Imaging

Chapter Opening — Patient Story

"After my biopsy showed Gleason 3+4, my urologist said I needed 'staging imaging.' I had no idea what that meant. Over the next two weeks, I had an MRI, a bone scan, and then something called a PSMA PET scan. Each one felt like waiting for a verdict. But understanding what each test was looking for — and what it could and couldn't tell us — made the whole process less frightening. The MRI showed the cancer was still inside the prostate. The bone scan was clear. And the PET scan confirmed there was no spread to lymph nodes. That information gave my doctors — and me — the confidence to choose the right treatment."

— Robert, 63, diagnosed with intermediate-risk prostate cancer

Part 1: Why Do We Need Imaging?

When prostate cancer is diagnosed through biopsy, the next critical question is: where exactly is the cancer, and has it spread? Imaging tests help answer these questions by creating pictures of the inside of your body without surgery.

Imaging serves several purposes in prostate cancer¹:

• Detecting cancer within the prostate before or during biopsy
• Staging — determining whether cancer has spread beyond the prostate to nearby tissues, lymph nodes, or distant organs like bones
• Planning treatment — helping doctors design surgery or radiation therapy
• Monitoring — checking whether treatment is working or whether cancer has returned
• Guiding procedures — directing biopsy needles or radiation beams to the right location

There are two broad categories of imaging²:

• Anatomic imaging shows the structure and shape of organs. Examples include ultrasound, CT scans, and MRI. Think of these as detailed photographs of your body's architecture.
• Functional imaging shows how tissues are behaving — whether they are metabolically active, have increased blood flow, or are turning over bone. Examples include bone scans, PET scans, and specialized MRI sequences like diffusion-weighted imaging (DWI). Think of these as showing what your body is doing, not just what it looks like.

The best imaging strategy often combines both types to get the most complete picture.

Part 2: Ultrasound — The Workhorse of Prostate Procedures

How it works: Ultrasound uses high-frequency sound waves (like sonar) that bounce off tissues and return to a probe, creating real-time images on a screen. It does not use radiation and is painless.³

Standard transrectal ultrasound (TRUS): This is the most common ultrasound used in prostate care. A small probe (slightly larger than a thumb) is inserted into the rectum because the prostate sits directly in front of it. TRUS provides real-time images of the prostate and is primarily used to:

• Guide biopsy needles during prostate biopsy
• Measure prostate size (volume)
• Identify obvious abnormalities (hypoechoic lesions — areas that appear darker than surrounding tissue)

However, standard TRUS has significant limitations for cancer detection. Prostate cancer can appear as a dark (hypoechoic) area, but many cancers look identical to normal tissue on standard ultrasound, and many dark areas are not cancer at all.⁴

Doppler ultrasound: This technique measures blood flow within the prostate. Because cancers often develop new blood vessels (a process called angiogenesis), areas of increased blood flow may indicate cancer. Power Doppler has shown sensitivity of approximately 81–92% and specificity of 68–72% in some studies, though results vary widely.⁵ ⁶ Color Doppler can identify focal areas of increased vascularity that may warrant targeted biopsy.⁷

Contrast-enhanced ultrasound (CEUS): This involves injecting tiny microbubbles (a safe contrast agent) into a vein. These bubbles highlight blood flow patterns in the prostate, making abnormal areas easier to see. CEUS has shown an area under the curve of 0.80 for detecting Gleason 3+4 or higher cancer, compared to 0.74 for standard B-mode ultrasound alone.⁸

Elastography: This technique measures tissue stiffness. Cancer tissue is typically stiffer than normal prostate tissue because of increased cell density. Real-time elastography can be performed during a standard ultrasound examination. When combined with B-mode ultrasound, sensitivity improves to approximately 80%.⁸

Multiparametric ultrasound (mpUS): Just as MRI combines multiple sequences, multiparametric ultrasound combines B-mode, Doppler, elastography, and contrast enhancement into a single comprehensive examination. The CADMUS trial — a prospective, multicenter study — found that mpUS detected clinically significant prostate cancers at rates similar to multiparametric MRI, although more patients required biopsy when mpUS was used alone.⁹ mpUS may be particularly useful when MRI is unavailable or when patients cannot undergo MRI (for example, due to metal implants or severe claustrophobia).

