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Medical Dosimetrist I/II

Posted: May 7, 2021

The Dosimetrist I/II is responsible for developing computer generated radiation dose distributions, calculating radiation dose treatment times or monitoring unit settings to deliver prescribed radiation to a defined tumor volume as prescribed by the radiation oncologist. At the direction of the Medical Dosimetry Manager, and on a regular basis, the Dosimetrist I/II will conduct quality assurance reviews, conduct quality checks on various pieces of equipment.


  • Works directly with the physician in verification simulation, treatment planning procedures, and patient specific radiation dose measurements, including all electronic documentation, charting and coding in Mosaiq and patient electronic medical record (EMR). 
  • Assists medical physicist in calibration of equipment and radioactive sources. 
  • Develops computerized treatment plan, calculates treatment doses and / or monitor unit setting to deliver dose to a tumor volume as prescribed by a radiation oncologist. 
  • Calculates and documents dose in the patient’s MOSAIQ electronic treatment records. 
  • Verifies the mathematical accuracy of all calculations. 
  • Assists in the selection, planning, fabrication and quality review and approval of treatment devices to aid in beam delivery modification. 
  • Assists in the planning, production and quality review and approval of immobilization devices and other treatment aids. 
  • Provides technical assistance to the therapeutic radiological physicist in radiation protection. 
  • Performs weekly quality assurance checks of radiotherapy treatment charts. 
  • Follows all policies and procedures established for the accurate, timely and effective development and QA of all dosimetry responsibilities. 
  • Responsible for thorough and timely documentation and coding of work in the EMR and MOSAIQ. 
  • Implements and assists in the maintenance of the quality system for medical dosimetry and record keeping. 
  • Participates in all internal Dosimetry and multidisciplinary meeting at the center, focusing on continuous quality improvement. 
  • Participates in quality check lists as source of intra-center communication. 
  • May act as teacher/instructor during orientation phases of new dosimetry hires. 
  • Ensures that all procedures are followed, verified and QA’d as they relate to the outsourcing or treatment devices, acceptance of said devices at the center, and implementation of said devices during patient treatment. 
  • Adheres to treatment protocol standards established by Seattle Proton Center for specific disease sites/stages/fields, and ensures that documentation is thorough and captured electronically. 
  • Participates in the development and/or implementation of new techniques as assigned by Dosimetry Manager. 


Work Experience Requirements

  • Minimum 1 year experience as a Medical Dosimetrist preferred.  
  • RayStation, XiO, MIM, MOSAIQ experience preferred. 
  • Proton therapy experience preferred. 

Required Skills and Abilities

  • Excellent computer skills. 
  • Excellent communication skills. 
  • Ability to work flexible hours, including occasional weekends to cover extended treatment times and to support center projects as needed. 
  • Ability to work under pressure. 
  • Teaching and coaching skills. 
  • Technical problem solving. 
  • Proficient in Microsoft Office products.


  • Cooperation/Building Collaborative Relationships 
  • Creativity/Innovation 
  • Competency/Dependability/Thoroughness 
  • Workflow Optimization/Efficiency 
  • Organization/Attention to Detail 
  • Flexibility/Managing Change 


  • Bachelor’s degree preferred, specifically in Radiation Therapy, Math, or Physics.   
  • Must be a graduate of a JRCERT accredited medical dosimetry program or have at least 2 years of on the job training as a medical dosimetrist.   
  • CMD strongly preferred, and if not, must be board eligible. Must be board-certified within 3 years of employment.  


Seattle Proton Center utilizes RFID (Radio-Frequency IDentification) tags at the centers for the purposes of analysis of productivity and patient throughput.  This information is not for use as a management tool for employee performance issues. 

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