCT) is a molecular radiation therapy approach based on the 10B (n, α) 7Li nuclear reaction in cancer cells. In BNCT, delivery of 10B in the form of 4-borono-phenylalanine conjugated with fructose (BPA-fr) to the cancer cells is important. The PET tracer 4-borono-2-18F-fluoro-phenylalanine (FBPA) has been used to predict the accumulation of BPA-fr before BNCT. Purpose To determine the biodistribution and dosimetric parameters in 18F-BPA PET/CT studies. Material and Methods Human biokinetic data were obtained during clinical 18F-BPA PET studies between February and June 2015 at one institution. Nine consecutive patients were studied prospectively. The internal radiation dose was calculated on the basis of radioactivity data from blood, urine, and normal tissue of the heart, liver, spleen, kidney, and other parts of the body at each time point using OLINDA/EXM1.1 program. We compared our calculations with published 18F-FDG data. Results Adult patients (3 men, 3 women; age range, 28-68 years) had significantly smaller absorbed doses than pediatric patients (3 patients; age range, 5-12 years) ( P = 0.003). The mean effective dose was 57% lower in adult patients compared with pediatric patients. Mean effective doses for 18F-BPA were 25% lower than those for 18F-FDG presented in International Commission of Radiation Protection (ICRP) publication 106. Conclusion We found significant differences in organ absorbed doses for 18F-BPA against those for 18F-FDG presented in ICRP publication 106. Mean effective doses for 18F-BPA were smaller than those for 18F-FDG in the publication by 0.5-38% (mean difference, 25%).

Estimation of radioactivity in single-photon emission computed tomography for sentinel lymph node biopsy in a torso phantom study.

OBJECTIVE: The number of lymph nodes to be removed is determined from residual counts. Advance estimation of residual radioactivity in lymphatic nodes before a biopsy is useful for reducing surgical operation time. The purpose of this study was to estimate the total radioactivity of a small hotspot in single-photon emission computed tomography (SPECT) of a torso phantom. METHODS: A cross-calibration study was performed to convert counts in SPECT images to radioactivity. A simulation study was performed to estimate the size of the volume of interest (VOI) covering a hotspot corrupted with full-width at half-maximum between 8 and 16 mm. The estimation of total radioactivity was validated in a torso phantom study using small sources. RESULTS: True radioactivity was approximately equal to integrated values of hotspots using the VOI with a diameter of 40 mm in our simulation study. The difference was less than 18% in cases of more than 9.4 kBq. CONCLUSION: The total radioactivity in small sources simulating a typical sentinel node was estimated from SPECT images using a VOI of 40 mm in a torso phantom study. Because the difference from actual values was less than 10% on average when radioactivities were more than 9.4 kBq, the total radioactivity of a lymph node can be estimated in a clinical examination.

Correlation of (18)F-BPA and (18)F-FDG uptake in head and neck cancers.

BACKGROUND AND PURPOSE: The aim of this study was to compare the accumulation of 4-borono-2-(18)F-fluoro-phenylalanine ((18)F-BPA) with that of (18)F-fluorodeoxyglucose ((18)F-FDG) in head and neck cancers, and to assess the usefulness of (18)F-FDG PET for screening candidates for boron neutron capture therapy (BNCT). MATERIAL AND METHODS: Twenty patients with pathologically proven malignant tumors of the head and neck were recruited from March 2012 to January 2014. All patients underwent both whole-body (18)F-BPA PET/CT and (18)F-FDG PET/CT within 2weeks of each other. The uptakes of (18)F-BPA and (18)F-FDG at 1h after injection were evaluated using the maximum standardized uptake value (SUVmax). RESULTS: The accumulation of (18)F-FDG was significantly correlated with that of (18)F-BPA. The SUVmax of (18)F-FDG ⩾5.0 is considered to be suggestive of high (18)F-BPA accumulation. CONCLUSIONS: (18)F-FDG PET might be an effective screening method performed prior to (18)F-BPA for selecting patients with head and neck cancer for treatment with BNCT.

64Cu-DOTA-trastuzumab PET imaging in patients with HER2-positive breast cancer.

UNLABELLED: The purpose of this study was to determine the safety, distribution, internal dosimetry, and initial human epidermal growth factor receptor 2 (HER2)-positive tumor images of (64)Cu-DOTA-trastuzumab in humans. METHODS: PET was performed on 6 patients with primary or metastatic HER2-positive breast cancer at 1, 24, and 48 h after injection of approximately 130 MBq of the probe (64)Cu-DOTA-trastuzumab. Radioactivity data were collected from the blood, urine, and normal-tissue samples of these 6 patients, and the multiorgan biodistribution and internal dosimetry of the probe were evaluated. Safety data were collected for all the patients after the administration of (64)Cu-DOTA-trastuzumab and during the 1-wk follow-up period. RESULTS: According to our results, the best timing for the assessment of (64)Cu-DOTA-trastuzumab uptake by the tumor was 48 h after injection. Radiation exposure during (64)Cu-DOTA-trastuzumab PET was equivalent to that during conventional (18)F-FDG PET. The radioactivity in the blood was high, but uptake of (64)Cu-DOTA-trastuzumab in normal tissues was low. In 2 patients, (64)Cu-DOTA-trastuzumab PET showed brain metastases, indicative of blood-brain barrier disruptions. In 3 patients, (64)Cu-DOTA-trastuzumab PET imaging also revealed primary breast tumors at the lesion sites initially identified by CT. CONCLUSION: The findings of this study indicated that (64)Cu-DOTA-trastuzumab PET is feasible for the identification of HER2-positive lesions in patients with primary and metastatic breast cancer. The dosimetry and pharmacologic safety results were acceptable at the dose required for adequate PET imaging.