Part 3: Micro-Ultrasound — A Newer Technology

Micro-ultrasound (microUS) is an exciting advancement that uses a much higher frequency probe (29 MHz) compared to standard ultrasound (9–12 MHz). This higher frequency provides approximately three times the resolution — about 70 micrometers — which is roughly the size of the ducts within the prostate.¹⁰ At this resolution, subtle changes in ductal architecture caused by cancer become visible that are invisible on standard ultrasound.

MicroUS has its own scoring system called PRI-MUS (Prostate Risk Identification using Micro-Ultrasound), which is analogous to the PI-RADS system used for MRI. Lesions are scored from 1 to 5 based on their likelihood of representing clinically significant cancer.¹¹

The OPTIMUM trial — a landmark multicenter, international, randomized trial published in JAMA in 2025 — compared microUS-guided biopsy to MRI fusion-guided biopsy in 678 biopsy-naive men. The results showed that microUS-guided biopsy was non-inferior to MRI fusion-guided biopsy for detecting Grade Group 2 or higher prostate cancer (47.1% vs. 42.6%; non-inferiority P 0.001).¹² Following this trial, the NCCN updated its guidelines to note that micro-ultrasound–guided biopsy at experienced centers is a recognized alternative to MRI-targeted fusion biopsy.¹³

A 2026 meta-analysis of 22 studies (over 11,000 patients) confirmed that microUS-targeted biopsy and MRI-targeted biopsy have comparable detection rates for clinically significant prostate cancer (pooled detection ratio 1.04, 95% CI 0.95–1.15).¹⁴

Key advantages of micro-ultrasound:

• Real-time imaging (no delay between imaging and biopsy)
• Lower cost than MRI
• Can be performed in the office during the biopsy itself
• No issues with metal implants or claustrophobia

Limitations:

• Requires specialized equipment and training
• Currently available at a limited number of expert centers
• Less data on its role in active surveillance monitoring and local staging compared to MRI
• More biopsies may be performed compared to an MRI-first approach (MRI can help avoid biopsy in some patients)

Part 4: MRI — The Gold Standard for Prostate Imaging

Magnetic resonance imaging (MRI) uses powerful magnets and radio waves — not radiation — to create highly detailed images of soft tissues. For prostate cancer, MRI has become the most important imaging tool for evaluating the prostate gland itself.¹⁵

Multiparametric MRI (mpMRI) combines several types of MRI sequences, each providing different information¹⁶:

• T2-weighted imaging: Shows the anatomy of the prostate in exquisite detail — the zones, capsule, seminal vesicles, and surrounding structures. Cancer in the peripheral zone typically appears as a dark area on T2 images.
• Diffusion-weighted imaging (DWI): Measures how freely water molecules move through tissue. Cancer cells are packed tightly together, restricting water movement. Areas of restricted diffusion "light up" on DWI and appear dark on the ADC (apparent diffusion coefficient) map. DWI is the most important sequence for detecting cancer in the peripheral zone.
• Dynamic contrast-enhanced (DCE) imaging: After injecting a gadolinium-based contrast agent into a vein, this sequence shows how quickly blood flows into and out of tissue. Cancers often show early, intense enhancement. DCE plays a supporting role, particularly for peripheral zone lesions.

