1
|
St James S, Bednarz B, Benedict S, Buchsbaum JC, Dewaraja Y, Frey E, Hobbs R, Grudzinski J, Roncali E, Sgouros G, Capala J, Xiao Y. Current Status of Radiopharmaceutical Therapy. Int J Radiat Oncol Biol Phys 2020; 109:891-901. [PMID: 32805300 DOI: 10.1016/j.ijrobp.2020.08.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/06/2020] [Indexed: 02/02/2023]
Abstract
In radiopharmaceutical therapy (RPT), a radionuclide is systemically or locally delivered with the goal of targeting and delivering radiation to cancer cells while minimizing radiation exposure to untargeted cells. Examples of current RPTs include thyroid ablation with the administration of 131I, treatment of liver cancer with 90Y microspheres, the treatment of bony metastases with 223Ra, and the treatment of neuroendocrine tumors with 177Lu-DOTATATE. New RPTs are being developed where radionuclides are incorporated into systemic targeted therapies. To assure that RPT is appropriately implemented, advances in targeting need to be matched with advances in quantitative imaging and dosimetry methods. Currently, radiopharmaceutical therapy is administered by intravenous or locoregional injection, and the treatment planning has typically been implemented like chemotherapy, where the activity administered is either fixed or based on a patient's body weight or body surface area. RPT pharmacokinetics are measurable by quantitative imaging and are known to vary across patients, both in tumors and normal tissues. Therefore, fixed or weight-based activity prescriptions are not currently optimized to deliver a cytotoxic dose to targets while remaining within the tolerance dose of organs at risk. Methods that provide dose estimates to individual patients rather than to reference geometries are needed to assess and adjust the injected RPT dose. Accurate doses to targets and organs at risk will benefit the individual patients and decrease uncertainties in clinical trials. Imaging can be used to measure activity distribution in vivo, and this information can be used to determine patient-specific treatment plans where the dose to the targets and organs at risk can be calculated. The development and adoption of imaging-based dosimetry methods is particularly beneficial in early clinical trials. In this work we discuss dosimetric accuracy needs in modern radiation oncology, uncertainties in the dosimetry in RPT, and best approaches for imaging and dosimetry of internal radionuclide therapy.
Collapse
Affiliation(s)
- Sara St James
- Department of Radiation Oncology, University of California San Francisco, San Francisco, California.
| | - Bryan Bednarz
- Department of Medical Physics and Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Stanley Benedict
- Department of Radiation Oncology, University of California Davis, Sacramento, California
| | - Jeffrey C Buchsbaum
- Radiation Research Program, Division of Cancer Treatment and Diagnosis, NCI, NIH, Bethesda, Maryland
| | - Yuni Dewaraja
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Eric Frey
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Robert Hobbs
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | | | - Emilie Roncali
- Department of Radiation Oncology, University of California Davis, Sacramento, California
| | - George Sgouros
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Jacek Capala
- Radiation Research Program, Division of Cancer Treatment and Diagnosis, NCI, NIH, Bethesda, Maryland
| | - Ying Xiao
- Hospital of the University of Pennsylvania
| |
Collapse
|
2
|
Besemer AE, Yang YM, Grudzinski JJ, Hall LT, Bednarz BP. Development and Validation of RAPID: A Patient-Specific Monte Carlo Three-Dimensional Internal Dosimetry Platform. Cancer Biother Radiopharm 2018; 33:155-165. [PMID: 29694246 DOI: 10.1089/cbr.2018.2451] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This work describes the development and validation of a patient-specific Monte Carlo internal dosimetry platform called RAPID (Radiopharmaceutical Assessment Platform for Internal Dosimetry). RAPID utilizes serial PET/CT or SPECT/CT images to calculate voxelized three-dimensional (3D) internal dose distributions with the Monte Carlo code Geant4. RAPID's dosimetry calculations were benchmarked against previously published S-values and specific absorbed fractions (SAFs) calculated for monoenergetic photon and electron sources within the Zubal phantom and for S-values calculated for a variety of radionuclides within spherical tumor phantoms with sizes ranging from 1 to 1000 g. The majority of the S-values and SAFs calculated in the Zubal Phantom were within 5% of the previously published values with the exception of a few 10 keV photon SAFs that agreed within 10%, and one value within 16%. The S-values calculated in the spherical tumor phantoms agreed within 2% for 177Lu, 131I, 125I, 18F, and 64Cu, within 3.5% for 211At and 213Bi, within 6.5% for 153Sm, 111In, 89Zr, and 223Ra, and within 9% for 90Y, 68Ga, and 124I. In conclusion, RAPID is capable of calculating accurate internal dosimetry at the voxel-level for a wide variety of radionuclides and could be a useful tool for calculating patient-specific 3D dose distributions.
Collapse
Affiliation(s)
- Abigail E Besemer
- 1 Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin , Madison, Wisconsin.,2 Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin , Madison, Wisconsin
| | - You Ming Yang
- 1 Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin , Madison, Wisconsin.,3 Department of Radiation Oncology, University of California - Los Angeles , Los Angeles, California
| | - Joseph J Grudzinski
- 1 Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin , Madison, Wisconsin
| | - Lance T Hall
- 4 Department of Radiology, School of Medicine and Public Health, University of Wisconsin , Madison, Wisconsin.,5 Carbone Cancer Center, University of Wisconsin-Madison , Madison, Wisconsin
| | - Bryan P Bednarz
- 1 Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin , Madison, Wisconsin
| |
Collapse
|
3
|
Lu CC, Dong SL, Lin HH, Ni YC, Jan ML, Chuang KS. Noninvasive measurement of radiopharmaceutical time-activity data using external thermoluminescent dosimeters (TLDs). Phys Med Biol 2016; 62:N58-N72. [PMID: 27992385 DOI: 10.1088/1361-6560/aa54a9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In this study, we present a new method for estimating the time-activity data using serial timely measurements of thermoluminescent dosimeters (TLDs). The approach is based on the combination of the measurement of surface dose using TLD and Monte Carlo (MC) simulation to estimate the radiopharmaceutical time-activity data. It involves four steps: (1) identify the source organs and outline their contours in computed tomography images; (2) compute the S values on the body surface for each source organ using a MC code; (3) obtain a serial measurement of the dose with numerous TLDs placed on the body surface; (4) solve the dose-activity equation to generate organ cumulative activity for each period of measurement. The activity of each organ at the time of measurement is simply the cumulative activity divided by the timespan between measurements. The usefulness of this method was studied using a MC simulation based on an Oak Ridge National Laboratory mathematical phantom with 18F-FDG filled in six source organs. Numerous TLDs were placed on different locations of the surface and were repeatedly read and replaced. The time-activity curves (TACs) of all organs were successfully reconstructed. Experiments on a physical phantom were also performed. Preliminary results indicate that it is an effective, robust, and simple method for assessing the TAC. The proposed method holds great potential for a range of applications in areas such as targeted radionuclide therapy, pharmaceutical research, and patient-specific dose estimation.
Collapse
Affiliation(s)
- Cheng-Chang Lu
- Department of Medical Imaging and Radiological Sciences, Chung-Shan Medical University, Taichung, Taiwan
| | | | | | | | | | | |
Collapse
|