Premium
Technical Note: ADAM PETer – An anthropomorphic, deformable and multimodality pelvis phantom with positron emission tomography extension for radiotherapy
Author(s) -
Gillmann Clarissa,
Homolka Noa,
Johnen Wibke,
Runz Armin,
Echner Gernot,
Pfaffenberger Asja,
Mann Philipp,
Schneider Verena,
Hoffmann Aswin L.,
Troost Esther G. C.,
Koerber Stefan A.,
Kotzerke Jörg,
BeuthienBaumann Bettina
Publication year - 2021
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.14597
Subject(s) - imaging phantom , nuclear medicine , medicine , prostate cancer , pelvis , positron emission tomography , magnetic resonance imaging , lymph node , prostate , radiology , cancer , pathology
Objective To develop an a nthropomorphic, d eformable a nd m ultimodal pelvis phantom with p ositron e mission t omography e xtension for r adiotherapy (ADAM PETer). Methods The design of ADAM PETer was based on our previous pelvis phantom (ADAM) and extended for compatibility with PET and use in 3T magnetic resonance imaging (MRI). The formerly manually manufactured silicon organ surrogates were replaced by three‐dimensional (3D) printed organ shells. Two intraprostatic lesions, four iliac lymph node metastases and two pelvic bone metastases were added to simulate prostate cancer as multifocal and metastatic disease. Radiological properties [computed tomography (CT) and 3T MRI] of cortical bone, bone marrow and adipose tissue were simulated by heavy gypsum, a mixture of Vaseline and K 2 HPO 4 and peanut oil, respectively. For soft tissues, agarose gels with varying concentrations of agarose, gadolinium (Gd) and sodium fluoride (NaF) were developed. The agarose gels were doped with patient‐specific activity concentrations of a Fluorine‐18 labelled compound and then filled into the 3D printed organ shells of prostate lesions, lymph node and bone metastases. The phantom was imaged at a dual energy CT and a 3T PET/MRI scanner. Results The compositions of the soft tissue surrogates are the following (given as mass fractions of agarose[w%]/NaF[w%]/Gd[w%]): Muscle (4/1/0.027), prostate (1.35/4.2/0.011), prostate lesions (2.25/4.2/0.0085), lymph node and bone metastases (1.4/4.2/0.025). In all imaging modalities, the phantom simulates human contrast. Intraprostatic lesions appear hypointense as compared to the surrounding normal prostate tissue in T2‐weighted MRI. The PET signal of all tumors can be localized as focal spots at their respective site. Activity concentrations of 12.0 kBq/mL (prostate lesion), 12.4 kBq/mL (lymph nodes) and 39.5 kBq/mL (bone metastases) were measured. Conclusion The ADAM PETer pelvis phantom can be used as multimodal, anthropomorphic model for CT, 3T‐MRI and PET measurements. It will be central to simulate and optimize the technical workflow for the integration of PET/MRI‐based radiation treatment planning of prostate cancer patients.