Biparametric MRI (bpMRI) uses only T2 and DWI sequences (no contrast injection). A 2025 randomized trial (the PRIME trial) found that bpMRI offered similar diagnostic quality to mpMRI for detecting clinically significant prostate cancer, and the NCCN now recognizes bpMRI as an acceptable alternative.¹³ ¹⁷

The PI-RADS Scoring System

To standardize how radiologists report prostate MRI findings, the Prostate Imaging Reporting and Data System (PI-RADS) was developed. The current version is PI-RADS v2.1. Each suspicious area is assigned a score from 1 to 5¹⁸ ¹⁹:

• PI-RADS 1 — Very low suspicion (clinically significant cancer highly unlikely) — ~5% cancer risk
• PI-RADS 2 — Low suspicion (clinically significant cancer unlikely) — ~10% cancer risk
• PI-RADS 3 — Intermediate/equivocal (uncertain) — ~20–30% cancer risk
• PI-RADS 4 — High suspicion (clinically significant cancer likely) — ~50–60% cancer risk
• PI-RADS 5 — Very high suspicion (clinically significant cancer very likely) — ~80–90% cancer risk

The scoring criteria differ depending on where the lesion is located:

• In the peripheral zone (where most cancers arise), DWI is the primary determinant
• In the transition zone (where BPH occurs), T2-weighted imaging is the primary determinant

Important points about PI-RADS:

• A PI-RADS score is NOT a diagnosis — it is a suspicion level based on how the area looks on MRI
• Even PI-RADS 5 lesions are not confirmed cancer until proven by biopsy
• PI-RADS 3 is the "gray zone" — additional factors like PSA density, biomarkers, and clinical judgment help determine whether biopsy is needed
• A negative MRI (PI-RADS 1–2) does not completely exclude cancer. Approximately 1 in 10 patients with a negative MRI may still have Grade Group 2 or higher cancer on biopsy.²⁰ PSA density is particularly helpful in this situation — patients with a higher PSA density and a negative MRI should still be encouraged to undergo biopsy.²¹

A large meta-analysis of 72 studies (36,366 patients) found that combining PI-RADS with PSA density was the optimal strategy for biopsy decisions, potentially avoiding 30–48% of unnecessary biopsies while maintaining 95–97% sensitivity for clinically significant cancer.²¹

What Else Can MRI Show?

Beyond cancer detection, prostate MRI provides valuable information about²²:

• Extracapsular extension (ECE) — whether cancer has grown through the prostate capsule
• Seminal vesicle invasion (SVI) — whether cancer has spread into the seminal vesicles
• Lymph node size — enlarged lymph nodes may suggest cancer spread (though MRI cannot distinguish between enlarged benign and malignant nodes based on size alone)
• Prostate size and shape — important for treatment planning
• BPH nodules — benign enlargement that can mimic cancer on some sequences
• Bladder wall thickness — may indicate obstruction from an enlarged prostate
• Bone lesions — occasionally, bone metastases are incidentally seen on pelvic MRI

Practical Considerations for Patients

Before your MRI:

• Inform your doctor about any metal implants, pacemakers, or devices — some are not MRI-compatible
• You may be asked to use an enema or avoid eating before the scan
• The scan takes approximately 30–45 minutes

During the MRI:

• You will lie on your back inside a tunnel-shaped machine
• The machine is noisy — you will be given earplugs or headphones
• You must remain still during the scan
• Some centers use an endorectal coil (a small inflatable balloon placed in the rectum) to improve image quality, particularly with 1.5 Tesla machines. Most 3 Tesla machines do not require this.
• If you experience claustrophobia, discuss this with your doctor beforehand. Options include:
• Anti-anxiety medication before the scan
• Open-bore or large-bore MRI machines (wider tunnel)
• Music or guided relaxation during the scan

MRI for monitoring after treatment:

• After surgery, MRI can evaluate the prostate bed for possible recurrence
• After radiation, MRI can help assess treatment response, though interpretation can be challenging due to post-treatment changes
• During active surveillance, MRI is repeated periodically to monitor for any changes

Part 5: CT Scan — Seeing the Big Picture

A computed tomography (CT) scan uses X-rays taken from many angles to create detailed cross-sectional images of the body. CT is widely available, fast, and excellent for evaluating²³:

• Lymph nodes — CT can detect enlarged lymph nodes in the pelvis and abdomen that may contain cancer. However, CT relies on size criteria (typically >1 cm) and cannot distinguish between enlarged nodes due to cancer versus inflammation.
• Visceral organs — CT can detect metastases in the liver, lungs, and other organs
• Bone — CT can show bone destruction or new bone formation from metastases
• Gross extracapsular disease — very large tumors extending beyond the prostate

Limitations of CT for prostate cancer:

• CT is generally not sufficient to evaluate the prostate gland itself — MRI is far superior for this purpose²³
• CT cannot reliably detect small or early-stage cancers within the prostate
• CT uses ionizing radiation (though modern techniques minimize dose)
• CT with IV contrast should be used cautiously in patients with kidney problems or contrast allergies

When is CT used?

