{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T01:46:55Z","timestamp":1791510415776,"version":"4.3.4"},"reference-count":15,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T00:00:00Z","timestamp":1772668800000},"content-version":"vor","delay-in-days":4,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,3,1]],"date-time":"2026-03-01T00:00:00Z","timestamp":1772323200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J Applied Clin Med Phys"],"published-print":{"date-parts":[[2026,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>An ionization chamber and electrometer allow measurement of the absorbed dose to water. A sensitivity comparison between electrometers is essential for quality control, and an efficient method is available to accurately measure the electrometer sensitivity coefficient without using a linear accelerator (linac). Although dual\u2010 circuit electrometers are becoming increasingly common, no calculation method for the sensitivity coefficient of their second\u2010circuit is available. Hence, we propose a method for calculating this sensitivity coefficient using the first\u2010circuit as the reference and evaluate its accuracy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Using the first\u2010circuit of a RAMTEC pro electrometer as a reference, the RAMTEC duo and SuperMAX electrometers were connected as test units to the simple yet accurate Japanese\u2010patented SCG002 current source powered by a dry cell battery. Sensitivity ratio\n                      <jats:italic>r<\/jats:italic>\n                      <jats:sub>elec<\/jats:sub>\n                      \u200b was calculated from the average of three charge measurements using RAMTEC Pro. This ratio was multiplied by the calibration coefficient of the first\u2010 circuit to obtain the sensitivity coefficient of the second\u2010circuit. The accuracy was obtained from the relative error of each electrometer based on the calibration coefficient (\n                      <jats:italic>k<\/jats:italic>\n                      <jats:sub>elec<\/jats:sub>\n                      ) provided by a standards laboratory.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The sensitivity coefficient of the second\u2010circuit of RAMTEC pro was 1.0004 (relative error, +0.030%). For RAMTEC duo, the first\u2010 and second\u2010circuit coefficients were 1.0014 and 1.0013, respectively (relative errors, +0.080% and +0.070%). For SuperMAX, the coefficients were 0.9986 and 0.9983 (relative errors, 0.0% and \u20130.050%) for the first and second circuits, respectively. Thus, the proposed method provided accurate measurements.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>\n                      We accurately determine the sensitivity coefficient of the second\u2010circuit in a dual\u2010circuit electrometer using the first\u2010circuit of the same or another electrometer as the reference. If the electrometer performance is verified, the coefficient\n                      <jats:italic>k<\/jats:italic>\n                      <jats:sub>elec<\/jats:sub>\n                      of the first\u2010circuit is likely applicable to the second\u2010circuit. This method may reduce the costs associated with electrometer calibration in clinical settings.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/acm2.70476","type":"journal-article","created":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T09:10:09Z","timestamp":1772961009000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Feasibility study of in\u2010house second\u2010channel calibration of dual\u2010channel electrometers using a battery\u2010powered current source"],"prefix":"10.1002","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6720-648X","authenticated-orcid":false,"given":"Hayato","family":"Tsuno","sequence":"first","affiliation":[{"name":"Gunma Prefectural College of Health Sciences  Gunma Japan"},{"name":"Japanese Red Cross Maebashi Hospital  Gunma Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruan","family":"Sasaki","sequence":"additional","affiliation":[{"name":"Gunma Prefectural College of Health Sciences  Gunma Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7027-9188","authenticated-orcid":false,"given":"Koji","family":"Sasaki","sequence":"additional","affiliation":[{"name":"Graduate School of Radiological Technology Gunma Prefectural College of Health Sciences  Gunma Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kohei","family":"Nishi","sequence":"additional","affiliation":[{"name":"JR Tokyo General Hospital  Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tae","family":"Ushikawa","sequence":"additional","affiliation":[{"name":"JR Tokyo General Hospital  Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daisaku","family":"Goto","sequence":"additional","affiliation":[{"name":"JR Tokyo General Hospital  Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasuhiro","family":"Kawashima","sequence":"additional","affiliation":[{"name":"Japanese Red Cross Maebashi Hospital  Gunma Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ririko","family":"Kosugi","sequence":"additional","affiliation":[{"name":"Gunma Prefectural College of Health Sciences  Gunma Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,3,5]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.598691"},{"key":"e_1_2_10_3_1","volume-title":"Absorbed dose determination in external beam radiotherapy: an international code of practice for dosimetry based on standards of absorbed dose\u2010to\u2010water","author":"International Atomic Energy Agency","year":"2025"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.3190392"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1088\/00319155\/45\/9\/301"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.6009\/jjrt.2023\u20101216"},{"key":"e_1_2_10_7_1","unstructured":"MatsubayashiF TsunoH MatsumotoK et\u00a0al.Current generator for precision control of electrometer precision control system and calibration 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