Radiation exposure to general public after permanent brachytherapy for prostate cancer.

Permanent prostate brachytherapy patients are generally told to limit their time around children and pregnant women. However, there is little data available to validate the instruction. For the skin effective dose rate, ion chamber survey meter model 451B-DE-SI was used. The meter was scanned at the point of 4.5, 20, 50 and 100 cm from the skin surface in each plane. Life time exposure was calculated from the average anterior data. At the point of 4.5 cm from the anterior skin surface, the lifetime equivalent dose was 46.5 mSv, at 20 cm it was 13.2 mSv, at 50 cm it was 3.5 mSv and at 100 cm it was 0.9 mSv. The risk from the prostate brachytherapy patients to general public is quite low. Only the case of close and long-time contact with the pregnant and the infant should be paid attention to.

Swelling of the prostate gland by permanent brachytherapy may affect seed migration.

OBJECTIVE: The purpose was to monitor implanted seeds and to determine factors contributing to seed migration after permanent prostate brachytherapy. METHODS: Sixty-two consecutive patients with Stage 1 prostate cancer who underwent brachytherapy with (125)I seeds between February 2008 and May 2009 were studied prospectively. On post-operative days 1, 7 and 30, scintigraphy was added to conventional radiography to monitor the migration of the implanted seeds. The prostate volume was measured during the pre-planning stage using ultrasound and during the post-planning stage using computed tomography on post-operative days 0 and 30. Magnetic resonance imaging was performed on day 30. RESULTS: Of the 4843 seeds implanted in the prostates of 62 patients, 108 seeds (2.2%) in 43 patients (69.4%) exhibited seed migration. Thirty-five seeds could not be identified using any of the imaging modalities and were likely passed during urination (0.7% of the total number of seeds). The maximum number of migrated seeds in one patient was 10 of the 85 implanted seeds. The fraction of patients with seed migration or loss increased from 27.4% on day 1 to 69.4% on day 30. The number of seeds that had migrated from the prostate increased from 48 (0.1% of the total number of seeds) on 1 day to 78 (1.0%) on day 7 and 108 (2.2%) on day 30. Of the seeds lost from the prostate, 38.9% embolized to the lungs. The seed loss during the first post-operative month was closely correlated with the swelling of the prostate gland between the pre-planning measurement and the post-planning measurement performed on day 0 (P < 0.0001). CONCLUSIONS: Prostate swelling between the pre-planning and post-planning (day 0) measurements was significantly associated with seed migration, and adequate attention should be given to this issue.

Scintigraphic detection of 125I seeds after permanent brachytherapy for prostate cancer.

UNLABELLED: The purpose of this investigation was to monitor the localization and migration of 125I seeds after permanent brachytherapy for prostate cancer using a new scintigraphic technique that may overcome the drawbacks of conventional x-ray methods. METHODS: 125I seeds emit gamma-rays with an average energy peak of 28 keV. We used a gamma-camera equipped with low-energy high-resolution collimators that were tuned to an energy level of 35 keV with a 70% window width. Sixteen patients with prostate cancer were examined after 125I seed insertion. The number of seeds remaining in the prostate was confirmed using pelvic CT for postoperative dose planning; however, seeds that had migrated outside the prostate could not be detected. Furthermore, the migrated seeds were not completely traceable using chest or abdominal radiography. Thus, we adopted a scintigraphic technique to perform this task. The evaluation of radiography and scintigraphy findings was masked, and the rates of migrated seed detection were statistically examined using the McNemar test. To localize the migrated seeds, we fused the scintigraphic images of the migrated seeds and the patients' contours. RESULTS: Scintigraphy was successfully used to detect 20 migrated seeds of a total of 1,182 implanted seeds, whereas radiography was successfully used to detect 7. The sensitivity of the scintigraphy results was 20 of 20 (100%), whereas that of the radiography results was 7 of 20 (35%). Seed migration was detected in 11 of 16 patients (69%) using scintigraphy, whereas seed migration was detected in only 4 patients (25%) using radiography; this difference was statistically significant (P = 0.016). CONCLUSION: Scintigraphy is more effective for detecting seed migration and monitoring the localization of 125I seeds than radiography. The precise anatomic location of migrated seeds can be pinpointed using fusion images. Scintigraphy may become a standard procedure for monitoring seed migration during 125I brachytherapy in patients with prostate cancer.