• For staging in high-risk and very-high-risk prostate cancer (to evaluate lymph nodes and distant organs)²⁴
• As part of workup for recurrence or progression
• For treatment planning (radiation therapy simulation)
• CT of the chest may be obtained to evaluate for lung metastases in advanced disease

When is CT NOT routinely needed?

• The AUA/ASTRO guidelines recommend that clinicians should not routinely perform CT or bone scan in asymptomatic patients with low- or intermediate-risk prostate cancer, because the probability of finding metastatic disease is very low.²⁴

Part 6: Bone Scan — Checking the Skeleton

Prostate cancer has a particular tendency to spread to bones — especially the spine, pelvis, ribs, and femur. A technetium-99m bone scan (also called a radionuclide bone scan or skeletal scintigraphy) is the traditional method for detecting bone metastases.²⁵

How it works:

1. A small amount of a radioactive tracer (technetium-99m MDP) is injected into a vein
2. You wait approximately 2–3 hours while the tracer circulates and is absorbed by areas of active bone turnover
3. A gamma camera takes images of your entire skeleton
4. Areas of increased tracer uptake ("hot spots") appear as dark areas on the scan

What hot spots mean:

• Hot spots indicate areas where bone is turning over rapidly
• This can be caused by cancer, but also by arthritis, old fractures, infection, or other benign conditions
• The pattern of hot spots helps distinguish cancer from benign causes — multiple scattered hot spots in typical locations (spine, pelvis, ribs) are highly suspicious for metastatic disease
• A single hot spot may need further evaluation with additional imaging (X-ray, CT, or MRI of that area)

Bone scan flare:

An important phenomenon to understand is "bone scan flare." When starting a new treatment (especially hormone therapy with agents like enzalutamide or abiraterone), new hot spots may appear on a bone scan even though the treatment is working. This happens because healing bone takes up more tracer than stable bone. If PSA is falling and there is no new pain, these new spots likely represent a flare reaction, not true progression. A repeat bone scan 8–12 weeks later can confirm this.²⁵

When is a bone scan recommended?²⁴ ²⁵

• Initial staging of high-risk and very-high-risk prostate cancer
• When PSA does not fall to undetectable levels after surgery
• When PSA rises after treatment and the patient is a candidate for additional therapy
• To monitor metastatic prostate cancer during treatment (every 6–12 months on ADT)
• For new bone pain or symptoms suggesting bone metastases

When is a bone scan NOT routinely needed?

• Low-risk and favorable intermediate-risk prostate cancer (very low probability of bone metastases)
• Bone scans are rarely positive in asymptomatic patients with PSA below 10 ng/mL²⁵

Limitations:

• Plain X-rays will not detect a bone lesion until nearly 50% of the mineral content is lost or gained²⁵
• Bone scans show increased bone turnover but cannot always distinguish cancer from benign causes
• Bone scans may miss purely destructive (lytic) lesions, though these are uncommon in prostate cancer

Part 7: PET Scans — The New Frontier

Positron emission tomography (PET) combined with CT or MRI represents the most significant advance in prostate cancer imaging in recent years. PET scans use radioactive tracers that are attracted to specific molecules on cancer cells, allowing detection of very small deposits of cancer that conventional imaging might miss.²⁶

PSMA PET — The Game Changer

PSMA (prostate-specific membrane antigen) is a protein found on the surface of prostate cancer cells. The more aggressive the cancer, the more PSMA it typically produces. PSMA PET uses radioactive tracers that bind to this protein, causing cancer cells to "light up" on the scan.²⁷

There are currently three FDA-approved PSMA PET tracers²⁸:

1. Ga-68 PSMA-11 — the first widely used PSMA tracer; half-life of 68 minutes; requires a generator or cyclotron
2. F-18 piflufolastat (DCFPyL) — longer half-life of 110 minutes; can be produced at a cyclotron and shipped to centers without on-site production
3. F-18 flotufolastat (rh-PSMA-7.3) — the newest approved tracer; also 110 minutes half-life; a "radiohybrid" ligand with two binding sites for radionuclides

How a PSMA PET scan is performed:

1. The radiotracer is injected into a vein
2. You wait approximately 60 minutes for the tracer to circulate and bind to PSMA-expressing cells
3. You lie on a scanning table that moves through a PET/CT or PET/MRI machine
4. The scan takes approximately 20–30 minutes
5. Images show the entire body, highlighting any areas where PSMA is concentrated

How accurate is PSMA PET?

The proPSMA randomized controlled trial compared PSMA PET to conventional imaging (CT + bone scan) for staging newly diagnosed intermediate- and high-risk prostate cancer. PSMA PET showed an accuracy of 92% compared to 65% for conventional imaging (P 0.0001), driven primarily by dramatically improved sensitivity (85% vs. 38%).²⁹

A comprehensive 2023 meta-analysis of 31 studies (2,431 patients) with head-to-head comparisons found that PSMA PET significantly outperformed conventional imaging across all staging domains³⁰:

• Nodal staging: PSMA PET sensitivity 73.7% vs. CT 38.5% and MRI 38.9%; specificity 97.8% vs. 83.6%
• Bone metastasis staging: PSMA PET sensitivity 98.0% vs. bone scan 73.0%; specificity 96.2% vs. 79.1%
• Extraprostatic extension: PSMA PET/MRI sensitivity 78.7% vs. mpMRI alone 52.9%

For biochemical recurrence (rising PSA after treatment), PSMA PET is particularly valuable because it can detect recurrence at very low PSA levels. A 2025 meta-analysis of 43 studies (8,119 patients) found that PSMA PET positivity rates increased with PSA level: 48% at PSA 0.2–0.5 ng/mL, rising to over 90% at PSA above 2 ng/mL. Positivity rates were higher after radiation therapy (92%) than after surgery (60%).³¹ A 2026 single-center study of 245 patients confirmed detection rates of 56.5% even at PSA 0.2–0.5 ng/mL, with independent predictors of PET positivity being serum PSA, ISUP grade, and PSA doubling time.³²

When is PSMA PET recommended?²⁷ ²⁸

• As an alternative to CT, MRI, and bone scan for initial staging of unfavorable intermediate-risk, high-risk, and very-high-risk prostate cancer
• For detection of biochemically recurrent disease (rising PSA after surgery or radiation)
• As workup for disease progression
• In M1 CRPC (metastatic castration-resistant prostate cancer), specifically to determine candidacy for Lu-177-PSMA-617 radioligand therapy

Important cautions about PSMA PET:²⁷ ³³

• False positives exist. Not every area that lights up on PSMA PET is cancer. PSMA is also expressed in the kidneys, salivary glands, small bowel, liver, spleen, and some benign conditions (such as ganglia and healing bone). Histologic or radiographic confirmation is recommended whenever feasible.
• PSMA imaging should be done before starting hormone therapy (ADT), because ADT may affect detection sensitivity.
• The Will Rogers effect: PSMA PET may detect tiny metastases that would have been missed by conventional imaging. This "stage migration" can make outcomes appear better in both the metastatic and non-metastatic groups, even without any change in treatment effectiveness. The clinical trials that established current treatment recommendations for metastatic disease used conventional imaging (CT and bone scan), not PSMA PET. Therefore, finding a tiny PSMA-positive lesion does not necessarily mean a patient needs the same intensive treatment as someone with obvious metastases on conventional imaging.³³
• Treatment changes should not be made solely based on a positive PSMA PET in patients with non-metastatic castration-resistant prostate cancer (M0 CRPC).²⁷
• FDG-PET (the type of PET scan commonly used for other cancers) should not be used routinely for staging prostate cancer, as prostate cancer cells often do not take up FDG well. However, FDG-PET may have a role in progressive castration-resistant disease, where some metastases may lose PSMA expression and become FDG-avid instead.³³

Other PET Tracers

While PSMA PET has largely replaced older tracers, several others remain available²⁸:

• C-11 choline — one of the earliest PET tracers for prostate cancer; short half-life (20 minutes) limits its use to centers with an on-site cyclotron; 53–96% positive predictive value in biochemical recurrence
• F-18 fluciclovine (Axumin) — targets amino acid transport; 87–91% correct localization rate in biochemical recurrence; now largely superseded by PSMA PET due to lower sensitivity
• F-18 sodium fluoride — specific to bone; 77–94% sensitivity and 92–99% specificity for bone metastases; may be considered for equivocal bone scan results

Part 8: Which Imaging Tests Do You Need?

Not every patient needs every imaging test. The choice depends on your risk group, PSA level, and clinical situation²⁴ ²⁷:

Low-risk prostate cancer:

• Prostate MRI (for treatment planning and active surveillance monitoring)
• No routine CT, bone scan, or PET scan needed

Favorable intermediate-risk:

• Prostate MRI
• No routine staging imaging needed (CT, bone scan, or PET)
• Confirmatory testing (biomarkers, genomic tests) may be used

Unfavorable intermediate-risk:

• Prostate MRI
• Soft tissue imaging (CT or MRI of abdomen/pelvis) and consider bone imaging
• OR PSMA PET/CT as an alternative to all of the above

High-risk and very-high-risk:

• Prostate MRI
• Bone scan AND soft tissue imaging (CT of chest/abdomen/pelvis or MRI)
• OR PSMA PET/CT or PET/MRI as an alternative

Biochemical recurrence (rising PSA after treatment):

• PSMA PET is preferred where available (AUA/SUO guideline)³⁴
• Alternatively: CT and bone scan
• MRI of the prostate bed (after surgery) or prostate (after radiation) may be helpful

Monitoring during treatment for metastatic disease:

• Bone scans and soft tissue imaging (CT or MRI) regularly during systemic therapy
• On ADT: bone scans as often as every 6–12 months
• In CRPC: imaging every 8–12 weeks²⁵

Part 9: Understanding Your Imaging Report

When you receive imaging results, here are key terms you may encounter:

• "No evidence of metastatic disease" — the scan did not find cancer spread (good news, but no scan is 100% sensitive)
• "Equivocal" — the finding is uncertain and may need additional testing
• "Indeterminate lesion" — a finding that could be cancer or something benign; further evaluation needed
• "Uptake" or "avidity" — on PET scans, this means the tracer is concentrated in that area (may indicate cancer)
• "SUV" (Standardized Uptake Value) — a number that quantifies how much tracer an area has absorbed; higher SUV generally suggests more aggressive disease
• "Hot spot" — an area of increased activity on bone scan or PET
• "Sclerotic lesion" — an area of increased bone density on CT; in prostate cancer, bone metastases are typically sclerotic (bone-forming) rather than lytic (bone-destroying)
• "Extracapsular extension (ECE)" — cancer extending beyond the prostate capsule
• "Seminal vesicle invasion (SVI)" — cancer involving the seminal vesicles
• "Lymphadenopathy" — enlarged lymph nodes

Part 10: Emerging Technologies and Ongoing Research

Imaging for prostate cancer continues to evolve rapidly:

• AI-assisted MRI interpretation: Artificial intelligence algorithms are being developed to help radiologists identify suspicious lesions more consistently and reduce inter-reader variability³⁵
• Whole-body MRI: Emerging as a radiation-free alternative for detecting bone and soft tissue metastases
• PSMA PET for treatment response monitoring: Research is exploring whether changes in PSMA PET findings during treatment can predict outcomes earlier than PSA changes
• Dual-tracer PET: Combining PSMA PET with FDG-PET may help identify biologically diverse metastases, particularly in castration-resistant disease where some lesions lose PSMA expression³³
• Radiomics and machine learning: Extracting quantitative features from imaging data that are invisible to the human eye, potentially improving cancer detection and outcome prediction
• Liquid biopsy integration: Combining imaging findings with circulating tumor DNA and other blood-based biomarkers for more comprehensive disease monitoring

Myth vs. Fact

Myth: "If my bone scan is normal, I definitely don't have cancer in my bones."

Fact: Bone scans are very good at detecting bone metastases, but they can miss very small or early lesions. PSMA PET is more sensitive. Also, bone scans detect bone turnover, not cancer directly — some bone metastases may not cause enough turnover to be detected.²⁵ ³⁰

Myth: "A PET scan can find every single cancer cell in my body."

Fact: Even the most sensitive PET scans have limits. Very small deposits (typically less than 3–5 mm) may not be detected. False negatives can occur, especially at very low PSA levels. And false positives can occur — not every "hot spot" is cancer.²⁷

Myth: "I need a PET scan right away after my diagnosis."

Fact: For low-risk and favorable intermediate-risk prostate cancer, PET scans are not routinely recommended because the chance of finding metastatic disease is extremely low. Unnecessary imaging can lead to false-positive findings, additional testing, anxiety, and cost.²⁴

Myth: "MRI uses radiation, so I should limit how many I get."

Fact: MRI does not use ionizing radiation. It uses magnetic fields and radio waves. There is no known cumulative risk from multiple MRI scans. However, the gadolinium contrast agent used in some MRI protocols should be used judiciously in patients with severe kidney disease.

Myth: "If my PSMA PET shows a spot, my cancer has definitely spread and is incurable."

Fact: PSMA PET can detect very small deposits that may be treatable with targeted therapy (such as metastasis-directed radiation). Finding a small spot on PSMA PET does not automatically mean the cancer is incurable — it means your doctors have more precise information to guide treatment.³³ ³⁴

Questions to Ask Your Doctor

1. Which imaging tests do I need based on my risk group and PSA level?
2. Do I need an MRI before my biopsy? Will it be multiparametric or biparametric?
3. What was my PI-RADS score, and what does it mean for my biopsy decision?
4. Is a PSMA PET scan available and appropriate for my situation?
5. Should my imaging be done before or after starting hormone therapy?
6. What does "equivocal" or "indeterminate" mean on my report, and what are the next steps?
7. If my bone scan shows a hot spot, does that definitely mean cancer?
8. How often will I need repeat imaging during treatment or surveillance?
9. Is micro-ultrasound available at your center, and would it be appropriate for me?
10. Can you walk me through my imaging report and explain the key findings?

Key Takeaways

• MRI is the gold standard for evaluating the prostate gland itself, using the PI-RADS scoring system to guide biopsy decisions.¹⁶ ¹⁸
• PSMA PET has revolutionized prostate cancer staging and recurrence detection, with significantly higher accuracy than conventional CT and bone scan.²⁷ ²⁹ ³⁰
• Micro-ultrasound is an emerging technology that has shown non-inferiority to MRI for guiding prostate biopsy at experienced centers.¹² ¹³
• Not every patient needs every test — imaging should be tailored to your risk group, PSA level, and clinical situation.²⁴
• No imaging test is perfect — false positives and false negatives occur with all modalities. Your doctor interprets imaging results in the context of your complete clinical picture.

Support Resources

• RadiologyInfo.org (radiologyinfo.org) — Patient-friendly explanations of all imaging tests, maintained by the American College of Radiology and the Radiological Society of North America
• Prostate Cancer Foundation (pcf.org) — Information on imaging advances and clinical trials
• ZERO Prostate Cancer (zerocancer.org) — Patient education on diagnosis and staging
• NCCN Patient Guidelines (nccn.org/patients) — Free patient-friendly versions of the NCCN prostate cancer guidelines
• ClinicalTrials.gov — Search for imaging clinical trials in your area

References

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